Abstracts of the 25th congress of Esctaic, Timisoara, Romania, October 23–25 2014. J Clin Monit...

Abstracts of the 25th congress of Esctaic, Timisoara, Romania,October 23–25 2014

� Springer Science+Business Media New York 2014

1 Monitoring the onset time: which muscle, which

technique?

Radmilo J Jankovic1, Massimiliano Sorbello2

1Department for Anesthesiology and Intensive Care, School of

Medicine, University of Nis, Serbia; 2Anesthesia and Intensive Care

AOU Policlinico, Vittorio Emanuele, Catania, Italy

Optimal management of neuromuscular blockade plays a pivotal role

in both clinical anesthesia and emergency medicine. Objective neu-

romuscular blockade (NMB) monitoring techniques are still not

widely used, with most anesthesiologists relying on visual or tactile

assessment of the train of four (TOF) ratio, or, in many cases, no

neuromuscular monitoring at all. In addition, published data support

the use of objective rather than subjective monitoring techniques in

the sight that this may improve patient outcome [1, 2]. Recently

published nationwide surveys from Germany and United Kingdom

revealed that neuromuscular monitoring was routinely used in only

10–18 % of the anesthesia departments [3, 4]. Similar unacceptable

results also came from Denmark and Mexico [5, 6]. The advantages

of using of objective NMB monitoring during induction period is

mainly attributed to the determination of onset time and intubation

conditions following administration of NMBAs.

Although stimulation at 1.0 Hz single twitch may provide a quicker

assessment of rapidly changing levels of block, such a relatively fast rate

of stimulation may be associated with significant fade and increased

blood flow to the stimulated neuromuscular junction and hence increased

delivery of relaxant. On the other hand, single twitch at 0.1 Hz is rela-

tively no disturbing to the neuromuscular junction and it is preferable

pattern in determination of onset time [7, 8]. Recently Bogicevic and

coauthors reported that monitoring the onset of rocuronium induced

neuromuscular blockade using 0.1 Hz single twitch enables irreproach-

able intubating conditions but it was associated with considerable delay

of intubation time in comparison to either TOF stimulation or clinical

assessment of onset time [9]. Disappearance of all TOF responses will

also correspond to optimal intubating conditions [9, 10].

Muscles differ in terms of onset, offset and peak effect of NMBAs.

Regarding the monitoring of the onset time, it must be remembered

that onset of NMB is faster in central muscles with a superior blood

supply, for example, diaphragm and larynx. The muscles of the upper

airway and pharynx behave as central muscles at onset of NMB.

Probably because of higher blood flow to the hand, most studies

have found significantly longer onset times and shorter recovery of

NMB at the great toe in comparison to the handmuscles. In comparison

to NMB at the adductor pollicis (AP), most studies confirm that onset

and recovery of NMB at the larynx is faster [11–13]. Some studies have

used EMG and MMG for monitoring the diaphragm. In general,

pharmacodynamics responses of NMBDs at the diaphragm have shown

a similar time course and degree of NMB as responses at the larynx

[14–15]. Current best evidence suggests that monitoring of the corru-

gator supercili or orbicularis occuli muscle should be used to establish

the earliest time for optimal conditions for tracheal intubation as they

reflect laryngeal relaxation better than monitoring of the AP.

References

1. Gatke MR, Viby-Mogensen J, Rosenstock C, Jensen FS,

Skovgaard LT: Postoperative muscle paralyis after rocuronium:

Less residual block when acceleromyography is used. Acta

Anaesthesiol Scand 2002; 46:207–13.

2. Mortensen CR, Berg H, El-Mahdy A, Viby Mogensen J:

Perioperative monitoring of neuromuscular transmission using

acceleromyography prevents residual neuromuscular block

following pancuronium. Acta Anaesthesiol Scand 1995;

39:797–801.

3. Grayling M, Sweeny BP. Recovery from neuromuscular

blockade: a survey of practice. Anaesthesia 2007; 62: 806–9.

4. Fuchs-Buder T, Fink H, Hofmockel R, Geldner G, Ulm K,

Blobner M Application of neuromuscular monitoring in Ger-

many. Anaesthesist 2008; 57: 908–14.

5. Sorgenfrei IF, Viby-Mogensen J, Swiatek FA. Does evidence

lead to a change in clinical practice? Danish anaesthetists’ and

nurse anesthetists’ clinical practice and knowledge of postop-

erative residual curarization. Ugeskr Laeger 2005; 167:

3878–82.

6. Nava-Ocampo AA. Preferences of Mexican anesthesiologists

for vecuronium, rocuronium, or other neuromuscular blocking

agents: a survey BMC. Anesthesiology 2002; 2: 2–8.

7. Brull S J, Silverman DG. Neuromuscular monitoring and

clinical applications: what to do, when, and why? Seminars in

Anesthesia, Perioperative Medicine and Pain 2002; 21: 104–19.

8. Fuchs-Buder T, Schreiber J.U, Meistelman C. Monitoring

neuromuscular block: an update. Anaesthesia, 2009; 64; 82–9.

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J Clin Monit Comput (2014) 28:441–463

DOI 10.1007/s10877-014-9603-5

9. Bogicevic A, Jankovic R, Stosic B, Djordjevic D, Marjanovic

V. Acceleromyography using 0.1 Hz single twitch enables

superior intubating conditions but with considerable delay of

intubation time compared to either train of four stimulation or

clinical assessment after rocuronium induced neuromuscular

blockade. Eur J Anaesthesiol 2010; 27 (Suppl 47): 3AP7-7.

10. Fush-Buder T, Claudius C, Skogvaard T, Eriksson LI, Mirakhur

RK, Viby-Mogensen J. Good clinical research practice in

pharmacodynamic studies of neuromuscular blocking agents II:

the Stockholm revision. Acta Anaesthesiol Scand 2007; 51:

789–808.

11. Hemmerling TM, Babin D, Donati F. Phonomyography as a

novel method to determine neuromuscular blockade at the

laryngeal adductor muscles: comparison with the cuff pressure

method. Anesthesiology 2003; 98: 359–63.

12. Hemmerling TM, Schurr C, Walter S, Dern S, Schmidt J, Braun

GG. A new method of monitoring the effect of muscle relaxants

on laryngeal muscles using surface laryngeal electromyography.

Anesth Analg 2000; 90: 494–7.

13. Dhonneur G, Kirov K, Slavov V, Duvaldestin P. Effects of an

intubating dose of succinylcholine and rocuronium on the larynx

and diaphragm: an electromyographic study in humans. Anes-

thesiology 1999; 90: 951–5.

14. Hemmerling TM, Schmidt J, Hanusa C, Wolf T, Jacobi KE. The

lumbar paravertebral region provides a novel site to assess

neuromuscular block at the diaphragm. Can J Anesth 2001; 48:

356–60.

15. Derrington MC, Hindocha N. Measurement of evoked diaphragm

twitch strength during anaesthesia. Adaptation and evaluation of

an existing technique. Br J Anaesth 1988; 61: 270–8.

2 Hemodynamique monitoring of cardiogenic shock

Karim Bendjelid

Service of Intensive Care, Geneva University Hospital, Geneva,

Switzerland

Cardiogenic shock (CS) is a state, in which the heart has been damaged

so much that it is unable to supply enough blood to the organs of the

body. The present medical condition with insufficient tissue perfusion

is a frequent pathologic state in ICU and results from several cardiac

dysfunctions. Isolated CS most frequently happens after loss of car-

diomyocyte function due to acute myocardial infarction and it

associated with a mortality rate around 50 % [1]. It is clinically defined

as a decrease in cardiac output and evidence of tissue hypoxia in the

presence of an adequate cardiac preload [2]. It may occur isolated as a

reflection of cardiac pathology, or it may be a part of a shock syndrome

involving other pathogenic mechanisms. As CS cannot be easily

identified by global hemodynamic criteria, the European Society of

Cardiology (ESC) has retained some criteria that usually symbolize the

CS [2]. Indeed, CS may also develop from other pathogenic mecha-

nisms as a part of a shock syndrome initiated by sepsis, anaphylaxis,

hypervolemia, etc. The clinical representation may then be less well

defined, as a low peripheral resistance may also be a part of the syn-

drome, together with an impaired cardiomyocyte function.

In this regards, over the last decade, the single transpulmonary

thermodilution (TPTD) technique has been recommended as a new

tool for hemodynamic monitoring of CS. And the technique has

started to supplant the pulmonary artery catheter as many European

surveys highlighted the widespread use of this variety of hemody-

namic monitoring instrument. The present hemodynamic monitoring

technique was also the subject of many recent studies and scientific

considerations as reflected by several publications in the international

medical literature. Indeed, TPTD allows the measurement of lung

water content, a parameter of huge importance when monitoring

heart–lung functions.

The cardiac output calculated by thismethod is determined using the

Stewart-Hamilton equation applied to a thermodilution curve as it is the

case when using a pulmonary artery catheter. Except that in comparison

to the right heart thermodilution curve, the TPTD curve is obtained by

the infusion of the thermal indicator into a central intra-thoracic vein

instead to the right atrium and the thermal shift is collected via an

arterial catheter placed in a large systemic arterial trunk (aorta, axillary

or brachial artery) instead of the pulmonary artery. The result is that

TPTD can be used to derive several hemodynamic parameters indi-

cating lung and heart functions. In the present setting, the present new

technique may be compared to the best hemodynamic technique

assessing CS, i.e. Echocardiography; as several cardiac parameters

measured by this ultra-sonographic technique may be estimated by

TPTD. Indeed, after the transpulmonary transit of the cold indicator,

some calculation and subtraction using the present technique allow the

bedside assessment of pulmonary blood volume and global end dia-

stolic ventricular volumes by ICU nurses! The purpose of this tutorial is

to review and assess the existing data related to the relevance of TPTD

as advanced hemodynamic monitoring of CS.

References

1. Mann HJ, Nolan PE Jr (2006) Update on the management of

cardiogenic shock. Curr Opin Crit Care 12:431–6

2. Task Force for Diagnosis and Treatment of Acute and Chronic

Heart Failure 2008 of European Society of Cardiology, Dickstein

K, Cohen-Solal A, Filippatos G, et al. (2008) ESC Guidelines for

the diagnosis and treatment of acute and chronic heart failure

2008. Eur Heart J 29:2388–442.

3 Pulmonary artery catheter (PAC) in the operating

room-when and why?

Gabriel M. Gurman

PAC history in the last 40 years, since its introduction in the clinical

practice, suffered a lot of ups and downs. The general enthusiasm

related to the simple fact that PAC opened a window to understanding

the cardiovascular pathophysiology behind acute conditions, was

followed by a stormy period of questioning even its right of existence

as part of our daily monitoring arsenal in the operating room and

intensive care units (ICU).

But in the last few years witness a reappraisal of PAC place in the

management of critically ill patients and of those candidates to major

surgery.

The aim of this presentation is not to explain the use and function-

ality of PAC, but rather to present the arguments for and against it use

and establish PAC importance in the currentmanagement of our patients

Pulmonary artery catheter use in daily practice

PAC was encountered with a lot of interest in the world of emergency

medicine.

In the year of 2001 25 % of the American physicians involved in

critical care inserted a PAC at least once every week. The data

obtained by using PAC assisted the physician to better understand the

cardiac function in acute disease and direct the treatment in accor-

dance to the hemodynamic profile obtained by using PAC.

But soon literature started to publish studies and reviews, which put

the PAC value under a serious question mark. Many researchers and

clinicians reached the conclusion that the frequency of use of PAC was

442 J Clin Monit Comput (2014) 28:441–463

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too high and only small groups of patients could benefit from the data

obtained by inserting a catheter into the pulmonary artery.

Beside some data on large groups of patients showed that actually

the use of PAC was accompanied by a higher morbidity and mortality,

due to a series of factors, among them:

• Use by incompetent or unskilled professionals.

• Errors in measuring and interpreting the obtained data.

• Serious complications accompanying its insertion and use.

• Incorrect decisions leading to a higher incidence of mortality and

a longer stay in ICU.

The situation created by the new wave of literature obliged the

American Society of Anesthesiologists to build up a task force with

the aim of establishing the indications, limits and pitfalls of using

PAC in the current practice.

The American Society of Anesthesiologists guidelines

The ASA Task Force conclusions, now already 10 years old, seem to

be relevant even today.

Here is the summary of their conclusions and suggestions.

1. There is no indication to use PAC in low-risk patients. It does not

reduce neither mortality nor any other markers of severity of illness.

2. But in selected surgical cases, PAC can reduce the incidence of

post-operative complications, by providing immediate access to

critical hemodynamic data.

3. By delaying treatment in order to insert a PAC, one could

endanger the patient and increase the risk of complications.

4. Emergency insertion of PAC under hastily prepared conditions,

may increase the risk of vascular injury and sepsis.

If so, only situations in which the patient is in moderate or very

high risk from comorbidity point of vu and surgery is risky too, would

profit from the insertion of a PAC.

But more than this, when the insertion setting conditions are poor

(no insertion skills, no training, no equipment to treat complications),

there would be a very low indication and justification for using a

sophisticated catheter like PAC.

What are the medical indications for using a PAC?

Evans et al. (Scand J Surg 2009;98:199) built up a list of medical

conditions which would benefit from the insertion of a PAC:

• Assessment of ventricular, Rt and Lt function, pulmonary

hypertension as well.

• Assessment of hemodynamic response to therapy.

• Diagnostic confirmation of intracardiac shunts, pulmonary

embolism.

• Differentiation between low-pressure and high-pressure edema.

• Differentiation of different kinds of shock

• Hemodynamic monitoring of multiple organ failure, burns, acute

MI.

• Therapeutic aspiration of intracardiac air emboli.

A well known paper published by JL Vincent and M. Pinsky (Crit

Care Med 2005;33:1119) used a very well chosen title: Let us use

PAC correctly and only when we need it.

They develop a series of good advises to be followed anytime

when one thinks that there would be a place for inserting a catheter in

the pulmonary artery.

They admit the fact that continuous measurements of hemody-

namic parameters is a unique PAC feature, worthwhile to be used

when indicated and necessary.

Errors in data interpretation are due to lack of education and training

But more important, no monitoring device, no matter how simple

or sophisticated, will improve the outcome unless coupled with

treatment, which itself improves the outcome.

So what the lessons to take home? We do not catheterize every

hemodynamically instable patient

We rather should weight carefully the risk and benefit of each indi-

cation for every single patient

Data offered by PAC measurements are to be correlated with the

clinical picture.

Finally, we must avoid any situation in which we would become

the slaves of our technological tools.

4 It is not all about equipment, stupid!

Peter Biro

Institute of Anesthesiology, University Hospital Zurich, Switzerland

Airway management enjoys a prominent attention in the ranks of pro-

fessionals in anesthesia. This is mainly due to the very practical nature of

airway problems, which are at the core of nearly all anesthesiological

procedures. Without a secured airway and granted gas exchange anes-

thesia is not feasible and even more than that: life is endangered as well.

And by this circumstance, the peace ofmind of the involved professional

is also over. Having understood this basic conjuncture, we might face

what’s recently published in the context of difficult airwaymanagement.

Agood insight into the distribution of interest is tofind in the frequency of

articles related to this topic. When isolating one hundred most recent

articles in PubMed, on find the following distribution of subtopics,

beginning with 1 % of articles dedicated to pharmacological aspects of

handling the difficult airway, in particular work that discusses the impact

of anesthetic drugs on the difficulty degree of intubation and the ability to

secure the airway. With six percent we find more attention for papers

dealingwith the role of teaching, training and simulation in dealingwith a

difficult airway. To the same extent we find articles dedicated to guide-

lines and recommendations, which instruct us about what’s generally

accepted and what one should follow. Some 11 % of the published

material deals with incidence, prevalence and probabilities of airway

related difficulties, or to put it into a more generalized sense: epidemio-

logical aspects. Articles containing tips and tricks for successful

management of airway difficulties and how to avoid complications occur

with a frequency of 14 %. Case reports either trumpeting the triumphant

or lamenting the deplorable experience of others are to be found in twenty

percent of reports, thus suggesting what to follow or what to avoid in

predominantly rare situations. The remainderof not\42 % is exclusively

dealing with equipment .

A large plethora of more or less novel airway devices and gadgets

are described, evaluated and mostly sent to compete against each

other under more or less fair conditions. As to compare the attention

in publications with the real world, a survey has been initiated in my

J Clin Monit Comput (2014) 28:441–463 443

123

department to find out the distribution of interests among clinically

working anesthesiologists. Forty medical doctors responded to the

inquiry and indicated their order of preference of difficult airway

related topics. They rated the pharmacological aspects with the least

priority of 9 %, followed by epidemiological reports in 10 %,

equipment descriptions and comparisons were rated 11 %, case

reports 12 %, know how or tips and tricks attained 16 %, teaching and

training of airway techniques was second largest with 20 % and

finally guidelines and recommendations were rated with priority over

all other topics in 23 %. Here we find a substantial imbalance

between the distribution of difficult airway related subtopics in

PubMed on the one hand, and the desire of the professional audience

on the other. One may subsume the equipment and anesthetic drug

related topics into a category called ‘‘hardware’’ versus anything else

that deals with knowledge and skills, called here ‘‘soft stuff’’. If

comparing these two entities, the public interest is far less hardware

oriented than what’s offered in the literature (Fig. 1). This observa-

tion proves a gross overrepresentation of equipment related matters in

the published literature on the expense of the rest. Besides, the

practical and scientific value of the very widespread device versus

device comparisons is limited, in particular due to the presence of

many confounders such as inappropriate study design, wrong choice

of devices, unfair comparative conditions, no or less clinically rele-

vant study conditions and of course the ignorance of grossly differing

skills among clinicians. In my opinion the reason for this abundance

of published device versus device comparisons is caused by the trivial

circumstance that such studies are simple to perform and to publish.

Therefore it’s worth to draw more attention to the soft stuff.

The knowledge of epidemiological data helps to avoid problematic

situations and to run inadvertently into unpredicted difficult airway

scenarios. Predictability of airway difficulties allows the adoption of

electivemanagement techniques, preparation of adequate personnel and

equipment and the ability to choose the best among various airway

techniques. Teaching and training (T&T) is important to widen the

users’ capability recognize the right approach and to perform at best the

chosen technique. T&T increases success rate and shortens performance

time of airway measures, and finally, it lowers failure rates and fre-

quency/severity of complications. The importance of observing tips and

tricks widens the user’s horizon beyond his personal experiences and

further increases success rate and performance quality. Finally, the

availability of guidelines and recommendations help to eliminate dan-

gerous deviations from proven and tested proceedings, offer evidence

basedguidance for the perplexed, and last but not least,mayprovide fool

proof cover for forensic challenges in case of unfavorable outcomes.

References

1. Rosenblatt WH. The Airway Approach Algorithm: a decision tree

for organizing preoperative airway information. J Clin Anesth

2004; 16: 312–316

2. Biro P et al. Concluding results from the first phase of the Zurich

Unexpected Difficult Airway course based on exercise of

technical skills. Anaesthesia 2014; 69: 452–457

3. Biro P. Reflective intubation: a simple and effective method to

improve intubation conditions by elevating the tip of the tube

without additional equipment. Br J Anaesth 2013; 111: 505–506

5 Computerized clinical decision support and airway

management

Ruggero M. Corso1, Matteo Buccioli1, Stefano Maitan1, Massi-

miliano Sorbello2, Flavia Petrini3

1 Emergency Department, Anesthesia and Intensive Care Section,

‘‘GB Morgagni-L. Pierantoni’’ Hospital, Forli, Italy; 2 Department of

Surgery, Transplantation and Advanced Technologies; Vascular

Surgery and Organ Transplant Unit, University Hospital of Catania,

Catania, Italy; 3 Department of Perioperative Medicine, Pain, ICU and

RRS Chieti University Hospital, ASL 2 Abruzzo, Italy

Introduction The Italian Ministry of Health and Welfare has

published in 2009 a Manual for Safety in Operating Room [1]

proposing the adoption of the recommendations (SSCL) developed

by the World Health Organization as part of the ‘‘Safe Surgery

Saves Lives ‘‘program. The Section 6 of the manual covers airway

management, identified by WHO as a fundamental aspect related to

patient safety in the operating room. Difficult airway (DA), in

general as difficulty to secure an airway and ventilate for optimal

patient’s oxygenation, occurs frequently (5–15 %) in clinical

practice, however a challenging difficult that could results in

morbidity or mortality is not so frequent yet it is fatal. The NAP4

study showed that mortality attributable to DA is still due to

organizational deficiencies, lack of communication and inadequate

management strategy especially in terms of DA prediction [2]. The

main objective of the Difficult Airway Project (DAP) is to stan-

dardize the approach to airway management in order to reduce the

clinical risk associated with the patient. Primary end-points: inci-

dence of predicted DA, incidence of unpredicted DA, incidence of

DA related complications.

Methods The first phase was the definition of the process steps for

DA management (Fig. 1), such as:

1. Preoperative: at this stage the anesthesiologist during the

preoperative evaluation has the opportunity to evaluate the

probability of DA

2. Intraoperative: includes the actual airway management according

to a specific algorithm

3. Postoperative: after surgery is important to know if any

complications related to airway management occured.

Purpose of the second phase was the adoption of a specific tool

integrated in the Institutional Electronic Health Record. During the

preoperative evaluation, El Ganzouri Risk Index (EGRI) (Fig. 2) is

compiled, providing automatically the probability of DA. The elec-

tronic system assigns a red flag to all patients at high risk of DA

allowing a proper triage of patients in the perioperative period i.e.

planning a patient at high risk undergoing major surgery as first on the

list or booking a bed in intensive care unit. The compilation of

intraoperative phase by the anesthesiologist allows to verify the air-

way management strategy and adherence to the algorithm. Finally, the

complications related to airway management are automatically

recorded in the system by integrating information from the Institu-

tional Emergency and Notification System for In Hospital

Emergency.

Results A total of 4,582 patients were included in the report from

October 2010 to December 2013. The results for the primary end-

points are:

1. Predicted DA: 4.5 %

2. Unpredicted DA: 6.8 %

3. Complications: none

Discussion The cases of unexpected difficulties reported (6.8 %)

compared with the previous data (incidence: 1.9 %) obtained through

voluntary incident reporting system, highlight the impact of the

Information Technology [IT] on the process of preoperative airway

management. Since the case-mix of the surgical population and

clinical competence of anesthesiologists have not changed can be

inferred that the introduction of the IT has allowed the identification

of several cases that although presenting a difficulty to control the

airway during anesthesia went unnoticed (near-misses). The


123

limitations of the system are the high number of false positives (6 %)

and the low rate of intraoperative phase records completed (\50 %).

Conclusions The introduction of the DAP leds to improvements in

the preoperative assessment of the airway, better planning of oper-

ating lists according to of the expected difficulties, monitoring of near

misses, the adoption of an Airway Alert Card released to the patients.

References

1. Ministero della Salute. Manuale per la sicurezza in sala operatoria:

Raccomandazioni e Cecklist. www.ministerosalute.it/imgs/C_17_

pubblicazioni_1119_allegato.pdf. Last access: March 2014

2. Cook TM1, Woodall N, Frerk C; Fourth National Audit Project.

Major complications of airway management in the UK: results of

the Fourth National Audit Project of the Royal College of

Anaesthetists and the Difficult Airway Society. Part 1: anaesthe-

sia. Br J Anaesth. 2011 May; 106(5):617–31

6 Use of Glidescope� videolaryngoscope with medium

blade for double lumen intubation: a clinical

experience

SorbelloM(1), Corso RM(2),Merli G(3), GiarlottaR(1), JankovicRJ(4)

(1)Department of Anaesthesia and Intensive Care Unit, AOU Poli-

clinico-Vittorio Emanuele, Via del Plebiscito, Catania, Italy; (2)

Department of Emergency, Anaesthesia and Intensive Care Section

‘‘G.B. Morgagni-Pierantoni’’ Hospital, Forlı, Italy; (3) Department of

Anaesthesia, Centro Cardiologico Monzino, Milano, Italy; (4)

Department for Anesthesiology and Intensive Care, School of Med-

icine, University of Nis, Nis, Serbia

Background and goal of study

Intubation with a double-lumen tube (DLT) is an important issue in

airway management, whereas DLT requires a more difficult approach

compared with a single-lumen tracheal tube, as DLTs are larger and

potentially traumatic. In case of unpredicted difficult airway, an

intubation with DLT might be particularly challenging. The Glide-

Scope � videolaryngoscope, GVL (Verathon Inc., Bothell, WA, USA)

is widely used for difficult airway management, but its use for DLT

intubation has not been extensively studied. The aim of this study was

to evaluate the clinical usefulness of the GVL for intubation with DLT.

Materials and methods

After institutional review board approval a retrospective observational

study was conducted in all DLT intubations performed with Glide-

scope from january 2011 to december 2012 in our hospital. Data

collected included identification of the operator, patient’s demo-

graphic data, success or failure to intubate, number of attempts,

difficulties encountered and complications. Timings for intubation

were not recorded. Airway assessment was performed according to

the Italian Society of Anesthesia and Intensive Care guidelines [1].

Results and discussion

During the period of study, 80 adult patients of ASA physical status 1–3

underwent toDLT intubation for thoracic surgery procedures (Table 1).

We placed 72 Left DLT (diameter was 37 FR in 10 patients, 39 FR in 24

patients, 41FR in 2 patient) and 8 Right DLT (the diameter was 39 FR),

with 8 cases presenting borderline criteria for difficult intubation and 4

cases with unpredicted difficult intubation in which the Glidescope �

(GVL) was used as airway rescue device. All patients were intubated at

first attempt and no complications were reported. We also used Glide-

scope � for tube exchange at the end of surgical procedure with the aid

of a airway exchange catheter (Cook Critical Care, AEC airway

exchange catheter �, Bloomington, USA) in 19 patients scheduled for

delayed extubation or Intensive Care Unit admission. Compared with

use of the Macintosh laryngoscope to assist DLT intubation, use of the

GlideScope is associated with a shorter intubation time and a reduced

incidence of sore throat and hoarseness [2]. Indeed with GVL much

more room is available in the hypopharyngeal space for DLTs place-

ment maneuvers if compared with the classic direct laryngoscopy: in

fact the more cranial position required bymedium size blade allowed to

obtain a very good glottic exposure, while providing more space to

move and target the DLT when in front of laryngeal inlet. Differently

fromBussieres [3] we don’t use a pre-shaped stylet, but wemaintain the

pre-inserted stylet of the DLT (Teleflex Medical left and right sided

DLTs), simply railroading the naturally bended tip of DLT towards

glottic opening. After vocal cords are passed, stylet is about 5 cm

withdrawn and DLT is then rotated clockwise or counterclockwise

according to operator’s personal experience and DLT used (right or left

sided). Glidescope � allows execution of all these maneuvers under

direct vision, providing a preliminary check of tube position just

observing the final position of the reference line in the posterior part of

the DLT; clinical exam and fiberoptic control were always performed

for definitive tube position check. In our experience GVL was very

useful not only in patients with easy intubation, but also in those with

borderline and unexpected difficulty. Finally we appreciated Glide-

scope � for tube exchanging maneuvers, as it allowed direct vision

during the whole procedure, making tube exchange easier and safer.

Conclusions

In conclusion our study confirms the value of Glidescope video

laryngoscope for DLT intubation also in patients with borderline and

unexpected difficult airway.

Fig. 2 El Ganzouri risk index

Fig. 1 Airway management phases


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References

1. Gruppo di Studio SIAARTI ‘‘Vie Aeree Difficili’’; IRC e

SARNePI; Task Force. Recommendations for airway control

and difficult airway management. Minerva Anestesiol. 2005 Nov;

71(11):617–57

2. H.-T. Hsu, S.-H. Chou, P.-J. Wu, K.-Y. Tseng, Y.-W. Kuo, C.-Y.

Chou and K.-I. Cheng. Comparison of the GlideScope video-

laryngoscope and the Macintosh laryngoscope for double-lumen

tube intubation. Anaesthesia 2012, 67, 411–415

3. Bussieres JS, Martel F, Somma J, Morin S, Gagne N. A

customized stylet for GlideScope� insertion of double lumen

tubes. Can J Anaesth. 2012 Feb 1. [Epub ahead of print]

7 How meaningful is the use of 3 D technology

in the anesthesia for morbid obesity?

Daniela Godoroja

Ponderas Hospital, Bucharest, Romania

Introduction The 3-dimensional 3D effects requires the simultaneous

recording of two images of the same object to be projected to one

single picture which corresponds as closely as in currently practical to

the physiological conditions of human vision.

Developments in 3D technology, thus far have been made in

advanced surgical laparoscopy, robotic systems and 4D with real-time

3D ultrasound [1].

The improvement of visual condition using 3D systems refers to

movements that are perpendicular to the main axis with enhancing

depth perception.

In morbidly obese patients, anaesthesiologists are recommended to

use an obstructive sleep apnoea safe anaesthetic technique (regional or

opioid free), consequently the peripheral and neuraxial blockade for

pain relief could avoid the use of long working sedatives and opioids.

In morbidly obese patients loco-regional anesthesia is a challenge

for the anaesthetist because of the difficulty in the location of the

landmarks, of the appropriate equipment, being associate with an

increased number of attempts and lower success rate.

The substantial challenges in 2 D conventional ultrasound guided

regional anesthesia remain such as maintaining the needle tip in view

during needle advancement and confirming catheter placement.

With the emergence of 4-dimensional (4D) ultrasonography, a

new tool for needle guidance is now available. This technology makes

possible the simultaneous visualization of 2 or 3 perpendicular

(orthogonal) planes of view in real time [2, 3]

Goal of the study We assessed how 4D ultrasound could be used to

perform interscalene brachial plexus block, transversus abdominis

plane block and epidural catheter insertion in morbidly obese for

postoperative analgesia.

Method Three sample groups of morbidly obese patients

(BMI[ 35 kg/sqm) undergoing orthopedic shoulder surgery, bariat-

ric surgery and abdominal hernia repair surgery were designed for 4 D

real time 3 D ultrasound guided loco regional procedures: interscalene

brachial plexus block, bilateral transversus abdominis plane block and

epidural catheter placement.

The ultrasound machine used Voluson i (GE Healthcare) with the

6–18 MHz Real time 4D linear transducer (RSP6-16-RS/H46701AC)

was operated by qualified sonographers experienced in the use of the

machine and in 3D and 4D imaging.

An anaesthesiologist experienced in ultrasound-guided procedures

and neuraxial anaesthetic techniques performed all needle insertions.

The author had not performed real-time ultrasound-guided needle

insertions before this study.

Results and discussion When performing a 3D/4D ultrasound, three

orthogonal planes named A, B, and C are commonly displayed

without probe adjustment. Plane A is the familiar 2D ultrasound

image. Plane B is perpendicular to plane A. If plane A is positioned

over the long axis (longitudinal) of a structure, plane B would display

its short axis (cross-sectional). Plane C (coronal) is perpendicular to

the other images and represents echoes from a plane positioned at a

distance from the transducer. 4D ultrasound provides information

about the spatial relationship between anatomical structures of

interest and allows accurate volume measurements of local anesthetic

spread.

For the 3D ultrasound interscalene nerve block observation of the

brachial plexus in cross-section demonstrated distinct linear hyper

echoic tissue structures with wider image volume and the capability to

manipulate the planes of the image without moving the probe [4, 5].

In obese patients, the performance of TAP block can be chal-

lenging due to excessive subcutaneous fat and increased depth of

TAP. The thick subcutaneous fat leads to difficulty in probe handling

and poor visualization of the needle during the procedure, thus 3D

real time ultrasound provide a better visualization of the needle during

the in-plane approach.

A feasible technique of real-time 4D ultrasound-guided epidural

catheter insertion used two perpendicular imaging planes to improve

the orientation of the operator on the vertebral column and identifying

an acoustic window between laminae (either the dura and the pos-

terior vertebral body being visible) allowed the insertion in plane of

the needle between the laminae and successful epidural catheteriza-

tion, the depth of insertion being clearly defined [6].

The all three techniques proved to be feasible and safe.

Conclusion Real-time three-dimensional ultrasound imaging (4D US)

is a useful tool for guiding placement of peripheral nerve blocks or

epidural catheter for postoperative analgesia, especially in the mor-

bidly obese where the technique can be challenging. The use of

advanced ultrasound guided techniques may address accurate needle

placement, through clearly visualizing of the echogenic needle and its

tip, at the same time with locating the catheter tip and measuring local

anesthetic spread.

Future refinements and developments in 4D technology, and pro-

spective randomized clinical trials comparing 4D needle guidance

with 2D techniques are necessary to determine whether the additional

imaging capabilities may offer clinical advantages as reduction of

adverse events, duration of performing blocks and improving clinical

outcomes in patients with difficulties in regional anesthesia

approaches.

Table 1 Characteristics of patients and outcomes. Data are mean

(SD) or number

Variable Result

Age; years 40.2 (15)

Male / female 48/32

BMI (kg m2) 23 (10)

First intubation attempt successful with GVL 80

Borderline difficulty (n) 8

Unexpected difficulty (n) 4

Number of intubation attempts with GVL

1 / 2 /[3

78/2

Complications (n) 0


123

References

1. Light ED, Idriss SF, Sullivan KF, Wolf PD, Smith SW. Real-time

3D laparoscopic ultrasonography. Ultrason Imaging. Jul

2005;27(3):129–144.

2. Zhao Y, Cachard C, Liebgott H. Automatic needle detection and

tracking in 3D ultrasound using an ROI-based RANSAC and

Kalman method. Ultrason Imaging. Oct 2013;35(4):283–306.

3. Mung J, Vignon F, Jain A. A non-disruptive technology for

robust 3D tool tracking for ultrasound-guided interventions. Med

Image Comput Comput Assist Interv. 2011;14(Pt 1):153–160.

4. N. J. Clendenen CBR, 2 and S. R. Clendenen2. A Standardized

Method for 4D Ultrasound-Guided Peripheral Nerve Blockade

and Catheter Placement. BioMed Research International.

2014;Volume 2014, Article ID 920538, 5 pages

5. Clendenen SR, Riutort K, Ladlie BL, Robards C, Franco CD,

Greengrass RA. Real-time three-dimensional ultrasound-assisted

axillary plexus block defines soft tissue planes. Anesth Analg.

Apr 2009;108(4):1347–1350.

6. Belavy D, Ruitenberg MJ, Brijball RB. Feasibility study of real-

time three-/four-dimensional ultrasound for epidural catheter

insertion. Br J Anaesth. Sep 2011;107(3):438–445.

8 Intraoperative respiratory care of the severely obese

patient

Joseph D. Tobias

Department of Anesthesiology & Pain Medicine, Nationwide Chil-

dren’s Hospital, The Ohio State University, Columbus, Ohio 43205

Introduction Regardless of the clinical setting (operating room or

ICU), the primary goals of mechanical ventilation are the mainte-

nance of adequate oxygenation and clearance of CO2 from the body in

the amount needed to maintain cellular homeostasis. Oxygenation is

regulated by the FiO2 and its impact on the partial pressure of oxygen

in the alveoli as determined by the alveolar air equation and the mean

airway pressure. Mean airway pressure is determined by the peak

inflating pressure (PIP), positive end-expiratory pressure (PEEP), and

the inspiratory time [1]. Increasing the mean airway pressure by

manipulation of any of the 3 previously mentioned variables recruits

alveoli, improves ventilation-perfusion matching, and decreases

intrapulmonary shunting. In addition to reducing ventilation-perfu-

sion inequalities and increasing functional residual capacity (FRC),

increasing mean airway pressure may also result in a significant

improvement in respiratory compliance thereby allowing for more

effective spontaneous ventilation and a decreased PIP with mechan-

ical ventilation thereby limiting the potential for barotrauma and

ventilator-induced lung injruy [2].

Several factors including anesthetic agents, positioning, and the use of

neuromuscular blocking agents results in a decreased FRC following

the induction of anesthesia. These factors may be magnified in obese

patients. One of the primary goals of intraoperative mechanical

ventilation, regardless of the mode and setting, is the restoration of

FRC. Critical in the maintenance of a normal ventilation-perfusion

ratio is the relationship between FRC and closing capacity (CC)(the

volume at which small airway closure occurs during expiration).

Conditions that decrease FRC below CC or increase CC above FRC

result in a maldistribution of ventilation/perfusion and adversely

affect the mechanics of breathing. At the extremes of age, CC may

normally exceed FRC; however, in school-aged children and adults,

FRC is normally greater than CC thereby preventing small airway

closure during normal tidal breathing [3]. Inadequate oxygenation

related to ventilation-perfusion inequalities may result from

pathologic conditions which decrease FRC or increase CC. Condi-

tions associated with a decreased FRC (i.e., pulmonary edema,

pneumonitis, infant and acute respiratory distress syndromes) are

treated with positive end-expiratory pressure PEEP to increase FRC

back to normal levels. Situations associated with increased CC (i.e.,

bronchiolitis, reactive airway disease) are treated with bronchodila-

tors and measures to control secretions to reduce CC and maintain

airway patency. Instrumental to the maintenance of FRC during

anesthetic care is the judicious use of PEEP and intermittent use of

recruitment maneuvers.

Effective mechanical ventilation also provides a minute ventila-

tion (respiratory rate [RR] 9 the tidal volume [VT]) that is adequate

for CO2 removal. PaCO2 is directly related to the body’s production

of CO2 during the catabolism of fats and carbohydrates and inversely

related to alveolar ventilation. In most clinical circumstances, the

control of PaCO2 will rely on alterations in the minute ventilation;

however, some control of the body’s endogenous CO2 production is

possible through the increase in the use of fats versus carbohydrates

for nutrition or by control of body temperature. As the respiratory

quotient (CO2 production/O2 consumption) for carbohydrates is 1

versus 0.7 for fats, an increased reliance on fats to provide caloric

requirements can be used to limit endogenous CO2 production and

thereby minimize ventilatory requirements. Furthermore, prevention

of hypothermia and even induction of mild hypothermia (35 �C) can

also be used clinically to control hypercarbia and limit mechanical

ventilatory requirements. It must also be stressed that in patients with

severe lung disease, ventilation to normocarbia is not necessary and

may in fact be harmful. Current practice includes the use of per-

missive hypercarbia or allowing the PaCO2 to increase provided

that the pH is kept above 7.25. This strategy has been shown to

improve outcome in patients with adult respiratory distress syndrome

(ARDS) [4].

Although minute ventilation is defined as RR times VT, not all of

the VT is involved in effective gas exchanged. That part of VT that

does not participate in gas exchange is referred to as physiologic dead

space. Total or physiologic dead space is composed of anatomic dead

space (that area of the conducting areas or the trachea and bronchi

that do not participate in gas exchange) and alveolar dead space (those

alveolar which are ventilated, but not perfused). In the healthy state,

the alveolar dead space is minimal so that anatomic and physiologic

dead space are approximately the same. Although anatomic dead

space, representing approximately 30 % of a normal tidal breath or

150 mL in an average-sized adult, does not generally change

regardless of the disease process, alveolar dead space may change

significantly in patients with pulmonary parenchymal disease, pul-

monary vascular disease, or with changes in cardiac output resulting

in alterations in pulmonary perfusion. The latter principle is clearly

demonstrated by the abrupt decline in end-tidal CO2 (ETCO2) that

occurs with cardiac arrest, a decrease in cardiac output, or pulmonary

embolism. The measurement of physiologic dead space can be per-

formed using Bohr’s method. This is based on the principle that all

exhaled CO2 comes from alveoli that are perfused since dead space

does not receive pulmonary perfusion and is therefore devoid of CO2.

The Bohr equation states: VD/VT = (PaCO2 - PECO2)/PaCO2

where VD = dead space ventilation, VT = tidal volume, and

PECO2 = partial pressure of CO2 in mixed expired gas. Since VD is

relatively constant in patients with healthy lungs, increasing the VT

decreases the ratio of VD to VT. In effect, the increased VT increases

alveolar ventilation. In patients with intrinsic lung disease undergoing

mechanical ventilation, there is ventilation of poorly perfused regions

of the lungs (alveolar VD). In this setting, increases in VT may not

decrease VD/VT since higher alveolar pressures as a result of larger VT

may result in a further decrease in pulmonary perfusion and increase in

alveolar VD. An estimation of the effect of changes in VT on VD/VT in

such clinical scenarios can be provided by estimating VD/VT using

capnography with ETCO2 measurements and the following equation:


123

VD=VT ¼ PaCO2�PETCO2ð Þ=PaCO2

Therefore, a change in the metabolic rate with an alteration in CO2

production, a change in minute ventilation (RR or VT), or a change in

VD may affect PaCO2.

Physiologic changes in respiratory function in obese patients

Alterations in respiratory function increase with body weight. These

changes include increased work-of-breathing during spontaneous

ventilation, a decrease in oxygenation assessed by the (PaO2), alve-

olar-to-arterial oxygen partial pressure difference, as well as the

arterial oxyhemoglobin saturation. Such changes become particularly

prominent as body mass index (BMI approaches 40 kg/m2) [5–7]. The

majority of patients with a BMI greater than 40 will also have a CC

that exceeds FRC. Zavorsky et al. reported an average increase of the

PaO2 by 1 mmHg for every 5–6 kg weight reduction in obese patients

[7]. Every unit of BMI reduces residual volume (RV), total lung

capacity, and vital capacity by 0.5 %. These factors are exaggerated

by the supine position, the effects of anesthetic agents and neuro-

muscular blocking agents, insufflation during laparoscopic procedures

Perioperative strategies Given these physiologic changes induced

by obesity, several interventions may be needed during the periop-

erative period to reverse or prevent alterations in respiratory function.

1. Preoperative strategies

a. Weight reduction as is feasible for elective procedures

b. Optimization of preoperative respiratory function with

bronchodilators

c. Education regarding postoperative respiratory exercises

d. Treatment of respiratory infections as indicated

e. Smoking cessation

2. Intraoperative strategies

a. Patient positioning

b. PEEP optimization

c. Recruitment maneuvers

d. Adjustment of inspiratory time as needed to maximize mean

airway pressure

e. Limit tidal volume to 6–8 mL/kg with normocarbia

f. Pressure-limited or volume-guaranteed modes of ventilation

g. Protective lung strategies

i. Limitation of PIP and tidal volume (6–8 mL/kg)

ii. Limitation of inspired oxygen concentration (\60 %)

3. Postoperative strategies

a. Optimization of analgesia

b. Limitation of analgesic agents with negative respiratory

effects

c. Aggressive pulmonary toilet and respiratory exercises

d. Early ambulation

e. Elective use of non-invasive ventilation

Summary The deleterious effects of morbid obesity on pulmonary

physiology present many challenges during anesthetic care. These

issues extend into the postoperative period thereby increase the risk of

postoperative respiratory insufficiency and perioperative complications.

The effects on pulmonary function increase as weight and BMI

increase with significant effects generally seen at a BMI greater than

40. These physiologic effects including increased work of breathing,

decreased FRC and ventilation-perfusion inequalities may be further

magnified by sleep disorder breathing and other co-morbid respiratory

conditions which may be seen in the obese patient. Effective intraop-

erative care requires attention to all facets of the perioperative course

with preoperative, intraoperative and postoperative interventions.

Most adverse pulmonary physiologic effects from

References

1. Boros SJ, Matalon SV, Ewald R, Lenard AS, Hunt CE. The effect

of independent variations in inspiratory-expiratory ratio and end-

expiratory pressure during mechanical ventilation in hyaline

membrane disease: the significance of mean airway pressure.

J Pediatr 1977;91:794–798.

2. Weisman IM, Rinaldo JE, Rogers RM, Sanders MH. Intermittent

mandatory ventilation. Am Rev Respir Dis 1983;127:641.

3. Mansell A, Bryan C, Levison H: Airway closure in children.

J Appl Physiol 1972;33:711-715-719.

4. Hickling KG, Walsh J, Henderson S, Jackson R. Low mortality

rate in adult respiratory distress syndrome using low-volume,

pressure-limited ventilation with permissive hypercapnia. Crit

Care Med 1994;22:1568–1578.

5. Kuchta KF. Pathophysiologic changes of obesity. Anesthesiol

Clin North Amer 2005;23:421–429.

6. Parameswaran K, Todd DC, Soth M. Altered respiratory phys-

iology in obesity. Can Respir J 2006;13:203–210.

7. Zavorsky GS, Hoffman SL. Complications of obesity. Pulmonary

gas exchange in the morbidly obese. Obes Rev 2008;9:326–339.

Additional references

1. Tobias JD. Conventional mechanical ventilation. Saud J Anaesth

2010;4:86–98.

2. Griffin J, Terry BE, Burton RK, Ray TL, Keller BP, Landrum AL,

Johnson JO, Tobias JD. Non-invasive carbon dioxide monitoring

during general anesthesia in obese adults: end-tidal versus

transcutaneous techniques. Br J Anaesth 2003;91:498–501.

3. Tobias JD. Transcutaneous carbon dioxide monitoring in infants

and children. Pediatr Anesth 2009;19:434–444.

4. Davis G, Patel JA, Gagne DJ. Pulmonary considerations in

obesity and the bariatric surgical patient. Med Clin North Am

2007;91:433–442.

5. Koenig SM. Pulmonary complications of obesity. Am J Med Sci

2001;321:249–279.

6. Schumann R. Pulmonary physiology of the morbidly obese and

the effects of anesthesia. Int Anesthesiol Clin 2013;51:41–51.

7. Aldenkortt M, Lysakowski1 C, Elia1 N, et al. Ventilation strategies

in obese patients undergoing surgery: a quantitative systematic

review and meta-analysis. Br J Anaesth 2012;109: 493–502.

S. Snoring (observed during sleep)

Do you snore loudly (louder than talking or loud enough to be heard through

T. Tiredness (in the daytime)

O. Observed apnea

Has anyone o

P. Blood Pressure

B. Body Mass Index

BMI more than 35 kg/m2

A. Age

N. Neck circumference

G. Gender

closed doors)? Yes No

Do you often feel tired, fatigued or sleepy during daytime? Yes No

bserved you stop breathing during your sleep? Yes No

Do you have or are you being treated for high blood pressure? Yes No

? Yes No

Age over 50 yr old? Yes No

Neck circumference greater than 40 cm? Yes No

Gender male? Yes No

Fig. 1 The STOP-BANG Questionnaire. A high risk of sleep apnea

is defined as a score of 3 or more; low risk of sleep apnea, a score of

\3


123

8. Nguyen NT, Wolfe BM. The physiologic effects of pneumoper-

itoneum in the morbidly obese. Ann Surg 2005;219:219–226.

9 Obesity, sleep apnea and perioperative care

Ruggero M. Corso1, Matteo Buccioli1, Stefano Maitan1,

Massimiliano Sorbello2, Flavia Petrini3

1Emergency Department, Anesthesia and Intensive Care Section,

‘‘GB Morgagni-L. Pierantoni’’ Hospital, Forli, Italy; 2Department of

Surgery, Transplantation and Advanced Technologies; Vascular

Surgery and Organ Transplant Unit, University Hospital of Catania,

Catania, Italy; 3Department of Perioperative Medicine, Pain, ICU and

RRS Chieti University Hospital, ASL 2 Abruzzo, Italy

In the western world, obesity is now considered an epidemic with

serious implications for Health Systems. In recent estimates almost

34 % of adults of the US population are obese [1]. Obesity has serious

health consequences with reduced life expectancy [2]. The obstructive

sleep apnea syndrome (OSAS) is a common medical condition

associated with obesity. The signs, symptoms and consequences of

OSA are a direct result of the derangements caused by the repetitive

collapse of the upper airway. They include sleep fragmentation,

hypoxemia, hypercapnia, marked variations in intrathoracic pressures

and increased sympathetic activity [3]. The prevalence of OSA in

obese patients is higher than in the general population, ranging

between 70 and 95 %. In most instances, the frequency of OSA in the

surgical populations is substantially higher than the incidence in the

general population, and varies with the surgical intervention. In ba-

riatric surgery the prevalence was as high as 70 % [4]. Despite its

widespread diffusion, most of the patients suffering from OSA

reaches surgery without a diagnosis and consequently without ther-

apy. The characteristic collapsibility of the upper airway and the

comorbidites associated also place the OSA surgical patients at

increased risk of complications during peri-operative period. The

body of evidence associating OSA with adverse peri-operative out-

comes calls to implement peri-operative strategies aiming to improve

the safety of this group of patients [5, 6]. Various Authors have

suggested guidelines or clinical pathways to improve the peri-oper-

ative care of this patients [7–9]. Conceptually, the process of care can

be divided into three phases: preoperative, intraoperative and post-

operative. The preoperative phase is characterized by the

identification of patients at high risk of OSA (screening phase) with

the use of a simple screening tool. Among these, the easiest is the

STOP-Bang questionnaire (Fig. 1), recently clinically validated [10].

In the intraoperative phase, the attention will be directed in particular

to the airway management and the use of anesthetic strategies aimed

at reducing the risk of airway obstruction and respiratory depression

in the immediate postoperative period. The postoperative phase

involves the implementation of strategies for safe tracheal extubation

and Post Anesthesia Care Unit (PACU) observation paths with

decision algorithms to choose the discharge to ward rather than to

ICU. The implementation of an effective peri-operative strategy for

the management of OSA patients is facilitated by the adoption of

electronic health-care records to facilitate and improve the recording,

presentation, and access of perioperative data. In the Anesthesia

Department of the General Community Hospital of Forlı, Italy

(12.000 surgical procedures per year), we developed a data recording

system of the surgical process of every patient within the operating

theatre [11]. The OSA clinical pathway is integrated in the system.

Every adult patient undergoing elective surgery is subjected to

screening during the pre-operative anesthesiological evaluation. The

electronic system assigns a red flag to all patients at high risk of OSA

allowing a proper triage of patients in the perioperative period i.e.

planning a patient at high risk for OSA undergoing major surgery as

first on the list or booking a bed in intensive care unit.

In conclusion, the perioperativemanagement ofOSA is characterized

by a variety of problems requiring the joint effort of anaesthesiologists,

surgeons and sleep experts. Anesthesiologists have the opportunity to

closely observe their patients in the PACU and can provide important

information on where ‘‘the patient is going.’’ Appropriate perioperative

protocols are the best way to avoid perioperative complications associ-

ated with this common syndrome, their implementation made easier by

widespread adoption of Information Technology.

References

1. Mitchell NS, Catenacci VA, Wyatt HR, et al. Obesity: overview

of an epidemic. Psychiatr Clin North Am. 2011;34:717–732.

2. Flegal KM, Kit BK, Orpana H, Graubard BI. Association of all-

cause mortality with overweight and obesity using standard

body mass index categories: a systematic review and meta-

analysis. JAMA. 2013 Jan 2;309(1):71–82

3. Jordan AS, McSharry DG, Malhotra A. Adult obstructive sleep

apnoea. Lancet. 2014 Feb 22;383(9918):736–47

4. Lopez PP, Stefan B, Schulman CI, et al. Prevalence of sleep

apnea in morbidly obese patients who presented for weight loss

surgery evaluation: more evidence for routine screening for

obstructive sleep apnea before weight loss surgery. Am Surg

2008;74:834–838

5. Flink BJ, Rivelli SK, Cox EA, White WD, Falcone G, Vail TP,

Young CC, Bolognesi MP, Krystal AD, Trzepacz PT, Moon

RE, Kwatra MM. Obstructive sleep apnea and incidence of

postoperative delirium after elective knee replacement in the

nondemented elderly. Anesthesiology. 2012 Apr;116(4):788–96

6. Kaw R, Chung F, Pasupuleti V, Mehta J, Gay PC, Hernandez

AV. Meta-analysis of the association between obstructive sleep

apnoea and postoperative outcome. Br J Anaesth. 2012

Dec;109(6):897–906

7. Seet E, Chung F. Management of sleep apnea in adults—functional

algorithms for the perioperative period: Continuing Professional

Development. Can J Anaesth. 2010 Sep;57(9):849–64

8. Adesanya AO, Lee W, Greilich NB, Joshi GP. Perioperative

management of obstructive sleep apnea. Chest. 2010

Dec;138(6):1489–98

9. Practice guidelines for the perioperative management of

patients with obstructive sleep apnea: an updated report by

the American Society of Anesthesiologists Task Force on

Perioperative Management of patients with obstructive sleep

apnea. Anesthesiology. 2014 Feb;120(2):268–86

10. Corso R, Petrini F, Buccioli M, et al. Clinical utility of

preoperative screeningwith STOP-Bang questionnaire in elective

surgery. Minerva Anestesiol. 2013 Nov 26. [Epub ahead of print]

11. Agnoletti V, Buccioli M, Padovani E, et al. Operating room data

management: improving efficiency and safety in a surgical

block. BMC Surg. 2013 Mar 11;13:7

10 Promoting robotic surgical safety during conversion

John Pawlowski, Michael Kent, Jeff Keane, Florence Egan, David

Feinstein, Maureen Houstle, Melissa Jones, Shari Pasley, Ruma

Bose, Andrew Wagner, Andreas Pleumann, Christopher Awtrey

Beth Israel Deaconess Medical Center, Harvard Medical School,

Boston, MA USA


123

Introduction The volume of robotic surgery is increasing as is the

number of procedures and of surgical specialties that use robotic

techniques. While the need to convert a robotic case to an open

procedure is rare, it does happen. The protocol to convert to open is

not standardized across surgical disciplines and the actual roles of the

operating room team members are unclear. We set out to define a

universal conversion protocol and to develop a plan and curriculum

for educating new staff about this contingency plan.

Methods A multidisciplinary team from surgery, nursing, and anes-

thesia that represented the surgical subspecialties of thoracic,

genitourinary, gynecologic and general surgery were assembled. The

team met weekly for 3 months and reviewed existing conversion

protocols, developed and piloted a questionnaire and simulated and

practiced key procedures in the conversion process.

Results The results of the multidisciplinary team were: (1) the

development of a process map (illustration 1), (2) the creation of story

boards, (3) the performance of outside interviews using a question-

naire to several medical centers, and (4) the production of a training

video to be used for education.

Discussion As a result of this project, the Robotic Surgical Safety

Team learned the following items: The conversion is a complex pro-

cess. The surgical subspecialties have unique concerns. Issues included

the use of the wrench, the considerations in the obese patient, the need

to retain a robotic arm to provide hemostasis, and Trendelenberg

position. Suggestions were made to simplify and shorten the conver-

sion, such as premarking the proposed conversion skin incision, making

ready the surgeon’s gown and gloves in the Operating Room, and

having the wrench in a prespecified and visible location in the room.

References

1. Pawlowski J, DB Jones. Simulation and OR Team Performance.

In: The SAGES Manual of Quality, Outcomes and Patient Safety

Tichansky DS, J Morton, DB Jones (Eds), Springer New York,

NY 2010

2. BarbashGI, SAGlied.NewTechnology andHealthCareCosts- The

Case of Robotic-Assisted Surgery. NEJM 2010; 363 (8): 701–704

3. Simulation Training in Laparoscopic and Robotic Surgery Patel

HRH, JV Joseph (Eds) Springer New York, NY 2012

11 New challenges in liver transplantation anesthesia-

obesity in donor and recipient population

Vater Y, Martay K, Vitin A

University ofWashington School ofMedicine, SeattleWashington USA

Obesity impact on recipients and donors due to metabolic syndrome

(MS). Obesity is linked to heart diseases, diabetes, and wound

infection. Immunosuppressive drugs with variable lipophilicity and

altered volume of distribution can affect the therapeutic usefulness of

drugs. Obese patients display a greater risk for non-alcoholic fatty

liver disease (NAFLD), which may lead to cirrhosis and end-stage

liver disease. Every day 18 people die (1,598/2011) due to not enough

organs available. 1, 349/2011 patients removed from the waiting list-

too sick to undergo surgery.

Morbid obesity was considered as contraindication for LT: high

incidence of primary graft non-function and mortality. Causes of mor-

tality in obese recipients have been noticed as progressive hepatic injury,

cirrhosis and MOF, wound infections, bile leak, vascular, lung function

alteration, and difficult ultrasonography due to thick/fatty subcutaneous

tissue. Long ICU/Hospital stay, high cost with BMI[ 40 kg/m2.

Each 1 L ascites—a risk inmortality by 7 %vs non- ascites LTpatient

with similar BMI. Ascites is independent factor with increased risk for

post-op morbidity & mortality. CT, MRI required to DD ascites vs adi-

posity.Weight distribution—factor estimating post-OP risk.BMImust be

corrected for ascites amount and should not be a barrier to LT. Excellent

outcomes in OLT have been noticed with BMI[30—35 kg/m2.

New data confirmed that obese have similar graft and patient

survival in comparison with normal weight recipients.

Anesthesia concerns: Obese recipients have increased intra-

abdominal, central venous and pulmonary arterial pressures. The

duration of mechanical ventilation were not increased among the

obese versus the non-obese group. Obesity was not a relevant factor

determining the need for or use of ventilator support.

Liver Low Damage Strategy is based on understanding the

hyperdynamic state and cirrhotic cardiomyopathy. Proper evaluation

of systemic & pulmonary HPT. analyses of hypoxia, hypercapnia and

risk for aspiration or difficult airway.

Proper anesthesia planning for patients with decreased kidney and

liver function is essential. Early extubation policy can minimize

complications and provide a short ICU stay.

Reference

1. Y. Vater, G. Dembo, K. Martay, A. Vitin, E. Amar, A.

A. Weinbroum Ascites characterizes perioperative clinical indi-

ces better than preoperative body mass index. A study in

orthotopic liver transplant candidates. MINERVA ANESTESIO-

LOGICA August 2012

12 Bleeding during liver transplantation: etiology

and treatment

M. Susan Mandell

Department of Anesthesiology, University of Colorado

Liver transplant surgery is often associated with large volume blood

loss. Strategies to mitigate excessive bleeding during surgery have

significantly improved perioperative survival. Regardless of these

advances, perioperative bleeding still poses a serious risk to patients.

It is therefore reasonable to ask if there are additional reasons liver

transplant recipients bleed during surgery. The aim of this review is to

provide a comprehensive view that addresses why patients bleed

during liver transplant surgery and present additional strategies to

promote hemostasis. The review will cover five causes of bleeding.

These include: (1) portal pressure gradients (2) severity of illness (3)

surgery (4) coagulation defects and (5) donor graft function.

An underestimated reason for bleeding during transplant surgery is

the portal pressure gradient. The splanchnic circulation is a low

volume and pressure vascular compartment. In contrast, patients with

portal hypertension sequester blood from the systemic circulation into

the splanchnic compartment. There is a resulting increase in pressure

and absolute blood volume. The propensity to bleed can in part be

explained by physiological laws of capillary flow [1].

Venous return is driven by a fall in the pressure gradient. Circulatory

changes in cirrhosis reduce this important pressure gradient. Increasing

volume and pressure in the portal circulation reduces venous return and

leads to conditions that favor a net outward movement of fluid. Surgical

disruption of blood vessels results in a greater than anticipated blood

loss due to mechanical reasons. Blood loss is also difficult to control

since the mesenteric vessels do not have a brisk mechanism that pro-

motes vasoconstriction [2]. Portal hypertension increases splanchnic

nitric oxide and can also inhibit vascular response to bleeding [4].

Greater severity of illness is associatedwith increasedblood loss (Xia).

The underlying cause is probably complex and due to the interaction of


123

comorbid conditions; reduced renal function, altered coagulation and

fibrinolysis, portal hypertension and hyperdynamic circulation. These

characteristics intersect and lead to a combination of high flow and pres-

sure in a vasculature with compromised clotting. In addition, the most

center specific factors are surgical skill and recipient selection. The pre-

sence of a clotted portal vein, previous abdominal surgery, retransplan-

tation or anastomotic technique has all been shown to affect blood loss.

The most studied variable affecting bleeding is changes in the

coagulation system. Recent evidence indicates that liver disease does

not usually selectively reduce clot formation [5]. Rather, the coagu-

lation system is ‘‘rebalanced’’ so that both pro and anticoagulation

factors are equally reduced. It is the lack of reserve in the coagulation

system that can add to excessive bleeding during surgery. Finally,

there are the independent effects of donor graft function on circula-

tory physiology and coagulation. Poor graft function can increase

hyperdynamic flow and portal pressures. The coagulation system can

be driven towards favoring fibrinolysis with factor consumption.

In summary, perioperative bleeding in liver transplantation can be

due to the complex interaction between circulatory physiology, surgical

conditions, coagulation defects and the effects of donor graft function.

Novel interventions are aimed at better control of systemic and portal

flow.Newer treatments for coagulation defects have improved outcome

compared to conventional treatment with blood products [6].

References

1. Aukland K J Physiol (Paris). Distribution of body fluids: local

mechanisms guarding interstitial fluid volume. 1984; 79: 395–400.

2. Chen X, Pavlish K, Zhang HY, Benoit JN. Effects of chronic

portal hypertension on agonist-induced actin polymerization in

small mesenteric arteries. Am J Physiol Heart Circ Physiol. 2006

May; 290: H1915-21. Epub 2005 Dec 9

3. Xu J, Cao H, Liu H, Wu ZY. Role of nitric oxide synthase and

cyclooxygenase in hyperdynamic splanchnic circulation of portal

hypertension. Hepatobiliary Pancreat Dis Int. 2008; 7: 503–8.

4. Xia VW, Du B, Braunfeld M, et al. Preoperative characteristics and

intraoperative transfusion and vasopressor requirements in patients

with low vs. high MELD scores. Liver Transpl. 2006; 12: 614–20.

5. Warnaar N, LismanT, Porte RJ. The two tales of coagulation in liver

transplantation. Curr Opin Organ Transplant. 2008; 13: 298–303.

6. Massicotte L, Perrault MA, Denault AY et al. Effects of

phlebotomy and phenylephrine infusion on portal venous

pressure and systemic hemodynamics during liver transplanta-

tion. Transplantation. 2010; 89: 920–7

13 Improving the management of the cardiorespiratory

system in liver transplantation

Alistair Lee

Royal Infirmary, Edinburgh, UK

As liver transplantation has become an established procedure the age

of patients undergoing transplantation has increased, and patients with

associated comorbidities are common. In Western Europe and the

USA, non-alcoholic fatty liver disease is an increasingly common

indication for transplantation and is associated with other features of

the metabolic syndrome—diabetes and hypertension. Ischaemic heart

disease remains common in this older age group. Management of

these patients first depends on effective preoperative assessment. The

benefits of cardiorespiratory exercise testing will be considered.

Identification of cardiorespiratory disorders specific to end stage

liver disease such as hepatopulmonary syndrome is important.

The age and state of donor organs has deteriorated as extended

criteria grafts are often used. In conjunction with an older, sicker

recipient this can prove problematic, and the ability to have a successful

outcome may depend on appropriate matching of donor and recipient.

Intraoperatively a variety of methods of monitoring the patient are

employed across centres. The reasons for this will be addressed.

Some practices from critical care management are now thought

important in the shorter term management of patients in the operating

theatre. Attention to detail regarding ventilatory technique, gas mixtures

and cardiovascular system support can affect the later postoperative

course.

The appropriate management of patients with hepatopulmonary

syndrome in the postoperative period is now more generally agreed.

14 Early extubation after liver transplantation

Dana Tomescu1,2, Mihai Popescu2

1Department of Anesthesia and Intensive Care III, Head of Departe-

ment Fundeni Clinical Institute Bucharest Romania; 2,,Carol Davila’’

University of Medicine and Pharmacy Bucharest Romania Email:

[email protected]

Introduction Early extubation (EE) of patients after liver transplant

(LT) and fast track has been successful in many patients and is

gradually being adopted in more and more hospitals [1] and seems

now to be the choice of the anesthesiologist, even if there are still

pro’s and con’s to this practice [2, 3]. The trend to extubate patients in

the operating room (OR) and the early discharge from the post-

anesthesia care unit (PACU) follows the trend of all types of surgery,

starting with cardiac surgery and well documented by colonic and

major abdominal surgery.

Definition of EE and Fast track Definition of EE after LT means in

a larger sense the removal of the endotracheal tube within the first few

postoperative hours, and in a narrow sense, it usually refers to

immediate tracheal extubation (\1 h) or in the OR [4].

Clinical considerations about EE and FT Early extubation after LT

is feasible, safe [4] and cost-effective in the majority of patients and

has been increasingly accepted as an option for conventional post-

operative ventilation. Decision to extubate a patient in the operating

room or in the very early hours after LT has to be made by an

experienced anesthesiologist and after a comprehensive and individ-

ualized evaluation of the patient’s condition before extubation. EE

after LT is often possible because of improvements in both surgical

and anesthetic techniques. Yet, there are considerable performance

differences between institutions in the number and severity of peri-

operative adverse events that can cause patient compromise.

Safe early or even immediate postoperative extubation of a majority

of liver transplant patients has been reported by some centers; how-

ever, the exact criteria, the benefits of early extubation to liver

recipients, and any cost benefits remains a matter of debate. The

multicenter cohort [4] study conducted by Dr. Mandell reported a

lower rate (7.7 %) of postoperative adverse events in the immediate

extubation group than that commonly reported for ventilated liver

transplant patients. This study showed great variability in rates of

extubation (5–67 %) and rates of complications between centers,

suggesting a significant impact of the regional patterns of practice,

intraoperative events, and physician experience.

The main reason to extubate patients very soon after LT is the

decreased blood flow in the splanchnic territory during positive

pressure ventilation that causes congestion of the inferior vena cava

and hepatic veins and may lead to altered graft oxygenation [5].

There is an increasing trend for physicians to extubate patients

immediately after major surgery to facilitate early discharge from/or


123

avoid admission to the PACU.Most studies found that outcomes after LT

are improved by early extubation. Most authors showed that there are

some important advantages of early extubation, like a better graft func-

tion and a shorter stay in the PACU with a faster hospital discharge and

with similar outcomes in terms of reintubation and pulmonary compli-

cations thus with a significant impact in terms of costs-benefit [6–10].

To date there is no evidence demonstrating that early extubation has

adverse effects on patient outcome. The incidence of reintubation is not

increased hereafter when compared to patients extubated later [4].

A lower rate (7.7 %) of postoperative adverse events in the

immediate extubation group than that commonly reported for venti-

lated Ltx patients. Standardized intraoperative protocols [1,3] are

needed to have a strong body of evidence in terms of benefits or risks

of EE [4,6].

Criteria for EE Criteria used for EE at the University of Colorado [4]

are intraoperative (UNOS status 3 or 4, no coexistent disease, age\50

and no encephalopathy) and postoperative (good liver function,\10

U of red blood cells administrated, no vasopressor support at the end

of surgery and alveolar-arterial oxygen gradient\150 mmHg).

Other criteria for EE are used by the Charite- Berlin group [7], and

others propose a score for EE (SORELT score [9]) proposing two

major criteria (C7 units of packed RBCs transfused intraoperatively

and end of surgery lactate C3.4 mmol/L) or one major criteria plus

two minor criteria (patient not at home, duration of surgery C5 h,

vasopressor drug infusions at the end of surgery-dopamine[5 ıg/kg/

min or norepinephrine[0.05 ıg/kg/min) or three minor criteria.

In our center, we started to extubate patients after LT at the end of

surgery or within 1 h in the PACU using criteria for EE listed below in

Table 1.

Numerous studies agree that encephalopathy, whether the result of

acute or chronic liver failure, is a strong predictor of the need for

prolonged ventilation. Other factors, such as volume of blood trans-

fused and RRT, are less consistent predictors among studies and may

be only indirect markers of poor graft function, severity of illness, and

a lack of standardized intraoperative protocols [4, 6].

There are still a lot of factors that were not studied, for example

the correlation between the intraoperative fluid management and

patient outcome. Restrictive versus liberal fluid regimens are on

debate lately, and more evidences are in favour for restrictive regi-

mens in terms of providing a better patient outcome.

A predicting model for EE after LT is difficult to design, because

each transplant team has it’s own protocols based upon personal

experience and local resources, but EE is often possible because of

improvements in both surgical and anesthetic techniques. Different

anesthetic management can lead in a different approach regarding EE.

There is no standardized anesthetic protocol for LT, and surgical

techniques are different also. There were some correlations found, with

the amount of blood transfused, the piggyback technique, and the use of

veno-venous by-pass, which were associated with adverse outcomes [4].

It is still a lot of information missing in order to assess all peri-

operative factors associated with early extubation, postoperative

mechanical ventilation and length of PACU stay. Most studies report

that the ‘‘do not early extubate patients’’ are very ill before trans-

plantation, or had an emergency LT for acute liver failure. Those are

preoperative factors, and it seems no one would think to extubate

such patients even in another setting other than LT. As for intraop-

erative factors -a complicated surgical procedure with a very long

duration, massive bleeding-thus leading to massive transfusion,

hypothermia, acid–base disorders, need for vassopressor or inotropic

support- are factors taken into consideration for prolonged mechan-

ical ventilation.

No study reports if monitoring specific parameters can help the

anaesthesiologist to decide for EE. It is important to asses all intra-

operative data useful to perform a safe procedure. A standard

intraoperative monitoring (ECG, NIBP, SpO2, EtCO2 urine output,

to) and advanced haemodynamic monitoring using an arterial line, a

central venous line and a cardiac output monitoring (either through a

pulmonary artery catheter or as a derived pulse contour analysis) are

reported by most centers. The trend is for less invasiveness, but with

trustful parameters.

A very important parameter which is not yet studied in correlation

with EE is the volume and type of intra-operative fluid administrated,

in order to find if a restrictive or liberal fluid administration can be a

predictor for EE, prolonged mechanical ventilation and duration of

PACU stay.

Conclusions The conclusion is that early extubation allows faster

recovery without increasing morbidity. Adherence to EE criteria was

low a decade ago, but variability seems to be everywhere, as shown in

2006 by Mandell [1] in a multicentric study that found rates of EE

between 5 and 67 %. A percentage of EE up to 88 % of the LT

patients is shown in a 2012 review [11], suggesting that adherence to

EE practice after LT gains more and more adepts.

Assessing perioperative factors in order to see if there are any cor-

relations with early extubation/postoperative MV and finding

modifiable factors might lead to a better perioperative management.

Standardized protocols seem to be impossible to implement because

of very different approach regarding perioperative management of the

liver transplant patient between centers and even in the same center

were more anesthetists are involved in the transplant activity.

In the future, additional trials are required to establish universal

EE guidelines and to determine factors that might influence outcome,

along with its benefits for both patients and practitioners. More data

are necessary to build a model for the IDEAL TO EARLY EXTU-

BATE/EARLY DISCHARGE FROM ICU PATIENT

References

1. Ozier Y, Klinck JR. Anesthetic management of hepatic

transplantation. Curr Opin Anaesthesiol 2008;21:391–400.

2. Mandell MS, Hang Y. Pro: early extubation after liver

transplantation. J Cardiothorac Vasc Anesth 2007;21:752–755.

3. Steadman RH. Con: immediate extubation for liver transplan-

tation. J Cardiothorac Vasc Anesth 2007;21:756–757

4. Mandell MS, Stoner TJ, Barnett R, et al. A multicenter

evaluation of safety of early extubation in liver transplant

recipients. Liver Transpl 2007;13:1557–63

5. Jullien T, Valtier B, Hongnat JM. Incidence of tricuspid

regurgitation and vena cava backward flow in mechanical

ventilated patients. A color Doppler and contrast echocardiog-

raphy study. Chest 1995; 107:488–493.

6. Mandell MS, Campsen J, Zimmerman M, Biancofiore G, Tsou

MY. The clinical value of early extubation. CurrOpin Organ

Transplant. 2009; Jun;14(3):297–302

Table 1 Criteria for early extubation

1 Spontaneous tidal volumes[ 6 ml/kgc

2 Respiratory rate RR = 12–20 breaths/min

3 SpO 2[ 95 %

4 Normocarbia

5 to[ 35 �C

6 Reversal of neuromuscular blockade TOF[ 90 %

7 Positive gag reflexes and the ability to follow verbal commands

8 Haemodynamic stability without vasopressor support

9 Transfusion\ 6 units of PRBc


123

7. GlanemannM, Langrehr J, Kaisers U, SchenkR,Muller A, Stange

B, et al. Postoperative tracheal extubation after orthotopic liver

transplantation. ActaAnaesthesiolScand 2001;45:333–339.

8. Biancofiore G, Bindi ML, Romanelli AM, Boldrini A, BisaM,

Esposito M, et al. Fast track in liver transplantation:

5 years’experience. Eur J Anaesthesiol 2005;22:584–590.

9. Skurzak S, Stratta C, Schellino MM, Fop F, Andruetto P, Gallo

M, et al. Extubation score in the operating room after liver

transplantation. ActaAnaesthesiolScand 2010;54:970–978.

10. Taner CB, Willingham Dl, Bullatao IG et al.: Is a mandatory

intensive care unit stay needed after liver transplantation?

Feasibility of fast-tracking to the surgical ward after liver

transplantation. Liver Transpl. 2012 Mar;18(3):361–9.

11. Wu J, Rastogi V, Zheng SS. Clinical practice of early extubation

after liver transplantation. HepatobiliaryPancreat Dis Int 2012;

11(6): 577–585.

15 Techniques of blood avoidance

Joseph D. Tobias


dren’s Hospital, The Ohio State University, Columbus, Ohio 43205;

[email protected]

Introduction More than half of all transfusions of allogeneic blood

products occur during the perioperative period. Although in most cir-

cumstances, the administration of blood and/or blood products can be

used safely and effectively to correct hemoglobin concentrations and

coagulation function, there is a growing body of evidence which dem-

onstrates an ever increasing recognition of the potential adverse effects of

the administration of allogeneic blood products. These adverse effects

include the transmission of infectious diseases, immunosuppression,

transfusion-related acute lung injury, transfusion reactions, and graft-

versus-host disease [1–3]. Most notably, the immunosuppressive effects

have been shown to potentially increase the incidence of surgical site

infections [3, 4]. Given these concerns, there remains significant interest

in avoiding or limiting the need for allogeneic blood products.

Techniques to limit allogeneic transfusions Effective preoperative

evaluation and preparation of the patient are essential to limit allo-

geneic blood product use. Identification and correction of

preoperative anemia is one of the most important interventions in

limiting the need for allogeneic transfusion. In many cases, simple

iron deficiency anemia can be treated prior to elective surgical pro-

cedures. The chronic administration of anticonvulsant agents

including phenytoin and carbamazepime may adversely affect coag-

ulation function. Additionally, in these patients or chronically ill

elderly patients, nutritional issues and poor intake of vitamin K may

predispose to chronic low levels of vitamin K dependent coagulation

factors resulting in chronic coagulation dysfunction. Preoperative

screening of coagulation function and simple measures such as the

administration of vitamin K (oral or intramuscular) may alleviate such

problems. Other associated medications may also affect platelet

function. Patients with chronic orthopedic problems and pain fre-

quently use non-steroidal anti-inflammatory agents (NSAID’s) which

may affect platelet function. Although acetylsalicylic acid irreversibly

inhibits cyclo-oxygenase and platelet function for the life of the

platelet, NSAID’s result in reversible inhibition of platelet function

that is dependent on the plasma concentration and hence the half-life

of the NSAID. Discontinuation of most NSAID’s for 2–5 days prior

to surgery will result in return of normal platelet function.

Maintenance of normothermia is also of paramount importance in

controlling blood loss in orthopedic surgery. Prospective trials have

shown a decrease in blood loss, requirements for allogeneic blood

products, postoperative infections, and hospital stay with the

maintenance of normothermia 5,6. In most anesthetic suites,

maintenance of normothermia is provided by a combination of

warming the room until the patient is anesthetized, positioned and

draped plus the use of forced air warming blankets as well as the

use of blood/fluid warmers to warm intravenous fluids. These

techniques effectively maintain normothermia without the need for

other modalities.

The choice of intraoperative fluid administration may affect

coagulation function thereby impacting on blood loss. During ANH

(see below), blood including red cells, coagulation factors, and

platelets is removed and replaced with crystalloids and/or colloids.

One may therefore assume that coagulation would be adversely

impacted; however, do the dilution of proteins with anti-coagulatory

effects such as anti-thrombin III, a 25–30 % hemodilution results in

increased coagulation function 7. Colloids used for volume expansion

and blood replacement may adversely effect coagulation function.

Albumin and gelatins have been found to have no effect or may

actually increase coagulation function, while several studies have

demonstrated that either medium or high molecular weight

hydroxyethyl starches because of their effects on von Willebrand

factor adversely effect coagulation function, in particular, platelet

function when used in doses exceeding 10–15 mL/kg [8, 9].

Several options are available to limit the perioperative need for

allogeneic transfusions including:

1. General considerations including optimization of preoperative

coagulation function and hemoglobin level, proper patient

positioning, and maintenance of normothermia;

2. Autologous transfusion therapy including preoperative donation

with the use of erythropoietin and intraoperative collection using

acute normovolemic hemodilution;

3. Intraoperative and postoperative blood salvage;

4. Pharmacologic manipulation of the coagulation cascade with epsilon

amino caproic acid, tranexamic acid, desmopressin (DDAVP)

5. Use of adjunctive agents to improve perioperative coagulation

function including fibrinogen concentration, recombinant factor

VIIa (rFVIIa), and recombinant factor XIII

6. Pharmacologic control of blood pressure (controlled hypo-

tension).

Summary Increasing evidence has demonstrated the potential

adverse effects of the use of allogeneic blood products. These effects

may have significant deleterious effects on patients which may impact

on cost and length of hospitalization and in specific circumstances

may even impact on mortality. Techniques to limit the need for

allogeneic blood products should be instituted in procedures during

which 20–25 % of patients require transfusion. Although many of the

potential techniques to limit transfusion requirements are effective

alone, the combination of several of these techniques can potentially

lead to the goal of performing major surgical procedures without the

use of allogeneic blood products. This may be feasible in even our

smaller and younger patients. Many of the techniques such as autol-

ogous donation, ANH, and controlled hypotension have been proven

in several studies to be effective. Studies regarding the efficacy of the

various pharmacologic agents may not be as compelling; however, the

antifibrinolytic agents seem promising. Future work is required to

fully define the efficacy of newer agents such as fibrinogen concen-

tration and factor XIII. Since the technology of artificial blood

products, which may limit the need for allogeneic transfusion, may

take years yet to perfect, use of the techniques described in this

review should be considered to limit the need for allogeneic products

during orthopedic surgical procedures.


123

References

1. Goodnough LT, Bercher ME, Kanter MH, et al. Transfusion

medicine: First of two parts—blood transfusion. New Engl J Med

1999;340:438–447.

2. Schriemer PA, Longnecker DE, Mintz PD. The possible immu-

nosuppressive effects of perioperative blood transfusion in cancer

patients. Anesthesiology 1988;68:422–428.

3. Taylor RT, Manganaro L, O’Brien J, et al. Impact of allogenic

packed red blood cell transfusion on nosocomial infection rates in

the critically ill patient. Crit Care Med 2002;30:2249–2254.

4. Carson JL, Altman DG, Duff A, et al. Risk of bacterial infection

with allogeneic blood transfusion among patients undergoing hip

fracture repair. Transfusion 199;39:694–700.

5. Kurz A, Sessler DI, Lenhardt R, for the Study of Wound

Infection and Temperature Control Group. Perioperative nor-

mothermia to reduce the incidence of surgical-wound associated

infection and shorten hospitalization. N Engl J Med 1996;334:

1209–1215.

6. Schmied H, Kurz A, Sessler D, et al. Mild hypothermia increases

blood loss and transfusion requirements during total hip arthro-

plasty. Lancet 1996;347:289–292.

7. Ruttmann TG, James MF, Viljoen JF. Haemodilution induces a

hypercoagulable state. Br J Anaesth 1996;76:412–414.

8. Karoutsos S, Nathan N, Lahrimi A, et al. Thromboelastogram

reveals hypercoagulability after administration of gelatin solu-

tion. Br J Anaesth 1999;82:175–177.

9. RuttmannTG, JamesMFM,Aronson I. In vivo investigation into the

effects of haemodilution with hydroxyethyl starch (200/0.5) and

normal saline on coagulation. Br J Anaesth 1998;80:612–616.


1. Testa LD, Tobias JD. Techniques of blood conservation: Part 1 -

isovolemic hemodilution. Am J Anesthesiol 1996;23:20–28.

2. Horrow JC. Desmopressin and anti-fibrinolytics. Int Anesthe-

siol Clin 1990;28:230–235.

3. Theroux MC, Corddry DH, Tietz AE, et al. A study of

desmopressin and blood loss during spinal fusion for neuro-

muscular scoliosis: A randomized, controlled, double-blinded

study. Anesthesiology 1997;87:260–267.

4. Florentino-Pineda I, Blakemore LC, Thompson GH, et al. The

effect of epsilon aminocaproic acid on perioperative blood loss

in patients with idiopathic scoliosis undergoing posterior spinal

fusion. Spine 2001;26:1147–1151.

5. Laupacis A, Fergusson D, for the International Study of

Perioperative Transfusions (ISPOT) Investigators: Drugs to

minimize perioperative blood loss in cardiac surgery: meta-

analyses using perioperative blood transfusion as the outcome.

Anesth Analg 1997;85:1258–1267.

6. Wells PS. Safety and efficacy of methods for reducing perioper-

ative allogeneic transfusion: A critical review. Am J Therap

2002;9:377–388.

7. Hersey SL, O’Dell NE, Lowe S, et al. Nicardipine versus

nitroprusside for controlled hypotension during spinal surgery

in adolescents. Anesth Analg 1997;84:1239–1244.

8. Tobias JD. Strategies for minimizing blood loss in orthopedic

surgery. Sem Hematol 2004;41 (suppl)145–156.

9. Tobias JD. Controlled hypotension in children undergoing

spinal surgery: a critical review of available agents. Paediatric

Drugs 2002;4:439–453.

10. Tobias JD, Tulman DB, Bergese SD. Clevidipine for perioper-

ative blood pressure control in infants and children.

Pharmaceuticals 2013;6:70–84.

16 Death does not wait: Implications for a modern

humanitarian and medical help system for countries

or regions in states of distress following human

or military castastrophies or those induced

by nature

Roland Inglis

Institution: Frankfurt University Hospital, Department of Trauma

Surgery, Frankfurt am Main, Germany

In the immediate aftermath of a disaster or catastrophe we always

have to cope with several dependent or independent factors influ-

encing or not influencing one the another.

First: The notice of what happened when and where.

In the succession of a catastrophe it is not unlikely even today, that

the first notion of what had happened is spread of a single satellite-

cellphone call from a victim to his/her family thousands of miles

away, rather than notice from an official site in the collapsed envi-

ronment. Next, the locality of the scenario might occasionally be

found by a weather satellite rather then by search planes, if there is

major damage at the regions’ air fields.

Even today and with no damage locally at all, depending on

telephone-traffic, to call ‘‘911’’ in downtown New York may lead to a

first response from somewhere in Canada, as, even in developed

countries the modern information system has no functional and fail-

safe backup, when the tech’s hit.

That means, the notice about the incident still depends on time and

chance, as long asworld-wide and internet-independent back-up-systems

are not implemented, however, techniques for those available already. It

is obvious, that the in normal times hyperfast reacting sozial networkswill

collapse together with the internet itself, and even, like the well known

criminal and intentional denial of service attacks, will add their part of

internet-overload; that means; there will be no help available fom here.

Second: The start, the onset of national OD international help.

After realizing what had happened, the national representatives of

the region influenced try to send help to the region affected and, at the

same time, try to get more information on the scenario, at the same

time trying to save their face against the ‘‘rest of the world’’ until it is

unavoidable to ask for external help. This mechanism, the routine-

mechanism of today takes about 3–4 days….

Third: Start of help induced by the international community:

This begins with an act of reconnaissance, officials of the inter-

national community try to find out, what is needed most urgently,

while parallel to this, acting as always, the international community

tries to raise funds for help, the International Red Cross sends blan-

kets and potable water and baby—food. Then, when it is mostly clear,

which kind of disaster struck the area, and, how lager the area is, and,

how many humans had dies immediately, or might be affected

immediately or long term, plans for effective help are carried out.

That takes 3–4 days…

Fourth: How to find them? Procedure as usual.

Up until now it is usual, to chose an airfield able to meet the needs

of the helpers and optionally, one located not too far away from the

(still) living victims.

After that trucks are gathered and helicopters, when anvailable and

weather permitting.

Then, after installing this ‘‘center of help’’, living victims are

searched starting from this place, this center, then searching some-

what in concentric circles, until the borders of the affected regions are

reached, or by declaration of an end of search for people living.

That however means, help is dependent on where the helpers have

landed, not on where the surviving victims are.


123

And, talking about scenarios with difficult situations of debris,

collapsed structures, earthquakes, floodings, tsunamies, the interna-

tional community decides and sends search dogs, mostly finding

corpses, rather seldom finding ‘‘a single surviving baby 10 day after

the earthquake’’ (a baby then taking the hero-part of the complete

rescue-situation). That takes 5–10 days.

Fifth: How and when to treat them.

How do we perform triages in mass casualties, what do we do, if

we find survivors, how do we rise the chance for survival for any

affected, and no matter WHEN he/she has been found. How do we

increase the number of victims found living still, how do we decrease

the number of victims, facing death only, because we use an anti-

quated system for reconnaissance and rescue, one that is obsolete

according the techniques employed, while methods for amelioration

are available, however not noticed yet predominantly.

To mention only one example of the already available modern

methods that are discussed:

How do dogs manage to smell (afferently)? How do they perform

directional smelling? What substances do they smell, when told to

find a human alive or not? Why do we still need dogs? How could we

make the function of finding victims airborne with automated sys-

tems? The next topic discussed: When making ‘‘automated-dog-

smell’’ airborne, why not make the complete desaster-relief-man-

agement and planning automated by methods that are already

available in/from industry, however, at this time, ‘‘thought of’’ as

‘‘island-solutions’’ for single problem-parts, parts, having nothing to

do with medicine, or with life-saving?

… and then there is psychology of daily life, that disables most of

us from thinking of drones employed as life-savers, a job more

suitable to them as is the contrary prevailing.

17 Non-contact monitoring of vital signs

S. Leonhardt

Helmholtz-Institut fur Biomedizinische, Aachen, Germany

There is increasing interest in monitoring techniques that avoid direct

mechanical or electrical contact with the skin. Such unobtrusive

measurements have a lot of advantages when skin is very sensitive

(e.g. premature neonates or after severe burns) or when touching and

cabling the skin is not desired (e.g. during car driving, during dialysis

or on the intermediate care unit). Also, in long-term monitoring such

technologies would avoid skin initiation.

In the talk, a selection of technologies that are candidates for non-

contact monitoring is presented, namely ballisto cardiography,

capacitive ECG-Monitoring, Infrared Thermography, Magnetic

Induction Monitoring and reflective Pulse Plethysmonography

Imaging. For conclusion, we compare different properties of these

methods in order to identify proper application scenarios.

18 Useful telemedical applications to improve safety

and quality in anesthesiology

Michael Czaplik1, Jorg Brokmann2, Bernd Valentin1, Freddy

Hirsch1, Sebastian Bergrath1, Rolf Rossaint1

1. Department of Anaesthesiology, University Hospital RWTH

Aachen, Germany; 2. Emergency Department, University Hospital

RWTH Aachen, Aachen, Germany

IntroductionAnaesthesiology covers all themedical chain, starting with

the pre-hospital emergency care via the peri-operative treatment right up

to the post-operative surveillance. Demographic changes affect all the

mentioned chain linksdiversely. First, increasingnumber and complexity

of emergency missions lead to lacking adequately qualified emergency

physicians in particular in rural regions. Consecutively, attendance times

are risingwith prolonged therapy-free intervals potentially leading to loss

of medical quality. Second, particularly maximum-care hospitals are

targeted by numerous ambulances without any prior notice and infor-

mation about the patient so that preparation for the individual emergency

patient normally is not possible.However, e.g. patients suffering fromso-

called tracer diagnoses such as stroke do not profit from running things by

the book (ECG, blood sample, etc.) but need an immediate specific

diagnosis and therapy (CTand thrombolytic therapy if applicable). Third,

intensive care units of smaller hospitals with relatively few number of

beds and operation rooms, are just equipped with limited resources—in

terms of certain medical devices and highly specialised personnel. Par-

ticularly, evaluation of rare disease patterns and suddenworsening of the

patient’s physical condition, pose a significant challenge.

MethodsTelemedicine opens up new possibilities for all mentioned

fields of anaesthesiologic care. First, tele-emergency medicine offers

meaningful options to improve patient care. During the latency time,

when paramedics are waiting for the emergency doctor on scene, a tele-

emergency doctor can already brief the team and initiate a medical

therapy in order to bridge time. Furthermore, diverse emergency cases

do not require manual skills of a doctor but their competence and finally

assumption of responsibility. By using modern communication tech-

nology in terms of telemetry and data transmission, information and

data from the patient that are assessed on scene can be transferred to the

admitting hospital. By doing so, following clinical processes can be

optimized regarding preparation of personnel and further required

resources. Tele-intensive care medicine can be used to support non-

maximum-care hospitals with respect to special cases. Highly specia-

lised physicians can be involved in ward rounds or specific issues.

Results In the last few years, different research project were carried

out to develop a so-called telemedical rescue assistance systems in

Aachen, Germany. Therefore, several medical and non-medical

devices that are available in the ambulance such as headsets, the

patient monitor and cameras were networked with a telemedical

center using a highly robust and reliable encrypted mobile radio

connection. By doing so, telemedical consultations were enabled that

meet all requirements in terms of usability and legal aspects. During

more than 1,000 missions up to date, the technical system and

organisational concepts were optimized. As related to the telemedical

rescue assistance system, no adverse events occurred during the

recent years. The field of application was huge—in most cases drug

treatment was initiated by the tele-doctor.

Tele-intensive care medicine is another application domain that is

carried out by the telemedical center of Aachen university hospital.

Therefore, another research project is currently in progress focusing

in supervising smaller hospitals in our region.

Conclusion There is an enormous potential of telemedical applica-

tions targeting in improving patient safety and treatment quality.

However, numerous circumstances—technical, legal and organisa-

tional have to be considered during the development and introduction

of telemedical assistance systems.

19 Monitoring depth of anesthesia monitoring

Joseph D. Tobias


dren’s Hospital, The Ohio State University, Columbus, Ohio;

[email protected]


123

Introduction In clinical practice, the pre-requisites of general

anesthesia include amnesia, analgesia, and control of the sympa-

thetic stress response. While patients may worry about mortality

during major surgical procedures, the lay press and the internet have

made patients acutely aware of what many consider a more drastic

outcome: intraoperative awareness. Intraoperative awareness is a

rare occurrence with a reported incidence of approximately 1 for

every 1,000 general anesthesia cases [1, 2]. During training, we

frequently learn and the literature reinforces that the incidence of

awareness is highest during 3 types of surgical procedures including

trauma, cesarean section and cardiovascular surgery. In such sce-

narios, awareness relates to intraoperative problems generally

hemodynamic instability or the need to rapidly move toward sur-

gical intervention such that the level of anesthesia is inadequate.

However, data from the closed claims analysis show a different

pattern with awareness occurring more commonly in young patients,

those with a lower ASA physical status (I and II) and women

presenting for relatively routine surgical procedures [3]. In these

cases, the problems generally relate not to the patient status, but

rather issues with anesthesia equipment (vaporizers or infusion

pumps) or the vigilance of the anesthesia provider. Not unexpect-

edly, awareness results in significant psychological effects with

prolonged disability in up to 50 % of patients [4].

Techniques to monitor the depth of anesthesia Until recently, an

assessment of the depth of anesthesia relayed upon clinical findings,

most notably hemodynamic and pupillary responses. Obviously in

critically ill patients with myocardial dysfunction, tachycardia and

hypertension may never occur regardless of a lack of effective

anesthesia. One of the more commonly used clinical depth of anes-

thesia scoring system can be remembered by the acronym, PRST

(otherwise known as the Evan’s score) [5]. This clinical score is

meant to assess autonomic activity:

a. P for systolic blood pressure)

b. R for heart rate

c. S for sweating

d. T for tears

The relative non-specificity of such monitoring left the anesthesia

provider with the relatively difficult task of providing what one

assumed would be enough anesthesia. Additionally, various medica-

tions and co-morbid conditions could obtund the responses. Given the

inter-patient variability that may be present with anesthetic require-

ments, this left some patients receiving either inadequate or excessive

doses. Such issues led to the search for technology to adequately

assess the depth of anesthesia.

In the majority of clinical scenarios, when depth of anesthesia mon-

itors are used, they are in general terms, based on the processed

electroencephalogram (EEG) or evoked brain electrical activity

monitors (auditory, visual or somatosensory evoked responses). The

latter devices are less commonly used in clinical practice and depend

on monitoring the EEG’s response following some sort of external

stimulus. Although an EEG can be obtained using the standard

19-electrode method, such devices are cumbersome, time consuming,

and impractical for clinical use as the majority of anesthesia providers

lack the needed education to make their interpretation useful. Given

such issues, there has been the introduction of several processed EEG

devices which have been used to varying extent to monitor the depth

of anesthesia. These include:

a. compressed spectral analysis

b. cerebral function monitor

c. cerebral function analysis monitor

d. the bispectral index or BIS

e. entropy monitoring

f. Narcotrend monitor�

g. patient state analyzer (Sed-line monitor)

h. SNAP index

i. cerebral state monitor/cerebral state index

To date, the majority of clinical experience and ongoing use

includes the BIS monitor, otherwise known as the bispectral index. BIS

is a proprietary algorithm developed by Aspect Medical Systems. It

uses a simple adhesive strip with 4 electrodes to record a single frontal

EEG and converts it to a numerical scale ranging from 0 (flat line) to

100 (awake, eyes open). The algorithm integrates several features of

the EEG. This includes information from the time domain (burst-sup-

pression analysis), frequency domain (power spectrum, bispectrum) as

well as the amplitude and frequency of the raw EEG. The algorithm

was developed in healthy adults during the administration of various

anesthetic agents that work through the c-amino butyric acid (GABA)

system including propofol and the volatile anesthetic agents [6, 7]. As

such, it is not effective with other agents including nitrous oxide,

ketamine and etomidate. Although initial studies suggested a decreased

incidence of awareness when compared to historical controls [8, 9],

more recent prospective trials have failed to demonstrate its efficacy

during a volatile-agent based anesthetic. Avidan et al. compared a BIS-

based protocol with a measurement of end-tidal anesthetic gas (ETAG)

for decreasing anesthesia awareness in patients at high risk for this

complication. Two thousand adults were randomly assigned to titration

of the volatile anesthetic agent to a target BIS range of 40–60 or a

target ETAG range of 0.7–1.3 minimum alveolar concentration. Post-

operatively, patients were assessed for awareness at three intervals

(0–24 h, 24–72 h, and 30 days after tracheal extubation). Two cases of

definite anesthesia awareness occurred in each group. The BIS value

was greater than 60 in one case of definite anesthesia awareness and the

ETAG concentrations were \0.7 MAC in the 3 other cases. The

authors concluded that their results did not reproduce the results of

previous studies that reported a lower incidence of anesthesia aware-

ness with BIS monitoring. Furthermore, they suggested that the use of

the BIS protocol was not associated with reduced administration of

volatile anesthetic gases. Anesthesia awareness occurred even when

BIS values and ETAG concentrations were within the target ranges.

Our findings do not support routine BIS monitoring as part of standard

practice during the use of volatile anesthetic agents.

Summary Monitoring the depth of anesthesia remains a relatively

new adjunct to perioperative care. Unlike vital signs monitoring, such

devices cannot be considered mandatory or the standard of care.

Large prospective, randomized trials have failed to show their effi-

cacy in decreasing awareness when compared with end-tidal gas

monitoring. That being said, such devices should be considered in

patients at high risk for awareness (previous awareness) and in spe-

cific clinical scenarios where awareness is more likely or when end-

tidal gas monitoring is not feasible (total intravenous anesthesia). The

American Society of Anesthesiologists task force on intraoperative

awareness summarized their recommendations by stating that depth

of anesthesia monitoring is not routinely indicated for general anes-

thesia patients and that the decision to use a brain function monitor

should be made on a case-by-case basis by the individual practitioner

for selected patients.

The prevention of awareness not only involves such monitoring

equipment, but more importantly vigilance and sound clinical judgment.

This should include the checking of all equipment, ensuring the unin-

terrupted delivery of anesthetic agents due to faulty vaporizers or

infusion devices. The use of depth of anesthesia monitoring may have

additional applications including the potential to monitor neurological

function as it has been suggested that an excessive depth of anesthesia

may have long-term negative impact especially in critically ill patients

with co-morbid conditions. Such monitoring may also have applications

during procedural sedation or sedation during mechanical ventilation in

the ICU setting. It is likely that this technology will continue to improve

and potentially facilitate the care we provide our patients.


123

References

1. Sandin RH, Enlund G, Samuelsson P, Lennmarken C. Aware-

ness during anaesthesia: A prospective case study. Lancet

2000;355:707–11.

2. Sebel PS, Bowdle TA, Ghoneim MM, et al. The incidence of

awareness during anaesthesia: A multicenter United States

study. Anesth Analg 2004;99:833–39.

3. Domino KB, Posner KL, Caplan RA, Cheney FW. Awareness

during anesthesia—A closed claim analysis. Anesthesiology

1999;90:1053–61.

4. Lennmarken C, Bildfors K, Enlund G, SamuelssonP, Sandin R.

Victims of awareness. ActaAnaesthesiol Scand 2002; 46:229–31.

5. Evans JM, Davies WL. Monitoring anaesthesia. Clin Anesth

1984;2:243–62.

6. Rosow C, Manberg PJ. Bispectral index monitoring. Anesth

Clin N Am 2001; 19: 947–66.

7. Glass PS, Bloom M, Kearse L, Rosow C, Sebel P, Manberg P.

Bispectral analysis measures sedation and memory effects of

propofol, midazolam, isoflurane, and alfentanil in healthy vol-

unteers. Anesthesiology 1997;86:836–47.

8. Myles PS, Leslie K, McNeil J, Forbes A, Chan MTV. Bispectral

index monitoring to prevent awareness during ana-esthesia: The

B-aware randomized controlled trial. Lancet 2004;363:1757–63.

9. Puri GD, Murthy SS. Bispectral index monitoring in patients

undergoing cardiac surgery under cardiopulmonary bypass. Eur

J Anaesth 2003;20:451–6.

10. Avidan MS, Zhang L, Burnside BA, et al. Anesthesia awareness

and the bispectral index. N Engl J Med 2008;358:1097–108.

11. Monk TG, Saini V, Weldon BC, Sigl JC. Anesthetic manage-

ment and one-year mortality after noncardiac surgery. Anesth

Analg 2005;100:4–10.

12. Sessler DI, Sigl JC, Kelley SD, Chamoun NG,Manberg PJ, Saager

L, Kurz A, Greenwald S. Hospital stay and mortality are increased

in patients having a ‘‘triple low’’ of low blood pressure, low

bispectral index, and low minimum alveolar concentration of

volatile anesthesia. Anesthesiology 2012;116:1195–203.


1. Avidan MS, Mashour GA. Prevention of intraoperative aware-

ness with explicit recall: making sense of the evidence.

Anesthesiology 2013;118:449–56.

2. Mashour GA, Shanks A, Tremper KK, et al. Prevention of

intraoperative awareness with explicit recall in an unselected

surgical population: a randomized comparative effectiveness

trial. Anesthesiology 2012;117:717–25.

3. Sinha PK, Koshy T. Monitoring devices for measuring the depth

of anaesthesia—an overview. Indian J Anaesth 2007;51:365–81.

4. MonkTG,WeldonBC.Doesdepthofanesthesiamonitoring improve

postoperative outcomes? Curr Opin Anaesthesiol 2011;24:665–9.

5. Somchai A. Monitoring for depth of anesthesia: a review.

J Biomed Graph Comput 2012;2:119–127.

6. Bruhn J, Myles PS, Sneyd R, Struys MRF. Depth of anaesthesia

monitoring: what’s available? Br J Anaesth 2006;97:85–94.

20 Deeper than anesthesia depth monitors: nociception

monitoring

Massimiliano Sorbello

Anesthesia and Intensive Care, AOU Policlinico Vittorio Emanuele,

Catania, Italy

Monitoring of analgesia remains the final challenge during GA. We

cannot count on nociception effects to measure it; not only because

we need to avoid them, but also because of their deleterious effects on

the intraoperative course and on the postoperative outcome, including

pain sensitisation and undesirable haemodynamic effects, especially

in compromised patients.

There is growing evidence of an association between the attenu-

ated surgical stress response and improved overall postoperative

recovery, requiring for individual titration of analgesics. Therefore,

monitoring of analgesia may turn out to be important in evaluating

different strategies for control of the intraoperative stress response

and their association with patient outcome.

Movement itself cannot be a good nociception indicator: first of all

because of the effects of NMBAs and then because it has been

demonstrated that motor responses to nociception depend on sub-

cortical structures. Evaluation of autonomic responses remains the

most powerful tool anaesthetists have ever had for detecting noci-

ception and driving analgesic administration.

In recent decades it was supposed that the available Anesthesia

Depth monitors could be extended to nociception monitoring, par-

ticularly for RE-SE couple with Entropy monitoring (GE Healthcare,

Helsinki, Finland).

So, which parameters to look at? Clinical signs represent the state

of the art, but they are difficult to monitor objectively, especially in

the anaesthetised patient. Blood pressure per se is a good parameter

but its usefulness is limited by too many confounding factors, such as

prior hypertension or pharmacological interferences, including

anaesthetic drugs. Heart rate is subject to similar limitations, though

tachycardia should always be considered the first sign of inadequate

antinociception. Spectral analysis criteria have been applied to HR

variability to obtain a more reliable assessment of autonomic system

activation, but with poor results when HR alone is considered. Skin

vaso- motor response (SVmR) measured by laser Doppler was con-

sidered useful as an expression of sympathetic-mediated

vasoconstriction elicited by nociception and pulse plethysmography

has also been widely considered, with controversial results. The only

possible approach is multiparametric, in order to minimise interfer-

ences and synergise advantages.

Integration of advanced analysis of HR variability and PPG

characteristics and dedicated Entropy measurements has recently

resulted in development of intraoperative nociception monitoring: the

Surgical Plethismographic IndexTM (SPI). Using data coming from

conventional operating room monitoring, a three-lead ECG and

conventional PPG, a dedicated software provides advanced analysis

of both ECG variability (through beat-to-beat R–R analysis) and PPG

signal (PPG amplitude and area analysis +PPG dicrotic notch loca-

tion); the latest release of the SSI software also includes analysis of

the Entropy data (RE + SE).

The rationale for such an approach lies in the combination of

various signs of autonomic activation (modulation of HR variability,

PPG morphology and dyna- mics variations because of vascular tone)

in order to minimise contamination and increase reliability in noci-

ception monitoring. Preliminary data reports [84, 85] and our group’s

unpublished data [86] suggest a good relationship between SSI and

intraoperative nociception assessed during several anaesthetic regi-

mens (sevoflurane, desflurane/fentanil; propofol/remifentanil;

combined anaesthesia), different types of surgery and heterogeneous

patient populations.

To date, finally, many candidate signs are available for analgesia

monitoring, and technical research is moving faster and faster;

according to our present knowledge, at least, whatever the latest

monitors are like, they will never be able to predict whether the depth

of analgesia is sufficient for the next painful surgical stimulus: they

can only monitor the anaesthetic state at the time of measurement and

the existing balance between excitation and responsiveness. The

anaesthetists’ role is still pivotal, their experience being ahead of any


123

technique for monitoring analgesia depth, and better than any monitor

despite their lower capacities in terms of number of operations per

second.

References

1. van Gils M, Korhonen I, Yli-Hankala A (2002). Methods for

assessing adequacy of anesthesia. Crit Rev Biomed Eng

30:99–130

2. Kehlet H (1997). Multimodal approach to control postoperative

pathophysiology and rehabilitation. Br J Anaesth 78:

606–617

3. Pomeranz B, Macaulay RJ, Caudill MA et al. (1985). Assessment

of autonomic function in humans by heart rate spectral analysis.

Am J Physiol 248:H151-H153

4. Seitsonen ERJ, Korhonen IKJ, Van Gils MJ et al. (2005). EEG,

spectral entropy, heart rate, photoplethysmography and motor

responses to skin incision during sevoflurane anaesthesia. Acta

Anaesthesiol Scand 49:284–292

21 How to prevent awareness during general anesthesia

Gabriel M. Gurman

[email protected]

Introduction Among other things, general anesthesia’s aims include

prevention of: perception of pain, awareness and recall of events

during surgery.

The term of awareness during general anesthesia (AGA) is to be

restricted to the true aspect of the problem, e.g. the ability of the

patient to recall spontaneously events occurred during anesthesia and

surgery.

In other words, in this presentation we will limit the description of

AGA to explicit memory, that which refers to information that is

consciously recalled.

This definition does not include aspects of implicit memory, which

occurs when information is stored but not accompanied by conscious

recollection.

How frequent is the phenomenon of AGA in modern anesthesia ?

The route of research of AGA has been opened some 40 years ago

by Levinson [1], who reported retrieval of facts stored during anes-

thesia when the patient was under hypnosis.

Data published more than a decade ago [2] presented a continuous

decrease in the percentage of AGA, from 1.2 % of all general anes-

thesias in 1960 to only 0.2 % in the last decade of the last century.

A study of the American Society of Anesthesiologists Closed

Claim Project database indicated that 1.9 % of the malpractice claims

involved AGA [3]. This incidence was, for instance, higher than that

related to cases of perioperative myocardial infarction

But some groups of patients or specific clinical situations might be

accompanied by a much higher incidence of AGA [4], among them:

cardiac and obstetric surgery, the morbid obese patient, intraoperative

hemodynamic instability as well as equipment failure.

In many cases the cause of AGA remains obscure. For ten out of

18 cases reported by Sandin [5] there was no evident explanation of

the episodes of AGA claimed by patients in the postoperative

interview.

AGA can produce a variety of postoperative psychological

disturbances.

In a recent study Moerman et al. [6] 26 patients who had com-

plained of AGA presented postoperatively anxiety, sensation of

weakness, sleep disturbances and nightmares. The clinical picture is

similar to the well known image of posttraumatic stress syndrome

(PTSS), described on veterans of the Vietnam war.

The inability of the anesthesiologist to diagnose constantly an AGA

episode is related to the lack of reliable clinical signs of awareness.

A long series of studies failed to prove a direct correlation between

AGA and the clinical classical signs of depth of anesthesia. No cor-

relation was found between hemodynamic parameters and hand

movements during general anesthesia when using isolated arm tech-

nique [7]. When studying retrospectively anesthesia charts of 26

patients who reported AGA [6] Moerman found a significant increase

in blood pressure and heart rate in only two-thirds of the cases.

The ethical and medicolegal implications of AGA as well as dif-

ficulties in diagnosing AGA in most cases oblige the anesthesiologist

to find the way to prevent episodes of awareness and in the same time

to be prepared to deal with patients who complain of AGA in the

postoperative period.

Prevention of AGA Prevention of AGA starts in the preoperative

period. The first rule implies a discussion with the patient and an

explanation about the remote (but still possible) complication of

AGA. The talk becomes important in the case of a patient who

belongs to a high risk group, like the parturient before a caesarian

section or a cardiac patient scheduled for coronary artery bypass graft.

In a recent review [8] we emphasized the importance of obtaining the

informed consent from such a patient after explaining the nature of

this complications and also the measures which are to be taken in

order to prevent the complication.

Some authors recommend the use of amnesic drugs such as ben-

zodiazepines or scopolamine in premedication [9]. This can prevent,

indeed, episodes of conscious recollection but it might open the door

to the phenomenon of implicit memory, unrecognized neither by the

patient nor by the anesthesiologist, with possible clinical implications,

difficult to assess and to treat, since this fact remains obscure, deeply

covered in the patient’s memory.

We recommend to dedicate enough time to the discussion with the

patient and to assure him/her that we will follow up the immediate

postoperative course in order to take the necessary measures when

needed (vide infra).

The last preoperative measure of precaution consists in a strict

check up of the anesthesia machine, with a special emphasize on

vaporizers and their periodical calibration, delivery of N2O and

prevention of circuit leaking. A MDU report for the last decade

mentioned failure to check anesthesia apparatus as responsible for

20 % of the equipment troubles which produced episodes of AGA.

The intraoperative vigilance includes a series of measures, which

might considerably reduce the percentage of AGA.

Use of volatile drugs for any general anesthesia is recommended

by some authors, which means that use of total i-v anesthesia (TIVA)

might be accompanied by a higher percentage of AGA. A glance on

MEDLINE for the years 1966–1999 will reveal that out of 1,563

papers on TIVA 34 deal with danger of awareness by using this

technique. Preventing a response to verbal commands necessitates

\0.4 MAC isoflurane [10], that is a very low of a volatile drug is

needed in order to prevent AGA.

As it was already suggested, episodes of hypotension must be

treated specifically, e.g. correcting hypovolemia, using inotropic

drugs as needed and correcting severe bradicardia. Stopping the

administration of anesthetic drugs in the presence of a decrease in

blood pressure may lead to an episode of AGA, unobserved if the

patient received an overdose of muscle relaxants. Needless to say that

in this scenario neither hypertension nor tachycardia could be of any

help in early diagnosing AGA.

If it is true that under general anesthesia patients can continue to

receive and process auditory stimuli, it becomes very important to

keep a very strict etiquette in the operating room. The OR personnel is

supposed to keep a nice atmosphere, avoiding high tones and con-

tradictory discussions. One must refrain from speaking about patient’s

condition, her/his inabilities or invalidity.


123

Some authors recommend the use of music, either in the air or

through earphones and thus preventing processing auditory informa-

tion during episodes of AGA.

A very interesting point to be discussed in the framework of

preventing AGA is the use of the new CNS monitoring technology

during general anesthesia.

Research on using various electroencephalographic (EEG)

parameters for monitoring depth of anesthesia did not offer reliable

data in all cases.

Not all the anesthetic drugs act in the same way on EEG. For

instance opoids in doses large enough to suppress movements have

only a slight effect on EEG [11]

One way to improve the early diagnosis of AGA would be to

correlate signs of cortical electrical activity with the classical signs of

superficial anesthesia. We developed an original matrix based on

spectral edge frequency (SEF) and its correlation with blood pressure

during general anesthesia [12] but the change of both parameters in

the same direction was observed only in some 75 % of cases.

Unfortunately all the EEG parameters proposed by today failed to

offer a 100 % assurance that AGA episodes would be detected in time

for preventing its side effects.

In the last years a long series of reports dealt with the use of

bispectral index (BIS) for monitoring adequacy of anesthesia and

reducing the percentage of AGA.

BIS is an empirical, statistical-derived measurement of cortical

electrical activity [13]. It is mainly correlated to the various stages of

hypnosis and sedation and much less with the level of analgesia. A

low BIS indicates hypnosis and in the vast majority of cases a value

lower than 60 is compatible with a lack of response to verbal com-

mands [14–16].

But if the aim of a monitor of depth of anesthesia is limited to the

separation of consciousness from unconsciousness, BIS is the closest

of all devices to this definition. Nevertheless a recent report using the

isolated forearm technique and BIS in forty unpremedicated patients

[17] found a large variation in BIS values compatible with lack of

response to verbal command and this fact was responsible for erro-

neously classifying six patients as unconscious.

BIS, like any other EEG parameter can be influenced by changes

in the patient’s condition with no connection to the level of general

anesthesia, such as cerebral ischemia, hypothermia, increase in EMG

activity of the facial muscles, etc.

A recent report from the ASPECT company regarding the use of

BIS [18] found a very low rate of AGA (1/40,000) among more than 2

millions patients monitored with this new device. The reported per-

centage is significantly lower than the acceptable rate of 2/1000,

frequently mentioned in the literature.

Nevertheless, BIS is not infallible. A recent report [19] described

three fully conscious volunteers to whom administration of muscle

relaxants produced a dramatic decrease of BIS to 9, 64 and 57

respectively. A normal value of BIS reappeared once the full muscle

tonus was recovered in each subject.

But above any doubt, using a processed EEG parameter during

general anesthesia, although not a prefect mode of monitoring, may

significantly reduce the percentage of AGA and thus improve patient

safety during general anesthesia.

Finally, the anesthesiologist must be alert in the immediate post-

operative period of untoward effects of AGA.

It means that the visiting the patient in the postoperative period, or

at least contacting him one way or another, becomes part of the

anesthesiologist professional obligations.

The postoperative interview must be conducted in a intelligent

way, avoiding the induction of a response. Patient has to be given a

possibility to tell his or her story related to the information received

during the stay in the operating room.

Report of AGA has to be accepted by the anesthesiologist.

Denying a possibility of AGA implies that the patient is to blame for

the report, and this might have significant negative effects from the

psychological point of vu.

Once an episode of AGA was reported the patient has to be

reassured and comforted, a logical explanation has to be offered and if

necessary the patient is to be referred to a professional, psychologist

or psychiatrist.

In the same time a complete report is to be sent to the defense

company and medicolegal advise is to be sought.

Conclusions AGA must be viewed as part of the every day activity in

the operating room. In spite of the relatively low percentage, detecting

episodes of awareness during anesthesia demands an alert

anesthesiologist.

It is his/her responsibility to detect pre-operatively those patients

who are in a high risk to develop AGA. These patients must be

prepared for this possibility and encouraged to report in the imme-

diate postoperative period any symptoms compatible with this

diagnosis.

The use of a EEG parameter, like BIS, as part of the monitoring

during general anesthesia can significantly reduce the danger of

AGA and this is the reason why its use must be encouraged and

enlarged.

Recently the ASA Task Force on this subject summarized the role

of monitoring brain function during anesthesia as follows [20]: It is

the consensus of the Task Force that brain function monitoring is not

routinely indicated for patients undergoing general anesthesia, either

to reduce the frequency of intraoperative awareness or to monitor

depth of anesthesia.

Prevention of AGA must go hand in hand with measures to reduce

to a minimum its secondary effects.

The danger of poststraumatic stress syndrome is a reality and

nobody can forecast its implications on patient’s life. Strange or

sudden changes in his/her behavior weeks or months after general

anesthesia could have a real connection with undetected AGA.

Further studies are needed in order to increase the reliability of the

CNS monitoring parameters to be used during general anesthesia and

to reach a 100 % prevention of awareness during anesthesia.

Till then the vigilance of the anesthesiologist, together with a

human attitude toward this phenomenon and the use of a correct

anesthesia technique could reduce the magnitude of this incident.

References

1. Levinson BW. Br J Anaesth 1965;37:544

2. Liu WHD et al. Anaesthesia 1991;46:435

3. Domino KB et al. Anesthesiology 1999;80:1053

4. Gurman GM. Minerva Anestesiol 2000;66:177

5. Sandin R et al. Lancet 2000;355:707

6. Moerman N et al. Anesthesiology 1993;79:454

7. Russell IF. Clinical anesthesiology (Ed. Jones JC). Bailere-

Tindall 1989:511

8. Gurman GM. Minerva Anestesiol 2002;68:905

9. Berrigan MJ. ASA Refresher course 2001;29:41

10. .Dwyer R et al. Anesthesiology 1992;77:888

11. Glass P et al. Anesthesiology 1994;81: suppl 3A –A407

12. Gurman GM Anasth Intensivmed (Germany) 1995;36:50

13. Rosow C, Manberg PJ. Anesthesiology Clinics of North

America 1998;2:89

14. Fleishon R et al. Anesthesiology 1997;86:613

15. Glass PSA et al. Anesthesiology 1997;86:836

16. Liu J et al. Anesth Analg 1997;84:185

17. Schneider G et al. Brit J Anaesth 2003;91:329

18. *** Proceedings of the 5th International Conference on Memory

and Awareness during Anesthesia, New York 2001;p 45

19. Messner G et al. Anesth Analg 2003;97:488


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20. ***Practice advisory for intraoperative awareness and brain

function monitoring: a report by the American Society of

Anesthesiologists task force on intraoperative awareness. Anes-

thesiology, 2006;104:847

22 Regional anesthesia: quo vadis?

Aurel Neamtu

Department of Anesthesiology and Perioperative Medicine, Univer-

sity of Louisville School of Medicine, Louisville, Kentucky, USA,

Email: [email protected]

Abstract Discovery of general anesthesia in the mid-19th century

prompted a huge step forward in the development of surgery and surgical

procedures. Regional anesthesia followed shortly after, with important

changes over the years with regards to drugs and techniques. Currently,

there is a large scientific body of evidence that regional anesthesia

improve outcomes: postsurgical functional recovery, antiinflammatory

effects, better cardiopulmonary and gastrointestinal parameters,

improved blood coagulation, decreased cancer recurrence, to name just a

few [1]. Clinical studies in various surgical settings have been shown to

result in improved perioperative parameters. For example, in orthopedic

surgery, and in particular in total joint arthroplasty, several advantages of

neuraxial anesthesia have been suggested: modification of the hyperco-

agulable state triggered by surgery, better pain control, better regional

blood flow, decreased need for transfusion, decreased neuroendocrine

and inflammatory stress response [2].At the same time, our knowledgeof

the mechanisms of pain, in particular acute pain, has increased consid-

erably. It is now known that the fundamental unit of pain is the cell, with

specialized nociceptors that respond in a complex and highly organized

interaction of signalingmolecules to a variety of extracellular inputs. The

advent of our genetic and molecular era has brought the discovery of a

tremendous amount ofmolecules involved in painmechanisms aswell as

the transition from acute to chronic pain [3]. In addition, solid research

has shown that activation of glial cells and neuro-glial interactions seem

to be key mechanisms underlying chronic pain [4]. The pain matrices

concept gains more and more research evidence. For example, a noci-

ceptive pain matrix receiving spinothalamic projections ensures the

bodily specificity of pain and is the only one whose destruction entails

selective pain deficits [5]. One cannot stopwonderingwhether the theory

of ‘‘anoci-association’’, introduced in 1914 by George Crile, surgeon at

Cleveland Clinic, does not play an important role in explaining the

current outcomes demonstrated by using regional anesthesia. He claimed

that blockade of the afferent neural input from the surgical area protected

the brain and other organs from the undesirable sequelae of surgical

injury [6]. Nowadays, various regional anesthetic techniques are pow-

erful tools providing almost perfect perioperative pain therapy. Using an

optimal balance between appropriate techniques, application of

advanced equipment, such as ultrasonography and peripheral nerve

stimulators, as well as adequate drugs, regional anesthesia plays an

important role in perioperative medicine.

References

1. Kettner SC, Willschke H, Marhofer P. Does regional anaesthesia

really improve outcome? British Journal of Anaesthesia 2011;

107 (S1): i90–i95.

2. Provenzano DA, Viscusi ER. Regional anesthesia for total joint

arthroplasty. Pain Medicine News 2012 (Special Edition); 10

(12): 16–21.

3. Reichling DB, Green PG, Levine JD. The fundamental unit of

pain is the cell. Pain 2013; 154: S2-S9.

4. Ji RR, Berta T, Nedergaard M. Glia and pain: Is chronic pain a

gliopathy? Pain 2013; 154: S10-S28.

5. Garcia-Larrea L, Peyron R. Pain matrices and neuropathic pain

matrices: A review. Pain 2013; 154: S29–S43.

6. Tetzlaff JE, Lautsenheiser F, Estafanous FG. Dr. George Crile—

Early contributions to the theoretic basis for twenty-first century

pain medicine. Reg Anesth PainMed 2004;29:600–605.

23 Ultrasound guided nerve blocks: should we write

better with this golden pen?

Adela Hilda Onutu*

*Emergency County Hospital Cluj-Napoca, Orthopaedic and Trau-

matology Clinic, Anaesthesiology and Intensive Care Department,

[email protected]

The answer to the above question should be, at a first glance, yes of

course, but controversies on this point still exist.

The technique of neurostimulation (NS) was introduced in current

practice many decades ago, and later on has reached the gold standard

in peripheral nerve blockade (PNB), but today it seems to be an

auxiliary tool.

The new approach of the postoperative pain management has been

introduced due to the increasing use of regional anesthesia (RA), as a

consequence of developing ultrasound-guided regional aneasthesia

(UGRA). This approach to PNB became a very attractive one,

especially for the young trainees and specialists. By producing a

bidimensional image of the anatomic structures the US technology

offers the feeling that UGRA would bring more success and less

complications when used with PNB.

There isn’t enough evidence to define ‘‘the effect’’ of UGRA on

acute pain management and its outcome, as compared to NS [1].

Cochrane Database analysis concluded that ‘‘there is currently limited

evidence to support the routine use of ultrasound over other methods

of peripheral nerve blockade’’ [2].

However it was proved that US enhances block qualities and offers

the opportunity to see in real-time the spread of the local anaesthetic, as

compared with NS. But it seems that larger studies are still necessary to

prove the superiority of US in decreasing complications such as nerve

injury and local anaesthetic systemic toxicity. The incidence of nerve

injury remains between 0.03 and 3 % evenwith UGRA [3] while Auroy

et al. gave a incidence of 0.004 % with the use of NS [4]. A recent

survey on 27,031 cases of US-guided axillary block confirms the low

incidence of neurologic injuries, down to 0.37 per 10,000 [5].

Plexopathies, nerve injuries, pleural and vascular punctures are

continuously reportedwithUGRA,all of thembeing attributedmostly to

the inability to correctly visualize the needle tip. Maybe in the near

future the new electromagnetic tracking systems for US guidance and

the three/four-dimensional ultrasound systemswill make the difference.

Today NS preserves its own place in RA due to its capacity to

detect intraneural placement of the needle, with a low sensitivity and

high specificity. Used in a new manner when combined with US, by

setting the work current at low intensities 0.3–0.5 mA, and preventing

a vigorous motor response, NS may attest the proximity of the un-

isolated needle tip to the nerve.

The usual NS continues to represent a low cost, low weight,

accessible and reliable device, that has increased its capabilities by

displaying tissue impedance, as a supplementary tool in order to avoid

intraneural needle placement.

An important argument for using NS is its safety.

In this regard there are many important studies on efficacy of

UGRA, and in contrast inexplicably few on its safety, about neuro-

toxicity in association with local anaesthetic solutions in high

concentrations


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It is a fact that US beam applied on human tissues produces

heating of the structures and as a result mitochondrial changes, ap-

opthosis and necrosis. These phenomena are strongly dependent on

the amount of energy absorbed by these tissues and the frequency of

the US bean and are attributed to the cavitation phenomenon.

The controversy on US versus NS will go on because there are still

many issues to be clarified and because there are three relevant

endpoints that still haven’t been significantly affected by UGRA:

onset of surgical anaesthesia, success rate and the need for conversion

to general anaesthesia [6].

References

1. Choi S, Brull R. Is ultrasound guidance advantageous for

interventional pain management? A review of acute pain

outcomes. Anesth Analg. 2011 Sep; 113(3):596–604

2. Walker KJ, McGrattan K, Aas-Eng K, Smith AF. Ultrasound

guidance for peripheral nerve blockade. Cochrane Database Syst

Rev. 2009 Oct 7;(4):CD006459

3. Liu SS, Ngeow JE, Yadeau JT. Ultrasound-guided regional

anesthesia and analgesia: a qualitative systematic review. Reg

Anesth Pain Med. 2009 Jan–Feb;34(1):47–59

4. Auroy Y, Benhamou D, Bargues L et al. Major complications of

regional anesthesia in France: The SOS Regional Anesthesia

Hotline Service. Anesthesiology. 2002 Nov;97(5):1274–80.

5. Ecoffey C, Oger E, Marchand-Maillet F, Cimino Y, Rannou JJ,

Beloeil H; Complications associated with 27 031 ultrasound-

guided axillary brachial plexus blocks: A web-based survey of 36

French centres. Eur J Anaesthesiol. 2014 May 6. [Epub ahead of

print]

6. Antonakakis JG, Ting PH, Sites B. Ultrasound-guided regional

anesthesia for peripheral nerve blocks: an evidence-based

outcome review. Anesthesiol Clin. 2011 Jun;29(2):179–91

24 ULTRASOUND versus NERVE STIMULATOR. 2

late 2 debate !?

Dr. Grunfeld Adrian

Sheba Medical Center Tel Hashomer Israel

‘‘I have a nerve stimulator. Shall I also buy an ultrasound? I have

an ultrasound. Shall I also buy a nerve stimulator?’’

If we go deep into the professional literature to find arguments for

efficacy and efficiency of the different medical equipment we’ll only

get very confused. What will bring us back to the surface is effec-

tiveness. So, let me clarify things:

EFFICACY = (means) capacity for producing a desired results

under best condition.

EFFICIENCY = (means) the ability to accomplish our mission

with minimum expenditure, time and resources.

EFFECTIVNESS = (means) what actually happens in the day by

day practice with efficacy and efficiency

Many medical studies end with the conclusion that further and

more efficient studies are still required

Meta-analysis is based on selection criteria which lead to a sig-

nificant reduction in the number of cases which remain the basis for

the conclusions of the study.

Obviously, professional polemics between physicians lead to

thriving for knowledge, seeking for information and mastering the

profession.

But, at the end of the day the ones who are making the decision on

investing funds in medical equipment, are the department directors

and hospital managers, while taking into account certain elements

such as expert opinion, guidelines and specific protocols applicable in

the respective country and in the specific hospital.

‘‘The man sanctifies the place’’

And therefore the problem may be that the medical needs sup-

ported by the level of evidence recommendations are interpreted by

financial and administrative personal and their criteria in making the

decision are different from the pure medical angle.

Seven years ago I got familiar with US modality. That happened

because of various reasons: the number of local and regional anesthesia

cases greatly decreased, lack of time, lack of professional interest, lack

of staff, failures and surgeons dissatisfaction. Thus in time we ended up

limited to 2 procedures: epidural and spinal anesthesia.

Currently, we are 66 anesthesiologists in the department and find

ourselves competing with our colleagues each morning for the use of

one of the 5 available US devices while in one of the drawers lays

forgotten a black box: the nerve stimulator.

In the institute for chronic and acute pain clinic the situation is

different. We operate a clinic with 11 pain physicians with 2 oper-

ating rooms, with C-arms running 5 day a weeks, 14 h a day. We

have only one US and 3 nerve stimulators. The staff is more expe-

rienced in using nerve stimulators. But every now and then we face a

difficult case that requires the use of all 3 modalities for pain treat-

ment. For these cases the expertise in US is a necessity.

Now, if we go back to the first questions the answer is YES to

both. It’s not a diplomatic answer. In many difficult cases you need

experience, knowledge and information! The one who knows how to

receive and merge information from US and NS together has more

chances to find the solution in difficult cases of regional anesthesia,

acute pain and chronic pain treatment.

25 Ultrasound for pediatric peripheral arterial

and venous cannulation

David P. Martin1,2, Tarun Bhalla1,2, Joseph D. Tobias1,2,3

1Department of Anesthesiology & Pain Medicine, Nationwide Chil-

dren’s Hospital, Columbus, Ohio; 2Department of Anesthesiology &

Pain Medicine, The Ohio State University College of Medicine,

Columbus, Ohio; Department of Pediatrics, The Ohio State University

College of Medicine, Columbus, Ohio. David P. Martin Department

of Anesthesiology & Pain Medicine, Nationwide Children’s Hospital

700 Children’s Drive Columbus, Ohio 43205 E-mail: David.Martin@

Nationwidechildrens.org

Introduction Apart from the management of a patient’s airway,

vascular access represents the next most critical component of peri-

operative care. Depending on the type of surgery, the expected blood

loss, and the patient’s co-morbidities, perioperative care may require

large-bore peripheral access as well as arterial cannulation. Although

in most patients such access is non-problematic, various factors

including obesity, prolonged hospitalizations, and associated co-

morbid conditions can exacerbate problems with vascular access. In

emergency situations when access to the circulation is required within

seconds, the intraosseous route (IO) can be used to provide life-saving

medications [1–3]. The standard availability of intraosseous cannu-

lation supplies is recommended in all anesthetizing locations.

In non-emergent situations, ultrasound imaging can be used to facil-

itate vascular access in patients of all ages in a timely manner.

Although used initially to facilitate central venous access, the use of

ultrasound is being translated for use when obtaining access to the


123

peripheral vasculature. With improvements in the quality of the

ultrasound imaging, portability of equipment, and improved vascular

access devices, ultrasound has allowed for more feasible use in the

perioperative arena. The addition of ultrasound has enabled providers

to obtain venous access in the most difficult of cases.

Arterial cannula placement Typically, arterial cannula placement is

performed by palpation of the arterial pulsation, and a blind approach to

cannula insertion is performed based upon where the arterial pulsation is

felt. This technique varies widely among providers and may include

direct placement of a standard intravenous cannula, use of specialized

kits and the Seldinger technique, or use of a commercially available

device with a needle, cannula and wire in a single product (Arrow

arterial catheterization kit, Teleflex Corporation). However, in specific

clinical scenarios (hypotension, hypoperfusion, systemic anticoagula-

tion, left ventricular assist devices), the use of ultrasound may increase

the success rate of the procedure while decreasing adverse effects.

In the pediatric population the utility of the ultrasound was demon-

strated by a decreased time to successful cannulation, fewer attempts,

and increased success rate in various studies [4, 5]. Schwemmer et al.

randomized 30 children requiring radial artery cannulation to ultra-

sound guidance or traditional palpation [4]. Using ultrasound the

success rate was 100 versus 80 % and required less attempts.

Although the adverse effect profile with radial artery cannulation

is generally less worrisome than central venous cannulation, it still

may be quite useful in younger infants and neonates given the size of

the vascular target. The use of ultrasound is especially suggested in

patients with bleeding diatheses or those receiving therapeutic anti-

coagulation as the risks of cannulation may be magnified.

Peripheral venous cannulation The timely establishment of

peripheral intravenous access in the pediatric patient may at times be

challenging given patient status and co-morbidities. As stated earlier,

multiple options have been suggested as an alternative when standard

approaches to peripheral venous access fail. In emergency scenarios

where the rapid administration of life-saving medications is neces-

sary, the intraosseous (IO) route should be used and equipment for the

establishment of IO access should be in every anesthetizing location

[2]. Apart from delays starting the operative procedure and its impact

on the economics of the operating room, a prolonged inhalational

induction before establishment of an airway may predispose the

patient to gastric air insufflation, vomiting with aspiration, atelectasis,

hypoxemia, hypercapnia, hypothermia, and hemodynamic instability.

While some have suggested the routine use of IO access for elective

surgical procedures, at our institution we have found great utility with

the use of ultrasound in securing rapid intravenous access. Further-

more, the use of ultrasound has resulted in a decrease in preparation

time as well as the ability to place large bore venous cannulae for the

rapid administration of blood and blood products by accessing deeper

venous structures not visualized through the skin. In a prospective,

randomized study in patients 10 years of age or less with a history of

difficult venous access or two unsuccessful attempts at peripheral

cannula placement, the use of ultrasound increased success rate (80

vs. 64 %), decreased the number of attempts (median of 1 vs. 3), and

decreased procedure time (average of 6.3 vs. 14.4 min) [7].

This study most parallels our department’s current use of ultrasound

for peripheral venous cannulation, as we turn to the ultrasound after

multiple failed attempts or when superficial identification of appro-

priate veins is not possible. When using ultrasound for peripheral

venous cannulation, basic knowledge of the venous drainage system

as well as basic proficiency in ultrasonography is necessary to facil-

itate both probe placement and identification of appropriate venous

structures. We prefer the saphenous vein above the medical malleolus

or more cephalad in the lower aspect of the leg or the saphenous as it

crosses the medical condyle of the femur into the thigh. Alternatively,

the deep veins of the forearm or upper arm can also be used. We often

avoid the antecubital area as flexion during positioning may occlude

these cannulae and make infusion impractical or impossible. During

cannulation of the vein, various techniques can be utilized in both in-

plane and out-of-plane fashions. Standard intravenous cannulae can

be used and advanced into the vein. We generally start with a

transverse, or out-of plane, view of the lumen of the vein and then

convert to a longitudinal, or in-plane, view as the cannula is advanced

off the needle into the vein. When available, we have found that

longer cannulae offer an increased chance of success when cannu-

lating deeper veins that are identified by ultrasound. A Seldinger

technique may also be employed with commercially available kits or

by using separate wires. We have begun utilizing a micropuncture kit

which has a 22 gauge needle and a 0.018’’ wire which has a dilator

and sheath. This allows placement of a 4 French sheath over a 0.018’’

with puncture of a vessel using the 22 gauge needle.

Summary Since its initial description, there has been growing use of

ultrasound guided techniques for vascular access in clinical practice.

These techniques started for central venous access and have continued

to expand to include peripheral vascular cannulation. As with any

technology, the use of ultrasound requires practice. This includes

knowledge of the machine and its working parameters as well as

experience to identify the appropriate deep vascular structures.

Practice will also increase the hand-eye coordination that is necessary

to hold the probe in one hand and cannulate the vessel with the other.

In our clinical practice, we have found significant decrease in prep-

aration time for major surgical procedures in patients with a history of

difficult venous access as well as the ability to place a peripheral

cannula when multiple attempts at peripheral cannulation have failed

and case cancellation is being considered. Regardless of the utility of

the technique, all anesthesia providers should be facile with place-

ment of an IO needle as it remains the technique of choice for access

during an emergency situation when peripheral access fails.

References

1. Joshi G, Tobias JD. The use of intraosseous infusions in the

operating room. J Clin Anesth 2008;20:469–73.

2. Tobias JD, Ross AK. Intraosseous infusions: A review for the

anesthesiologist with a focus on pediatric use. Anesth Analg

2010;110:391–401.

3. Neuhaus D, Weiss M, Engelhardt T, Henze G, Giest J, Strauss J,

Eich C. Semi-elective intraosseous infusion after failed intravenous

access in pediatric anesthesia. Paediatr Anaesth 2010;20:168–71.

4. Schwemmer U, Arzet HA, Trautner H, et al. Ultrasound-guided

arterial cannulation in infants improves success rate. Eur J

Anaesthesiol 2006;23:476–80.

5. Ishii S, Shime N, Shibasaki M, Sawa T. Ultrasound-guided radial

artery cannulation in infants and small children. Pediatr Crit Care

Med 2013;14:471–3.

6. Costantino TG, Parikh AK, Satz WA, et al. Ultrasonography-

guided peripheral intravenous access versus traditional

approaches in patients with difficult intravenous access. Ann

Emerg Med 2005;46:456–61.

7. Doniger SJ, Ishimine P, Fox JC, et al. Randomized controlled

trial of ultrasound-guided peripheral intravenous catheter place-

ment versus traditional techniques in difficult-access pediatric

patients. Pediatr Emerg Care 2009;25:154–9.

26 Low Flow Anesthesia: An Update

Jan FA Hendrick

Department of Anesthesiology, OLV Hospital, Aalst Belgium


123

During the lecture, the attendees will learn to appreciate the added

value of automated low flow anesthesia and place these in proper

perspective.

During anesthesia, the difference between the inspired and end-

expired concentrations of inhaled anesthetics and carrier gases

depends on the mass balances at the Y-piece of the circle breathing

system (inspired amounts- expired amounts = uptake or wash-out by

the patient,). The difference between the delivered and inspired

concentration depends on the degree of rebreathing in the circle

breathing system, which mainly depends on minute ventilation and

fresh gas flow. If rebreathing is present, the delivered concentration

no longer matches the inspired concentrations because the composi-

tion of the inspired gas will also depend on that of the exhaled gas.

This difference pertains to agent and carrier gas concentrations.

The lower the fresh gas flows, the more pronounced this difference

is. This difference can be perceived as lack of control because what

the anesthesiologists ‘‘gives’’ (delivered concentration) no longer

matches what the patient ‘‘gets’’ (inspired concentration), and it

explains why most anesthesiologist intuitively use a fresh gas flow of

2L/min in adults.

In addition, more frequent vaporizer and rotameter settings are

required. Especially during the first 15 min because of the rapidly

decreasing uptake pattern, potentially distracting the anesthesiologist,

especially during the induction period when these differences are

most pronounced. Targeting the end-expired agent concentration and

the inspired or end-expired concentration and having the machine

take care of agent and carrier gas delivery to achieve these targets

alleviates this burden, and may improve safety by directly targeting

the inspired (or end-expired) O2 concentrations. An argument is made

for active inspired hypoxic guards when conventional (non-auto-

mated) low flow anesthesia is used.

The benefits of heat and humidity conservation a well as the

environmental benefits of low flow anesthesia will be placed in proper

perspective.

Agent usage and canister usage with the different commercially

available automated low flow anesthesia machines will be discussed

and will be translated into cost for a few specific examples. Total cost

savings cost will be discussed, and the complexity of the economics

of automated low flow anesthesia will be examined.


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