Post on 15-May-2023
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.
123
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
123
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
444 J Clin Monit Comput (2014) 28:441–463
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
J Clin Monit Comput (2014) 28:441–463 445
123
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
446 J Clin Monit Comput (2014) 28:441–463
123
References
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3D laparoscopic ultrasonography. Ultrason Imaging. Jul
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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
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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:
J Clin Monit Comput (2014) 28:441–463 447
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.
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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
448 J Clin Monit Comput (2014) 28:441–463
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
J Clin Monit Comput (2014) 28:441–463 449
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
450 J Clin Monit Comput (2014) 28:441–463
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:
danatomescu@gmail.com
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
J Clin Monit Comput (2014) 28:441–463 451
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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
452 J Clin Monit Comput (2014) 28:441–463
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
Department of Anesthesiology & Pain Medicine, Nationwide Chil-
dren’s Hospital, The Ohio State University, Columbus, Ohio 43205;
Joseph.Tobias@Nationwidechildrens.org
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.
J Clin Monit Comput (2014) 28:441–463 453
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.
Additional references
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.
454 J Clin Monit Comput (2014) 28:441–463
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
Department of Anesthesiology & Pain Medicine, Nationwide Chil-
dren’s Hospital, The Ohio State University, Columbus, Ohio;
Joseph.Tobias@Nationwidechildrens.org
J Clin Monit Comput (2014) 28:441–463 455
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.
456 J Clin Monit Comput (2014) 28:441–463
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.
Additional references
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 (sevoflu- rane, 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
J Clin Monit Comput (2014) 28:441–463 457
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
gurman@bgumail.bgu.ac.il
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.
458 J Clin Monit Comput (2014) 28:441–463
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: a0neam01@louisville.edu
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,
adela_hilda@yahoo.com
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
460 J Clin Monit Comput (2014) 28:441–463
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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
J Clin Monit Comput (2014) 28:441–463 461
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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
462 J Clin Monit Comput (2014) 28:441–463
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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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