SHOCK in pediatric

Epidemiology

• Leading cause of morbidity and mortality in pediatric population

• Shock is reversible cause of death in children• Early recognition of a ‘clinical state of shock’ is

important to avoid a progression• From a compensated reversible state to an irreversible of

cellular and organ damage

Definition

1. A state of energy failure due to inadequate glucose substrate delivery, oxygen delivery or mitochondrial failure at cellular level

2. A syndrome that result from inadequate oxygen delivery to meet metabolic demand

3. A cardiovascular dysfunction and the inability of circulatory system to provide oxygen and nutrient to meet metabolic demand of vital organ

Definition

• Supply < demand• Oxygen delivery(DO2) < oxygen consumption(VO2)• Failure to remove metabolic end product• Result from inadequate blood flow and/or oxygen

delivery

Oxygen delivery

DO2 = Cardiac output(CO) X arterial oxygen content(CaO2)

CO= heart rate X stroke volume Stroke Volume preload (end diastolic filling volume cardiac contractility after load (systemic vascular resistance)

Hb X SaO2 X 1.34 + (0.003 X PaO2)

Hemoglobin (Hb) levelArterial oxygen saturation (SaO2) Airway Breathing Fraction in inspire oxygen (FiO2)

Adapted from Strange GR. APLS: The Pediatric Emergency Medicine Course. 3rd ed. Elk Grove Village, Ill: American Academy of Pediatrics; 1998:34.

Pathophysiology

• Non stressed physiological state: • Oxygen +glucose = 36 ATP via aerobic metabolism and

Kerb’s cycle• In stress state in children:• Limited ability to compensate via gluconeogenesis and

glycogenolysis due to small hepatic and skeletal muscle mass

Pathophysiology

• In anaerobic pathways, cellular metabolism become less effective• 2 ATP molecules produced instead of 36• Lactic acid accumulation

• Ultimately• Cell membrane ion pump dysfunction• Intracellular edema• Progression of acidosis• Cell death

Classification

• Etiology• Stages

ETIOLOGY

Obstructive Cardiogenic

DestributiveHypovolemic

In each categories, one or more of the physiologic principle that govern oxygen delivery or consumption is disturb

Hypovolemic Shock

• Most common cause of shock in children • Number one cause of death • Causes of hypovolemic shock• Non-hemorrhagic: gastroenteritis(vomiting & diarrhea) • Hemorrhagic: trauma, surgery

• Decrease cardiac filling decrease preload decrease cardiac output

Larger volume of blood flows into the ventricle, the blood will stretch the walls of the heart, causing a greater expansion during diastole, which in turn increases the force of the contraction and thus

the quantity of blood that is pumped into the aorta during systole

• In hypovolemic due to hemorrhage there is decrease oxygen carrying capacity through direct loss of hemoglobin

Frank Starling curve

Clinical symptoms

• Sunken eye/frontanel • Dry mucous membrane • Poor skin turgor • Delayed CRT • Tachycardia in compensated shock • Normal BP until volume loss > 30-40%

Blood Pressure and Volume

% blood loss

% BP

25% Normal50% 60% o

•BP drops quickly after reaching 50% blood loss•CO follows BP closely

Distributive Shock

• Due to vasodilatation and pooling of the blood• Causes: sepsis, anaphylaxis, drug intoxication,

envenomation, spinal cord injury, head injury

Anaphylactic ShockPathophysiology

• Result from most cell degranulation • Histamine release inappropriate vasodilatation,

endothelial dysfunction with capillary leak, and loss of vascular tone, or a combination of all three factors

reducing the preload resulting in interruption of oxygen delivery(DO2)

Septic Shock

• Over 18 million cases worldwide each year• Sepsis kills approximately 1,400 people worldwide

EVERYDAY

Definitions

• Systemic Inflammatory Response Syndrome (SIRS): 2 of 4 criteria • Temp <36 or >38.5• HR >2 SD above normal for age (or bradycardia if <1 year

old*)• RR > 2 SD above normal for age• Abnormal WBC or > 10% immature neutrophils

• Sepsis: SIRS with suspected or confirmed infection• Severe sepsis: Sepsis + organ dysfunction or failure

Definitions

• Septic shock: Hypothermia or hyperthermia and signs of cardiovascular organ dysfunction including• Altered or decreased mental status (inconsolable irritability,

lack of interaction with parents and inability to be aroused)• Capillary refill ≥3sec (cold shock) or flash capillary refill

(warm shock)• Diminished (cold shock) or bounding peripheral pulses

(warm shock)• Mottled cool extremities (cold shock)• Decreased urine output <1 mL/kg/hr• Hypotension

Carcillo Crit Care Med 2002 30(6):1365-1378

Sepsis Disease Spectrum

Presentation of sepsis reflects a spectrum

SIRS Sepsis Severe Sepsis

Septic Shock

Septic ShockPathophysiology

SIRS/Sepsis/Septic shock

Mediator release:exogenous & endogenous

Maldistributionof blood flow

Cardiacdysfunction

Imbalance of oxygen

supply and demand

Alterations inmetabolism

Peripheral vasodilatation

Decrease systemic vascular

resistance

2 Major Types of Septic Shock

• Warm Shock• Warm extremities• Flash capillary refill • Vasomotor Paralysis• High cardiac output and

low SVR• Hyperdynamic heart

with vasodilation

*Early, compensated

• Cold Shock• Cold extremities• Capillary refill ≥ 3 sec• Myocardial Dysfunction• Low cardiac output and high

SVR• Sick heart with significant

vasoconstriction to maintain perfusion to organs

*Late, uncompensated stage

Sepsis: A Disease Continuum

•Patients with life-threatening infection often present with fever and excessive, persistent tachycardia

•Tachycardia, tachypnea, and signs of worsening perfusion precede hypotension•Hypotension is a late, ominous sign in pediatrics•Often followed by cardiopulmonary collapse

•Stopping progression to hypotension (decompensated shock) via early aggressive interventions improves outcomes

The Evidence

Early Rapid Fluid Resuscitation in Pediatric Septic Shock is Associated with Improved Outcomes

Time-sensitive Fluid-sensitive

% M

orta

lity

Oliveira et al, Ped Emergency Care 24:2008

Cardiogenic Shock

• Not very common in children• Etiology: “pump failure”• Congenital heart disease • Abnormal heart rhythm, heart block in neonatal SLE• Heart infection, myocarditis • Drug ingestion• Thyrotoxicosis, pheochromocytoma

Obstructive Shock

• Blood flow to/from the heart is obstructed• Causes: cardiac temponade, tension pneumothorax,

massive pulmonary embolism• In neonate• Aortic stenosis• Hypoplastic left heart syndrome• Coarctation of the aorta• Interrupted aortic arch

Stages of shock

• COMPENSATED– blood flow is normal or increased and may be maldistributed;

vital organ function is maintained

• UNCOMPENSATED– microvascular perfusion is compromised; significant

reductions in effective circulating volume

• IRREVERSIBLE– inadequate perfusion of vital organs; irreparable damage; death

cannot be prevented

Compensatory Mechanisms

• Baroreceptors-In aortic arch and carotid sinus, low MAP vasoconstriction, increases BP, CO and HR

• Chemoreceptors- Respond to cellular acidosis, results in vasoconstriction and respiratory stimulation

Compensatory Mechanisms

• Renin Angiotensin- Decreased renal perfusion leads to angiotensin causing vasoconstriction and aldosterone causing salt and water retentions

• Humoral Responses-Catecholamines• Autotransfusion-Reabsorption of interstitial fluid

How to differentiate

• History• Etiology of shock may depend on the age of the child and

the presence of any comorbid conditions• Immunodeficiency• Preceding events, recent illness or trauma• Allergies & exposure• Vaccination status

Physical Exam Findings of Shock

• Neurological: fluctuating mental status, sunken fontanel• Skin and extremities: cool, pallor, mottling, cyanosis,

poor cap refill, weak pulses, poor muscle tone.• Cardiovascular-pulmonary: tachypnea, tachycardia, gallop

murmur, rales, jugular venous distention• Renal: scant, concentrated urine

Type Pathophysiology Signs & Symptoms

Hypovolemic ↓ PRELOAD: ↓CO, ↑ SVR, intravascular volume loss

↑HR, ↓ pulses, delayed cap refill, dry skin, sunken eyes, oliguria

Distributive ↓ AFTERLOAD (SVR) Anaphylactic ↑ CO, ↓ SVR Angioedema, low BP,

wheezing, resp. distress Spinal Normal CO, ↓ SVR Low BP without

tachycardia; paralysis, h/o trauma

Cardiogenic ↓ CO, variable SVR Normal to ↑ HR, ↓ pulses, delayed CR, JVD, murmur or gallop, hepatomegaly

Septic Variable More to come

Workup

• Blood glucose levels• Arterial (ABG) or venous blood gas (VBG)

measurements• Serum lactate levels• FBC, RFT, LFT• Coagulation profiles• Fluid culture(s) (eg, blood, urine, cerebrospinal fluid

[CSF])• Chest Radiography

chest radiograph in a patient with cardiomegaly, which may accompany cardiogenic shock

Evaluation & Treatment

Goals• Immediate identification of life-threatening conditions• Rapid recognition of circulatory compromise• Early classification of the type and cause of shock

Increase O2 delivery

Decrease O2

demands

Increase O2 contentsIncrease cardiac outputIncrease blood pressure

Early intubationSedationAnalgesia

Treatment

Approach to the child with shock

• Primary assessment• Resuscitation• Approach to the child with fluid loss• Approach to the child with septic shock• Approach to the child with anaphylaxis

Primary assessment

• Airway• Assess vocalization – crying or talking• Looking – symmetry, recession• Listening – breath sound, stridor• Feeling – expired air

• Breathing • Effort of breathing – respiratory rate, recession, stridor,

wheeze, grunting, accessory muscle use, flaring of the nostril, gasping

• Efficacy of breathing – chest expansion, breath sound, SpO2 in air

• Effect of respiratory failure on other physiology• Heart rate, skin color, mental status

ExceptionIncreased effort of breathing does not occur in three circumstances1. Exhaustion2. Central respiratory depression – drug intoxication, head/spinal cord trauma3. Neuromuscular disease

• Circulation• Vital sign – heart rate, pulses, blood pressure• Skin – capillary time, temperature, color• Organ perfusion – effect on breathing, mental status, urine

output

If heart rate is above 200 (infant) or above 150 (child) or the rhythm is abnormal, perform a standard electrocardiogram (ECG)

• Disability• Mental status/conscious level (AVPU)• Pupillary size and reaction• Posture: children in shock usually

hypotonic

• Exposure• Rash: this is often a key clinical indicator for the cause of

shock• There is pathognomonic hemorrhagic rash associated with

meningococcal septicemia• Fever – suggests an infective cause• Injury – evidence of trauma• Consider evidence for poisoning

pathognomonic hemorrhagic rash of meningococcal sepsis (from Cohen J, Powderly WG: Infectious disease, ed 2, St Louis, 2004, Mosby.)

Classic purpuric rash

Resuscitation

• Same principle

• PALS Shock Algorithm

Early recognition of shock improve outcome

Prevent compensated uncompensated shock

Caution in cardiogenic shock!!.. Give 10mL/kg

Early tracheal intubation and mechanical ventilation should be considered in patients who have received more than 40mL/kg and have

signs of ongoing shock.Mechanical ventilation decrease energy requirement of the heart and respiratory muscle

Renal perfusion should be monitored with urinary catheter and hourly urine output measurementReassess disability• Monitor CO2 level• Maintenance of a normal blood pressure to ensure an adequate cerebral perfusion pressure

is mandatory• Lumbar puncture must be avoided as its performance may cause death through coning of

the brainstem through the foramen magnum

Special consideration

• In gastroenteritis initiate enteral of gastric tube oral rehydration solution.• Recheck acid base status and electrolytes

• In septic shock children often required repeated boluses of fluid to achieve relative stability (up to 200 mL /kg in first 24Hr has been used to treat severe shock)

• Ensure that an antibiotic such as cefotaxime or ceftriaxone has been given

• Considered an intravenous infusion of inotropes • If these treatments are required PICU must be involve early to give advice

and to retrieve the patient

Call for help Remove allergen

Administer O2 via face mask Administer IM adrenaline

Assess B

Repeat IM adrenaline if no responseNebulized adrenaline and repeat

every 10 minutes as required Hydrocortisone

Assess A

Assess C

Repeat IM adrenaline if no responseNebulized salbutamol, repeat as

required Hydrocortisone

Consider salbutamol IV or aminophylline IV

Repeat IM adrenaline if no responseCrystalloid

Adrenaline IV infusion

Reassess ABC

Intubation or surgical airway

Bag ventilation via mask or ET tubeRepeat adrenaline IM if no response

Hydrocortisone

Basic and advanced life support

Complete obstruction Partial obstruction

NO problem

Apnea Wheeze

NO problem

NO problem

No pulse Shock

Take home message

• Early recognition of shock may improve the outcome• History and physical examination will help us in finding

the etiology• ABCDE in every patient with shock