brain) and displays a number (rSO2 ) that varies with local oxygen delivery and
extraction. A decrease in NIRS rSO2 has been correlated with a fall in local tissue
perfusion in animal models of shock, decreased cardiac output in infants
following cardiac surgery, and predicted fluid responsiveness in dehydrated
children.

FLUID-REFRACTORY AND CATECHOLAMINE-RESISTANT
SHOCK
Fluid-refractory, catecholamine-resistant shock is the persistence of insufficient
tissue perfusion despite at least 60 mL/kg of fluid resuscitation and epinephrine or
norepinephrine ≥1 μg/kg/min. Such patients are at risk for worse outcomes than
those who respond to fluid and/or low-dose vasoactive support. The European
Society of Paediatric and Neonatal Intensive Care validated a modified definition
of refractory septic shock as high vasoactive support, myocardial dysfunction,
and arterial lactate >8 mmol/L, which portended a mortality of 60.3% compared
to only 2.2% without these features. Principles of management for children with
refractory shock include treatment of reversible etiologies, combination
vasoactive drug therapy, reducing metabolic demand through mechanical
ventilation, stress-dose corticosteroid therapy for patients with absolute adrenal
insufficiency, and extracorporeal membrane oxygenation (ECMO) support. In
addition, there is increasing interest in the potential of adjunctive metabolic
therapies, such as thiamine and vitamin C, to treat refractory shock, although at
this point, these remain investigational therapies.
Reversible Etiologies. Treatment of reversible etiologies includes relieving
causes of obstructive shock (tamponade, pneumothorax), prostaglandins for a
closing ductus arteriosus, controlling hemorrhage (often requires surgical
intervention), relieving intra-abdominal hypertension through drainage of ascites
or surgery, and specific therapy for anaphylaxis. Identification and removal of an
infectious source (e.g., infected catheter, empyema, abdominal abscess) may also
enhance resuscitative efforts in septic shock.
Mechanical Ventilation. Sedation and endotracheal intubation reduce the

work of breathing which can divert cardiac output away from the muscles of
respiration and improve perfusion to other organs. Of the sedative agents
available for intubation, ketamine is generally preferred due to its favorable
hemodynamic effects that typically augment cardiac output and blood pressure.
As several studies have reported adverse outcomes following intubation with
etomidate, pediatric septic shock guidelines now recommend against using
etomidate in these patients.


Stress-Dose Corticosteroids. For patients with septic shock, absolute or
relative adrenal insufficiency is a common condition that is frequently associated
with refractory shock. Stress doses of hydrocortisone (50 to 100 mg/m2/day) are
recommended for those with risk factors for adrenal insufficiency (e.g., septic
shock with purpura, prior steroid therapy for chronic illness, known pituitary or
adrenal abnormalities). Even patients without risk factors may develop critical
illness–related corticosteroid insufficiency with an inadequate adrenal response
and, although evidence for a clinical benefit is not clear, stress-dose
hydrocortisone is currently recommended for children with fluid-refractory,
catecholamine-resistant shock without a reversible etiology pending further data
from clinical trials.
ECMO. ECMO has been used to support neonates and children with refractory
septic shock with reported survival rates of ∼70% for newborns and ∼50% for
older children. One study suggests that central cannulation via sternotomy may
achieve survival rates of 74% for refractory septic shock. In cardiogenic shock
due to myocarditis, survival rates of 70% have been reported following ECMO.
Although counterintuitive, due to the need for systemic anticoagulation, ECMO
has also been used successfully in hemorrhagic shock in small series. In most
cases of refractory shock, venoarterial ECMO is preferred over venovenous due
to the presence of hemodynamic instability. Given the risk of ECMO-related
complications, the optimal timing for ECMO cannulation remains unclear.


CONSIDERATIONS FOR INTENSIVE CARE AND TRANSPORT
After initial resuscitation in the ED, ongoing management of children with shock
should be transitioned to clinicians with the appropriate critical care and trauma
expertise in a setting that has the necessary resources to provide pediatric
intensive care. Individuals requiring significant fluid resuscitation, vasoactive
infusions, noninvasive/invasive mechanical ventilation, or high risk for recurrent
hemorrhage should be considered for admission to a PICU. Children with shock
who present to facilities without the necessary resources to treat shock-associated
organ dysfunction (e.g., acute kidney injury requiring dialysis) following the
initial resuscitation period should undergo timely transfer to an appropriate
facility once cardiopulmonary stability has been achieved. Use of a pediatric
specialized team is associated with improved patient survival and fewer adverse
effects during transport. Thus, the use of pediatric specialized teams for transport
of children with shock is recommended whenever it is available.

OUTCOMES


Overall, mortality following pediatric shock has declined dramatically over the
past several decades with improved recognition and implementation of goaldirected resuscitation protocols. Recent estimates suggest mortality rates between
3% and 6% for pediatric patients presenting to an ED with shock from all
etiologies. The World Health Organization reports that hypovolemic shock due to
diarrhea accounts for 760,000 deaths in children less than 5 years each year. In
the United States, estimates of in-hospital mortality following pediatric septic
shock range from 4.2% to ∼20% depending on the patient population and how
the diagnosis of sepsis is determined (e.g., billing codes vs. chart review). Infants
<1 year, bone marrow transplant recipients, and those with shock-associated
MODS have the highest risk of death following sepsis. Mortality following
hemorrhagic shock due to trauma is estimated at 16%, but these data are largely

from injuries in combat areas and mortality varies substantially depending on the
cause of hemorrhage.
There is increasing emphasis on long-term outcomes, including quality of life
(QOL), following shock because increasing data support that cognitive,
emotional, social, and physical morbidities can persist for weeks or months
following shock resolution. For example, a recent study demonstrated a decrease
in health care QOL scores in 24% of children in the weeks following ICU
admission for community-acquired sepsis. The Life After Pediatric Sepsis
Evaluation (LAPSE) study will determine long-term health-related QOL changes
following sepsis, but data following nonseptic causes of shock are lacking.
CLINICAL PEARLS AND PITFALLS


The keys to treating the child with shock are (1) early recognition of
shock, (2) aggressive treatment to rapidly reverse shock, and (3) rapid
diagnosis and correction of the underlying cause of shock. The
principles described in this chapter are broadly applicable to children
with various causes of shock and comprise the basic management
strategies for emergency stabilization. The most common pitfalls in
emergency stabilization of the child with shock are the following:
Delayed recognition of shock. Shock is a state of decreased tissue
perfusion resulting in cellular/metabolic dysfunction, but hypotension
does not need to be present and is a late finding in children.
Incomplete reversal of shock etiology. The underlying cause of shock
must be sought expeditiously and treated to ultimately reverse shock.
Important considerations are hemorrhagic shock in which the source of
bleeding must be controlled, the use of epinephrine for anaphylactic
shock, early antibiotics for septic shock, and caution with fluid
administration in cardiogenic shock.
Delayed establishment of vascular access for fluid and medication

administration. If peripheral IV access cannot be obtained rapidly,
intraosseous access should be obtained and used until definitive
access is obtained.
Suggested Readings and Key References
Arlt M, Philipp A, Voelkel S, et al. Extracorporeal membrane oxygenation in
severe trauma patients with bleeding shock. Resuscitation 2010;81(7):804–809.
Balamuth F, Alpern E, Abbadessa MK, et al. Improving recognition of pediatric
severe sepsis in the emergency department: contributions of a vital sign based
electronic alert and bedside clinician identification. Ann Emerg Med
2017;70(6):759–768.
Balamuth F, Weiss SL, Neuman MI, et al. Pediatric severe sepsis in US children’s
hospitals. Pediatr Crit Care Med 2014;15(9):798–805.
Carcillo JA, Davis AL, Zaritsky A. Role of early fluid resuscitation in pediatric
septic shock. JAMA 1991;266(9):1242–1245.
Choong K, Bohn D, Fraser DD, et al. Canadian Critical Care Trials Group.
Vasopressin in pediatric vasodilatory shock: a multicenter randomized
controlled trial. Am J Respir Crit Care Med 2009;180(7):632–639.