Post-cardiac arrest syndrome

Reviewed and revised 15 November 2016

OVERVIEW

aka post-resuscitation syndrome

• occurs after return of spontaneous circulation (ROSC) following cardiorespiratory arrest and  involves multiple systems
• Reflects a state of whole-body ischaemia and subsequent reperfusion
• Often super-imposed on the underlying condition, which caused the cardiac arrest and pre-existing comorbidities, and other complications of resuscitation
• Severity depends on the duration and cause of cardiac arrest

Mortality and morbidity following cardiac arrest

• Early mortality due to cardiovascular instability
• Late mortality and morbidity occurs from brain injury (the most common cause of death after ROSC), multi-organ failure and sepsis

MECHANISM

Postcardiac arrest syndrome was once thought to be largely due to production of free radicals, although the pathophysiology is more complex

• Hypoperfusion and ischaemia cause a cascade of events
  • disruption of homeostasis
  • free radical formation
  • protease activation
  • a SIRS response resembling severe sepsis
• The disruption may continue for hours or days
• Hypothermia may slow down this cascade

MAJOR MANIFESTATIONS

1. Postcardiac arrest brain injury
   • Disruption on both a micro- and macro- circulatory levels may result in either ischaemia or hyperaemia
2. Postcardiac arrest myocardial dysfunction
   • Although the heart initially becomes hyperkinetic, likely due to circulating catecholamines, global hypokinesis often follows
   • Usually resolves within 72 hours
3. Systemic ischaemia/reperfusion response
   • The response of the body is similar to the septic shock with activation of the immune and complement systems, and release of inflammatory cytokines and a wide range of cellular responses
4. Persistent precipitating pathology
   • The cause of the arrest may continue to impact physiological parameters

CONTRIBUTING FACTORS

Post cardiac arrest brain injury

• Impaired cerebrovascular autoregulation
• Cerebral oedema
• Neurodegeneration

Post cardiac arrest myocardial dysfunction

• Myocardial stunning – global hypokinesis
• Poor cardiac output
• Acute coronary syndromes

Systemic ischaemia / reperfusion response

• Systemic inflammatory response syndrome (SIRS)
• Poor vasoregulation
• Microcirculatory failure
• Activation of coagulation cascade
• Adrenal suppression
• Poor tissue oxygen deliver and utilization
• Susceptibility to infection

Persistent precipitating pathology

• Cardiovascular disease (e.g. myocardial ischemia, cardiomyopathy)
• Pulmonary disease (e.g. pulmonary embolus, asthma)
• CNS disease (e.g. stroke, subarachnoid hemorrhage)
• Poisoning
• Infection / Sepsis
• Hypovolaemia

Other complications of resuscitation such as injuries (e.g. rib fractures, sternal fractures), medication adverse effects and complications of invasive lines and monitoring.

References and Links

LITFL

• CCC — Prognosis After Cardiac Arrest
• CCC — Post-cardiac arrest care
• CCC — Targeted temperature management (TTM) after cardiac arrest

Journal articles

• Mongardon N, Dumas F, Ricome S, Grimaldi D, Hissem T, Pène F, Cariou A. Postcardiac arrest syndrome: from immediate resuscitation to long-term outcome. Ann Intensive Care. 2011 Nov 3;1(1):45. PMC3223497.
• Neumar RW, et al. Post-cardiac arrest syndrome: epidemiology, pathophysiology, treatment, and prognostication. A consensus statement from the International Liaison Committee on Resuscitation. Circulation. 2008 Dec 2;118(23):2452-83. PMID: 18948368. [Free Full Text]
• Stub D, Bernard S, Duffy SJ, Kaye DM. Post cardiac arrest syndrome: a review of therapeutic strategies. Circulation. 2011 Apr 5;123(13):1428-35. doi: 10.1161/CIRCULATIONAHA.110.988725. PMID: 21464058. [Free Full Text]
• Zia A, Kern KB. Management of postcardiac arrest myocardial dysfunction. Curr Opin Crit Care. 2011 Jun;17(3):241-6. PMID: 21378558.

FOAM and web resources

• EMCrit — Post-Arrest Hypothermia Protocols and Resources
• FET — Post Arrest Care – It’s More than Hypothermia by Michael Winters (2013)
• FET — Post Cardiac Arrest Management by Michael Kuiper (2009)