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)

CCC Differential Diagnosis Series
NEURO	Anosmia, Ataxia, Blepharospasm, Bulbar and Pseudobulbar palsy, Central Pontine Myelinosis, Cerebellar Disease, Chorea, Cranial nerve lesions, Dementia, Dystonia, Exophthalmos, Eye trauma, Facial twitches, Fixed dilated pupil, Horner syndrome, Loss of vision, Meningism, Movement disorders, Optic disc abnormality, Parkinsonism, Peripheral neuropathy, Radiculopathy, Red eye, Retinal Haemorrhage, Seizures, Sudden severe headache, Tremor, Tunnel vision
RESP	Bronchial breath sounds, Bronchiectasis, High airway pressures, Massive haemoptysis, Sore throat, Tracheal displacement
CVS	Atrial Fibrillation, Bradycardia, Cardiac Failure, Chest Pain, Murmurs, Post-resuscitation syndrome, Pulseless Electrical Activity (PEA), Pulsus Paradoxus, Shock, Supraventricular tachycardia (SVT), Tachycardia, VT and VF, SVC Obstruction
GIT	Abdominal distension, Abdominal mass, Abdominal pain, Asterixis, Dysphagia, Hepatomegaly, Hepatosplenomegaly, Large bowel obstruction, Liver palpation abnormalities, Lower GI haemorrhage, Malabsorption, Medical causes of abdominal pain, Rectal mass, Small bowel obstruction, Upper GI Haemorrhage
GUT	Genital ulcers, Groin lump, Scrotal mass, Urine colour, Urine Odour, Urine transparency,
MSK	Arthritis, Shoulder pain, Wasting of the small muscles of the hand
DERM	Palmar erythema, Serious skin signs in sick patients, Thickened Tethered Skin, Leg ulcers, Skin Tumour, Acanthosis Nigricans
ENDO	Diabetes Insipidus, Diffuse Goitre, Gynaecomastia, Hirsutism, Hypoglycaemia, SIADH, Weight Loss
HAEM	Splenomegaly
PAEDS	Floppy infant
MISC	Anaphylaxis, Autoimmune associated diseases, Clubbing, Parotid Swelling, Splinter haemorrhages, Toxic agents and abnormal vitals, Toxicological causes of cardiac arrest
IMAGING	CHEST: Atelectasis, Hilar adenopathy, Hilar enlargement on CXR, Honeycomb lung, Increased interstitial markings, Mediastinal widening on mobile CXR, Pulmonary fibrosis, Pseudoinfiltrates on CXR, Pulmonary opacities on CXR, ABDO: Gas on abdominal X-ray, Kidney mass, BRAIN: Intracranial calcification, Intracranial structures with contrast, Ventriculomegaly, OTHER: Pseudofracture on X-Ray,
LABS	LOW: Anaemia, Hypocalcaemia, hypochloraemia, Hypomagnesaemia,  HIGH: Bilirubin and Jaundice, Hyperammonaemia, Hypercalcaemia, Hyperchloraemia, Hyperkalaemia, Hypermagnesaemia,  ACID BASE: Acid base disorders, Resp. acidosis, Resp. alkalosis, Creatinine, CRP, Dipstick Urinalysis, Laboratory Urinalysis, Liver function tests (LFTs), Pleural fluid analysis, Urea, Urea Creatinine Ratio, Uric acid, Urinalysis, Urine Electrolytes

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