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Three Part Question

In an [adult patient who survives out-of-hospital cardiac arrest] [what are the prospective] [long-term neurologic and cognitive outcomes]?

Clinical Scenario

A 48-year-old, well-trained, long-distance runner collapsed at the finish of a half marathon. Against his usual practice, the athlete tried to accelerate on the last hundred meters towards the finish line. Immediately after the collapse, cardiopulmonary resuscitation with defibrillation of ventricular fibrillation was successfully carried out. After ROSC, the patient was arousable but not fully alert. We sought to understand the long term neurological outcomes for patients with out of hospital cardiac arrest from ventricular fibrillation?

Search Strategy

Medline 1946-10/13 using OVID interface, CochranLibrary (2013), PubMed clinical queries
[(exp Out-of-Hospital Cardiac Arrest) AND (exp Treatment Outcome OR neurologic outcome.mp OR cognitive outcome.mp). Limit to English language

Search Outcome

136 papers were identified; of which one population-based study answered the clinical question

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Mateen FJ, Josephs KA, Trenerry MR, Felmlee-Devine MD, Weaver AL, Carone M, White RD. Oct 2011 United States	332 patients with out-of-hospital cardiac arrest from ventricular fibrillation	prospective cohort	neuropsychological testing and neurological examination	Compared to patients from the general population, the study subjects performed above average on WASI Index Score Performance IQ and Mayo Estimated Verbal IQ, but were below average on MOANS standardized score, learning efficiency, Delayed recall, and Mini Mental State Examination	1) The study has a relatively small sample size. Out of the 332 people with OHCA from 1990-2008, only 47 were alive at the time of neurological and neuro-psychological evaluation ~7.8 years later. 2) In Olmsted county, MN where the study was conducted, 42% of patients with OHCA from ventricular fibrillation survived to discharge, as compared to 18-22% for the national average. Thus, this study sample may not be representative of most other communities in the US. 3)The observation of better performance on a measure of verbal intelligence among survivors calls to question the neuropsychological measures used to ascertain cognition. 4) Therapeutic temperature management was only initiated in 4 patients in the study despite its widely accepted use nationwide.

Comment(s)

Even though long term survivors of OHCA were expected to sustain lasting cognitive deficits that would impair their ability to live independently post-arrest, the majority of survivors (85%) in this population-based study had, overall, positive neurologic outcomes (OPC score of 1). While only 42% of patients survived to hospital discharge, all but 15% of the long-term survivors were functionally independent and had a score in the high normal range on the Mini-Mental State Examination. Detailed neuropsychological assessment revealed lower scores on measures of episodic memory, presumably reflecting the sensitivity of the hippocampus to hypoxic-ischemic injury, while they had higher than average scores on a verbal intelligence test.

Clinical Bottom Line

Long term survivors of out-of-hospital cardiac arrest have long term memory deficits compared to the normal population at the same age.

References

1. Mateen FJ, Josephs KA, Trenerry MR, Felmlee-Devine MD, Weaver AL, Carone M, White RD. Long-term Cognitive outcomes following out -of-hospital cardiac arrest: a population-based study Neurology. 2011 Oct 11;77(15):1438-45 Oct 2011; 1438-45