In-hospital cardiac arrest leads to chronic memory impairment.

Objective: To assess the prevalence and severity of memory deficits in a group of patients who survived an in-hospital cardiac arrest (IHCA) in comparison with patients resuscitated after cardiac arrest outside hospital (OHCA) and patients with acute myocardial infarction (MI).

Subjects: Thirty-five IHCA survivors, 35 OHCA survivors, and 35 patients who had suffered MI uncomplicated by cardiac arrest.

Procedure: Participants were assessed 8.2 (4.5) months after the event for current affective state (Hospital anxiety and depression scale (HADS)), pre-morbid intelligence (National adult reading test (NART)), short-term memory (digit span test) and long-term episodic memory (Rivermead behavioural memory test-RBMT).

Results: IHCA patients scored lower on the RBMT than MI controls but did not score significantly differently OHCA patients. Moderate or severe memory impairment was found in 26% of the IHCA group and 38% of the OHCA group. None of the MI group was found to have this degree of impairment. This difference in prevalence of memory impairment between the two cardiac arrest groups was not statistically significant. However, both arrest groups had significantly greater memory impairment than the MI control group.

Conclusions: Clinically important memory impairment was found in one in four patients surviving IHCA. The shorter arrest durations that are thought to be associated with IHCA may not be sufficient to protect patients from memory impairment associated with cerebral hypoxia.