Hyperthermia after cardiac arrest is associated with an unfavorable neurologic outcome

Background: Moderate elevation of brain temperature, when present during or after ischemia, may markedly worsen the resulting injury. Objective: To evaluate the impact of body temperature on neurologic outcome after successful cardiopulmonary resuscitation. Methods: In patients who experienced a witnessed cardiac arrest of presumed cardiac cause, the temperature was recorded on admission to the emergency department and after 2, 4, 6, 12, 18, 24, 36, and 48 hours. The lowest temperature within 4 hours and the highest temperature during the first 48 hours after restoration of spontaneous circulation were recorded and correlated to the best-achieved cerebral performance categories' score within 6 months. Results: Over 43 months, of 698 patients, 151 were included. The median age was 60 years (interquartile range, 53-69 years); the estimated median no-flow duration was 5 minutes (interquartile range, 0-10 minutes), and the estimated median low-flow duration was 14.5 minutes (interquartile range, 3-25 minutes). Forty-two patients (28%) underwent bystander-administered basic life support. Within 6 months, 74 patients (49%) had a favorable functional neurologic recovery, and a total of 86 patients (57%) survived until 6 months after the event. The temperature on admission showed no statistically significant difference (P=.39). Patients with a favorable neurologic recovery showed a higher lowest temperature within 4 hours (35.8 degreesC [35.0 degreesC-36.1 degreesC] vs 35.2 degreesC [34.5 degreesC-35.7 degreesC]; P=.002) and a lower highest temperature during the first 48 hours after restoration of spontaneous circulation (37.7 degreesC [36.9 degreesC-38.6 degreesC] vs 38.3 degreesC [37.8 degreesC-38.9 degreesC]; P < .001) (data are given as the median [interquartile range]). For each degree Celsius higher than 37 degreesC, the risk of an unfavorable neurologic recovery increases, with an odds ratio of 2.26 (95% confidence interval, 1.24-4.12). Conclusion: Hyperthermia is a potential factor for an unfavorable functional neurologic recovery after successful cardiopulmonary resuscitation.