To study possible adverse effects associated with mild therapeutic hypothermia in resuscitated cardiac arrest patients, researchers conducted a systematic review of randomized controlled trials, prospective and retrospective comparative studies, and case reports that provided original data on adverse effects and mortality.
Pooled data from 63 studies showed that arrhythmias (relative risk, 1.25) and hypokalemia (RR, 2.35) were more common in patients treated with hypothermia than in those treated without. However, the studies showed a high degree of heterogeneity, and one study accounted for the difference in each of these adverse effects. No differences in risk for adverse effects were noted based on the type of cooling (surface or invasive). Mild therapeutic hypothermia was associated with reduced mortality in the hospital (RR, 0.86), and at 1 month (RR, 0.61) and at 6 months (RR, 0.73). Data on children were limited (only 3 studies) and suggest that hypothermia is not associated with adverse effects and that it is not as effective as in adults.
COMMENT: For patients with return of spontaneous circulation and minimal neurologic recovery after cardiac arrest due to ventricular fibrillation, the 2010 Advanced Cardiac Life Support guidelines recommend cooling to 32° to 34°C for 12 to 24 hours. This practice has been shown to improve mortality and neurologic recovery (number needed to treat, 5 to 7), and this study supports its safety.
CITATION: Xiao G et al. Safety profile and outcome of mild therapeutic hypothermia in patients following cardiac arrest: Systematic review and meta-analysis. Emerg Med J 2013 Feb; 30:91. (http://dx.doi.org/10.1136/emermed-2012-201120)
SOURCE: Journal Watch