Hypothermia or Normothermia after Cardiac Arrest

Published
Posted by Carla Rothaus

How did targeted hypothermia compare with targeted normothermia in the trial by Dankiewicz et al.? 

In an open-label, blinded-outcome-assessor trial, Dankiewicz et al. randomly assigned 1900 adults with coma who had had an out-of-hospital cardiac arrest of presumed cardiac or unknown cause to undergo targeted hypothermia at 33°C, followed by controlled rewarming, or targeted normothermia with early treatment of fever (body temperature, ≥37.8°C). They hypothesized that at 6 months, the incidence of death would be lower in the hypothermia group than in the normothermia group. Read the NEJM Original Article here.

Clinical Pearls

Q: Have the results of prior trials supported the use of targeted hypothermia in adults with coma after out-of-hospital cardiac arrest?

A: International guidelines recommend targeted temperature management to prevent hypoxic–ischemic brain damage in patients with coma after cardiac arrest. The evidence to support these recommendations originated in trials involving patients who had been resuscitated from out-of-hospital cardiac arrest due to a presumed cardiac cause and shockable initial rhythms. These trials suggested an increased survival and improved neurologic outcome in patients who underwent hypothermia at 33°C.

Q: How did targeted hypothermia compare with targeted normothermia in the trial by Dankiewicz et al.?

A: In this randomized trial, there was no significant difference between the two groups with respect to death. At 6 months, 465 of 925 patients (50%) in the hypothermia group and 446 of 925 patients (48%) in the normothermia group had died (relative risk with hypothermia, 1.04; 95% confidence interval [CI], 0.94 to 1.14; P=0.37). The effect of the temperature intervention on death at 6 months was consistent across the prespecified subgroups. Of the 1747 patients in whom the functional outcome was assessed, 488 of 881 (55%) in the hypothermia group had moderately severe disability or worse (modified Rankin scale score ≥4), as compared with 479 of 866 (55%) in the normothermia group (relative risk with hypothermia, 1.00; 95% CI, 0.92 to 1.09).


Morning Report Questions

Q: What were some of the other secondary outcomes of the trial by Dankiewicz et al.?

A: Health-related quality of life, which was assessed with the use of the visual-analogue scale on the European Quality of Life–5-Dimension–5-Level questionnaire, was similar in the hypothermia and normothermia groups. The distribution of days when the patients were alive and out of the hospital was similar in both groups. Hypothermia did not increase the frequency of pneumonia, sepsis, or bleeding. 

Q: What adverse event was more common in the hypothermia group than in the normothermia group in the trial by Dankiewicz et al.?

A: Arrhythmias resulting in hemodynamic compromise were more common in the hypothermia group than in the normothermia group (in 24% vs. 17%; P<0.001). There were no significant differences in other prespecified adverse events. Two unexpected serious, possibly intervention-related adverse events occurred in each group: an intravascular device–related thrombosis in one patient in the hypothermia group and two patients in the normothermia group, and bradycardia with worsening hemodynamic function in one patient in the hypothermia group.

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