Does targeted hypothermia improve outcomes in cardiac arrest survivors?

Targeted temperature management, compared with normothermia, does not appear to result in improved survival or neurological outcomes in comatose patients following cardiac arrest, claims a recent study.

A team of investigators searched the databases of Medline, Embase, and Cochrane through July 2021 for randomized trials that assessed the outcomes of targeted hypothermia vs normothermia in comatose patients after cardiac arrest with shockable or nonshockable rhythm. Mortality at the longest reported follow-up was the primary outcome.

Eight studies involving a total of 2,927 patients, with a weighted follow-up period of 4.9 months, met the eligibility criteria. The average targeted temperature in the hypothermia arm in these trials ranged from 31.7 °C to 34 °C.

No difference was noted in long-term mortality between the hypothermia and normothermia groups (56.2 percent vs 56.9 percent; risk ratio [RR], 0.96, 95 percent confidence interval [CI], 0.87‒1.06). No significant between-group difference was also seen in rates of favourable neurological outcome (37.9 percent vs 34.2 percent; RR, 1.31, 95 percent CI, 0.99‒1.73), in-hospital mortality (RR, 0.88, 95 percent CI, 0.77‒1.01), bleeding, sepsis, or pneumonia.

Ventricular arrhythmias were more common in the hypothermia group than in the normothermia group (RR, 1.35, 95 percent CI, 1.17‒1.58; p=0.42). In sensitivity analysis, excluding the Targeted Hypothermia vs Targeted Normothermia after Out-of-Hospital Cardiac Arrest trial, targeted hypothermia was associated with a favourable neurological outcome compared with normothermia (RR, 1.45, 95 percent CI, 1.17‒1.79).

“Further studies are warranted to further clarify the value of targeted hypothermia compared with targeted normothermia,” the investigators said.