Hypothermia versus Normothermia after Out-of-Hospital Cardiac Arrest

This randomized controlled trial (TTM2) evaluated whether targeted hypothermia (33℃) improves survival and neurologic outcomes compared to targeted normothermia (≤37.5℃ with early fever management) in 1900 adults with coma following out-of-hospital cardiac arrest of presumed cardiac or unknown cause. At 6 months, mortality rates were similar: 50% in the hypothermia group vs. 48% in the normothermia group (RR: 1.04; 95% CI: 0.94–1.14; P=0.37). Functional outcomes (modified Rankin score ≥4) also did not differ (55% in both groups). Adverse events were mostly comparable, though arrhythmias causing hemodynamic compromise occurred more frequently with hypothermia (24% vs. 17%, P<0.001). The study concluded that therapeutic hypothermia did not reduce death or disability compared to normothermia and highlighted the need for reevaluation of current post-cardiac arrest temperature management guidelines.

This randomized controlled trial (TTM2) evaluated whether targeted hypothermia (33℃) improves survival and neurologic outcomes compared to targeted normothermia (≤37.5℃ with early fever management) in 1900 adults with coma following out-of-hospital cardiac arrest of presumed cardiac or unknown cause. At 6 months, mortality rates were similar: 50% in the hypothermia group vs. 48% in the normothermia group (RR: 1.04; 95% CI: 0.94–1.14; P=0.37). Functional outcomes (modified Rankin score ≥4) also did not differ (55% in both groups). Adverse events were mostly comparable, though arrhythmias causing hemodynamic compromise occurred more frequently with hypothermia (24% vs. 17%, P<0.001). The study concluded that therapeutic hypothermia did not reduce death or disability compared to normothermia and highlighted the need for reevaluation of current post-cardiac arrest temperature management guidelines.