Photo Credit: Jelena Stanojkovic

The following is a summary of “Hypothermia versus normothermia in patients with cardiac arrest and shockable rhythm: a secondary analysis of the TTM-2 study,” published in the October 2024 issue of Critical Care by Taccone et al. 

Researchers conducted a retrospective study to determine if hypothermia led to increased survival and enhanced functional outcomes in patients with OHCA compared to normothermia, focusing on patients with characteristics like those in previous studies with benefits for hypothermia.  

They analyzed a subset of patients from a randomized clinical trial (TTM-2, NCT02908308) with characteristics similar to those of patients in a previous study and, focused on patients randomized to hypothermia at 33 °C or normothermia (target < 37.8 °C). The primary outcome was survival at 6 months and secondary outcomes included favorable functional outcomes at 6 months (modified Rankin scale of 0–3), time-to-death, and adverse events.  

The results showed that from 1,891 participants in the TTM-2 study, 600 (31.7%) were analyzed, with 294 in the hypothermia group and 306 in the normothermia group. At 6 months, survival rates were similar: 70.4% (207/294) in the hypothermia group and 71.8% (220/306) in the normothermia group (relative risk 0.96, 95% CI 0.81–1.15; P = 0.71). Favorable functional outcomes were observed in 67.3% (198/294) in the hypothermia group and 66.0% (202/306) in the normothermia group (relative risk 1.03, 95% CI 0.87–1.23; P = 0.79). There was a significant increase in arrhythmias in the hypothermia group (21.2%, 62/294) compared to the normothermia group (14.1%, 43/306—odds ratio 1.49, 95% CI 1.05–2.14; P = 0.026).  

They concluded that the hypothermia at 33˚C did not improve survival or functional outcomes in a subset of patients with similar cardiac arrest characteristics to those who benefited from hypothermia.   

Source: ccforum.biomedcentral.com/articles/10.1186/s13054-024-05119-3