Here are the surprising findings of the retrospective cohort study carried out at 21 centers in their integrated delivery system:
Retrospective cohort study of patients with OHCA admitted to 21 medical centers between January 2007 and December 2012. A standardized TTM protocol and educational program were introduced throughout the system in early 2009. Comatose patients eligible for treatment with TTM were included. Adjusted odds of good neurologic outcome at hospital discharge and survival to hospital discharge were assessed using multivariate logistic regression.
A total of 1119 patients were admitted post-OHCA with coma, 59.1% (661 of 1119) of which were eligible for TTM. The percentage of patients treated with TTM markedly increased during the study period: 10.5% in the years preceding (2007–2008) vs. 85.1% in the years following (2011–2012) implementation of the practice improvement initiative. However, unadjusted in-hospital survival (37.3% vs. 39.0%, p = 0.77) and good neurologic outcome at hospital discharge (26.3% vs. 26.6%, p = 1.0) did not change. The adjusted odds of survival to hospital discharge (AOR 1.0, 95% CI 0.85–1.17) or a good neurologic outcome (AOR 0.94, 95% CI 0.79–1.11) were likewise non-significant.
Despite a marked increase in TTM rates across hospitals in an integrated delivery system, there was no appreciable change in the crude or adjusted odds of in-hospital survival or good neurologic outcomes at hospital discharge among eligible post-arrest patients.
The authors were unable to explain the negative findings, which go against the strength of prior high level evidence, and correctly point out that this study should not be taken as evidence against the use of therapeutic hypothermia.