Abstract Body: Introduction/Background
Targeted temperature management (TTM) is a core component of post–cardiac arrest care, but the optimal duration of hypothermia remains uncertain. Landmark trials have established the benefit of 12 to 24 hours of mild hypothermia (32–34C) for out-of-hospital cardiac arrest (OHCA) survivors with shockable rhythms. Subsequent randomized controlled trials (RCTs) have investigated temperature targets (e.g., TTM1 and TTM2 trials) or durations (e.g., Kirkegaard et al., 2017) independently, but no study has directly compared more distant durations, such as 0 vs. 48 hours or 12 vs. 48 hours. As a result, clinical practice remains heterogeneous, with implications for ICU resource utilization and outcomes.
Research Question/Hypothesis
We hypothesize there is a difference in the effectiveness of TTM durations (at a fixed temperature) on survival following cardiac arrest.
Methods
We conducted a network meta-analysis (NMA) of RCTs comparing durations of TTM in comatose adult OHCA patients. This was pre-registered on the PROSPERO registry. Studies are eligible if they report mortality and neurologic outcomes that are stratified by temperature or duration of hypothermia. Trials with varying durations but consistent target temperature (e.g., 33C) were included. Normothermia arms were defined as 0 hours of hypothermia.k. Direct and indirect comparisons were synthesized using a Bayesian hierarchical model. The primary outcome is all-cause mortality at study follow-up.
Results
The sample sizes of the included arms varied from 16 to 2018. Only 12-hours (OR 2.51, 95% CI 1.01 - 6.51.31) was associated with survival relative to 0 hours (normothermia). The estimates for all eligible arms are in the figure. 48 hours also had an effect size in a potentially clinically meaningful range.
Conclusions
This is the first network meta-analysis to systematically evaluate and compare cooling durations in TTM. By enabling indirect comparisons where head-to-head trials do not exist, our findings help guide clinical decision-making and reduce practice variability. Importantly, this work provides a critical evidence synthesis in the interim while awaiting final results from the ICECAP (Influence of Cooling duration on Efficacy in Cardiac Arrest) trial, which may further refine or validate duration-based strategies in post–cardiac arrest care.