Water Temperature Variability Is Associated with Neurologic Outcomes in Out-of-Hospital Cardiac Arrest Survivors Who Underwent Targeted Temperature Management at 33°C.

We examined the association between variability in body temperature (BT) and water temperature (WT) during the maintenance period of targeted temperature management (TTM) and neurologic outcomes in out-of-hospital cardiac arrest (OHCA) survivors. Adult (≥18 years), comatose OHCA survivors who underwent TTM at 33°C between October 2015 and December 2019 were included. We collected data on BT and WT recorded every minute during the TTM maintenance period. Temperature variability was measured as the standard deviation of BT and WT during the 33°C maintenance period. The primary outcome was a poor neurologic outcome, defined as a cerebral performance category scale 3-5 at 6 months. Of the 154 included patients, 96 (62.3%) had poor outcomes. The BT variability in the poor outcome group was lower than that in the good outcome group (0.16°C [0.13-0.27°C] vs. 0.13°C [0.11-0.18°C]). In addition, the WT variability during the maintenance period in the poor outcome group was lower than that in the good outcome group (2.24°C [1.80-3.96°C] vs. 1.77°C [1.26-2.32°C]). In the multivariate analysis, WT variability (odds ratio 0.508; 95% confidence interval, 0.295-0.874; p = 0.014) was independently associated with poor neurologic outcome. BT variability and cooling beyond 33.0°C ± 1.0°C were not associated with poor neurologic outcomes. WT variability during the maintenance period was independently associated with neurologic outcomes in OHCA survivors who underwent TTM at 33°C. In addition, overcooling or undercooling during the maintenance period was not associated with neurologic outcomes.