To determine the association between the induction rate and 6-month neurologic outcomes in out-of-hospital cardiac arrest (OHCA) survivors who underwent targeted temperature management (TTM). This retrospective observational study analyzed data prospectively collected from adult comatose OHCA survivors treated with TTM at the Chonnam National University Hospital in Gwangju, Korea, between October 2015 and December 2020. We measured the core body temperature (BT) through an esophageal probe and recorded it every 5 minutes throughout TTM. Induction time was defined as the elapsed time between the initiation of TTM and the achievement of target BT of 33°C. We calculated the induction rate as the change of BT divided by induction time. The primary outcome was a poor 6-month neurologic outcome, defined as cerebral performance category 3-5. Of the OHCA survivors, 218 patients were included, and 137 (62.8%) patients had a poor neurologic outcome. Patients with a poor neurologic outcome had lower BT at the initiation of TTM, shorter induction time, and higher induction rate than those with good neurologic outcomes. After adjusting for confounders, induction time (odds ratio [OR] 0.995; 95% confidence interval [CI], 0.992-0.999) and induction rate (OR 2.362; 95% CI, 1.178-4.734) were independently associated with poor neurologic outcome. BT at TTM initiation was not associated with a poor neurologic outcome. Induction rate was independently associated with a poor neurologic outcome in OHCA survivors who underwent TTM at 33°C.
Keywords: body temperature regulation; induced hypothermia; out-of-hospital cardiac arrest; prognosis; variability.