Abstract Body: Introduction: Temperature management (TM) to prevent fever is crucial to mitigate neurological deterioration post-cardiac arrest. Whether hypothermic TM (h-TM) is superior or equal to normothermic TM (n-TM) after out-of-hospital cardiac arrest (OHCA) is debatable, prompting ongoing effects to identify patients who might benefit more from h-TM. We hypothesized that effect of TM would differ based on body temperature at hospital arrival.
Aim: Explore which post-cardiac arrest patient subsets might benefit from h-TM by stratifying them based on body temperature at hospital arrival.
Methods: This retrospective, observational study used data from the OHCA registry in Japan. Patients 18 years and older who experienced OHCA due to medical cause and received TM in the intensive care unit were included. Primary outcome measure was 30-day favorable neurological outcomes, defined as a Cerebral Performance Category score of 1 or 2. Patients were stratified into groups based on body temperature at hospital arrival: normothermia (36.0-38.0°C), hypothermia (<36.0°C), and hyperthermia (>38.0°C). Effect of TM post-cardiac arrest (h-TM [32-34°C] or n-TM [35-36°C]) was evaluated in each stratified group. Univariable and multivariable logistic regression analysis was used for comparison. Adjusted odds ratio (OR) for favorable neurological outcome with h-TM was calculated using n-TM as a reference. Hyperthermia was excluded from multivariable analyses due to small sample size.
Results: We analyzed 3,044 patients, 1,273 in the normothermia group, 1,747 in the hypothermia group, and 24 in the hyperthermia group. Numbers of patients with favorable neurological outcomes were as follows: 530/1,273 (41.6%) in the normothermia group, 584/1,747 (33.4%) in the hypothermia group, and 4/24 (16.7%) in the hyperthermia group. There were no differences in favorable 30-day neurological outcomes between h-TM and n-TM in any stratified group in the univariable analysis: normothermia (h-TM 323/785 [41.2%] vs. n-TM 207/488 [42.4%], p=0.66); hypothermia (411/1,185 [34.7%] vs. 173/562 [30.8%], p=0.11); hyperthermia (3/13 [23.1%] vs. 1/11 [9.1%], p=0.59). Multivariable analysis also showed no differences: normothermia (OR: 0.96, 95% CI: 0.72-1.26), hypothermia (OR: 1.10, 95% CI: 0.85-1.42).
Conclusion: TM (h-TM vs. n-TM) did not significantly affect 30-day neurological outcomes, regardless of initial temperature at hospital arrival.