Effect of target temperature management at 32–34 °C in cardiac arrest patients considering assessment by regional cerebral oxygen saturation: A multicenter retrospective cohort study

Abstract Aim Target temperature management (TTM) is used in comatose post-cardiac arrest patients, but the recommended temperature range is wide. This study aimed to assess the effectiveness of TTM at 32–34 °C while considering the degree of cerebral injury and cerebral circulation, as assessed by regional cerebral oxygen saturation (rSO 2 ). Methods This is a secondary analysis of prospectively collected registry data from comatose patients who were transferred to 15 hospitals in Japan after out-of-hospital cardiac arrest (OHCA) from 2011 to 2013. The primary outcome was all-cause mortality at 90 days after OHCA, and the secondary outcome was favorable neurological outcomes as evaluated according to the Cerebral Performance Category. We monitored rSO 2 noninvasively with near-infrared spectroscopy, which could assess cerebral perfusion and the balance of oxygen delivery and uptake. Results We stratified 431 study patients into three groups according to rSO 2 on hospital arrival: rSO 2 ≤40% (n = 296), rSO 2 41–60% (n = 67), and rSO 2 ≥61% (n = 68). Propensity score analysis revealed that TTM at 32–34 °C decreased all-cause mortality in patients with rSO 2 41–60% (average treatment effect on treated [ATT] by propensity score matching [PSM] −0.51, 95%CI −0.70 to −0.33; ATT by inverse probability of treatment weighting [IPW] −0.52, 95%CI −0.71 to −0.34), and increased favorable neurological outcomes in patients with rSO 2 41–60% (ATT by PSM 0.50, 95%CI 0.32–0.68; ATT by IPW 0.52, 95%CI 0.35–0.69). Conclusion TTM at 32–34 °C effectively decreased all-cause mortality in comatose OHCA patients with rSO 2 41–60% on hospital arrival in Japan.