Optimal Targeted Temperature in Targeted Temperature Management without Automated Devices Using a Temperature Feedback System: A Prospective, Multicenter Observational Study (KoCARC Registry)

Abstract

Background: Targeted temperature management (TTM) at 32ºC–36ºC improves patient outcomes following out-of-hospital cardiac arrest (OHCA). TTM using automated temperature management devices with feedback systems (TFDs) is recommended, but the equipment is often unavailable. This study aimed to investigate therapeutic relations between targeted temperatures and TFDs on the outcomes of OHCA patients with TTM. To the best of our knowledge, this is the first study to identify the optimal targeted temperature in TTM without TFD with regards to neurological outcomes in OHCA patients. Methods: This prospective multicenter study analyzed nontraumatic OHCA registry data between October 2015 and June 2020 from 62 institutions. Patients were classified into four groups based on targeted temperatures and TFD implementation: TTM at 36ºC with TFD (36TFD), TTM at 33ºC with TFD (33TFD), TTM at 36°C without TFD (36NTFD), and TTM at 33°C without TFD (33TNFD). Clinical outcomes were neurological status at discharge. Results: A total of 938 patients were included in the analysis. A significant interaction was found between targeted temperatures and TFD use on neurological outcomes (P=0.032). There was an independent association between the 33NTFD patients with the least favorable neurological outcomes among the four groups after adjustment for covariates. However, no significant differences were observed in neurological outcomes among the 36TFD, 33TFD, and 36NTFD groups after adjusting for covariates. Compared to 33NTFD patients, 36NTFD patients exhibited significantly higher adjusted ORs for favorable neurological status (OR: 4.28, 95% CI: 1.50–12.16, P<0.01). Conclusions: In OHCA patients receiving TTM without TFDs, the adjusted predicted probability of favorable neurological outcomes at hospital discharge was greater for TTM at 36°C than that at 33°C. The 36NTFD group displayed similar therapeutic effect as the TFD groups. This suggests that a TTM of 36°C rather than 33°C is associated with more favorable neurological outcomes if TFDs are unavailable.