The association between prehospital post-return of spontaneous circulation core temperature and survival after out-of-hospital cardiac arrest.

Background and importance: Following the return of spontaneous circulation (ROSC) after out-of-hospital cardiac arrest (OHCA), a low body temperature on arrival at the hospital and on admission to the ICU is reportedly associated with increased mortality. Whether this association exists in the prehospital setting, however, is unknown.

Objective: The objective of this study was to investigate whether the initial, prehospital core temperature measured post-ROSC is independently associated with survival to hospital discharge in adult patients following OHCA.

Design, setting and participants: This retrospective observational study was conducted at East Anglian Air Ambulance, a physician-paramedic staffed Helicopter Emergency Medical Service in the East of England, UK. Adult OHCA patients attended by East Anglian Air Ambulance from 1 February 2015 to 30 June 2023, who had post-ROSC oesophageal temperature measurements were included.

Outcome measure and analysis: The primary outcome measure was survival to hospital discharge. Core temperature was defined as the first oesophageal temperature recorded following ROSC. Multivariable logistic regression evaluated the adjusted association between core temperature and survival to hospital discharge.

Main results: Resuscitation was attempted in 3990 OHCA patients during the study period, of which 552 patients were included in the final analysis. The mean age was 61 years, and 402 (72.8%) patients were male. Among them, 194 (35.1%) survived to hospital discharge. The mean core temperature was lower in nonsurvivors compared with those who survived hospital discharge; 34.6 and 35.2 °C, respectively (mean difference, -0.66; 95% CI, -0.87 to -0.44; P  < 0.001). The adjusted odds ratio for survival was 1.41 (95% CI, 1.09-1.83; P  = 0.01) for every 1.0 °C increase in core temperature between 32.5 and 36.9 °C.

Conclusion: In adult patients with ROSC following OHCA, early prehospital core temperature is independently associated with survival to hospital discharge.