Changing target temperature from 33°C to 36°C in the ICU management of out-of-hospital cardiac arrest: A before and after study.

INTRODUCTION: In December 2013, our institution changed the target temperature management (TTM) for the first 24h in ventricular fibrillation out-of-hospital cardiac arrest (VF-OHCA) patients from 33°C to 36°C. This study aimed to examine the impact this change had on measured temperatures and patient outcomes.

METHODS: We conducted a retrospective cohort study of consecutive VF-OHCA patients admitted to a tertiary referral hospital in Melbourne (Australia) between January 2013 and August 2015. Outcomes were adjusted for age and duration of cardiac arrest.

RESULTS: Over the 30-month period, 76 VF-OHCA cases were admitted (24 before and 52 after the TTM change). Patient demographics, cardiac arrest features and hospital interventions were similar between the two periods. After the TTM change, less patients received active cooling (100% vs. 70%, p < 0.001), patients spent less time at target temperature (87% vs. 50%, p < 0.001), and fever rates increased (0% vs. 19%, p = 0.03). ​During the 36°C period, there was a decrease in the proportion of patients who were discharged: alive (71% vs. 58%, p=0.31), home (58% vs. 40%, p=0.08); and, with a favourable neurological outcome (cerebral performance category score 1-2: 71% vs. 56%, p=0.22).

CONCLUSION: After the change from a TTM target of 33°C to 36°C, we report low compliance with target temperature, higher rates of fever, and a trend towards clinical worsening in patient outcomes. Hospitals adopting a 36°C target temperature to need to be aware that this target may not be easy to achieve, and requires adequate sedation and muscle-relaxant to avoid fever.