Association Between Maximum Temperature 24 Hours After Resuscitation and Survival for In‐Hospital Cardiac Arrest

BACKGROUND: Avoiding fever is a central tenet of postresuscitation care. However, few data exist describing the association between postresuscitation temperature and survival after in-hospital cardiac arrest, where response is usually prompt. METHODS: Within the GWTG-Resuscitation (Get With The Guidelines-Resuscitation) registry, we identified adults from 2015 to 2024 with an index in-hospital cardiac arrest and return of spontaneous circulation who survived at least 24 hours after resuscitation. Patients were excluded if they received therapeutic hypothermia after return of spontaneous circulation to better understand the natural history of postresuscitation temperature. The primary exposure was maximum temperature 24 hours after return of spontaneous circulation, categorized by 0.5 °C intervals from <36.3 °C to ≥38.8 °C. Multivariable hierarchical logistic regression evaluated the association between maximum temperature and both survival to hospital discharge and favorable neurological survival. RESULTS: Of 36 514 with return of spontaneous circulation, mean age was 64.2±16.6 years; 61.8% were men, and 69.4% were White individuals. Median maximum temperature was 37.2 °C (interquartile range, 36.8-37.8 °C), 66.3% survived to discharge, and 57.0% had favorable neurological survival. The highest survival (72.7%) was observed in the 36.8 to <37.3°C group (reference), with all other temperature ranges with lower rates of survival to hospital discharge (inverted U-shaped relationship), with the worst being those in the lowest (<36.3 °C, 48.4%; adjusted odds ratio, 0.42 [95% CI, 0.37-0.46]) and highest (≥38.8 °C, 51.5%; adjusted odds ratio, 0.40 [95% CI, 0.36-0.44]) ranges. A similar relationship was observed with favorable neurological survival. CONCLUSIONS: Among patients not treated with therapeutic hypothermia, a postresuscitation temperature of 36.8 to 37.3°C after in-hospital cardiac arrest was associated with the highest survival rate, with temperatures at high and low extremes with the lowest survival.