Extreme temperatures and out-of-hospital cardiac arrest: a systematic review and narrative synthesis.

In 30 seconds

This systematic review evaluated the link between extreme ambient temperatures and out-of-hospital cardiac arrest (OHCA) incidence and outcomes across 31 studies globally. A U- or J-shaped relationship was identified, with cold exposure contributing more significantly to OHCA cases than heat. The review highlights the urgent need for integrating environmental data into OHCA management strategies.

Key findings

• Cold exposure accounted for a substantially greater proportion of temperature-attributable OHCAs compared with heat.
• Extreme temperatures were linked to lower rates of return of spontaneous circulation and reduced survival to hospital discharge.
• Worse neurological outcomes were particularly noted during periods of cold exposure.

Why it matters

Understanding the impact of extreme temperatures on OHCA can inform emergency medical services and public health strategies. As climate change increases temperature variability, recognizing these environmental factors is crucial for improving patient outcomes.