Extreme temperatures and out-of-hospital cardiac arrest: a systematic review and narrative synthesis
Remember that both extreme cold and extreme heat are associated with increased OHCA risk; however, the evidence suggests colder environments contribute a larger proportion of these attributable cases. When developing local EMS protocols or conducting outbreak surveillance, consider integrating real-time ambient temperature data into your risk stratification tools. This is an area where environmental awareness can significantly improve pre-hospital preparedness.
This systematic review synthesized thirty-one international studies to assess the relationship between extreme ambient temperatures and the incidence and outcomes of out-of-hospital cardiac arrest (OHCA). The authors concluded that there is a clear association, describing a U- or J-shaped curve suggesting elevated OHCA rates at both very cold and very hot extremes. Notably, the review highlighted that while both temperature poles increase risk, colder exposure appears to account for a larger proportion of the attributable cases. Given the projected intensification of temperature variability due to climate change, the authors strongly emphasize the necessity of incorporating environmental data into existing OHCA surveillance systems, risk forecasting models, and pre-hospital emergency medical services planning.