Cardiac arrest & resuscitation
Extreme temperatures and out-of-hospital cardiac arrest: a systematic review and narrative synthesis
Authors' conclusion
Extreme ambient temperatures represent significant, climate-sensitive and potentially modifiable determinants of OHCA incidence and outcomes.
Study context
- Population
- Observational studies of OHCA incidence and outcomes across Asia, Europe, North America, the Middle East, and Oceania
- Participants
- 31 studies
- Comparison
- Extreme ambient temperatures vs non-extreme temperatures
- Outcome
- OHCA incidence and outcomes
Methodological detailsPRISMA 2020, ROBINS-E risk of bias, prospectively registered, Most studies used time-series or case-crossover designs with Emergency Medical Services (EMS) or cardiac arrest registry data
- PRISMA 2020
- ROBINS-E risk of bias
- Prospectively registered
- Most studies used time-series or case-crossover designs with EMS or cardiac arrest registry data
Pooled result
As reported in the abstract
OHCA incidence
- U- or J-shaped exposure-response relationship across most settings, with elevated OHCA incidence at both cold and hot extremes; effect magnitudes, thresholds and lag structures varied substantially
- Cold exposure accounted for a substantially greater proportion of temperature-attributable OHCAs than heat
Further pooled results
Clinical outcomes (ROSC, survival to hospital discharge, neurological outcome)
- Temperature extremes associated with lower ROSC, reduced survival to hospital discharge and worse neurological outcomes, particularly in cold exposure
Original publication
Extreme temperatures and out-of-hospital cardiac arrest: a systematic review and narrative synthesis. Resuscitation. Published 22 July 2026. doi:10.
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