Simulation study finds no significant overall care decline at 3,450 m

High-altitude rescue work may expose emergency medical services (EMS) teams to hypobaric hypoxia, which could affect cognition and performance. In this randomized, assessor-blinded crossover simulation study in Switzerland, 20 non-acclimatized EMS physicians managed scenarios at 540 m, during acute exposure at 3,450 m, at 3,450 m while receiving supplemental oxygen at 4 L/min, and after 20 hours at altitude. Seventeen participants completed all four conditions. Three blinded experts assessed video-recorded medical and non-technical performance; the primary outcome combined the two components equally.

Median composite scores were 82% at baseline, 74% during acute altitude exposure, 82% with oxygen, and 83% after 20 hours. The overall difference across conditions was not statistically significant (p=0.082). Acute exposure did not differ significantly from baseline (−1 percentage point; 95% CI −5 to 3), and oxygen did not improve scores compared with acute exposure alone (0 points; 95% CI −4 to 4). Scores after 20 hours were 5 points higher than during acute exposure (95% CI 1 to 9; p=0.03).

The findings concern simulated performance in a small group, not patient outcomes or real-world rescue missions. The confidence interval for acute exposure does not rule out a small clinically relevant decline; the results do not establish that oxygen improves performance in this setting. Greater prehospital experience was associated with better acute-exposure performance in exploratory adjusted analyses.