Reduction of Arterial Oxygen Saturation Among Rescuers During Cardiopulmonary Resuscitation in a Hypobaric Hypoxic Environment.

We experienced a case involving prolonged cardiopulmonary resuscitation (CPR) during cardiac arrest on Mt. Fuji (3776 m), demanding lengthy exertion by the rescuers performing CPR. Considering the effects of exertion on the rescuers, we examined their percutaneous arterial oxygen saturation during simulated CPR and compared the effects of compression-only and conventional CPR at 3700 m above sea level. The effects of CPR on the physical condition of rescuers were examined at the summit of Mt. Fuji: three rescue staff equipped with pulse-oximeters performed CPR with or without breaths using a CPR mannequin. At 3700 m, the rescuers' heart rate increased during CPR regardless of the presence or absence of rescue breathing. Percutaneous arterial oxygen saturation measured in such an environment was reduced only when CPR without rescue breathing was performed. Scores on the Borg scale, a subjective score of fatigue, after CPR in a 3700 m environment were 13 to 15 of 20 (somewhat hard to hard). Performing CPR at high altitude exerts a significant physical effect upon the condition of rescuers. Compression-only CPR at high altitude may cause a deterioration in rescuer oxygenation, whereas CPR with rescue breathing might ameliorate such deterioration.