Evaluation of functional and electrical features of automatic external defibrillators in extreme altitude and temperature environments.

Aims: Human exposure to high-altitude and/or low-temperature areas is increasing and cardiac arrest in these circumstances represents an increasing proportion of all treated cardiac arrests. However, little is known about the performance of automated external defibrillators (AED) in these circumstances. The objective of this study is to assess the functional and electrical features of 6 commercially available AEDs in extreme environments. Methods: Accuracy of shockable rhythm detection, the time required for self-test, rhythm analysis, and capacitor charging, together with total energy, peak voltage, peak current, and phasic duration of defibrillation waveform measured after placing the AEDs in simulated high-altitude, simulated low-temperature, and natural composite high-altitude and low-temperature environment for 30 min, were compared to those measured in the standard environment. Results: All of the shockable rhythms were correctly detected and all of the defibrillation shocks were successfully delivered by the AEDs. However, the time required for self-test, rhythm detection, and capacitor charging was shortened by 1.2% (3 AEDs, maximum 12.4%) in the simulated high-altitude environment, was prolonged by 3.6% (4 AEDs, maximum 40.8%) in the simulated low-temperature environment, and was prolonged by 4.1% (5 AEDs, maximum 52.1%) in the natural environment. Additionally, the total delivered energy was decreased by 2.5% (2 AEDs, maximum 6.8%) in the natural environment. Conclusion: All of the investigated AEDs functioned properly in simulated and natural environments, but a large variation in the functional and electrical feature change was observed. When performing cardiopulmonary resuscitation in extreme environments, the impact of environmental factors may need consideration.