Comparison of the HRV of Emergency Physicians in the HEMS During Helicopter Operations: Analysis of Differences as a Function of Number of Operations and Workload.

Abstract

Chronic stress can lead to physiological illness. Emergency physicians in danger of developing such illnesses due to their demanding working environment. The aim of this study was to investigate the physiological stress level of emergency physicians (EPs) of the Helicopter Emergency Medical Service (HEMS) between emergency operations in one shift. Furthermore, the phases of the operations were compared with respect to the activity of the autonomic nervous system. The physiological and self-perceived stress levels of 20 EPs were recorded on a HEMS air-rescue-day (age: M = 44.95, SD = 4.80). The measurement of the heart rate variability (HRV) was performed during a complete air-ambulance day and examined using analyses of variance. The heart rate rises significantly at the beginning of the emergency operationto its highest valueafter landing at the operation site. The HRV parameter standard deviation of all NN intervals shows a significant decrease between the alarm phase and the end of the operation. Furthermore, high values were reached regarding chronic stress. On the Symptom Checklist-90 the EPs show lower values than the norm sample. In conclusion, over the course of three emergency operations, no physiological fatigue indicators were found. In contrast, the subjective stress load was assessed as high among EPs and on average higher than the norm sample. Compared to standard values, the EPs showed lower HRV values, which indicates a strong activation of the autonomic nervous system. These lower HRV findings might be caused by a high psychological stress load.