Heart rate variability as a strain indicator for psychological stress in emergency medical services personnel during working days: a systematic review

Abstract

Introduction. Emergency medical services personnel have highly variable workloads. The resulting stress can differ intra- or inter-individually. Consequences for health arise when there is insufficient compensation for prolonged stress. The analysis of heart rate variability (HRV) is a valid noninvasive method for the objective monitoring of workload in the occupational medicine. The aim of the research is to systematically evaluate the literature on HRV as an objective indicator of the mental stress faced by emergency medical services рersonnel. Materials and methods of the research. A systematic literature review examining the HRV of prehospital emergency medical services personnel in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement for reporting systematic reviews was performed. PubMed, Ovid, Cochrane Library, Scopus, and Web of Science electronic databases were used. Modified STARD for HRV was used to evaluate the methodological quality of HRV measurement. Two authors independently reviewed the papers and performed the evaluations. Results. The literature search identified 5,637 citations. Four studies were included that investigated HRV during working days compared to nonworking days, but no focus on alert operations. Two studies used Holter electrocardiographic, and two used chest belts. Two studies evaluated cardiac autonomic function in the time and frequency domains, and the other two studies used only the time domain. The results showed an adaptation of HRV under working conditions. The studies were not comparable, because the study protocols were different. Conclusions. There is a need for аccupational health studies that examine the strains and stress of emergency medical services personnel, especially under alert interventions. The well-established HRV parameters seem to be suitable for objectively measuring stress. HRV measurement is also suitable for active alert and operation around the patient. Future research should further additionally investigate nonlinear parameters or parameters without clear assignment. Guideline standards should be respected.