Stress load of emergency service: effects on the CAR and HRV of HEMS emergency physicians on different working days (N = 20)

Physiological adjustment effects of viewing natural environment images on heart rate variability in individuals with depressive and anxiety disorders

Nature-based interventions improve mood and reduce stress, but their effects on heart rate variability (HRV) remain inconsistent. The physiological adjustment effect theory proposes HRV adjusts to an optimal value during nature contact-increasing when baseline HRV is low and decreasing when high. This study tested this theory in patients with depressive and anxiety disorders and investigated its association with mood changes. A randomized crossover trial was conducted with 60 patients. We assessed the correlation between baseline HRV during control images and HRV change after 3 min natural image viewing. We also examined mood changes in comfort, relaxation, and vigor. A significant negative correlation was found between baseline low-frequency/high-frequency (LF/HF) ratio and changes after viewing natural images, indicating a physiological adjustment effect in sympathetic activity. No significant correlation was found with the parasympathetic indicator, HF. Participants with adjustment effects in LF/HF had greater improvement in vigor. Those without these effects had higher alcohol use and tended towards more comorbid hypertension. Natural interventions may enhance vigor through physiological adjustment in sympathetic activity. The lack of adjustment effects is linked to behaviors and conditions associated with autonomic dysfunction, highlighting the need for targeted therapies in depressive and anxiety disorders.

The relationship between self-reported chronic stress, physiological stress axis dysregulation and medically-unexplained symptoms

The positive feedback model of medically-unexplained symptoms posits that chronic stress affects the activity of the physiological stress axes, which in turn generates medically-unexplained symptoms. As a first step to empirically test its model assumptions, we investigated potential associations between chronic stress, physiological stress axis activity and medically-unexplained in a cross-sectional study. One hundred-ninety-nine healthy individuals provided self-reports on chronic stress and medically-unexplained symptoms, resting heart rate/variability (HR/HRV; e.g., root mean square of successive differences/RMSSD, low frequency/LF power), cortisol awakening response (CAR) and diurnal cortisol. Significant positive contributors to medically-unexplained symptoms were the chronic stress scales 'lack of social appreciation' and 'chronic worries', as well as CAR and LF HRV; diurnal cortisol was a negative contributor. Mediation analyses showed that the impact of neural indicators associated with physiological stress axis activity (HR/HRV) related to medically-unexplained symptoms, which was mediated by chronic stress, whereas the mediation effect as suggested by the positive feedback model was not significant. These cross-sectional findings do not support the positive feedback model. Longitudinal studies are required to conclude about potential mechanistic and causal relationships in the model. Nevertheless, our mediation analyses give first indication that the constitution of physiological stress axes may play a major role in how stressors are perceived and which kind of health-consequences (e.g., medically-unexplained symptoms) this may have.

Influence of COVID-19 on Stress at Work During the First Wave of the Pandemic Among Emergency Health Care Workers

OBJECTIVES

For more than 2 years, coronavirus disease (COVID-19) has forced worldwide health care systems to adapt their daily practice. These adaptations add to the already stressful demands of providing timely medical care in an overcrowded health care system. Specifically, the COVID-19 pandemic added stress to an already overwhelmed emergency and critical care health care workers (HCWs) on the front lines during the first wave of the pandemic.This study assessed comparative subjective and objective stress among frontline HCWs using a visual analog scale and biometric data, specifically heart rate variability (HRV).

METHODS

This is a prospective, observational study using surveys and heart rate monitoring among HCWs who work in 3 frontline health care units (emergency department, mobile intensive care unit, and intensive care unit) in the University Hospital of Clermont-Ferrand, France. Two sessions were performed: 1 during the first wave of the pandemic (April 10 to May 10, 2020) and 1 after the first wave of the pandemic (June 10 to July 15, 2020).The primary outcome is the difference in stress levels between the 2 time points. Secondary objectives were the impact of overcrowding, sociodemographics, and other variables on stress levels. We also assessed the correlation between subjective and objective stress levels.

RESULTS

Among 199 HCWs, 98 participated in biometric monitoring, 84 had biometric and survey data, and 12 with only biometric data. Subjective stress was higher during the second time point compared to the first (4.39 ± 2.11 vs 3.16 ± 2.34, P = 0.23). There were higher objective stress levels with a decrease in HRV between the first and the second time points. Furthermore, we found higher patient volumes as a source of stress during the second time point. We did not find any significant correlation between subjective and objective stress levels.

CONCLUSION

HCWs had higher stress levels between the 2 waves of the pandemic. Overcrowding in the emergency department is associated with higher stress levels. We did not find any correlation between subjective and objective stress among intensive care and emergency HCWs during the first wave of the pandemic.

A Systematic Review of Heart Rate Variability as a Measure of Stress in Medical Professionals

Understanding the physiological effects of responding to crises is a critical component in understanding how to manage and prepare medical professionals to be crisis responders. Heart rate variability (HRV) is the variation in rate between a succession of R-R intervals. This variation is not only affected by physiological processes such as respiration or metabolic rate but is also directly controlled by the autonomic nervous system. As such, heart rate variability has been proposed as a noninvasive tool to measure the physiological stress response. The aim of this systematic review is to consolidate heart rate variability literature in the context of medical emergencies to determine if heart rate variability changes predictably from baseline when responding to medical crises. This may demonstrate utility as an objective, noninvasive measure of stress response. A systematic literature review of six databases yielded 413 articles, 17 of which met our inclusion criteria of being written in English, measuring HRV in healthcare providers, and measuring HRV in real or simulated medical resuscitations or procedures. Articles were then analyzed using the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) scoring system. Out of the 17 articles reviewed, 11 demonstrated statistically significant results showing heart rate variability responding in a predictable manner to stress. Three articles utilized a medical simulation as the stressor, six used medical procedures, and eight used medical emergencies encountered during clinical work. Overall, a predictable trend in heart rate variability metrics of standard deviation from the mean value of normal-to-normal (N-N) intervals (SDNN), root mean square of the successive differences (RMSSD), mean number of times per time interval in which the change in successive normal sinus (N-N) intervals exceeds 50 ms (PNN50), low frequency % (LF%), and low-frequency-to-high-frequency ratio (LF/HF) was observed when responding to stress. This systematic literature review showed that heart rate variability among healthcare providers responding to stressful scenarios follows a predictable pattern of change and expands our understanding of the physiology of stress in healthcare providers. This review supports the use of HRV to monitor stress during high-fidelity simulation to ensure that appropriate physiological arousal is achieved during the training of medical personnel.

Monitoring stress and allostatic load in first responders and tactical operators using heart rate variability: a systematic review

BACKGROUND

Awareness of the cumulative stress placed on first responders and tactical operators is required to manage acute fatigue, which can impair occupational performance, and may precipitate negative chronic health outcomes. The aim of this review was to investigate the utility of heart rate variability (HRV) to monitor stress and allostatic load among these populations.

METHODS

A systematic search of Academic Search Complete, MEDLINE complete, PsycINFO, SPORTDiscus and Scopus databases was conducted. Eligibility criteria: original peer reviewed research articles, written in English, published between 1985 and 2020, using human participants employed as a first responder or tactical operator, free from any psychological disorder.

RESULTS

Of the 360 articles screened, 60 met the inclusion criteria and were included for full text assessment. Articles were classified based on single or repeated stressor exposure and the time of HRV assessment (baseline, during stressor, post stressor). Singular stressful events elicited a reduction in HRV from baseline to during the event. Stressors of greater magnitude reduced HRV for extended durations post stressor. Lower resting HRV was associated with lower situational awareness and impaired decision-making performance in marksmanship and navigation tasks. There were insufficient studies to evaluate the utility of HRV to assess allostatic load in repeated stressor contexts.

CONCLUSION

A reduction in HRV occurred in response to acute physical and cognitive occupational stressors. A slower rate of recovery of HRV after the completion of acute occupational stressors appears to occur in response to stressors of greater magnitude. The association between lower HRV and lower decision-making performance poses as a useful tool but further investigations on within subject changes between these factors and their relationship is required. More research is required to investigate the suitability of HRV as a measure of allostatic load in repeated stress exposures for fatigue management in first responder and tactical operators.

Heart rate variability as a strain indicator for psychological stress for emergency physicians during work and alert intervention: a systematic review

BACKGROUND

The workloads of emergency physicians are severe. The prevalence of burnout among emergency physicians is higher than with other physicians or compared to the general population. The analysis of heart rate variability (HRV) is a valid method for objective monitoring of workload. The aim of this paper is to systematically evaluate the literature on heart rate variability as an objective indicator for mental stress of emergency physicians.

METHODS

A systematic literature review examining heart rate variability of emergency physicians in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement for reporting systematic reviews was performed. PubMed, Ovid, Cochrane Libary, Scopus, and Web of Science electronic databases were used. The methodological quality was evaluated by using a modified STARD for HRV.

RESULTS

Two studies matched the inclusion criteria by using HRV between alert intervention and two other studies were considered that used HRV in other question areas. It showed an adaptation of HRV under stress. The studies were not comparable.

CONCLUSIONS

There is a need for occupational health studies that examine strains and stress of emergency physicians. The well-established parasympathetic mediated HRV parameters seem to be suitable parameters to objectify the stress.

Rescue Operations Lead to Increased Cardiovascular Stress in HEMS Crew Members: A Prospective Pilot Study of a German HEMS Cohort

Helicopter emergency medical service (HEMS) is an essential part of prehospital emergency medicine. The working conditions lead to high physical stress, especially in rescue operations. The study aimed to determine the cardiovascular stress profile during rescue situations in HEMS crew members. Twenty-one HEMS crew members (male n = 20) participated in the prospective study. Heart rate, blood pressure and long-term ECG measurements were recorded during the whole operation day. The changes of measurements during rescue operation (52 operations in total) were compared to these of standby time. Rescue operations lead to increased load on the cardiovascular system, as expressed by significantly higher blood pressure, heart rate values and rate of cardiac events compared to standby time. Of special note, the difference in systolic blood pressure mean was 7.4 ± 9.0 mmHg (CI [5.1; 9.7], p < 0.001). Maximal heart rate was on average 33.7 bpm higher during rescue operation than in the standby time (CI [26.2; 40.8], p < 0.001). Cardiac events occurred significantly more frequently during the period of rescue operation than in standby time hours (p = 0.02). The results reported a significant load on the cardiovascular system during rescue operations in HEMS crew members. Therefore, it is necessary to carry out a risk stratification of the HEMS crew members to prevent cardiovascular risk and events.

Prehospital Stressors: A Cross-sectional Study of Norwegian Helicopter Emergency Medical Physicians

OBJECTIVE

Personnel working in helicopter emergency medical services (HEMS) and search and rescue (SAR) are exposed to environmental stressors, which may impair performance. The aim of this survey was to study the extent HEMS and SAR physicians report the influence of specific danger-based and non-danger-based stressors.

METHODS

The study was performed as a cross-sectional, anonymous, Web-based (Questback AS, Bogstadveien 54, 0366 Oslo, Norway) survey of Norwegian HEMS and SAR physicians between December 2, 2019, and February 25, 2020.

RESULTS

Of the recipients, 119 (79.3%) responded. In helicopter operations, 33.6% (n = 40) reported involvement in a minor accident and 44.5% (n = 53) a near accident. In the rapid response car, 26.1% (n = 31) reported near accidents, whereas 26.9% (32) reported this in an ambulance. Of physicians, 20.2% (n = 24) received verbal abuse or threats during the last 12 months. When on call, 50.4% (n = 60) of physicians reported sometimes or often being influenced by fatigue.

CONCLUSION

This study shows that Norwegian HEMS and SAR physicians are exposed to several stressors of both a danger-based and non-danger-based nature, especially regarding accidents, threatening patient behavior, and fatigue. Very serious incidents appear to be seldom, and job satisfaction is high.

Continuous HRV analysis of HEMS emergency physicians to specify the work load over the different working days

INTRODUCTION

Up to date, there has been little research about the acute stress load of emergency physicians of the Helicopter Emergency Medical Service (HEMS). Therefore, this study investigates the physiological stress level between an air-rescue day, a clinic day, and a day off (control day). Furthermore, phases of activity and resting were compared to assess the activity of the autonomic nervous system (ANS).

METHODS

In this field study (within-subjects design), heart rate variability (HRV) and self-perceived stress levels were monitored on an air-rescue day, a clinic day, and a control day of 20 HEMS EPs [three females, 17 males; age: mean (M) = 44.95, standard deviation (SD) = 4.80].

RESULTS

When comparing the activity phases, significant differences were found for HR and HRV. The highest HR was found on the air-rescue day during the phase of landing at the operation site with M = 107.30 bpm (SD = 22.66 bpm), which was significantly higher than during activity phases of the clinic day (M = 88.28 bpm, SD = 11.81 bpm) and the control day (M = 83.28 bpm, SD = 14.83 bpm). The SDNN is significantly higher on the air-rescue day for the phase before the alarm (M = 72.23 ms, SD = 38.60 ms), the phase of the alarm (M = 77.52 ms, SD = 40.52 ms), and the average of all phases (M = 60.04 ms, SD = 34.07 ms) than on the clinic day (M = 38.42 ms, SD = 15.16 ms) and the control day, where the lowest value was reached (M = 39.11 ms, SD = 17.65 ms). The highest LF/HF was found during activity phases of the clinic day with M = 1281.84% (SD = 587.33%), which was significantly higher than the first five phases of the emergency operations and the average of all phases of the emergency operations of the air-rescue day, where a maximum of M = 896.57 ms (SD = 681.79 ms) during the phase before the alarm and a minimum of M = 764.69 ms (SD = 372.28 ms) during the phase of landing at the operation site. The lowest LF/HF for all testing days was found during the activity phases of the control day with M = 693.74% (SD = 404.73%). Overall, 60 observations were analyzed. In the psychological assessment, on average, the EPs shows lower values than the norm sample.

DISCUSSION

In the comparison of the activity phases, significant effects were found on the clinic day and during the phases of the emergency operations of the air-rescue day for the HR and HRV. Hereby, a significant activation of the EPs ANS and an outweigh of the sympathetic nervous system could be shown, whereby the subjective stress load was reported mainly as low. For the resting phases, no significant differences were found between all testing days. We interpret this as a good sign for the ability of regeneration between the phases of high stress load.