Heart rate variability as a measure of mental stress in surgery: a systematic review

Stress responses in surgical trainees during simulation-based training courses in laparoscopy

BACKGROUND

Simulation-based training courses in laparoscopy have become a fundamental part of surgical training programs. Surgical skills in laparoscopy are challenging to master, and training in these skills induces stress responses in trainees. There is limited data on trainees' stress levels, the stress responses related to training on different laparoscopic simulators, and how previous experiences influence trainees' stress response during a course. This study investigates physiologic, endocrine and self-reported stress responses during simulation-based surgical skills training in a course setting.

METHODS

We conducted a prospective observational study of trainees attending basic laparoscopic skills training courses at a national training centre. During the three-day course, participants trained on different laparoscopic simulators: Two box-trainers (the D-box and P.O.P. trainer) and a virtual reality simulator (LAPMentor™). Participants' stress responses were examined through heart rate variability (HRV), saliva cortisol, and the State Trait Anxiety Inventory-6 (STAI-6). The correlation between previous laparoscopic experiences and stress response measurements was explored.

RESULTS

Twenty-four surgical trainees were included in the study. Compared to resting conditions, stress measures were significantly higher during simulation-training activity (the D-box (SDNN = 58.5 ± 23.4; LF/HF-ratio = 4.58 ± 2.71; STAI-6 = 12.3 ± 3.9, P < 0.05), the P.O.P trainer (SDNN = 55.7 ± 7.4; RMSSD = 32.4 ± 17.1; STAI-6 = 12.1 ± 3.9, P < 0.05), and the LAPMentor™ (SDNN = 59.1 ± 18.5; RMSSD = 34.3 ± 19.7; LF/HF-ratio = 4.71 ± 2.64; STAI-6 = 9.9 ± 3.0, P < 0.05)). A significant difference in endocrine stress response was seen for the simulation-training activity on the D-box (saliva cortisol: 3.48 ± 1.92, P < 0.05), however, no significant differences were observed between the three simulators. A moderate correlation between surgical experience, and physiologic and endocrine stress response was observed (RMSSD: r=-0.31; SDNN: r=-0.42; SD2/SD1 ratio: r = 0.29; Saliva cortisol: r = 0.46; P < 0.05), and a negative moderate correlation to self-reported stress (r=-0.42, P < 0.05).

CONCLUSION

Trainees have a significant higher stress response during simulation-training compared to resting conditions, with no difference in stress response between the simulators. Significantly higher cortisol levels were observed on the D-box, indicating that simulation tasks with time pressure stress participants the most. Trainees with more surgical experience are associated with higher physiologic stress measures, but lower self-reported stress scores, demonstrating that surgical experience influences trainees' stress response during simulation-based skills training courses.

The effect of music on the operating surgeon: a pilot randomized crossover trial (the MOSART study)

OBJECTIVE

The experience of stress is common among surgeons while working in the operating theatre (OT). Understanding and finding ways to mitigate this stress is important for optimizing surgical quality and maintaining clinician wellbeing. In this pilot study, we tested the feasibility and reported the outcomes of measuring the effect of background music on intra-operative surgeon stress in the clinical environment.

METHODS

The effect of Music on the Operating Surgeon: A pilot Randomized crossover Trial (the MOSART study) was conducted over a 9-month period in a single-centre. Vascular and general surgeons acting as primary operators (POs) performing elective, general anaesthetic operations were included. The intervention was surgeon-selected music, and the control was the absence of music. Outcome measures were feasibility (recruitment rate, practicability, and completeness of data), heart rate variability (HRV) indices, the Six-Item State-Trait Anxiety Inventory (STAI-6), and the Surgical Task-load Index (SURG-TLX).

RESULTS

Five POs performed 74 eligible randomized cases. The protocol was well tolerated, and no cases were abandoned. Data was incomplete in 8% of cases. The overall mean (SD) operative SURG-TLX score was 48 (±22). Mean HR increased and RMSSD decreased significantly from baseline, suggesting reduced parasympathetic activity while operating. The presence of intra-operative music was not found to affect the psychological or physiological outcomes.

CONCLUSIONS

A music interventional study of this nature is feasible in the operating theatre environment, though no difference was found between in the music and non-music conditions. Follow-up research in a simulated environment with intensive physiological monitoring could be considered.

Amidst the clamor: Effects of emergency department noise on Physicians' health and attention

OBJECTIVE

This study aims to assess effects of noise on physicians' stress levels and attention capacities within an emergency department.

METHODS

In this prospective cross-sectional study, 15 physicians from a state hospital emergency department with 300,000 annual visits provided demographics, work factors, and physiologic data. Attention was evaluated through smartphone-based Stroop tests, while noise and heart rates were monitored via smartwatches.

RESULTS

Median physician age was 26, with 16 months' emergency department experience. Average sound intensity was 68.80 dB. Despite noise, physicians in green/yellow areas showed increased Stroop scores (p = 0.002). Heart rate responses correlated with noise changes. End-of-shift surveys highlighted physicians' adaptability and resilience to high noise levels.

CONCLUSION

Noisy emergency departments pose health risks to physicians, but noise-related stress did not significantly affect attention, beneficial for patient care.

The Value of the Endoscope-Holding Arm in Transoral Pharyngeal Surgery

BACKGROUND

Transoral pharyngeal surgery is mainly feasible with the use of a microscope or robotic systems. Data about alternative methods, with lower costs and easier availability, are sparse. We intended to examine to what extent the endoscope-holding arm is a suitable alternative to the microscope or robotic systems.

MATERIAL AND METHODS

We retrospectively reviewed subjects who underwent pharyngeal tumor resection with the endoscope-holding arm in our university department.

RESULTS

We identified 13 subjects who underwent transoral pharyngeal surgery between November 2020 and November 2023. Most subjects presented with an oropharyngeal tumor (6/11 in the lateral wall or tonsil; 4/11 in the tongue base). The oropharyngeal lateral wall or tonsillar tumors were exposed with a standard mouth gag. The tongue-base tumors or hypopharyngeal tumors were exposed with an operating laryngoscope. Advantages over the microscope included an angled view. Advantages over robotic systems included haptic feedback and a faster setup. Advantages over both the microscope and robotic systems included lower costs and easier availability. Visualization with the endoscope was sufficient and similar to that of the microscope. Bimanual action was possible with surgical forceps and a monopolar electrode.

CONCLUSIONS

Transoral pharyngeal surgery was feasible with the endoscope-holding arm. The endoscope-holding arm could be a cost-efficient alternative to the microscope or robotic systems.

Exposure to prenatal stressors and infant autonomic nervous system regulation of stress

OBJECTIVES

The purpose of this study was to determine the relationship between fetal exposure to maternal prenatal stressors and infant parasympathetic (PNS) and sympathetic (SNS) nervous function at 3 timepoints across the first year of life.

BACKGROUND

Autonomic nervous system impairments may mediate associations between gestational exposure to stressors and later infant health problems. Heart rate variability (HRV) provides a sensitive index of PNS and SNS function. However, no studies have assessed longitudinal associations between prenatal stressors and infant HRV measures of both PNS and SNS over the first year of life.

METHODS

During the third trimester of pregnancy, 233 women completed measures of life stressors and depression. At 1, 6 and 12 months of age, a stressor protocol was administered while infant electrocardiographic (ECG) data were collected from a baseline through a post-stressor period. HRV measures of PNS and SNS activity (HF, LF, LF/HF ratio) were generated from ECG data. We used multilevel regression to examine the aims, adjusting for maternal depression and neonatal morbidity.

RESULTS

There were no associations between prenatal stressors and any baseline or reactivity HRV metric over the infant's first year of life. However, exposure to more stressors was associated with lower post-stressor LF HRV at both 6 (β = -.44, p = .001) and 12 (β = -.37, p = .005) months of age.

CONCLUSIONS

Findings suggest potential alterations in development of the vagally mediated baroreflex function as a result of exposure to prenatal stressors, with implications for the infants' ability to generate a resilient recovery in response to stressors.

The physiology of intraoperative error: using electrokardiograms to understand operator performance during robot-assisted surgery simulations

BACKGROUND

No platform for objective, synchronous and on-line evaluation of both intraoperative error and surgeon physiology yet exists. Electrokardiogram (EKG) metrics have been associated with cognitive and affective features that are known to impact surgical performance but have not yet been analyzed in conjunction with real-time error signals using objective, real-time methods.

METHODS

EKGs and operating console point-of-views (POVs) for fifteen general surgery residents and five non-medically trained participants were captured during three simulated robotic-assisted surgery (RAS) procedures. Time and frequency-domain EKG statistics were extracted from recorded EKGs. Intraoperative errors were detected from operating console POV videos. EKG statistics were synchronized with intraoperative error signals.

RESULTS

Relative to personalized baselines, IBI, SDNN and RMSSD decreased 0.15% (S.E. 3.603e-04; P = 3.25e-05), 3.08% (S.E. 1.603e-03; P < 2e-16) and 1.19% (S.E. 2.631e-03; P = 5.66e-06), respectively, during error. Relative LF RMS power decreased 1.44% (S.E. 2.337e-03; P = 8.38e-10), and relative HF RMS power increased 5.51% (S.E. 1.945e-03; P < 2e-16).

CONCLUSIONS

Use of a novel, on-line biometric and operating room data capture and analysis platform enabled detection of distinct operator physiological changes during intraoperative errors. Monitoring operator EKG metrics during surgery may help improve patient outcomes through real-time assessments of intraoperative surgical proficiency and perceived difficulty as well as inform personalized surgical skills development.

Cardiac autonomic and cortisol stress responses to real operations in surgeons: relationship with individual psychobiological characteristics and experience

BACKGROUND

Surgeons are exposed to high levels of intraoperative stress, which could compromise their psychological well-being in the long term. This study aimed at exploring the effects of real operations on the activity of stress response systems (i.e., cardiac autonomic function and hypothalamic-pituitary-adrenal axis) during and in the aftermath of surgery, and the moderating role of individual psychobiological characteristics and different levels of experience (senior vs expert surgeons).

METHODS

Heart rate, heart rate variability, and salivary cortisol measures (as indexes of cardiac autonomic and hypothalamic-pituitary-adrenal axis activity, respectively) were assessed during real operations and in the perioperative period in a sample of surgeons (n = 16). Surgeons' psychometric characteristics were collected using questionnaires.

RESULTS

Real operations triggered both cardiac autonomic and cortisol stress responses which were independent from surgeons' level of experience. Intraoperative stress responses did not affect cardiac autonomic activity during the following night but were associated with a blunted cortisol awakening response. Moreover, senior surgeons reported higher levels of negative affectivity and depressive symptoms than expert surgeons prior to the surgery. Lastly, the magnitude of heart rate responses to surgery positively correlated with scores on negative affectivity, depression, perceived stress, and trait anxiety scales.

CONCLUSION

This exploratory study allows to put forward the hypotheses that in surgeons cardiac autonomic and cortisol stress responses to real operations (i) may be associated with specific individual psychological characteristics regardless of the level of experience, (ii) and may have a longer lasting impact on hypothalamic-pituitary-adrenal axis function with potential implications for surgeons' physical and psychological well-being.

Immediate Effects of Hypnosis, Mindfulness Meditation, and Prayer on Cold Pressor Outcomes: A Four-Arm Parallel Experimental Study

Purpose

Previous research supports the usefulness of hypnosis (HYP), mindfulness meditation (MM), and prayer as pain self-management strategies in adults with chronic pain. However, their effects on acute pain have been less researched, and no previous head-to-head study compared the immediate effects of these three approaches on pain-related outcomes. This study compared the immediate effects of HYP, MM, and Christian prayer (CP) on pain intensity, pain tolerance, and stress as assessed by heart rate variability (HRV).

Participants and Methods

A total of 232 healthy adults were randomly assigned to, and completed, a single 20-minute session of MM, SH, CP, or an attention control (CN), and underwent two cycles (one pre- and one post-intervention) of Cold Pressor Arm Wrap (CPAW). Sessions were audio-delivered. Participants responded to pre- and post-intervention pain intensity measurements. Pain tolerance (sec) was assessed during the CPAW cycles. HRV was assessed at baseline, and at pre- and post-intervention CPAW cycles. The study protocol was pre-registered at the ClinicalTrials.gov registry (NCT04491630).

Results

Small within-group decreases in pain intensity and small increases in pain tolerance were found for HYP and MM from the pre- to the post-intervention. Small within-group improvements in the LH/HF ratio were also found for HYP. The exploratory between-group pairwise comparisons revealed a medium effect size effects of HYP on pain tolerance relative to the control condition. The effects of CP were positive, but small and not statistically significant. Only small to medium, though non-significant, Time × Group interaction effects were found.

Conclusion

Study results suggest that single short-term HYP and MM sessions, but not biblical-based CP, may be useful for acute pain self-management, with HYP being the slightly superior option. Future research should compare the effects of different types of prayer and examine the predictors and moderators of these pain approaches' effects on pain-related outcomes.

Impact of autonomic regulation on burnout and performance in thoracic surgery residents

Objective

This study sought to determine the feasibility of collecting physiologic data in thoracic surgery residents and whether it would correlate with burnout and burnout with performance.

Methods

This was a prospective study of thoracic surgery residents over a 5-month period. Participants were evaluated with a wearable biometric device (heart rate variability and sleep) and the Maslach Burnout Inventory. Resident performance was quantified using Accreditation Council for Graduate Medical Education Milestones (scale, 1-5) normalized to program-designated targets (3 for postgraduate year 6 or lower residents and 4 for postgraduate year 7 residents).

Results

The cohort consisted of 71% female participants (5/7) with 86% of residents having 1 or more children. High levels of emotional exhaustion (median, 30 [interquartile range, 20-36], where >26 is high) and high levels of depersonalization (median, 16 [interquartile range, 14-22], where >12 is high) were common, but personal accomplishment was also uniformly high (median, 43 [interquartile range, 41-46], where >38 is high). There was a significant correlation between heart rate variability and emotional exhaustion (r(12) = 0.65, P = .01) but not depersonalization (P = .28) or personal accomplishment (P = .24). Depersonalization and personal accomplishment did not correlate with resident performance (P = .12 and P = .75, respectively); however, increased emotional exhaustion showed a significant correlation with higher resident performance during periods when burnout was reported (r(6) = 0.76, P = .047).

Conclusions

Dynamic measurement of resting heart rate variability may offer an objective measure of burnout in thoracic surgery residents. Thoracic surgery residents who report high levels of burnout in this cohort maintained the ability to meet program-designated milestones at or above the level expected of their postgraduate year.

Methods and Measures for Mental Stress Assessment in Surgery: A Systematic Review of 20 Years of Literature

Real-time mental stress monitoring from surgeons and surgical staff in operating rooms may reduce surgical injuries, improve performance and quality of medical care, and accelerate implementation of stress-management strategies. Motivated by the increase in usage of objective and subjective metrics for cognitive monitoring and by the gap in reviews of experimental design setups and data analytics, a systematic review of 71 studies on mental stress and workload measurement in surgical settings, published in 2001-2020, is presented. Almost 61% of selected papers used both objective and subjective measures, followed by 25% that only administered subjective tools - mostly consisting of validated instruments and customized surveys. An overall increase in the total number of publications on intraoperative stress assessment was observed from mid-2010 s along with a momentum in the use of both subjective and real-time objective measures. Cardiac activity, including heart-rate variability metrics, stress hormones, and eye-tracking metrics were the most frequently and electroencephalography (EEG) was the least frequently used objective measures. Around 40% of selected papers collected at least two objective measures, 41% used wearable devices, 23% performed synchronization and annotation, and 76% conducted baseline or multi-point data acquisition. Furthermore, 93% used a variety of statistical techniques, 14% applied regression models, and only one study released a public, anonymized dataset. This review of data modalities, experimental setups, and analysis techniques for intraoperative stress monitoring highlights the initiatives of surgical data science and motivates research on computational techniques for mental and surgical skills assessment and cognition-guided surgery.

Activation of the stress response among the cardiac surgical residents: comparison of teaching procedures and other (daily) medical activities

BACKGROUND

The aim of this Pilot study was to investigate the cardiac surgical residents' workload during different surgical teaching interventions and to compare their stress levels with other working time spent in the intensive care unit or normal ward.

METHODS

The objective stress was assessed using two cardiac surgical residents' heart rate variability (HRV) both during surgical activities (32 selected teaching operations (coronary artery bypass graft n = 26 and transcatheter aortic valve implantation n = 6), and during non-surgical periods. Heart rate, time and frequency domains as well as non-linear parameters were analyzed using the Wilcoxon test.

RESULTS

The parasympathetic activity was significantly reduced during the surgical phase, compared to the non-surgical phase: Mean RR (675.7 ms vs. 777.3 ms), RMSSD (23.1 ms vs. 34.0 ms) and pNN50 (4.7% vs. 10.6%). This indicates that the residents had a higher stress level during surgical activities in comparison to the non-surgical times. The evaluation of the Stress Index during the operations and outside the operating room (8.07 vs. 10.6) and the parasympathetic nervous system index (- 1.75 to - 0.91) as well as the sympathetic nervous system index (1.84 vs. 0.65) confirm the higher stress level during surgery. This can be seen too used the FFT Analysis with higher intraoperative LF/HF ratio (6.7 vs. 3.8).

CONCLUSION

HRV proved to be a good, objective method of identifying stress among physicians both in and outside the operating room. Our results show that residents are exposed to high psychological workloads during surgical activities, especially as the operating surgeon.

Crisis recovery in surgery: Error management and problem solving in safety-critical situations

BACKGROUND

Surgical crises, both clinical and executive, carry risk of harm to patients, staff, and organizations. Once stabilized and contained, crisis recovery requires complex decision-making and problem-solving to address primary failures (errors) and their consequences. In contrast to other safety-critical professions, surgeons may lack access to crisis recovery strategies and tools that go beyond the technical aspects of clinical practice. This study aims to develop a framework for surgical crisis recovery based on problem-solving interventions used by pilots in commercial aviation.

METHODS

This study undertook observational fieldwork, semistructured interviews, and focus groups with senior airline pilots and health care safety experts. Thematic analysis using the framework method identified key interventions applicable to surgical crisis recovery. Subsequently, expert group consensus adapted and content validated this model for clinical use.

RESULTS

Qualitative data from 22 aviation and health care safety experts informed surgical crisis resolution. This consisted of 3 strategies: (1) building cognitive capacity by improving situational awareness and workload management; (2) using checklists in abnormal situations to implement emergency operating procedures; (3) undertaking structured decision-making using analysis-based problem-solving cycles (eg, T-DODAR framework). Twelve tools were validated and adapted to aid implementation of these strategies.

CONCLUSION

Once stabilized, surgical crises may be resolved using 3 sequential strategies derived from commercial aviation.

Fuzzy Approach to Computational Classification of Burnout—Preliminary Findings

There is a common belief that medical professions generate more work-related stress and earlier job burnout. We tested two groups: study group 1: medical (physical therapists, n = 30), and study group 2: non-medical (informaticians, n = 30). The purpose of this study was to find new, more reliable models for calculating work-related stress and burnout in the two aforementioned different professional groups. In the paper, we focused on a new model of algorithm based on AI methods that extends the interpretability of the scale of results obtained using the MBI test. The outcomes of the Maslach Burnout Inventory (MBI) were analysed in both study groups. These became the starting point for the development of three different fuzzy models, from which, after comparison, the one best suited to the study groups and the way they were evaluated was selected. Among the patients participating in the study, the following results were obtained: MBI values expressed as median values were significantly higher in group 2 than in group 1. The computational analysis showed that the contribution of the different parts of the MBI test to the final score was unequal in both groups. AI allowed for optimal selection of the model parameters for the study group, from which an algorithm was created to optimise the selection of tools or their parameters. A computational tool can do this faster, more accurately, and more efficiently, becoming an important supporting tool. In the medical context, the main benefit of the results presented in this paper is the definition of an evaluation model that transforms the MBI test scores into a universal percentage scale while preserving the properties of the guidelines underlying the MBI. An additional advantage of the proposed solution is the readability and flexibility resulting from the linguistic rules underlying the model.

Heart Rate Variability in Different Levels of Burnout-Cross-Sectional Study of Different Occupational Groups Heart Rate Variability and Burnout

OBJECTIVES

The aim of this study was a subjective and objective stress analysis of occupational groups.

METHODS

The study examined 414 employees with patients or children contact on work. The age ranged from 22 to 63 years. Subjective stress was measured using the Maslach Burnout Inventory and objective stress with heart rate variability (HRV).

RESULTS

Twenty-one percent of subjects showed a high level of exhaustion, 12.9% a high level of cynicism and low performance. There were significant group differences between cynicism levels in meanNN (P = .008) and meanHR (P = .002). There were no significant differences in HRV for exhaustion and professional efficacy.

CONCLUSIONS

The health-impairing manifestations of the three dimensions of the burnout syndrome are not associated with the lower HRV. However, healthy subjects from a "screening" study who had not been clinically diagnosed with burnout were examined here.

Crisis Containment: Tools for Harm Mitigation in Surgery

BACKGROUND

Surgical crises represent unrecognized opportunities for improving patient safety and adding value in healthcare. The first step in a crisis response is to contain and mitigate harm. While the principles of damage control are well established in surgery, methods of containing harm on broader clinical and organizational levels are not clearly defined.

STUDY DESIGN

A multimethods qualitative study identified crisis containment strategies and tools in commercial aviation. These were translated and clinically adapted in 3 stages: semi-structured observational fieldwork with commercial airlines, interviews with senior pilots, and focus groups with both healthcare and aviation safety experts. Thematic analysis and expert consensus methods were used to derive a framework for crisis containment.

RESULTS

Fieldwork with 2 commercial airlines identified 2 crisis containment concepts: the detrimental impact of surprising or startling events on operator performance; and the use of prioritization tools to take basic but critical actions (Aviate, Navigate and Communicate model). Twenty-two experts in aviation and healthcare practice informed the topic of crisis containment in 17 interviews and 3 focus groups. Three strategies were identified and used to form a crisis containment algorithm: 1. Manage the operators' startle response to facilitate meaningful mitigating actions (STOP tool); 2. Take priority actions to secure core functions. These included managing patients' physiologic shock, optimizing environmental risks, and mobilizing resources (Perfuse, Move and Communicate tool); 3. Deploy well-rehearsed drills targeting case-specific harms or errors (Memory Actions). This model requires validation in clinical practice.

CONCLUSIONS

Crisis containment can be achieved by controlling operators' startle response, applying prioritization tools, and deploying drills against specific failures. The application of this model may extend to healthcare areas outside surgery.

Literature Review: Heart Rate Variability as a Biomonitoring of Occupational Stress

Introduction: Occupational stress is a modern epidemic. In terms of stress assessment, tools such as questionnaires are believed to be more subjective, especially in the assessment of stress in the workplace, while of course an objective assessment of stress also needs to be carried out. Objective examination for occupationalsstress will be very useful in the occupationalhhealth settings, which can early detect stress at work and prevent the long term effects. Therefore, this literature review aims to investigate the role of HRV in determining occupational stress. Methods: The searching methods used were PubMed and Google Scholar to find related journals about occupational stress and HRV, published in English. The articlessthatmmet the inclusion criteria were analysed basedoonothesstudy design, study population, occupationalsstressaand HRV assessment based on the Centre of Evidence-based Medicine, the University of Oxford for therapy study. Moreover, sample size varied from 8 to 1788. Results: It was found that there are three studies that fit the criteria, which are one systematic review study, one longitudinal study, and one cross-sectional study. The main finding from those articles was that occupational or job stress is found to be associated with lowered HRV value. Conclusion: HRV can be recommended for practicing occupational physicians and company doctors to identify the core areas of work- related stress.Keywords: biomonitoring, heart rate variability, coccupational stress

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.

HRV Features as Viable Physiological Markers for Stress Detection Using Wearable Devices

Stress has been identified as one of the major causes of automobile crashes which then lead to high rates of fatalities and injuries each year. Stress can be measured via physiological measurements and in this study the focus will be based on the features that can be extracted by common wearable devices. Hence, the study will be mainly focusing on heart rate variability (HRV). This study is aimed at investigating the role of HRV-derived features as stress markers. This is achieved by developing a good predictive model that can accurately classify stress levels from ECG-derived HRV features, obtained from automobile drivers, by testing different machine learning methodologies such as K-Nearest Neighbor (KNN), Support Vector Machines (SVM), Multilayer Perceptron (MLP), Random Forest (RF) and Gradient Boosting (GB). Moreover, the models obtained with highest predictive power will be used as reference for the development of a machine learning model that would be used to classify stress from HRV features derived from heart rate measurements obtained from wearable devices. We demonstrate that HRV features constitute good markers for stress detection as the best machine learning model developed achieved a Recall of 80%. Furthermore, this study indicates that HRV metrics such as the Average of normal-to-normal (NN) intervals (AVNN), Standard deviation of the average NN intervals (SDNN) and the Root mean square differences of successive NN intervals (RMSSD) were important features for stress detection. The proposed method can be also used on all applications in which is important to monitor the stress levels in a non-invasive manner, e.g., in physical rehabilitation, anxiety relief or mental wellbeing.

Effect of noise on the electrocardiographic parameters

PURPOSE

Noise, defined as any sound that is unpleasant, is one of the most important environmental problems. Prolonged exposure to noise has been shown to be associated with the development of cardiovascular diseases. No study investigated the effect of noise on surface electrocardiography (ECG).

AIMS

The aim of our study is to investigate the effect of noise on surface ECG parameters including P-wave dispersion (PWD), QT intervals, corrected QT interval (QTc), T-wave peak to end (Tp-e) interval, and Tp-e/QT and Tp-e/QTc ratios.

METHODS

A total of 51 people working in the textile factory affected by the noise and 43 volunteers without any disease and who were not exposed to noise were included in this study. The average noise level in the textile factory was 112 dB. A 12-lead ECG was obtained from all individuals. PR interval, PWD, QRS duration, QT interval, QTc interval, Tp-e interval, and Tp-e/QT and Tp-e/QTc ratios were calculated for all individuals.

RESULTS

The noise group had significantly increased PWD [35 (28-40) vs. 28 (22-36) p = 0.029], QT interval ( 373.5 ± 27.3 vs. 359.3 ± 2.74, p = 0.001), QTc interval [(409 ± 21 vs. 403 ± 13 p = 0.045)], Tp-e interval [(90.6 ± 6.0 vs. 83.5 ± 7.3 p < 0.001)], Tp-e/QT [(0.24 ± 0.03 vs. 0.23 ± 0.02, p = 0.015)] and Tp-e/QTc [(0.22 ± 0.02 vs. 0.21 ± 0.02 p < 0.001)] compared to control group. Also, duration of working was positively correlated with PWD (r = 0.468, p = 0.001) and Tp-e/QTc ratio (r = 0.328, p = 0.019). In multiple linear regression linear regression analysis, noise was the independent predictor of both PWD (β = 0.244, p = 0.032) and Tp-e/QTc (β = 0.319, p = 0.003) CONCLUSION: We showed that noise significantly increased PWD, QT and Tp-e interval measurements. Also, noise was the independent predictor for both PWD and Tp-e/QTc.

Wearable Devices Suitable for Monitoring Twenty Four Hour Heart Rate Variability in Military Populations

Heart rate variability (HRV) measurements provide information on the autonomic nervous system and the balance between parasympathetic and sympathetic activity. A high HRV can be advantageous, reflecting the ability of the autonomic nervous system to adapt, whereas a low HRV can be indicative of fatigue, overtraining or health issues. There has been a surge in wearable devices that claim to measure HRV. Some of these include spot measurements, whilst others only record during periods of rest and/or sleep. Few are capable of continuously measuring HRV (≥24 h). We undertook a narrative review of the literature with the aim to determine which currently available wearable devices are capable of measuring continuous, precise HRV measures. The review also aims to evaluate which devices would be suitable in a field setting specific to military populations. The Polar H10 appears to be the most accurate wearable device when compared to criterion measures and even appears to supersede traditional methods during exercise. However, currently, the H10 must be paired with a watch to enable the raw data to be extracted for HRV analysis if users need to avoid using an app (for security or data ownership reasons) which incurs additional cost.

Subjective and objective demands on different types of differential stress inventory

Purpose

To validate the differential stress inventory (DSI) by evaluating the objective and subjective stress differences in the five DSI types in the occupational setting.

Methods

A total of 119 German participants working as medical assistants (n = 40) or in a bank (n = 79) were recruited. They completed the Maslach Burnout Inventory–General Survey, the DSI, and wore ECG measuring devices for 24 h to measure heart rate variability. The DSI was used to group people into one of five types according to how they perceived and coped with stress: normal, overstressed, stress-resistant, low stress/high coping, or high stress/high coping.

Results

The overstressed type had significantly more burnout symptoms than the other types. The high stress/high coping type also had more symptoms of emotional exhaustion and total burnout compared to the other types, while the low stress/high coping and the stress-resistant types generally had the lowest levels of burnout. There were no differences on the HRV parameters among the DSI types.

Conclusion

Categorising people into types like in the DSI can help make workers aware of unhealthy stress and coping patterns before they turn into more severe pathology. Proper application and targeted preventive measures can save the individual’s health and the company’s budget. While the DSI picked up on differences in burnout symptoms as a long-term consequence of stress, there is evidence that it cannot pick up on short-term stress or physical stress as measured by HRV from the 24 h recording.

The effect of preferred music on mental workload and laparoscopic surgical performance in a simulated setting (OPTIMISE): a randomized controlled crossover study

BACKGROUND

Worldwide, music is commonly played in the operation room. The effect of music on surgical performance reportedly has varying results, while its effect on mental workload and key surgical stressor domains has only sparingly been investigated. Therefore, the aim is to assess the effect of recorded preferred music versus operating room noise on laparoscopic task performance and mental workload in a simulated setting.

METHODS

A four-sequence, four-period, two-treatment, randomized controlled crossover study design was used. Medical students, novices to laparoscopy, were eligible for inclusion. Participants were randomly allocated to one of four sequences, which decided the exposure order to music and operation room noise during the four periods. Laparoscopic task performance was assessed through motion analysis with a laparoscopic box simulator. Each period consisted of ten alternating peg transfer tasks. To account for the learning curve, a preparation phase was employed. Mental workload was assessed using the Surgery Task Load Index. This study was registered with the Netherlands Trial Register (NL7961).

RESULTS

From October 29, 2019 until March 12, 2020, 107 participants completed the study, with 97 included for analyzation. Laparoscopic task performance increased significantly during the preparation phase. No significant beneficial effect of music versus operating room noise was observed on time to task completion, path length, speed, or motion smoothness. Music significantly decreased mental workload, reflected by a lower score of the total weighted Surgery Task Load Index in all but one of the six workload dimensions.

CONCLUSION

Music significantly reduced mental workload overall and of several previously identified key surgical stressor domains, and its use in the operating room is reportedly viewed favorably. Music did not significantly improve laparoscopic task performance of novice laparoscopists in a simulated setting. Although varying results have been reported previously, it seems that surgical experience and task demand are more determinative.