Evaluation of attention, perception, and stress levels of clinical cardiovascular perfusionists during cardiac operations: a pilot study

Simultaneous Control of Venous Reservoir Level and Arterial Flow Rate in Cardiopulmonary Bypass With a Centrifugal Pump

Cardiopulmonary bypass (CPB) is an indispensable technique in cardiac surgery, providing the ability to temporarily replace cardiopulmonary function and create a bloodless surgical field. Traditionally, the operation of CPB systems has depended on the expertise and experience of skilled perfusionists. In particular, simultaneously controlling the arterial and venous occluders is difficult because the blood flow rate and reservoir level both change, and failure may put the patient's life at risk. This study proposes an automatic control system with a two-degree-of-freedom model matching controller nested in an I-PD feedback controller to simultaneously regulate the blood flow rate and reservoir level. CPB operations were performed using glycerin and bovine blood as perfusate to simulate flow-up and flow-down phases. The results confirmed that the arterial blood flow rate followed the manually adjusted target venous blood flow rate, with an error of less than 5.32%, and the reservoir level was maintained, with an error of less than 3.44% from the target reservoir level. Then, we assessed the robustness of the control system against disturbances caused by venting/suction of blood. The resulting flow rate error was 5.95%, and the reservoir level error 2.02%. The accuracy of the proposed system is clinically satisfactory and within the allowable error range of 10% or less, meeting the standards set for perfusionists. Moreover, because of the system's simple configuration, consisting of a camera and notebook PC, the system can easily be integrated with general CPB equipment. This practical design enables seamless adoption in clinical settings. With these advancements, the proposed system represents a significant step towards the automation of CPB.

Eye Tracking Use in Surgical Research: A Systematic Review

INTRODUCTION

Eye tracking (ET) is a popular tool to study what factors affect the visual behaviour of surgical team members. To our knowledge, there have been no reviews to date that evaluate the broad use of ET in surgical research. This review aims to identify and assess the quality of this evidence, to synthesize how ET can be used to inform surgical practice, and to provide recommendations to improve future ET surgical studies.

METHODS

In line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, a systematic literature review was conducted. An electronic search was performed in MEDLINE, Cochrane Central, Embase, and Web of Science databases up to September 2020. Included studies used ET to measure the visual behaviour of members of the surgical team during surgery or surgical tasks. The included studies were assessed by two independent reviewers.

RESULTS

A total of 7614 studies were identified, and 111 were included for data extraction. Eleven applications were identified; the four most common were skill assessment (41%), visual attention assessment (22%), workload measurement (17%), and skills training (10%). A summary was provided of the various ways ET could be used to inform surgical practice, and three areas were identified for the improvement of future ET studies in surgery.

CONCLUSIONS

This review provided a comprehensive summary of the various applications of ET in surgery and how ET could be used to inform surgical practice, including how to use ET to improve surgical education. The information provided in this review can also aid in the design and conduct of future ET surgical studies.

When medical trainees encountering a performance difficulty: evidence from pupillary responses

BACKGROUND

Medical trainees are required to learn many procedures following instructions to improve their skills. This study aims to investigate the pupillary response of trainees when they encounter moment of performance difficulty (MPD) during skill learning. Detecting the moment of performance difficulty is essential for educators to assist trainees when they need it.

METHODS

Eye motions were recorded while trainees practiced the thoracostomy procedure in the simulation model. To make pupillary data comparable among trainees, we proposed the adjusted pupil size (APS) normalizing pupil dilation for each trainee in their entire procedure. APS variables including APS, maxAPS, minAPS, meanAPS, medianAPS, and max interval indices were compared between easy and difficult subtasks; the APSs were compared among the three different performance situations, the moment of normal performance (MNP), MPD, and moment of seeking help (MSH).

RESULTS

The mixed ANOVA revealed that the adjusted pupil size variables, such as the maxAPS, the minAPS, the meanAPS, and the medianAPS, had significant differences between performance situations. Compared to MPD and MNP, pupil size was reduced during MSH. Trainees displayed a smaller accumulative frequency of APS during difficult subtask when compared to easy subtasks.

CONCLUSIONS

Results from this project suggest that pupil responses can be a good behavioral indicator. This study is a part of our research aiming to create an artificial intelligent system for medical trainees with automatic detection of their performance difficulty and delivering instructional messages using augmented reality technology.

Cognitive demands and mental workload: A filed study of the mining control room operators

Cognitive demand and mental workload assessment are essential for the optimal interaction of human-machine systems. The aim of this study was to investigate the cognitive demands and mental workload as well as the relationship between them among the mining control room operators.

This cross-sectional study was performed on 63 control room operators of a large mining plant located in Iran. Cognitive demands and mental workload were assessed using cognitive task analysis (CTA) and NASA Task Load Index (NASA-TLX), respectively and the analysis was performed using SPSS version 21. Independent samples T-test, Mann-Whitney U test and multivariate linear regression were used for data analysis.

Twelve cognitive demands were extracted after observing the tasks and conducting semi-structured interviews with the control room staff. The mean scores of total cognitive demands and MWL were 6.60 and 72.89, respectively, and these two indicators showed a positive and significant correlation (r = 0.286; P = 0.023). The participants’ demographic characteristics such as age, education, and work experience did not affect mental workload, but the two cognitive demands (memory and defect detection) affected MWL.

High cognitive demands and mental workload indicate poor interaction between humans and machines. Due to the effect of memory load and defect detection on mental workload, it is recommended to assign cognitive tasks based on memory and defect detection to the machine to reduce the mental workload and improve human-machine interaction.

Clinical Characteristics and Outcomes Among Patients Undergoing High-Risk Percutaneous Coronary Interventions by Single or Multiple Operators: Insights From the Veterans Affairs Clinical Assessment, Reporting, and Tracking Program

Background High-risk percutaneous coronary intervention (HR-PCI) is increasingly common among contemporary patients with coronary artery disease. Experts have advocated for a collaborative 2-operator approach to support intraprocedural decision-making for these complex interventions. The impact of a second operator on patient and procedural outcomes is unknown. Methods and Results Patients who underwent HR-PCI from 2015 to 2018 within the Veterans Affairs Healthcare System were identified. Propensity-matched cohorts were generated to compare the outcomes following HR-PCI performed by a single or multiple (≥2) operators. The primary end point was the 12-month rate of major adverse cardiovascular events. We identified 6672 patients who underwent HR-PCI during the study period; 6211 (93%) were treated by a single operator, and 461 (7%) were treated by multiple operators, with a nonsignificant trend toward increased multioperator procedures over time. A higher proportion of patients treated by multiple operators underwent left main (10% versus 7%, P=0.045) or chronic total occlusion intervention (11% versus 5%, P<0.001). Lead interventionalists participating in multioperator procedures practiced at centers with higher annual HR-PCI volumes (124±71.3 versus 111±69.2; standardized mean difference, 0.197; P<0.001) but otherwise performed a similar number of HR-PCI procedures per year (34.4±35.3 versus 34.7±30.7; standardized mean difference, 0.388; P=0.841) compared with their peers performing single-operator interventions. In a propensity-matched cohort, there was no significant difference in major adverse cardiovascular events (32% versus 30%, P=0.444) between patients who underwent single-operator versus multioperator HR-PCI. Adjusted analyses accounting for site-level variance showed no significant differences in outcomes. Conclusions Patients who underwent multioperator HR-PCI had similar outcomes compared with single-operator procedures. Further studies are needed to determine if the addition of a second operator offers clinical benefits to a subset of HR-PCI patients undergoing left main or chronic total occlusion intervention.

Automatic control of blood flow rate on the arterial-line side during cardiopulmonary bypass

The operation of the cardiopulmonary bypass (CPB) system requires skilled techniques and experience. Intraoperatively, the perfusionist needs to intermittently manipulate both of the occluders on the venous- and arterial-line sides to achieve the desired blood flow rates. To facilitate the occluder operation, we propose an automatic control system for the arterial-line side blood flow rate based on a dynamic model that addresses the relationship between the occluder operation and blood flow rate in the CPB system. The simulation results demonstrated that the proposed system was able to control the blood flow rate even when the estimation error of the model parameters was presented. Then, we implemented this control system in the CPB system and conducted an experiment to automatically control the arterial-line side blood flow rate. We confirmed that the blood flow rate on the arterial-line side could follow the manually operated venous-line side blood flow rate.Clinical Relevance--- The automatic blood flow rate control system for a cardiopulmonary bypass system, proposed in this paper, contributes to reducing the burden of occluder operation on a perfusionist.

Analysis of Dynamic Changes in Cognitive Workload During Cardiac Surgery Perfusionists' Interactions With the Cardiopulmonary Bypass Pump

OBJECTIVE

This novel preliminary study sought to capture dynamic changes in heart rate variability (HRV) as a proxy for cognitive workload among perfusionists while operating the cardiopulmonary bypass (CPB) pump during real-life cardiac surgery.

BACKGROUND

Estimations of operators' cognitive workload states in naturalistic settings have been derived using noninvasive psychophysiological measures. Effective CPB pump operation by perfusionists is critical in maintaining the patient's homeostasis during open-heart surgery. Investigation into dynamic cognitive workload fluctuations, and their relationship with performance, is lacking in the literature.

METHOD

HRV and self-reported cognitive workload were collected from three Board-certified cardiac perfusionists (N = 23 cases). Five HRV components were analyzed in consecutive nonoverlapping 1-min windows from skin incision through sternal closure. Cases were annotated according to predetermined phases: prebypass, three phases during bypass, and postbypass. Values from all 1min time windows within each phase were averaged.

RESULTS

Cognitive workload was at its highest during the time between initiating bypass and clamping the aorta (preclamp phase during bypass), and decreased over the course of the bypass period.

CONCLUSION

We identified dynamic, temporal fluctuations in HRV among perfusionists during cardiac surgery corresponding to subjective reports of cognitive workload. Not only does cognitive workload differ for perfusionists during bypass compared with pre- and postbypass phases, but differences in HRV were also detected within the three bypass phases.

APPLICATION

These preliminary findings suggest the preclamp phase of CPB pump interaction corresponds to higher cognitive workload, which may point to an area warranting further exploration using passive measurement.

Using Eye Tracking for Measuring Cognitive Workload During Clinical Simulations: Literature Review and Synthesis

High-fidelity clinical simulations can be used by clinicians to acquire technical (physical ability and knowledge) and non-technical (cognitive and social processes) skills. Excessive cognitive workload contributes to medical errors because of the impact on both technical and non-technical skills. Many studies measure cognitive workload with psychometric instruments that limit the assessment of cognitive workload to a single time period and may involve response bias. Using eye tracking to measure task-evoked pupillary responses allows the measurement of changes in pupil diameter related to the cognitive workload associated with a specific activity. Incorporating eye tracking with high-fidelity clinical simulations provides a reliable and continuous assessment of cognitive workload. The purpose of this literature review is to summarize the use of eye-tracking technology to measure cognitive workload of healthcare providers to generate evidence-based guidelines for measuring cognitive workload during high-fidelity clinical simulations. What this manuscript adds to the body of literature is a summary of best practices related to the different methods of measuring cognitive workload, benefits and limitations of using eye tracking, and high-fidelity clinical simulation design considerations for successful integration of eye tracking.

Comparison of a perfusion simulator to a clinical operating room: evaluation of eye tracking data and subjective perception. A pilot study

Background:

With the aim of evaluating the perfusion simulator at the German Heart Center Berlin, similarity between simulation and clinical operation room (OR) was investigated regarding subjective perception and eye movement.

Methods:

Eight perfusionists performed an operation on the heart-lung machine (HLM) wearing eye tracking glasses, each in real OR and simulator. The three most important phases for perfusionists (going on bypass, cardioplegia administration and coming off bypass) were considered. Additional to eye tracking data as objective measure, questionnaires were completed, and interviews conducted afterwards.

Results:

The structure of simulator and real OR is perceived as basically the same. Yet there are differences in the HLM-models used and the temporal sequence. Different perception of both situations is reported in interviews and reflected in significant differences in the rating scales (NASA-TLX) on three of six subscales. In eye tracking data, certain AOIs could be identified for the individual phases, both in OR and simulator—an indication of fundamental similarity. However, differences regarding the proportions of the individual AOIs, especially in the first and third phase, are leading to the assumption that the simulator, and especially the simulation process, is only valid to a limited extent regarding subjective perception and eye tracking data.

Conclusion:

The use of the simulator for (advanced) training is accepted and explicitly requested by perfusionists. Yet further research is needed to identify the decisive factors (like simulation duration or additional tasks) for a valid execution in the simulator. Furthermore, a larger sample size should be regarded to allow statistical analysis.

Simulation-based training of critical events during cardiopulmonary bypass: importance of a critical events checklist

Objectives:

Evaluation of critical events training for clinical perfusionists is necessary to improve this educational approach. Critical events checklists are effective in reducing clinical complications, but should be tested in a simulation environment first. Individual behavior and stress response of clinical perfusionists during simulated critical events on cardiopulmonary bypass have not been evaluated yet. This study focuses on the evaluation of critical events training and critical events checklists in simulated cardiopulmonary bypass.

Methods:

A total of 19 clinical perfusionists from a single hospital took part in two simulated critical event scenarios. Clinical perfusionist behavior and physiological responses were recorded using eye tracking, heart rate variability, video, and audio. In addition, workloads were determined and participants were interviewed.

Results:

Relevant areas of interest were identified for each simulation phase. During critical event detection and subsequent decision-making, areas of interest hits and fixation durations varied with the use of a critical events checklist. Times to decision were shorter, decision quality was higher, and temporal workload was increased when the checklist was used. Evaluation of selected heart rate variability measures revealed a good correlation with pupil diameters.

Conclusion:

Evaluation of critical events during simulated cardiopulmonary bypass shows that the scenario is realistic and relevant for clinical practice. Integrating a critical events checklist improves the probability of correct decision-making and shortens the correct decision time. Temporal workload is increased when using a checklist. Eye tracking and heart rate variability are well suited to evaluate participants’ behaviors and stress levels. All participants welcomed simulation training for critical incidents.

Association of Electronic Health Record Use With Physician Fatigue and Efficiency

IMPORTANCE

The use of electronic health records (EHRs) is directly associated with physician burnout. An underlying factor associated with burnout may be EHR-related fatigue owing to insufficient user-centered interface design and suboptimal usability.

OBJECTIVE

To examine the association between EHR use and fatigue, as measured by pupillometry, and efficiency, as measured by mouse clicks, time, and number of EHR screens, among intensive care unit (ICU) physicians completing a simulation activity in a prominent EHR.

DESIGN, SETTING, AND PARTICIPANTS

A cross-sectional, simulation-based EHR usability assessment of a leading EHR system was conducted from March 20 to April 5, 2018, among 25 ICU physicians and physician trainees at a southeastern US academic medical center. Participants completed 4 simulation patient cases in the EHR that involved information retrieval and task execution while wearing eye-tracking glasses. Fatigue was quantified through continuous eye pupil data; EHR efficiency was characterized through task completion time, mouse clicks, and EHR screen visits. Data were analyzed from June 1, 2018, to August 31, 2019.

MAIN OUTCOMES AND MEASURES

Primary outcomes were physician fatigue, measured by pupillometry (with lower scores indicating greater fatigue), and EHR efficiency, measured by task completion times, number of mouse clicks, and number of screens visited during EHR simulation.

RESULTS

The 25 ICU physicians (13 women; mean [SD] age, 32.1 [6.1] years) who completed a simulation exercise involving 4 patient cases (mean [SD] completion time, 34:43 [11:41] minutes) recorded a total of 14 hours and 27 minutes of EHR activity. All physician participants experienced physiological fatigue at least once during the exercise, and 20 of 25 participants (80%) experienced physiological fatigue within the first 22 minutes of EHR use. Physicians who experienced EHR-related fatigue in 1 patient case were less efficient in the subsequent patient case, as demonstrated by longer task completion times (r = -0.521; P = .007), higher numbers of mouse clicks (r = -0.562; P = .003), and more EHR screen visits (r = -0.486; P = .01).

CONCLUSIONS AND RELEVANCE

This study reports high rates of fatigue among ICU physicians during short periods of EHR simulation, which were negatively associated with EHR efficiency and included a carryover association across patient cases. More research is needed to investigate the underlying causes of EHR-associated fatigue, to support user-centered EHR design, and to inform safe EHR use policies and guidelines.

Simulation in perfusion: evaluating the efficacy of a specific training with eye-tracking

BACKGROUND

With the aim of integrating simulation training into the training of perfusionists, we examined whether the participants were able to transfer a specific learning content to the same and different situations and assessed their feedback on the simulation training. Eye-tracking was tested as a measure and supplemented by additional measures.

METHODS

A 2 × 2 mixed design was used, with test time (pre- and post-test) and training group (same and different content training) as factors. In the pre- and post-test, the participant had to handle a critical situation on the cardiopulmonary bypass, namely, a drop in arterial partial oxygen pressure. Between the two test times, the participant practised under guidance the handling of either the same critical situation (Group 1) or a different one, that is, impaired venous return (Group 2). Dependent measures were fixations of the eyes on specific areas of interest on the heart-lung machine, measures of latency and subjective assessments. Moreover, participants gave feedback on the simulation training.

RESULTS

Fixation analyses showed that the training led to an increased gaze on areas of interest relevant to the drop in arterial partial oxygen pressure in both groups, with a significant increase only for Group 1. The surveys revealed a great interest in the integration of simulation training into education.

CONCLUSION

In combination with other measures, eye-tracking is suitable for the evaluation of simulation training. Due to the positive training effects and positive participant feedback, the integration of simulation into the training of perfusionists is advocated. Concerning transfer of learning content, more research is needed.