Systematic review of measurement tools to assess surgeons' intraoperative cognitive workload

Surgery Task Load Index in Cardiac Surgery: Measuring Cognitive Load Among Teams

Background. The most commonly used subjective assessment of perceived cognitive load, the NASA Task Load Index (TLX), has proven valuable in measuring individual load among general populations. The surgery task load index (SURG-TLX) was developed and validated to measure cognitive load specifically among individuals within a surgical team. Notably, the TLX lacks temporal sensitivity in its typical retrospective administration. Objective. This study sought to expand the utility of SURG-TLX by investigating individual measures of cognitive load over time during cardiac surgery, and the relationship between individual and team measures of cognitive load and proxies for surgical complexity. Materials & Methods. SURG-TLX was administered retrospectively in the operating room immediately following each case to approximate cognitive load before, during, and after cardiopulmonary bypass for cardiac surgery team members (surgeon, anesthesiologist, and perfusionist). Correlations were calculated to determine the relationship of individual and team measures of cognitive load over the entire procedure with bypass length and surgery length. Results. Results suggest that perceived cognitive load varies throughout the procedure such that cognitive load during bypass significantly differs compared to before or after bypass, across all 3 roles. While on bypass, results show that anesthesiologists experience significantly lower levels of perceived cognitive load than both surgeons and perfusionists. Correlational analyses reveal that perceived cognitive load of both the surgeon and the team had significant positive associations with bypass length and surgery length. Conclusion. Our findings support the utility of SURG-TLX in real cardiac cases as a measure of cognitive load over time, and on an individual and team-wide basis.

Augmented Reality for Acetabular Component Placement in Direct Anterior Total Hip Arthroplasty

BACKGROUND

Malposition of the acetabular component of a hip prosthesis can lead to poor outcomes. Traditional placement with fluoroscopic guidance results in a 35% malpositioning rate. We compared the (1) accuracy and precision of component placement, (2) procedure time, (3) radiation dose, and (4) usability of a novel 3-dimensional augmented reality (AR) guidance system vs standard fluoroscopic guidance for acetabular component placement.

METHODS

We simulated component placement using a radiopaque foam pelvis. Cone-beam computed tomographic data and optical data from a red-green-blue-depth camera were coregistered to create the AR environment. Eight orthopedic surgery trainees completed component placement using both methods. We measured component position (inclination, anteversion), procedure time, radiation dose, and usability (System Usability Scale score, Surgical Task Load Index value). Alpha = .05.

RESULTS

Compared with fluoroscopic technique, AR technique was significantly more accurate for achieving target inclination (P = .01) and anteversion (P = .02) and more precise for achieving target anteversion (P < .01). AR technique was faster (mean ± standard deviation, 1.8 ± 0.25 vs 3.9 ± 1.6 minute; P < .01), and participants rated it as significantly easier to use according to both scales (P < .05). Radiation dose was not significantly different between techniques (P = .48).

CONCLUSION

A novel 3-dimensional AR guidance system produced more accurate inclination and anteversion and more precise anteversion in the placement of the acetabular component of a hip prosthesis. AR guidance was faster and easier to use than standard fluoroscopic guidance and did not involve greater radiation dose.

Learning theories and principles in surgical education and technical learning

What is important to think about in surgical education and technical skills training? Technical skills training is grounded in social cognitive theory and the concepts of modeling and self-efficacy. Cognitive and nontechnical learning is critical to supplement the overall proficiency of the surgical learner in performing an operation. Technical learning is cemented by deliberate practice and there is benefit to productive struggle and failure. External cognitive load should be minimized to maximized operative skills advancement.

Learning Intracorporeal Suture on Pelvitrainer Using a Robotized Versus Conventional Needle Holder

BACKGROUND

Laparoscopy is the gold standard approach in numerous surgical procedures. A new generation of robotized instruments has been developed to compensate for the ergonomic constraints of conventional instruments. The main objective was to compare the learning curves of novices for intracorporeal suturing on a laparoscopy pelvitrainer, using either a robotized needle holder or conventional needle holders. The post-training performances under ergonomically difficult conditions were also analyzed.

MATERIALS AND METHODS

Fifth-year medical students were randomized in group A using a robotized needle holder (JAIMY; Endocontrol, Grenoble, France) and group B using straight conventional needle holders. They undertook four training sessions (intracorporeal knot-tying task) followed by an evaluation session (intracorporeal knots-tying task, frontal suture, and hexagonal suture).

RESULTS

Twenty participants were included. The performances of the two groups (n = 10) were not significantly different at baseline. During the training sessions, there was a learning curve with a plateau at the third session for both the groups. At the final evaluation session, there was no significant difference between group A and group B for the intracorporeal knot-tying task (median fundamentals of laparoscopic surgery score: 468 versus 474.5 respectively; P = 0.762). There was a significant difference between group A and group B for the frontal suture (median global score: 15.75 versus 3.75 respectively; P = 0.005) but not for the hexagonal suture (median global score: 18 versus 15 respectively; P = 0.284).

CONCLUSIONS

Learning curves were equally fast using the robotized needle holder versus conventional instruments and led to equivalent performances. Under ergonomically difficult conditions, the robotized needle holder provided an advantage relative to conventional instruments.

Results of exploratory investigation into adherence to auditory coping instructions during an acutely stressful task

Healthcare providers often perform under significant stress, during which their performance must be optimal, but is known to suffer. Stress management interventions in this context can provide cognitive support to rescue performance. This exploratory study sought to evaluate the effect of stress intervention components on stress and performance while clinicians engaged in two versions of a computer-based task, differing in overall level of demand: one high-stress and one low-stress. Participants (N = 45) were assigned to one of five groups (N = 9 per group), where they each completed both versions of the task, under different conditions of cognitive support. Group 1 received no intervention; Group 2 received biofeedback; and Group 3 received biofeedback and explicit coping instructions. Group 4 received emotional intelligence training, and Group 5 received emotional intelligence training and biofeedback. We hypothesized that Group 3 participants would present the lowest self-reported and physiological measures of stress, and the highest performance. Results reveal that the high-stress task induced significantly higher self-reported and physiological stress/anxiety, and lower task performance. No significant main effects of experimental condition or interaction effects were detected, indicating that intervention components had minimal effect on stress and performance. However, ultra-short term physiological analysis, analyzing <5 min of HRV data, revealed significantly decreased stress (SDNN, the standard deviation of normal-to-normal peaks) following auditory coping instructions. Exploratory study results suggest that although cognitive intervention components had minimal effect on stress and performance, physiological stress may be significantly reduced immediately following adherence to a coping instruction intervention. Future work is needed.Lay summaryThis exploratory study evaluated the potential benefit of providing healthcare practitioners with various stress management components during an acutely stressful task. Our results support the positive effect of following behavioral coping instructions on immediate physiological measures of stress.

A pilot study comparing ergonomics in laparoscopy and robotics: beyond anecdotes, and subjective claims

We aimed to use hand dexterity and grip strength test as objective measures to compare the difference in surgeon fatigue associated with robotic and laparoscopic colorectal surgery. We used the Purdue Pegboard Test to assess hand dexterity and the Camry Electronic Handgrip Dynamometer to assess hand grip strength. Eighteen patients were operated on, including 10 robotic and 8 laparoscopic cases. Statistical analysis revealed no difference in dexterity or muscle fatigue after operating with the robot. In contrast, there was a significant difference in the hand grip strength of both hands after laparoscopic surgery. Our results show that the resultant fatigue after laparoscopy affects both hands of the surgeon. In contrast, there was no difference in dexterity or muscle fatigue after operating with the robot. Given the demands of complex colorectal surgeries, robotics may be a means of optimizing surgeon performance by reducing fatigue.

Factors Predicting Operative Difficulty of Laparoscopic Total Mesorectal Excision

BACKGROUND

Laparoscopic total mesorectal excision is a challenging procedure requiring high-quality surgery for optimal outcomes. Patient, tumor, and pelvic factors are believed to determine difficulty, but previous studies were limited to postoperative data.

OBJECTIVE

This study aimed to report factors predicting laparoscopic total mesorectal excision performance by using objective intraoperative assessment.

DESIGN

Data from a multicenter laparoscopic total mesorectal excision randomized trial (ISRCTN59485808) were reviewed.

SETTING

This study was conducted at 4 centers in the United Kingdom.

PATIENTS AND INTERVENTION

Seventy-one patients underwent elective laparoscopic total mesorectal excision for rectal adenocarcinoma with curative intent: 53% were men, mean age was 69 years, body mass index was 27.7, tumor height was 8.5 cm, 24% underwent neoadjuvant therapy, and 25% had previous surgery.

MAIN OUTCOME MEASURES

Surgical performance was assessed through the identification of intraoperative adverse events by using observational clinical human reliability analysis. Univariate analysis and multivariate binomial regression were performed to establish factors predicting the number of intraoperative errors, surgeon-reported case difficulty, and short-term clinical and histopathological outcomes.

RESULTS

A total of 1331 intraoperative errors were identified from 365 hours of surgery (median, 18 per case; interquartile range, 16-22; and range, 9-49). No patient, tumor, or bony pelvimetry measurement correlated with total or pelvic error count, surgeon-reported case difficulty, cognitive load, operative data, specimen quality, number or severity of 30-day morbidity events and length of stay (all r not exceeding ±0.26, p > 0.05). Mesorectal area was associated with major intraoperative adverse events (OR, 1.09; 95%CI, 1.01-1.16; p = 0.015) and postoperative morbidity (OR, 1.1; 95% CI, 1.01-1.2; p = 0.033). Obese men were subjectively reported as harder cases (24 vs 36 mm, p = 0.042), but no detrimental effects on performance or outcomes were seen.

LIMITATIONS

Our sample size is modest, risking type II errors and overfitting of the statistical models.

CONCLUSION

Patient, tumor, and bony pelvic anatomical characteristics are not seen to influence laparoscopic total mesorectal excision operative difficulty. Mesorectal area is identified as a risk factor for intraoperative and postoperative morbidity. See Video Abstract at http://links.lww.com/DCR/B35. FACTORES QUE PREDICEN LA DIFICULTAD OPERATIVA DE LA ESCISIÓN MESORRECTAL TOTAL LAPAROSCÓPICA: La escisión mesorrectal total laparoscópica es un procedimiento desafiante. Para obtener resultados óptimos, se requiere cirugía de alta calidad. Se cree que, factores como el paciente, el tumor y la pelvis, determinan la dificultad, pero estudios previos solamente se han limitado a datos postoperatorios.Informar de los factores que predicen el resultado de la escisión mesorrectal total laparoscópica, mediante una evaluación intraoperatoria objetiva.Datos de un ensayo multicéntrico y randomizado de escisión mesorrectal total laparoscópica (ISRCTN59485808).Cuatro centros del Reino Unido.Un total de 71 pacientes fueron sometidos a escisión mesorrectal total laparoscópica electiva, para adenocarcinoma rectal con intención curativa. 53% hombres, edad media, índice de masa corporal y altura del tumor 69, 27.7 y 8.5 cm respectivamente, 24% terapia neoadyuvante y 25% cirugía previa.Rendimiento quirúrgico evaluado mediante la identificación de eventos intraoperatorios adversos, mediante el análisis clínico observacional de confiabilidad humana. Se realizaron análisis univariado y la regresión binomial multivariada para establecer factores que predicen el número de errores intraoperatorios, reportes del cirujano sobre la dificultad del caso y los resultados clínicos e histopatológicos a corto plazo.Se identificaron un total de 1,331 errores intraoperatorios en 365 horas de cirugía (media de 18 por caso, IQR 16-22, rango 9-49). Ningún paciente, tumor o medición de pelvimetría pélvica, se correlacionó con la cuenta de errores pélvicos o totales, reporte del cirujano sobre dificultad del caso, carga cognitiva, datos operativos, calidad de la muestra, número o gravedad de eventos de morbilidad de 30 días y duración de la estadía (todos r <± 0.26, p > 0.05). El área mesorrectal se asoció con eventos adversos intraoperatorios importantes (OR, 1.09; IC 95%, 1.01-1.16; p = 0.015) y morbilidad postoperatoria (OR, 1.1; IC 95%, 1.01-1.2; p = 0.033). Como información subjetiva, hombres obesos fueron casos más difíciles (24 mm frente a 36 mm, p = 0.042) pero no se observaron efectos perjudiciales sobre el rendimiento o los resultados.Nuestro tamaño de muestra es un modesto riesgo de errores de tipo II y el sobreajuste de los modelos estadísticos.No se observa que las características anatómicas del paciente, tumor y pelvis ósea influyan en la dificultad operatoria de la escisión mesorrectal laparoscópica total. El área mesorrectal se identifica como un factor de riesgo para la morbilidad intraoperatoria y postoperatoria. Vea el resumen del video en http://links.lww.com/DCR/B35.

Workload and influencing factors in non-emergency medical transfers: a multiple linear regression analysis of a cross-sectional questionnaire study

Background

Human workload is a key factor for system performance, but data on emergency medical services (EMS) are scarce. We investigated paramedics’ workload and the influencing factors for non-emergency medical transfers. These missions make up a major part of EMS activities in Germany and are growing steadily in number.

Methods

Paramedics rated missions retrospectively through an online questionnaire. We used the NASA-Task Load Index (TLX) to quantify workload and asked about a variety of medical and procedural aspects for each mission. Teamwork was assessed by the Weller teamwork measurement tool (TMT). With a multiple linear regression model, we identified a set of factors leading to relevant increases or decreases in workload.

Results

A total of 194 non-emergency missions were analysed. Global workload was rated low (Mean = 27/100). In summary, 42.8% of missions were rated with a TLX under 20/100. TLX subscales revealed low task demands but a very positive self-perception of performance (Mean = 15/100). Teamwork gained high ratings (Mean TMT = 5.8/7), and good teamwork led to decreases in workload. Aggression events originating from patients and bystanders occurred frequently (n = 25, 12.9%) and increased workload significantly. Other factors affecting workload were the patient’s body weight and the transfer of patients with transmittable pathogens.

Conclusion

The workload during non-emergency medical transfers was low to very low, but performance perception was very positive, and no indicators of task underload were found. We identified several factors that led to workload increases. Future measures should attempt to better train paramedics for aggression incidents, to explore the usefulness of further technical aids in the transfer of obese patients and to reconsider standard operating procedures for missions with transmittable pathogens.

Cognitive Engineering to Improve Patient Safety and Outcomes in Cardiothoracic Surgery

Cognitive engineering is focused on how humans can cope and master the complexity of processes and technological environments. In cardiothoracic surgery, the goal is to support safe and effective human performance by preventing medical errors. Strategies derived from cognitive engineering research could be introduced in cardiothoracic surgery practice in the near future to enhance patient safety and outcomes.

Comparison of 3- vs 2-Dimensional Endoscopy Using Eye Tracking and Assessment of Cognitive Load Among Surgeons Performing Endoscopic Ear Surgery

Importance

Endoscopic ear surgery (EES) is an emerging technique to treat middle ear diseases; however, the interventions are performed in 2-dimensional (2D) endoscopic views, which do not provide depth perception. Recent technical developments now allow the application of 3-dimensional (3D) endoscopy in EES.

Objective

To investigate the usability, advantages, and disadvantages of 3D vs 2D endoscopy in EES under standardized conditions.

Design, Setting, and Participants

This cohort study conducted at a tertiary academic medical center in Bern, Switzerland, included 16 residents and consultants of the Department of Otorhinolaryngology, Head & Neck Surgery, Inselspital, Bern.

Interventions

Each participant performed selected steps of a type I tympanoplasty and stapedotomy in 3D and 2D views in a cadaveric model using a randomized, Latin-square crossover design.

Main Outcomes and Measures

Time taken to perform the EES, number of attempts, and accidental damage during the dissections were compared between 3D and 2D endoscopy. Eye tracking was performed throughout the interventions. Cognitive load and subjective feedback were measured by standardized questionnaires.

Results

Of the 16 surgeons included in the study (11 inexperienced residents; 5 experienced consultants), 8 were women (50%); mean age was 36 years (range, 27-57 years). Assessment of surgical time revealed similar operating times for both techniques (181 seconds in 2D vs 174 seconds in 3D). A total of 64 surgical interventions were performed. Most surgeons preferred the 3D technique (10 for 3D vs 6 for 2D), even though a higher incidence of eye strain, measured on a 7-point Likert scale, was observed (3D, 2.19 points vs 2D, 1.44 points; mean difference , 0.74; 95% CI, 0.29-1.20; r = 0.67). Eye movement assessment revealed a higher duration of fixation for consultants in 2D (0.79 seconds) compared with 3D endoscopy (0.54 seconds), indicating a less-efficient application of previously acquired experiences using the new technique. Residents (mean [SD], 49.02 [16.4]) had a significantly higher workload than consultants (mean [SD], 27.21 [12.20]), independent of the used technique or task.

Conclusions and Relevance

Three-dimensional endoscopy is suitable for EES, especially for inexperienced surgeons whose mental model of the intervention has yet to be consolidated. The application of 3D endoscopy in clinical routines and for educational purposes may be feasible and beneficial.

Factors associated with surgeon's perception of distraction in the operating room

BACKGROUND

Distractions in the operating room (OR) can create stress among surgeons and lead to higher chances of errors and adverse events. The objective is to determine intraoperative factors that are associated with surgeons' perception of distraction.

METHODS

We conducted a prospective cohort study in 265 consecutive patients undergoing elective laparoscopic general surgery during the 2 years after the implementation of a data capture system called the OR Black Box to identify intraoperative sources of distraction. At the end of each operation, human-factor surveys were administered to assess whether surgeons felt distracted. Using a multivariable logistic model, we determined which intraoperative sources of distraction were associated with the surgeons feeling distracted in the OR.

RESULTS

The attending surgeon reported feeling distracted in 120 of 265 operations (45%). Auditory sources of distraction, such as the OR door opening occurred at a median of 41 times per case (interquartile range (IQR), 32-54). Cognitive distractions such as teaching (142 cases (54%)), device malfunction (91 (34%)), irrelevant conversations (72 (27%)), management of the next case (41 (15%)), and time pressure (22 (8%)) occurred in a significant number of operations. In a multivariable analysis, presence of irrelevant conversations (odds ratio 2.14, 95% confidence interval (CI) 1.16-3.94, p = 0.015) and patient history of previous abdominal surgery (odds ratio 2.2, 95% CI 1.18-4.1, p = 0.013) were independently associated with increased likelihood of the surgeons feeling distracted.

CONCLUSIONS

Irrelevant conversation in the OR is a modifiable factor that was independently associated with surgeon's perception of distraction.

Using objective robotic automated performance metrics and task-evoked pupillary response to distinguish surgeon expertise

PURPOSE

In this study, we investigate the ability of automated performance metrics (APMs) and task-evoked pupillary response (TEPR), as objective measures of surgeon performance, to distinguish varying levels of surgeon expertise during generic robotic surgical tasks. Additionally, we evaluate the association between APMs and TEPR.

METHODS

Participants completed ten tasks on a da Vinci Xi Surgical System (Intuitive Surgical, Inc.), each representing a surgical skill type: EndoWrist^® manipulation, needle targeting, suturing/knot tying, and excision/dissection. Automated performance metrics (instrument motion tracking, EndoWrist^® articulation, and system events data) and TEPR were recorded by a systems data recorder (Intuitive Surgical, Inc.) and Tobii Pro Glasses 2 (Tobii Technologies, Inc.), respectively. The Kruskal-Wallis test determined significant differences between groups of varying expertise. Spearman's rank correlation coefficient measured associations between APMs and TEPR.

RESULTS

Twenty-six participants were stratified by robotic surgical experience: novice (no prior experience; n = 9), intermediate (< 100 cases; n = 9), and experts (≥ 100 cases; n = 8). Several APMs differentiated surgeon experience including task duration (p < 0.01), time active of instruments (p < 0.03), linear velocity of instruments (p < 0.04), and angular velocity of dominant instrument (p < 0.04). Task-evoked pupillary response distinguished surgeon expertise for three out of four task types (p < 0.04). Correlation trends between APMs and TEPR revealed that expert surgeons move more slowly with high cognitive workload (ρ < - 0.60, p < 0.05), while novices move faster under the same cognitive experiences (ρ > 0.66, p < 0.05).

CONCLUSIONS

Automated performance metrics and TEPR can distinguish surgeon expertise levels during robotic surgical tasks. Furthermore, under high cognitive workload, there can be a divergence in robotic movement profiles between expertise levels.

Physiological synchronization and entropy as measures of team cognitive load

The operating room (OR) is a high-risk and complex environment, where multiple specialized professionals work as a team to effectively care for patients in need of surgical interventions. Surgical tasks impose high cognitive demands on OR staff and cognitive overload may have deleterious effects on team performance and patient safety. The aim of the present study was to investigate the feasibility and describe a novel methodological approach to characterize dynamic changes in team cognitive load by measuring synchronization and entropy of heart rate variability parameters during real-life cardiac surgery. Cognitive load was measured by capturing interbeat intervals (IBI) from three team members (surgeon, anesthesiologist and perfusionist) using an unobtrusive wearable heart rate sensor and transmitted in real-time to a smartphone application. Clinical data and operating room audio/video recordings were also collected to provide behavioral and contextual information. We developed symbolic representations of the transient cognitive state of individual team members (Individual Cognitive State - ICS), and overall team (Team Cognitive State - TCS) by comparing IBI data from each team member with themselves and with others. The distribution of TCS symbols during surgery enabled us to display and analyze temporal states and dynamic changes of team cognitive load. Shannon's entropy was calculated to estimate the changing levels of team organization and to detect fluctuations resulting from a variety of cognitive demands and/or specific situations (e.g. medical error, emergency, flow disruptions). An illustrative example from a real cardiac surgery team shows how cognitive load patterns shifted rapidly after an actual near-miss medication event, leading the team to a more organized and synchronized state. The methodological approach described in this study provides a measurement technique for the assessment of team physiological synchronization, which can be applied to many other team-based environments. Future research should gather additional validity evidence to support the proposed methods for team cognitive load measurement.

Detecting Mental Workload in Surgical Teams Using a Wearable Single-Channel Electroencephalographic Device

OBJECTIVE

To assess the sensitivity of an electroencephalographic (EEG)-based index, the prefrontal beta power, to quantify the mental workload in surgeons in real scenarios. Such EEG-based index might offer unique and unbiased measures of overload, a crucial factor when designing learning and training surgical programs.

DESIGN

The experiment followed a 2 × 2 × 2 within subjects design with 3 factors: (1) Surgical Role during the surgery (primary surgeon vs. assistant surgeon), (2) the Surgical Procedure (laparo-endoscopic single-site [LESS] surgery vs. multiport laparoscopic surgery [MPS]), and (3) the Suturing Techniques (interrupted vs. continuous suture).

SETTING

The study was carried out at the Advanced Multi-Purpose Simulation and Technological Innovation Complex situated at IAVANTE (Granada, Spain).

METHODS

Four surgical teams (primary surgeon and assistant surgeon, experts in MPS) performed 8 surgical exercises on porcine models, under different task complexities. They performed 2 suturing techniques (continuous and interrupted), employing a low complex procedure (MPS) and a high complex procedure (LESS). Surgeons acted as the primary surgeon during half of the exercises, and, as the assistant surgeon, during the rest of them. Simultaneously, we monitored EEG prefrontal EEG beta power spectra of both surgeons, using 2 synchronized wearable EEG devices. We also collected performance and subjective data.

RESULTS

Surgical complexity modulated prefrontal beta power. LESS surgery caused significant higher prefrontal beta power for both suturing techniques for both surgical roles which indicates higher demands than MPS. Perceived task complexity, overall surgical evaluation, and laparoscopic execution time confirmed EEG-based results. Finally, subjective ratings of surgical complexity differentiated between surgical roles within the same exercise, even when prefrontal beta power did not.

CONCLUSIONS

To detect mental overload when surgeons are engaged with complex surgeries, real or simulated, is still guesswork. EEG-based indices have great potential as objective and nonintrusive measures to assess mental overload in surgeons. Furthermore, EEG-based indices might play a relevant role in monitoring surgeons and residents' cognitive state during their training.

Head-Mounted Mixed-Reality Technology During Robotic-Assisted Transanal Total Mesorectal Excision

INTRODUCTION

Head-mounted mixed-reality technologies may enable advanced intraoperative visualization during visceral surgery. In this technical note, we describe an innovative use of real-time mixed reality during robotic-assisted transanal total mesorectal excision.

TECHNIQUE

Video signals from the robotic console and video endoscopic transanal approach were displayed on a virtual monitor using a head-up display. The surgeon, assistant, and a surgical trainee used this technique during abdominal and transanal robotic-assisted total mesorectal excision. We evaluated the feasibility and usability of this approach with the use of validated scales.

RESULTS

The technical feasibility of the real-time visualization provided by the current setup was demonstrated for both the robotic and transanal parts of the surgery. The surgeon, assistant, and trainee each used the mixed-reality device for 15, 55, and 35 minutes. All participants handled the device intuitively and reported a high level of comfort during the surgery. The task load was easily manageable (task load index: <4/21), although the surgeon and assistant both noted a short delay in the real-time video.

CONCLUSION

The implementation of head-mounted mixed-reality technology during robotic-assisted transanal total mesorectal excision can benefit the operating surgeon, assistant, and surgical trainee. Further improvements in display quality, connectivity, and systems integration are necessary.

2D versus 3D laparoscopic total mesorectal excision: a developmental multicentre randomised controlled trial

AIMS

The role of laparoscopy in rectal cancer has been questioned. 3D laparoscopic systems are suggested to aid optimal surgical performance but have not been evaluated in advanced procedures. We hypothesised that stereoscopic imaging could improve the performance of laparoscopic total mesorectal excision (TME).

METHODS

A multicentre developmental randomised controlled trial comparing 2D and 3D laparoscopic TME was performed (ISRCTN59485808). Trial surgeons were colorectal consultants that had completed their TME proficiency curve and underwent stereoscopic visual testing. Patients requiring elective laparoscopic TME with curative intent were centrally randomised (1:1) to 2D or 3D using Karl Storz IMAGE1 S D3-Link™ and 10-mm TIPCAM®1S 3D passive polarising laparoscopic systems. Outcomes were enacted adverse events as assessed by the observational clinical human reliability analysis technique, intraoperative data, 30-day patient outcomes, histopathological specimen assessment and surgeon cognitive load.

RESULTS

88 patients were included. There were no differences in patient or tumour demographics, surgeon stereopsis, case difficulty, cognitive load, operative time, blood loss or conversion between the trial arms. 1377 intraoperative adverse events were identified (median 18 per case, IQR 14-21, range 2-49) with no differences seen between the 2D and 3D arms (18 (95% CI 17-21) vs. 17 (95% CI 16-19), p = 0.437). 3D laparoscopy had non-significantly higher mesorectal fascial plane resections (94 vs. 77%, p = 0.059; OR 0.23 (95% CI 0.05-1.16)) but equal lymph node yield and circumferential margin distance and involvement. 30-day morbidity, anastomotic leak, re-operation, length of stay and readmission rates were equal between the 2D and 3D arms.

CONCLUSION

Feasibility of performing multicentre 3D laparoscopic multicentre trials of specialist performed complex procedures is shown. 3D imaging did not alter the number of intraoperative adverse events; however, a potential improvement in mesorectal specimen quality was observed and should form the focus of future 3D laparoscopic TME trials.

First Reported Use of Team Cognitive Workload for Root Cause Analysis in Cardiac Surgery

Cognitive workload data of members of the cardiac surgery team can be measured intraoperatively and stored for later analysis. We present a case of a near-miss (medication error) that underwent root cause analysis using workload data. Heart rate variability data, representing workload levels, were collected from the attending surgeon, attending anesthesiologist, and lead perfusionist using wireless heart rate monitors. An episode of cognitive overload of the anesthesiologist due to a distractor was associated with the preventable error. Additional studies are needed to better understand the role of psychophysiological data in enhancing surgical patient safety.

Intelligent Interruption Management System to Enhance Safety and Performance in Complex Surgical and Robotic Procedures

Procedural flow disruptions secondary to interruptions play a key role in error occurrence during complex medical procedures, mainly because they increase mental workload among team members, negatively impacting team performance and patient safety. Since certain types of interruptions are unavoidable, and consequently the need for multitasking is inherent to complex procedural care, this field can benefit from an intelligent system capable of identifying in which moment flow interference is appropriate without generating disruptions. In the present study we describe a novel approach for the identification of tasks imposing low cognitive load and tasks that demand high cognitive effort during real-life cardiac surgeries. We used heart rate variability analysis as an objective measure of cognitive load, capturing data in a real-time and unobtrusive manner from multiple team members (surgeon, anesthesiologist and perfusionist) simultaneously. Using audio-video recordings, behavioral coding and a hierarchical surgical process model, we integrated multiple data sources to create an interactive surgical dashboard, enabling the identification of specific steps, substeps and tasks that impose low cognitive load. An interruption management system can use these low demand situations to guide the surgical team in terms of the appropriateness of flow interruptions. The described approach also enables us to detect cognitive load fluctuations over time, under specific conditions (e.g. emergencies) or in situations that are prone to errors. An in-depth understanding of the relationship between cognitive overload states, task demands, and error occurrence will drive the development of cognitive supporting systems that recognize and mitigate errors efficiently and proactively during high complex procedures.

Development of an Interactive Dashboard to Analyze Cognitive Workload of Surgical Teams During Complex Procedural Care

In the surgical setting, team members constantly deal with a high-demand operative environment that requires simultaneously processing a large amount of information. In certain situations, high demands imposed by surgical tasks and other sources may exceed team member's cognitive capacity, leading to cognitive overload which may place patient safety at risk. In the present study, we describe a novel approach to integrate an objective measure of team member's cognitive load with procedural, behavioral and contextual data from real-life cardiac surgeries. We used heart rate variability analysis, capturing data simultaneously from multiple team members (surgeon, anesthesiologist and perfusionist) in a real-time and unobtrusive manner. Using audio-video recordings, behavioral coding and a hierarchical surgical process model, we integrated multiple data sources to create an interactive surgical dashboard, enabling the analysis of the cognitive load imposed by specific steps, substeps and/or tasks. The described approach enables us to detect cognitive load fluctuations over time, under specific conditions (e.g. emergencies, teaching) and in situations that are prone to errors. This in-depth understanding of the relationship between cognitive load, task demands and error occurrence is essential for the development of cognitive support systems to recognize and mitigate errors during complex surgical care in the operating room.

Toward Improving Surgical Outcomes by Incorporating Cognitive Load Measurement into Process-Driven Guidance

This paper summarizes the accomplishments and recent directions of our medical safety project. Our process-based approach uses a detailed, rigorously-defined, and carefully validated process model to provide a dynamically updated, context-aware and thus, "Smart" Checklist to help process performers understand and manage their pending tasks [7]. This paper focuses on support for teams of performers, working independently as well as in close collaboration, in stressful situations that are life critical. Our recent work has three main thrusts: provide effective real-time guidance for closely collaborating teams; develop and evaluate techniques for measuring cognitive load based on biometric observations and human surveys; and, using these measurements plus analysis and discrete event process simulation, predict cognitive load throughout the process model and propose process modifications to help performers better manage high cognitive load situations. This project is a collaboration among software engineers, surgical team members, human factors researchers, and medical equipment instrumentation experts. Experimental prototype capabilities are being built and evaluated based upon process models of two cardiovascular surgery processes, Aortic Valve Replacement (AVR) and Coronary Artery Bypass Grafting (CABG). In this paper we describe our approach for each of the three research thrusts by illustrating our work for heparinization, a common subprocess of both AVR and CABG. Heparinization is a high-risk error-prone procedure that involves complex team interactions and thus highlights the importance of this work for improving patient outcomes.