A novel multimodal, intraoperative cognitive workload assessment of cardiac surgery team members

Objective: To characterize cognitive workload (CWL) of cardiac surgery team members in a real-world setting during coronary artery bypass grafting (CABG) surgery using providers' heart rate variability (HRV) data as a surrogate measure of CWL.

Methods: HRV was collected from the surgeon, anesthesiologist, perfusionist, and scrub nurse, and audio/video recordings were made during isolated, nonemergency CABG surgeries (n = 27). Eight surgical phases were annotated by trained researchers, and HRV was calculated for each phase.

Results: Significant differences in CWL were observed within a given role across surgical phases. Results are reported as predicted probability (95% confidence interval [CI]). CWL was significantly higher for anesthesiologists during "preparation and induction" (0.57; 95% CI, 0.42-0.71) and "anastomoses" (0.44; 95% CI, 0.30-0.58) compared to other phases, and the same held for nurses during the "opening" (0.51; 95% CI, 0.37-0.65) and "postoperative" (0.68; 95% CI, 0.42-0.86) phases. Additional significant differences were observed between roles within a given surgical phase. For example, surgeons had significantly higher CWL during "anastomoses" (0.81; 95% CI, 0.69-0.89) compared to all other phases, and the same was true of perfusionists during the "opening" (0.79; 95% CI, 0.66-0.88) and "prebypass preparation" (0.50; 95% CI, 0.36-0.64) phases.

Conclusions: Our innovative analysis demonstrates that CWL fluctuates across surgical procedures by role and phase, which may reflect the distribution of primary tasks. This corroborates earlier findings from self-report measures. The data suggest that team-wide, peak CWL during a phase decreases from early phases of surgery through initiation of cardiopumonary bypass (CPB), rises during anastomosis, and decreases after termination of CPB. Knowledge of these trends could encourage the adoption of behaviors to enhance team dynamics and performance.