Team-Level Heart Rate Variability Dispersion Across Surgical Stages of Coronary Artery Bypass Grafting Procedures

The operating room is a safety-critical environment where effective teamwork is essential to patient safety. In the cardiac operating room, heart rate variability (HRV) offers a noninvasive window into psychophysiological activity of providers that may provide insight into team-level physiological responses in this safety-critical context. In this exploratory study, team-level HRV dispersion of surgical teams during coronary artery bypass grafting (CABG) procedures was assessed using HRV metrics from the time-domain, frequency-domain, and nonlinear domain. Data from 15 CABG procedures and surgical teams were used to derive team-level HRV dispersion values for each surgical team and procedure stage, then analyzed using repeated-measures ANOVA to determine whether HRV dispersion varied significantly across stages. CABG procedures were analyzed using the original 14-stage segmentation and a condensed 8-stage segmentation for sensitivity analysis. The original segmentation served as the primary framework, with the condensed segmentation as a sensitivity analysis. Time-domain (SDNN) and log-transformed frequency-domain (HF) dispersion differed significantly across CABG stages under both segmentation schemes, whereas nonlinear domain (SampEn) dispersion did not show statistically significant stage effects. Holm-adjusted post hoc pairwise comparisons for SDNN did not identify significant differences between stages. In contrast, HF dispersion was significantly higher during closure than during selected earlier stages under both segmentations of the CABG procedures. These findings indicate stage-related variation in team-level SDNN and HF dispersion during CABG and support further investigation of HRV dispersion as a physiological measure in surgical team research.