How Does Surgeons' Autonomic Physiology Vary Intraoperatively?: A Real-time Study of Cardiac Reactivity

To measure the physiological responses of surgical team members under varying levels of intraoperative risk.

Measurement of intraoperative physiological responses provides insight into how operation complexity, phase of surgery, and surgeon seniority impact stress.

Autonomic nervous system responses (interbeat intervals, IBIs) were measured continuously during different surgical operations of various complexity. The study investigated whether professional role (eg attending surgeon), operative risk (high vs. low), and type of primary operator (attending surgeon vs. resident) impacted IBI reactivity. Physiological synchrony captured the degree of correspondence between individuals' physiological responses at any given time point.

A total of 10,005 observations of IBI reactivity were recorded in 26 participants during 16 high-risk (renal transplant and laparoscopic donor nephrectomy) and low-risk (arteriovenous fistula formation) operations. Attending surgeons showed greater IBI reactivity (faster heart rate) than residents and nurses during high-risk operations and while actively operating (Ps<0.001). Residents showed lower reactivity during high-risk (relative to low-risk) operations (P<0.001) and similar reactivity regardless of whether they or the attending surgeon was operating (P=0.10). Nurses responded similarly during low-risk and high-risk operations (P=0.102) but were more reactive when the resident was operating compared to when the attending surgeon was the primary operator (P<0.001). In high-risk operations, attending surgeons had negative physiological covariation with residents and nurses (P<0.001). In low-risk operations, only attending surgeons and nurses were synchronized (P<0.001).

Attending surgeons' physiological responses were well-calibrated to operative demands. Residents' and nurses' responses were not callibrated to the same extent. This suggests that risk sensitivity is an adaptive response to stress that surgeons acquire.