The Imperial Stress Assessment Tool (ISAT): A Feasible, Reliable and Valid Approach to Measuring Stress in the Operating Room

Stress can impair surgical performance and may compromise patient safety. This prospective, cross-sectional study describes the feasibility, reliability, and validity of the Imperial Stress Assessment Tool (ISAT) as an approach to measuring stress during surgery. A total of 54 procedures were observed with 11 surgeons (4 attendings, 4 senior residents and 3 junior residents) in a large university teaching hospital in London, UK. Data collection involved physiological measures of operating surgeons [heart rate (HR) and salivary cortisol] and self-report questionnaires (State Trait Anxiety Inventory, or STAI). In all, 23 of 54 procedures were stressful, as identified by self-reporting. For stressful procedures compared to nonstressful ones, STAI was higher (mean +/- A SD) 9.81 +/- A 2.20 vs. 12.87 +/- A 4.27, t (30.64) = 3.15 as was the HR (mean +/- A SD) 79.94 +/- A 8.55 vs. 93.17 +/- A 14.94, t(32.57) = 3.81) (p < 0.05). Significant positive correlations were obtained between the measures indicating concurrent validity: Pearson's r = 0.47 (HR vs. STAI), 0.34 (cortisol vs. STAI), and 0.57 (HR vs. cortisol) (p < 0.05). Perfect correlation of subjective and objective measures was found for 70% of the procedures. HR and cortisol had specificities of 78% and 91% and sensitivities of 91% and 70% respectively for detecting stress during surgery. ISAT is a nonintrusive, feasible approach that combines subjective and objective methods for measuring stress in the operating room. The ISAT may increase understanding of the effects of stress on clinical performance and outcomes, leading to improved patient care.