Inter-anesthesiologist Practice Variation in Vasopressor Administration for Intraoperative Hypotension: A Retrospective Cohort Study

Introduction Intraoperative hypotension (IOH) is common and has been associated with postoperative organ injury, morbidity, and mortality. Although its incidence and treatment thresholds have been investigated, variation in vasopressor administration across individual anesthesiologists remains incompletely characterized. We aimed to assess inter-anesthesiologist variation in documented vasopressor administration in response to IOH during elective non-cardiac surgery. Methods We conducted a single-center retrospective cohort study of adults undergoing elective non-cardiac surgery with at least one mean arterial pressure measurement below 65 mmHg. The primary unit of analysis was the hypotensive episode, and the primary outcome was documented ephedrine or phenylephrine administration associated with each episode. Inter-anesthesiologist variation was assessed using multivariable logistic regression adjusted for case-mix and episode order, with procedure-clustered robust covariance. Adjusted probabilities were estimated by marginal standardization. Results Among 900 procedures managed by 20 anesthesiologists, 2,146 hypotensive episodes were analyzed, of which 734 (34.2%) were associated with vasopressor administration. After adjustment, anesthesiologist identity remained associated with episode-level vasopressor administration (p<0.001), with marginal standardized probabilities ranging from 3.7% to 52.2%. Findings were consistent across sensitivity analyses. Conclusions Substantial inter-anesthesiologist variation in documented vasopressor use was observed after adjustment for measured case-mix variables, highlighting the need to better understand the determinants and clinical significance of provider-associated variation.