Influence of Annual Meetings of the American Society of Anesthesiologists and of Large National Surgical Societies on Caseloads of Major Therapeutic Procedures.

Statistical methods to calculate the hours into which cases are scheduled, based on minimizing the inefficiency of use of anesthesia and/or operating room (OR) time, assure that anesthesiologists and OR nurses are available on each day to care for patients while infrequently working late. The method assumes that anesthesia staffing is planned based on the workload and not vice-versa. We used the American Society of Anesthesiologists (ASA) meeting to test the assumption across a large population. The observational study cohort was all 3,191,282 major therapeutic procedures performed during 2,517,842 cases at all 121 non-federal hospitals in the State of Iowa, 2007-16. The Fridays to Wednesdays of the annual ASA meetings were compared pairwise by year with those days of the other (mean = 43.0 [SE =0.3]) weeks without a federal holiday. Differences in counts of procedures (P = 0.45, 0.5% [0.7%]) and cases performed (P = 0.93, 0.1% [1.0%]) were not significant. In contrast, compared to non-meeting weeks, during the American College of Surgeons meeting, there were fewer general surgery procedures performed (P = 0.0009, -9.1% [1.9%]), fewer procedures performed of any type (P = 0.022, -2.1% [0.8]), and fewer cases of any type (P = 0.003, -2.5% [0.6%]). Similarly, during the American Academy of Orthopaedic Surgeons meeting, there were fewer joint arthroplasties performed (P < 0.0001, -27.1% [3.1%]), fewer procedures (P = 0.011, -6.3% [2.0%]), and fewer cases (P = 0.018, -5.9% [2.0%]). The results show that, in routine practice, anesthesia staffing and staff scheduling are being chosen to prevent the meeting from affecting patients' and surgeons' access to OR time.