The assessment of a growing mobile anesthesia practice from 2016 to 2019: A retrospective observational cohort study of 89,999 cases comparing ambulatory surgery (ASC) and office-based surgery (OBS) centers using a high-fidelity, anesthesia-specific electronic medical record (EMR).

Office-based surgery (OBS) has emerged as a significant subspecialty of ambulatory surgery. There are few clinical trials and limited published data on patient characteristics, anesthesia, or outcomes distinguishing OBS from ambulatory surgery centers (ASCs). We examined retrospective data from a large mobile anesthesia practice for 89,999 procedures from 2016 to 2019. Data was abstracted from billing and an anesthesia-specific electronic medical record, segregating procedures performed in ASCs versus OBS. The number and breadth of procedures increased substantially. Compared to ASCs, OBS patients were more likely male (52% vs. 48%), older (61 years vs. 55 years), and to have a higher American Society of Anesthesiologists (ASAs) status (33% vs. 20% ASA 3 or higher). The procedure mix varied substantially between the two settings. The major complication rate was 0.07% for the ASCs and 0.24% for OBS (p = 0.2, confidence interval [CI] -0.15 to 0.04). Minor complications were 11.2% in OBS versus 17.3% the ASCs (p < 0.0001, 95% CI 5.2-7). The practice demonstrates a low rate of complications, and despite the limitations of this study, the organization and structure of this large mobile anesthesia practice serves as a template for effective risk mitigation and patient safety.