Patterns of intra-arterial blood pressure monitoring for patients undergoing total shoulder arthroplasty under general anesthesia: a retrospective analysis of 23,073 patients

Total shoulder arthroplasty (TSA) is typically performed in the beach-chair position. Maintenance of adequate mean arterial pressure is required to provide appropriate cerebral perfusion pressure and prevent cerebral ischemia. Placement of an arterial line to facilitate invasive monitoring is discretionary, based on clinical judgment. We aimed to describe patient, surgical and institutional factors associated with the current use of blood pressure monitoring via an arterial line for TSA. We used de-identified patient data from the National Anesthesia Clinical Outcomes Registry between 2010 and 2015 to identify patients undergoing TSA under general anesthesia. We conducted a multivariable logistic regression model to demonstrate factors significantly associated with arterial line placement. We report results as odds ratios (OR) with their associated 95 % confidence intervals (CI). Of 23,073 patients undergoing TSA under general anesthesia, 443 (1.92 %) had intra-arterial blood pressure monitoring. Patient age over 65 years old (OR 1.74, CI 1.37–2.21), congestive heart failure (OR 7.09, CI 2.63–19.14) and surgery lasting at least 180 min (OR 4.10, CI 3.33–5.05) were all associated with increased odds for arterial line placement. Compared to university hospitals, arterial line placement was more likely in attached or freestanding surgical centers (OR 2.01, CI 1.37–2.96) and less likely in medium sized community hospitals (OR 0.62, CI 0.42–0.93), small community hospitals (OR 0.11, CI 0.03–0.34) and facilities performing less than 100 TSAs per year (OR 0.19, CI 0.12–0.31). Utilization of arterial line monitoring for TSA has associations with both institutional and patient factors. This study demonstrates the national patterns for the use of arterial lines for TSA and may serve as a resource to aid in clinical judgment.