Effect of anaesthesia type on postoperative mortality and morbidities: a matched analysis of the NSQIP database

Background. The anaesthetic technique may influence clinical outcomes, but inherent confounding and small effect sizes makes this challenging to study. We hypothesized that regional anaesthesia (RA) is associated with higher survival and fewer postoperative organ dysfunctions when compared with general anaesthesia (GA). Methods. We matched surgical procedures and type of anaesthesia using the US National Surgical Quality Improvement database, in which 264,421 received GA and 64,119 received RA. Procedures were matched according to Current Procedural Terminology (CPT) and ASA physical status classification. Our primary outcome was 30-day postoperative mortality and secondary outcomes were hospital length of stay, and postoperative organ system dysfunction. After matching, multiple regression analysis was used to examine associations between anaesthetic type and outcomes, adjusting for covariates. Results. After matching and adjusting for covariates, type of anaesthesia did not significantly impact 30-day mortality. RA was significantly associated with increased likelihood of early discharge (HR 1.09; P<0.001), 47% lower odds of intraoperative complications, and 24% lower odds of respiratory complications. RA was also associated with 16% lower odds of developing deep vein thrombosis and 15% lower odds of developing any one postoperative complication (OR 0.85; P<0.001). There was no evidence of an effect of anaesthesia technique on postoperative MI, stroke, renal complications, pulmonary embolism or peripheral nerve injury. Conclusions. After adjusting for clinical and patient characteristic confounders, RA was associated with significantly lower odds of several postoperative complications, decreased hospital length of stay, but not mortality when compared with GA.