Anesthesia duration as an independent risk factor for postoperative complications in free flap surgery: A review of 1,305 surgical cases

Surgical dogma and objective data support the relationship between increased operative times and perioperative complications. However, there has been no large-scale, multi-institutional study that evaluates the impact of increased anesthesia duration on microvascular free tissue transfer. The National Surgical Quality Improvement Program (NSQIP) database was retrospectively reviewed to identify all free-flap patients between 2006 and 2011. Included patients were subdivided into quintiles of anesthesia time. Univariate and multivariate analyses were performed to assess its impact on 30-day postoperative complications. The mean anesthesia duration for all patients was 603±222 minutes. In univariate analysis, 30-day overall/medical complications, reoperation, and free flap loss demonstrated statistically significant increases as anesthesia duration increased (p<0.05). However, in multivariate analyses, these trends and significances were abolished, with exception of the utilization of postoperative transfusions. Of interest, increasing anesthesia duration did not predict flap failure on multivariate analysis. We found that increased anesthesia time correlates with increased postoperative transfusions in free flap patients. As a result, limiting blood loss and avoiding prolonged anesthesia times should be goals for the microvascular surgeon. This is the largest multidisciplinary study to investigate the ongoing debate that longer anesthesia times impart greater risk.