Factors Affecting Morbidity/Mortality of Emergency General Surgery

Abstract

Introduction/Background: Emergency status has been documented as adversely affecting the outcome of general surgery. However, the predictors of increased morbidity and mortality of emergency general surgery (EGS) are unclear, including the possibility of modifying these factors. This study aims to determine the predictive factors for postoperative complications of EGS. Methods: A retrospective study of all randomly selected Brigham and Women's Hospital (BWH) American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) patients who had an EGS procedure from January 1, 2007 to December 31, 2008 were selected for this study. BWH IRB approved this study. The study applied the inclusion and exclusion criteria as defined by ACS NSQIP using select preoperative and all postoperative data variables. Additional non-ACS NSQIP data points were added and analyzed as possible predictors of poor outcomes. These included blood glucose levels closest to the time of surgical incision, length of time from ED arrival to incision, total volume of intravenous fluids (IVF) administered within 24 hours prior to incision, and time of antibiotic administration prior to incision. Our primary outcomes were whether or not the patient had experienced any of the pre-defined ACS NSQIP postoperative occurrences within 30 days and/or died while hospitalized for the target emergency procedure. Univariate statistical analyses were done using Wilcoxon signed rank sum test for continuous variables and Chi square test/Fisher Exact test for categorical variables. Multivariate analyses were done to identify independent predictors using logistic regression. Results: We identified 263 cases. 46.4% were male. 60 (22.8%) had complications, and 25 (9.5%) died within 30 days. Those without complications had a mean age of 51 years while those with complications had a mean age of 66 years. The most common procedures were appendectomies (22.4%), colectomies (18.6%) and enterectomies (17.1%). The most common postoperative occurrences were prolonged ventilator support>48hrs (12%), unplanned intubations (6%), and superficial incisional infections (5%). In univariate analyses, age (p<0.0001), male gender (p<0.001), length of operation (p<0.0001), preoperative blood transfusion (p<0.001), elevated blood glucose (p=0.026), elevated BUN (p<0.0001), functional health status (p=0.007), ASA (p<0.001), presence of COPD (p=0.002), and history of smoking (p=0.009) were found to be significant predictors of postoperative complications. Length of time from ED arrival to time of incision (p=0.42), total volume of IVF administered within 24 hours prior to incision (p=0.19), and time of antibiotic administration prior to incision (p=0.74) were not found to be significant. Multivariate analyses using stepwise logistic regression found male gender (OR 2.01, 95% CI 1.05, 4.10), smoking (OR 2.69, 1.15, 6.26), elevated BUN (OR 1.04, 95% CI 1.02, 1.06), and length of operation time (OR 1.001, 95% CI 1.000, 1.003) to be independent predictors for postoperative complications. Conclusions: Emergency general surgery patients who develop postoperative complications are more likely to be male, smokers, have a higher preoperative BUN, and experience longer operative times. Preoperative fluid resuscitation to address elevated BUN and experienced surgical teams to decrease operative times are potential targets to improve outcomes in emergency general surgery patients.