A. Ejaz1, F. Gani1, S. M. Frank1, C. L. Wolfgang1, M. J. Weiss1, F. M. Johnston1, J. He1, T. M. Pawlik2 1Johns Hopkins University School Of Medicine,Baltimore, MD, USA 2Ohio State University,Columbus, OH, USA
Introduction: Surgical site infections (SSI) are a common source of postoperative morbidity and a marker of surgical quality. The ability to predict the incidence of SSI is limited and most models have poor predictive value. We sought to identify risk factors associated with SSI and develop a prediction model for SSI following major abdominal surgery.
Methods: 1,744 patients undergoing pancreatic, hepato-biliary, and colorectal resections between January 1, 2010 and August 31, 2013 at Johns Hopkins Hospital were identified. Risk factors for any SSI (superficial and deep) were evaluated using multivariable logistic regression.
Results: Median patient age was 58 years (IQR: 47, 68); operative procedures included colorectal (59.0%), liver (26.2%) and pancreas (14.8%) resections. SSI occurred in 7.6% (n=132) of patients. Factors associated with SSI included preoperative weight loss >10lbs. (OR 2.12, 95%CI 1.06-4.25), emergency operations (OR 2.05, 95%CI 1.32-3.17), and colorectal resections (OR 1.65, 95%CI 1.13-2.43)(all P≤0.003). Intraoperative risk factors included transfusion (OR 2.01, 95%CI 1.33-3.04), estimated blood loss (EBL)>600mL (OR 2.54, 95%CI 1.74-3.71), and maximum respiratory rate (tachypnea) >20 breaths/min (OR 2.65, 95%CI 1.62-4.36)(all P=0.001). Intraoperative hypo/hyperthermia, bradycardia/tachycardia and hypotension/hypertension were not associated with SSI (all P>0.05). After controlling competing risk factors, transfusion, EBL>600mL, tachypnea, and colorectal resection were independently associated with SSI (all P<0.003). Based on beta-coefficients in the multivariable model, an SSI scoring system was created by assigning 2 points for EBL>600mL, 2 points for a colorectal resection, 3 points for tachypnea, and 3 points for a transfusion. The model showed good discriminatory ability to predict SSI (c-statistic=0.7232; AIC 875.37) (Figure).
Conclusion: A novel, simple 10-point SSI scoring system that incorporated perioperative risk factors such as blood transfusion, EBL, tachypnea and type of surgical procedure accurately stratifies patients according to SSI risk.
