DIRECT OBSERVATIONS OF SURGICAL-WOUND INFECTIONS AT A COMPREHENSIVE CANCER CENTER

Objectives: To identify the rate of surgical site infection and risk f actors for surgical site infection in patients with cancer and to eval uate antibiotic use patterns on surgical oncology services. Design: Cr iterion standard. Setting: Memorial Sloan-Kettering Cancer Center, a c omprehensive cancer center at a university hospital. Patients: Over a 15-month period, 1226 patients undergoing 1283 surgical procedures per formed by the Breast, Colorectal, and Gastric-Mixed Tumor surgical ser vices. Main Outcome Measure: Direct observation of surgical sites was performed by a single, surgeon-trained member of the hospital's Infect ion Control Section, adhering to an established protocol for grading o f the surgical site. Results: Operative procedures accounted for the f ollowing traditional wound class distributions: class I (clean), 630 c ases; class II (clean-contaminated), 577 cases; class III (contaminate d), 29 cases; and class IV (dirty-infected), 47 cases. Surgical site i nfection rates were 3.8% in class I; 8.8% in class II; 20.7% in class III; and 46.9% in class IV procedures. The mean (+/-SD) age was 57.7+/ -14.3 years and the Anesthesiology Society of America physical assessm ent score, 2.3+/-0.7. The mean (+/-SD) operation time was 145+/-104.9 minutes. Logistic regression analysis demonstrated several risk factor s for surgical site infection: obesity (P<.0001); a contaminated or di rty-infected surgical procedure category (P<.0001); operation time gre ater than 4 hours (P=.0004); Anesthesiology Society of America physica l. assessment score of 3 or greater (P<.01); and preoperative length o f slay of 3 or more days (P=.03). Conclusions: Risk factors for surgic al site infection in patients with cancer are similar to those found i n the National Nosocomial Infections Surveillance System. However, as an individual risk factor among our patient population, obesity contri buted as strongly as the surgical procedure category to a patient's li kelihood of acquiring a surgical site infection. In addition to Anesth esiology Society of America status, length of the surgical procedure, and surgical procedure category, obesity should warrant consideration as an individual risk factor for surgical site infection.