Direct observations of surgical wound infections at a comprehensive cancer center
G. R. Barber, J. Miransky, A. E. Brown, D. G. Coit, F. M. Lewis, H. T. Thaler, T. E. Kiehn and D. Armstrong
Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.
OBJECTIVES: To identify the rate of surgical site infection and risk
factors for surgical site infection in patients with cancer and to evaluate
antibiotic use patterns on surgical oncology services. DESIGN: Criterion
standard. SETTING: Memorial Sloan-Kettering Cancer Center, a comprehensive
cancer center at a university hospital. PATIENTS: Over a 15-month period,
1226 patients undergoing 1283 surgical procedures performed by the Breast,
Colorectal, and Gastric-Mixed Tumor surgical services. MAIN OUTCOME
MEASURE: Direct observation of surgical sites was performed by a single,
surgeon-trained member of the hospital's Infection Control Section,
adhering to an established protocol for grading of the surgical site.
RESULTS: Operative procedures accounted for the following traditional wound
class distributions: class I (clean), 630 cases; class II
(clean-contaminated), 577 cases; class III (contaminated), 29 cases; and
class IV (dirty-infected), 47 cases. Surgical site infection 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 assessment score, 2.3 +/- 0.7.
The mean (+/- SD) operation time was 145 +/- 104.9 minutes. Logistic
regression analysis demonstrated several risk factors for surgical site
infection: obesity (P < .0001); a contaminated or dirty-infected
surgical procedure category (P < .0001); operation time greater than 4
hours (P = .0004); Anesthesiology Society of America physical assessment
score of 3 or greater (P < .01); and preoperative length of stay of 3 or
more days (P = .03). CONCLUSIONS: Risk factors for surgical site infection
in patients with cancer are similar to those found in the National
Nosocomial Infections Surveillance System. However, as an individual risk
factor among our patient population, obesity contributed as strongly as the
surgical procedure category to a patient's likelihood of acquiring a
surgical site infection. In addition to Anesthesiology 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.
