Risk Factors for Adverse Outcomes Following Surgery for Small Bowel Obstruction

Abstract

OBJECTIVE: To construct risk indices predicting adverse outcomes following surgery for small bowel obstruction (SBO). METHODS: The VA National Surgical Quality Improvement Program contains prospectively collected data on more than 1 million patients. Patients undergoing adhesiolysis only or small bowel resection for SBO from 1991 to 2002 were selected. Independent variables included 68 presurgical and 12 intraoperative risk factors; dependent variables were 21 adverse outcomes including death. Stepwise logistic regression was used to construct models predicting 30-day morbidity and mortality and to derive risk index values. Patients were then divided into risk classes. RESULTS: Of the 2002 patients, 1650 underwent adhesiolysis only and 352 underwent small bowel resection. Thirty-seven percent undergoing adhesiolysis only and 47% undergoing small bowel resection had more than 1 complication (P < 0.001). The overall 30-day mortality was 7.7% and did not differ significantly between the groups. Odds of death were highest for dirty or infected wounds, ASA class 4 or 5, age >80 years, and dyspnea at rest. Morbidity ranged from 22%, among patients with 0 to 7 risk points, to 62% for those with >19 risk points. Mortality ranged from 2% among patients with 0 to 12 risk points to 28% for those with >31 risk points. CONCLUSIONS: Morbidity and mortality after surgery for SBO in VA hospitals are comparable with those in other large series. The morbidity rate, but not the mortality rate, is significantly higher in patients requiring small bowel resection compared with those requiring adhesiolysis only (P < 0.001). The risk indices presented provide an easy-to-use tool for clinicians to predict outcomes for patients undergoing surgery for SBO.