A multivariate analysis of the risk of pulmonary complications after laparotomy.

We evaluated the relationship between PPC and various putative risk factors in a prospective longitudinal study of 1,000 patients undergoing abdominal surgery. Transient subclinical events were excluded by defining PPC as positive clinical findings in combination with either positive sputum microbiology, unexplained pyrexia, or positive chest roentgenographic findings. The overall incidence of PPC was 23.2 percent (232/1,000). Multivariate analysis identified seven factors which were associated with PPC: ASA classification greater than 2, upper abdominal surgery, residual intraperitoneal sepsis, age greater than 59 years, BMI greater than 25, preoperative hospital stay greater than 4 days, and colorectal or gastroduodenal surgery (overall F score = 33.5, p less than 0.0001). The ASA classification was the most powerful indicator of risk in both the univariate and the multivariate analyses. The combination of ASA classification greater than 1 and age greater than 59 years identified 88 percent (205 of 232) of the patients who developed PPC. These findings provide clinicians and clinical investigators with a simple means of identifying patients who are at high risk of PPC after abdominal surgery.