DESIGN: Nested case-control.

SETTING: University-affiliated Department of Veterans Affairs Hospital.

PATIENTS: Computerized registry of all 2,291 patients undergoing elective abdominal operations from 1982 to 1991.

MEASUREMENT AND MAIN RESULTS: Strategy for ascertainment and verification of complications was systematic and explicit. The charts of all 116 patients identified by the registry as having complications and 412 (19%) randomly selected from 2,175 remaining patients were reviewed to verify presence or absence of cardiac or pulmonary complications, using explicit criteria and independent abstraction of pre- and postoperative components of charts. From these 528 validated cases and controls (23% of the cohort), 96 cases and 96 controls were matched by operation type and age within ten years. Hospital and intensive care unit stays were significantly longer (p<0.0001) for the cases than for the controls (24.1 vs 10.3 and 5.8 vs 1.5 days, respectively). All 19 deaths occurred among the cases. Among the cases, pulmonary complications occurred significantly more often than cardiac complications (p<0.00001) and were associated with significantly longer hospital stays (22.7 vs 10.4 days, p=0.001). Combined cardiopulmonary complications occurred among 26% of the cases. Misclassification-corrected incidence rates for the entire cohort were 9.6% (95% CI 7.2–12.0) for pulmonary and 5.7% (95% CI 3.8–7.7) for cardiac complications.

CONCLUSIONS: For noncardiac surgery, previous research has focused on cardiac risk. In this study, pulmonary complications were more frequent, were associated with longer hospital stay, and occurred in combination with cardiac complications in a substantial proportion of cases. These results suggest that further research is needed to fully characterize the clinical epidemiology of postoperative cardiac and pulmonary complications and better guide preoperative risk assessment.