PREOPERATIVE RISK-EVALUATION FOR LUNG-CANCER RESECTION - PREDICTED POSTOPERATIVE PRODUCT AS A PREDICTOR OF SURGICAL MORTALITY

We assessed the capacity to predict surgical mortality, complications, and functional loss by using the results of resting and exercise respiratory function. Measurements were made before and 4 mo after lung resection in 54 consecutive patients with bronchogenic carcinoma. Predicted postoperative (ppo) FEV(1) and DL(CO) were derived using quantitative lung perfusion scans when baseline FEV(1) was < 55% predicted, and by proportional loss of pulmonary segments(total = 19 segments) when FEV(1) was > 55% predicted. The patients were aged 67 +/- 7 (mean +/- SD) yr, with an FEV(1) of 76 +/- 23% predicted, FEV(1)/FVC of 55 +/- 13%, and DL(CO) of 85 +/- 22% predicted. Eleven of the patients had pneumonectomy, 29 had lobectomy, 12 had wedge resection, and two had no resection. Wilcoxon and stepwise logistic regression analyses were used to determine which indices best predicted outcome. Postoperative values were correlated (r = 0.87, p < 0.0001) with actual 4/12 postoperative values of FEV(1)% and of DL(CO) (r = 0.56, p < 0.0001). The best predictors (all p < 0.05) for each outcome, in order of usefulness, were as follows. For surgical mortality: (1) the predicted postoperative product (PPP) of ppo FEV(1)% x ppo DL(CO)%; (2) ppo DL(CO)%; (3) ppo FEV(1)%, and (4) RV, FRC, and Sa(O2) on the maximal step exercise test, For respiratory complications: body mass index (BMI) (for patients undergoing lobectomy or wedge resection only.) For cardiac complications: (1) age; (2) Sa(O2) at baseline and on the maximal step exercise test; (3) Pa-CO2 (4) Pace,; and (5) minute ventilation at maximal exercise. For surgical complications: (1) DL(CO)%; (2) ppo DL(CO); (3) BMI; (4) maximal work rate on the step test; and (5) Borg score for leg discomfort on the cycle test. For respiratory failure: (1) 6-min minimal walking distance (6MWD); and (2) decreased Sa(O2) on exercise. All complications: Pa-CO2. The PPP was < 1,650 in six of eight deaths and in five of 44 survivors, and less than or equal to 1,850 in seven of eight deaths and five of 44 survivors in the first 2 postoperative months. Prediction equations were derived on the basis of the best predictors of survival and complications. The best predictor of surgical mortality was PPP.