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 resp iratory function. Measurements were made before and 4 mo after lung re section in 54 consecutive patients with bronchogenic carcinoma. Predic ted postoperative (ppo) FEV(1) and DL(CO) were derived using quantitat ive 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 +/- 1 3%, and DL(CO) of 85 +/- 22% predicted. Eleven of the patients had pne umonectomy, 29 had lobectomy, 12 had wedge resection, and two had no r esection. Wilcoxon and stepwise logistic regression analyses were used to determine which indices best predicted outcome. Postoperative valu es were correlated (r = 0.87, p < 0.0001) with actual 4/12 postoperati ve values of FEV(1)% and of DL(CO) (r = 0.56, p < 0.0001). The best pr edictors (all p < 0.05) for each outcome, in order of usefulness, were as follows. For surgical mortality: (1) the predicted postoperative p roduct (PPP) of ppo FEV(1)% x ppo DL(CO)%; (2) ppo DL(CO)%; (3) ppo FE V(1)%, and (4) RV, FRC, and Sa(O2) on the maximal step exercise test, For respiratory complications: body mass index (BMI) (for patients und ergoing 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 disco mfort on the cycle test. For respiratory failure: (1) 6-min minimal wa lking distance (6MWD); and (2) decreased Sa(O2) on exercise. All compl ications: Pa-CO2. The PPP was < 1,650 in six of eight deaths and in fi ve 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. P rediction equations were derived on the basis of the best predictors o f survival and complications. The best predictor of surgical mortality was PPP.