LUNG-SCANNING AND EXERCISE TESTING FOR THE PREDICTION OF POSTOPERATIVE PERFORMANCE IN LUNG RESECTION CANDIDATES AT INCREASED RISK FOR COMPLICATIONS

Objective: To analyze the value of preoperative lung scanning and exercise testing for the prediction of postoperative complications and of the short- as well as long-term performance in lung resection candidates at increased risk for complications. Design: Prospective clinical trial. Setting: Clinical pulmonary function laboratory in a university teaching hospital. Patients: Twenty-five (mean age, 63 years; 17 men) of 84 consecutive lung resection candidates were considered at increased risk for postoperative complications due to impaired pulmonary function (FEV(1) <2 L or diffusion of carbon monoxide [Dco] <50% predicted, or FEV(1) and Dco less than or equal to 80% predicted combined with New York Heart Association dyspnea index greater than or equal to 2). Interventions: Candidates underwent radionuclide ventilation/perfusion scans and exercise testing to predict postoperative (=ppo) values for FEV(1), Dco, and maximal O-2 uptake (Vo(2)max). They all underwent thoracotomy for neoplastic lesions; 7 had pneumonectomies, 18 lobectomies. Six patients had postoperative complications (within 30 days), of whom three died. Three and 6 months postoperatively, pulmonary function tests and Vo(2)max were repeated. Measurements and results: In the 22 survivors, the observed values were then compared with the predicted values, At 3 months, there were excellent correlations (absolute/predicted values): for FEV(1) r=0.78 and 0.81; for Dco, r=0.77 and 0.74; and for Vo(2)max, r=0.71 and 0.83. The means of FEV(1) and Vo(2)max did not differ from the predicted values, whereas the predicted Dco was lower than the observed value (mL/min/mm Hg: 15.1 vs 17.9; percent predicted: 59.6 vs 70.9) (p<0.05). At 6 months, correlations remained very good for FEV(1) (r=0.81 and 0.84) and for Dco (r=0.76 and 0.74), but had decreased for Vo(2)max to 0.56 and 0.65, respectively. Ah means were higher than predicted (p<0.05) owing to recovery in the lobectomy group. Patients with postoperative complications (group B) had a lower preoperative Vo(2)max in percent predicted (62.8+/-7.5% vs 84.6+/-19.7%) (p<0.01) and also a lower Vo(2)max-ppo (10.6+/-3.6 vs 14.8+/-3.5 ml/kg/min and 44.3+/-13.5 vs 68.0+/-20.7% predicted) (p<0.05) than patients without complications (group A). A Vo(2)max-ppo <10 ml/kg/min was associated with a 100% mortality, Although FEV(1)-ppo and Dco-ppo were lower in group B, the difference did not reach significance. Conclusions: Radionuclide-based calculations of postoperative Vo(2)max are predictive of operative morbidity and mortality: a Vo(2)max-ppo of <10 mL/kg/min may indicate inoperability. Further, short-term postoperative performance is accurately predicted by FEV(1)-ppo and Vo(2)max-ppo, but long-term function is underestimated after lobectomy.