Prediction of FEV1 reductions in patients undergoing pulmonary resection

In the assessment of functional operability of lung cancer the simple calculation of predicted postoperative forced expiratory volume in one second (ppoFEV1) based on the number of the bronchopulmonary segments removed, has recently been found to underestimate the actual postoperative forced expiratory volume in one second (FEV1). We checked whether this could be accounted for by lesions causing uneven ventilation or perfusion. We performed a retrospective study of 12 patients with atelectasis, hilar disease or endobronchial involvement (Group A) versus 24 patients with peripheral lung cancer (Group B). Baseline and postoperative FEV1 were measured and ppoFEV1 and ppoFEV1/actual postoperative FEV1 were calculated. In all subjects in Group A ppoFEV1 grossly underestimated the measured postoperative FEV1 (mean (SD) ratio between the two parameters: 67.0 (12.1)%). In Group B, ppoFEV1 was almost identical to the measured value in all but three patients, in whom it only slightly underestimated the actual postoperative value (mean ratio between the two parameters: 94.9 (12.6) %). In conclusion, predicted postoperative forced expiratory volume in one second is useful in the preoperative assessment of patients undergoing lung resection for lesions other than those causing uneven ventilation or perfusion. When this condition is suspected, before declaring a given case ineligible for surgery or at high risk of complications, more sophisticated procedures, such as radionuclide perfusion studies, should be performed.