133Xe radiospirometry in prediction of ventilatory function and vital capacity after pneumonectomy in patients with an endobronchial tumour.

The ventilatory parameters FEV1 and VC were predicted after pneumonectomy in 18 patients operated on because of an endobronchial carcinoma. Preoperative dynamic spirometry and radiospirometrically determined regional ventilation, perfusion and VC were used in the prediction. In the whole patient material the predicted postoperative FEV1 and VC correlated significantly with the measured postoperative values; the correlation coefficients of the estimates based on preoperative regional perfusion (rFEV1 = 0.760, rVC = 0.707) differed, however, somewhat from those of the estimates based on regional ventilation (rFEV1 = 0.736, rVC = 0.767). The use of regional VC did not improve the accuracy of estimation. The mean predicted values of FEV1 were 0.35-0.46/l and those of VC were 0.23-0.44/l smaller than the values actually measured 2-12 months after operation, probably owing to dilatation of the remaining lung.