[133 Xe radiospirometry: prediction of VC and FEV1 (author's transl)].

In patients with impaired lung function who are scheduled for lung surgery, a means of estimating the ventilatory consequences of parenchymal resection is needed. We have tested the ability of lung scanning with aerosolized and intravenous 133Xe to fulfil this purpose in 100 pneumonectomized or lobectomized patients. Postsurgery VC and FEV1 values were evaluated as follows: each lung was horizontally divided into two areas and lower and upper VC values were calculated as percentages of the total radioactivity count. Using the regional percentages and the absolute values of VC measured spirometrically, the VC expected postsurgery values were calculated according to the type of resection planned (e.g. if the left lung was to be removed and if it accounted for 50% of the radioactivity on the scan, the postsurgery VC would be halved). Postsurgery FEV1 values were estimated by using the VC value and the FEV1/VC ratio measured before surgery. A significant correlation (p less than 0.001) was found between the values estimated in such way and the actual FEV1 and VC values obtained shortly after surgery (between 6 and 15 days). From these results, we conclude that the xenon scan is a valuable technique for estimating the consequences of lung removal on ventilation.