[Examination of post operative split lung function using quantitative xenon 133 (133Xe) inhalation scan]

133Xe inhalation scan and ordinary lung function testing were performed three times in 34 patients undergoing pulmonary resection: before surgery, and one and six months postoperatively. Forced vital capacity (FVC) and forced expiratory volume in the first second (FEV1.0) were used as spirometric parameters. From the 133Xe inhalation scan, a split lung capacity (right to left, upper, middle and lower) and T1/2 (time required for half of the inhalation of 133Xe gas to be expired) were calculated by computer and used as indices of split lung capacity and ventilation, respectively. Results obtained from this study are as follows. 1) The predicted postoperative lung functions were calculated using preoperative spirometric respiratory function and 133Xe inhalation data according to the formula reported by Ali and associates. At sixth postoperative month, both predicted FVC (r = 0.895, p < 0.001) and FEV1.0 (r = 0.897, p < 0.001) correlated highly with those actually observed. These results appear to be very useful for preoperative evaluation of operative indications and the choice of surgical methods. 2) The ratios of observed to predicted lung capacity in the post operative state were examined by splitting the right and left lung and the means +/- S.D. (%) were as follows. One month after surgery, operated side; 80.5 +/- 9.7%, opposite side; 119.2 +/- 11.7%. Six months after surgery, operated side; 111.0 +/- 5.6%, opposite side; 96.7 +/- 16.4%. The post operative T1/2 values on the operated sides were about 2.4 times the preoperative values at one month after surgery but had recovered to the preoperative values by the six postoperative month.(ABSTRACT TRUNCATED AT 250 WORDS)