Improvement of contralateral pulmonary function after unilateral lung volume reduction surgery (LVRS).

We evaluated contralateral pulmonary function after unilateral lung volume reduction surgery using pulmonary washout with Xe 133 gas before and 3 months after the operation. Eight patients underwent unilateral lung volume reduction surgery by video-assisted thoracoscopy. Dynamic single photon emission tomography was performed and the real half-time (T1/2) of each lung, defined as the time required to reach 50% of the equilibrium count during washout, was assessed on transaxial images. The preoperative total lung T1/2 was 126+/-12 sec, and this decreased significantly to 97+/-14 sec after surgery (p<0.01). The T1/2 of the operated lung decreased from 124+/-12 sec to 101+/-16 sec, but it increased postoperatively in two patients. The T1/2 of the contralateral lung also decreased significantly from 129+/-14 sec to 88+/-10 sec after surgery, including these two patients (p<0.01). Three patients (including these two) subsequently underwent contralateral volume reduction surgery 3 to 5 months after the first operation. The total lung T1/2 increased in one patient, although it improved slightly in the other two patients after the second operation. Unilateral volume reduction surgery does appear to have some benefit for contralateral pulmonary function. Even when the T1/2 of the operated lung increased postoperatively, the contralateral washout time was improved resulting in improvement of the total lung T1/2. In patients who did not benefit from unilateral volume reduction surgery, subsequent contralateral surgery may fail to improve pulmonary function.