Objective: We investigated the mechanism involved with the initial drop and subsequent recovery of exercise capacity in the early postoperative period of thoracotomy patients. Methods: Sixteen patients (13 who had undergone lobectomy, 3 who had undergone pneumonectomy) underwent a routine pulmonary function test (PFT) and a cardiopulmonary exercise test preoperatively, within 14 postoperative days (POD; post-1; mean ± SD, 9 ± 2 POD), and after 14 POD (post-2; mean, 26 ± 12 POD). Results: After surgery on post-1, PFT results of FVC, FEV1, and maximum ventilatory volume (MW) significantly decreased. Oxygen uptake (VO2) at a venous blood lactate level of 2.2 mmol/L (La-2.2), which was adopted as the empirical anaerobic threshold, and maximum VO2 (VO2max) decreased significantly to 88.2 ± 7.9% and 73.1 ± 15.4% of the preoperative values, respectively. La-2.2 min ventilation (VE)/MVV and maximum VE (VEmax)/MVV increased significantly from 0.36 ± 0.08 to 0.66 ± 0.20 and from 0.58 ± 0.14 to 0.80 ± 0.09, respectively. On post-2, though La-2.2 VO2 did not change, VO2max improved significantly to 81.5 ± 19.7% of the preoperative values, in association with significant increases in maximal tidal volume and VEmax, which were produced by significant increases in the PFT results. La-2.2 VE/MVV also decreased significantly to 0.49 ± 0.13, which indicated a sufficient recovery of respiratory reserve at submaximal exercise. Conclusions: The initial drop of exercise capacity after lung resection seems to be derived from both circulatory and ventilatory limitations. Further, the subsequent recovery within 1 month seems to be produced by an improvement in ventilatory limitation, which was caused by the surgical injury to the chest wall.
- Cardiopulmonary exercise testing
- Postoperative recovery
ASJC Scopus subject areas
- Pulmonary and Respiratory Medicine
- Critical Care and Intensive Care Medicine
- Cardiology and Cardiovascular Medicine