[Changes in ventilation efficacy due to pulmonary resection and postoperative exercise restricting factors].

An exercise test was performed before and after surgery on patients who underwent at least a lobectomy, and changes in ventilation efficacy due to pulmonary resection (n = 40) and postoperative exercise restricting factors (n = 11) were investigated. When the degree of exercise was the maximal, the tidal volume (TV), expired volume per minute (VE), VO2 and VO2 significantly decreased after surgery. As a result of comparing preoperative values corresponding to postoperative VO2 max, both VE and VCO2 were found to increase. When the preoperative exercise load was the same as the postoperative maximum load, there was no significant difference in VE or VCO2, but VO2 decreased postoperatively. Cumulative VE, VO2 and VCO2 values increased postoperatively. In the 11 patients in whom the parameters were investigated preoperatively and postoperatively using an invasive method, the VO2 max, cardiac index (CI), stroke volume index (SVI) and TV decreased when the degree of exercise was maximal. There was no significant difference in total pulmonary vascular resistance (TPVR), heart rate (HR) or respiratory rate. There were significant correlations among HR, mean pulmonary arterial pressure (mPAP) and VO2 before and after surgery (R = 0.88, 0.78 and 0.77 respectively). The ventilation efficacy during exercise decreased after pulmonary resection, and anaerobic metabolism increased at the same exercise load. When the degree of exercise was maximal, mPAP was maintained, SVI decreased, HR was unchanged, and CO and VO2 decreased. These data suggested that mPAP and HR are postoperative exercise restricting factors.