Respiratory muscle strength after lung resection with special reference to age and procedures of thoracotomy

Changes in respiratory muscle strength after lung resection were examined concerning age and procedures of thoracotomy. Maximum inspiratory (MIP) and expiratory (MEP) mouth pressure were measured before operation and 1, 2, 4, and 12 weeks after operation in 81 patients undergoing lung resection. In 48 patients undergoing pneumonectomy, lobectomy, or segmentectomy, patients older than 70 showed a significantly lower MIP and MEP before operation and throughout the postoperative period compared to younger ones (P<0.01). Furthermore, the older patients showed a significantly lower percentage of postoperative MIP and MEP 4 weeks after operation than the younger ones (P<0.01). In 31 patients undergoing lung wedge resection, patients undergoing limited thoracotomy (LT) and video-assisted thoracic surgery (VATS) showed significantly higher percentages of postoperative MIP and MEP than those undergoing posterolateral thoracotomy (PLT) 1 and 2 weeks after operation (P<0.01 or 0.05), But there was no significant difference in the values between LT and VATS. We concluded that (1) elderly patients suffered respiratory muscle weakness before and after operation and their postoperative recovery of respiratory muscle strength was slower than in younger patients, and (2) VATS and LT resulted in more rapid recovery of respiratory muscle strength than PLT, but the difference between VATS and LT was not significant.