Fig. 1. Forced expiratory volume in 1 s (FEV¹), vital capacity (VC) (percent predicted), and ratio of FEV¹over VC (percent) of 20 patients with chronic obstructive pulmonary disease or asthma in sitting (open bars) and in supine position before (gray bars) and during (black bars) epidural anesthesia with either ropivacaine (left , n = 10) or bupivacaine (right , n = 10). Mean ± SD; *P < 0.05. VC and FEV¹decreased significantly both when attaining supine position and during high thoracic segmental epidural anesthesia. As a measure of airway obstruction, FEV¹as a percentage of VC increased significantly when attaining supine position and during segmental high thoracic epidural anesthesia (sTEA).