Regional lung function in erect humans after lobectomy.

By using the 133Xe technique, we studied five erect adult subjects who had undergone lobectomy at least 2 mo previously and were otherwise normal, to allow comparison between operated and unoperated lungs; four subjects had undergone upper lobectomy, and one had undergone lower lobectomy. In addition we studied a sixth subject who had undergone lower lobectomy and had residual disease in the contralateral lung, and results from the diseased lung were discarded. At the same overall volume, lungs that had undergone lobectomy were more expanded than contralateral control lungs, and their washout half times were prolonged more than could be accounted for by their increased functional residual capacity-to-total lung capacity ratio. In subjects with upper lobectomy, apex-to-base gradients of regional lung volume were normal on the operated side when lung expansion was accounted for. In subjects with lower lobectomy, apex-to-base volume gradients were reduced on the side that had undergone resection, suggesting relative overexpansion of basal regions. These interpretations were supported by distributions of regional washout half times and of boluses inhaled at residual volume. We interpreted these results as indicating that both lung weight and lung-chest wall shape interaction determine the distribution of regional lung volumes.