EFFECTS UPON PULMONARY FUNCTION OF PNEUMONECTOMY PERFORMED DURING CHILDHOOD - CONTINUOUS SPECTRUM OF DISTRIBUTION OF SPECIFIC TIDAL VOLUME IN REMAINING LUNG

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Abstract
[long dash]The physiologic effects of pneumonectomy performed during childhood were studied in 9 subjects from 1 to 27 yr. after the operation. The pulmonary function studies included measurements of lung volumes, maximal breathing capacity (MBC), respiratory gases in arterial blood, and respiratory gas exchange. The distribution function of the specific tidal volume was assessed by applying the appropriate integral transformations to the N washout data. After pneumonectomy, all of the subjects showed distention of the remaining lung. In those patients in whom the resected lung was severely affected by the disease, there was little or no increase in functional residual capacity, residual volume, and Residual volume/Total lung capacity RV/TLC ratio. Those with relatively less involvement of the pulmonary parenchyma showed marked hyperdistention. This suggests that the remaining lung had already adapted itself to the pathologic intrathoracic conditions existing before the resection. No further decrease in MBC could be demonstrated in 2 patients studied both preoperatively and postoperatively; in the remaining patients, there was a moderate reduction in MBC when no complications, such as chronic bronchitis, were present. The arterial O2 saturation and PcO2 aiK* *ne respiratory gas exchange were within normal limits, even after moderate exercise. The distribution of specific tidal volume was comparable with that found in normal subjects. This indicates that the overdistention of the lung was accomplished in a uniform manner by simple elongation of the linear dimensions of the existing lung units without physiologic evidence of pulmonary emphysema.