An open-circuit technique is described for the simultaneous and separate determination of the residual volume of each lung. The method includes provisions for estimation of the effectiveness of intrapulmonary mixing, for determination of the place in the respiratory cycle where- the examination is begun, for recording bronchospirometry before lung volume study and for maintenance of proper catheter position. In four normal volunteers the functional distribution between the two lungs differed considerably. In each individual, however, the percentage of the total inspiratory capacity, expiratory reserve volume and residual volume contributed by a single lung was the same so that the ratio of residual volume to total lung capacity was the same on both sides. In eight patients with localized unilateral parenchymal tuberculosis the vital capacity was only slightly reduced and the residual volume was little affected or even increased. Intrapulmonary mixing was normal on both sides. In eight patients with extensive unilateral parenchymal disease the vital capacity was severely reduced and the residual volume was moderately decreased. Intrapulmonary mixing was impaired occasionally on the involved side. The disproportionate reduction of vital capacity and residual volume was most marked in five patients with "imprisoned" lungs due to pyopneumothorax. On the affected side the vital capacity was only slightly larger than the resting tidal volume while the residual volume often amounted to nearly one-half of the residual volume of both lungs together. Intrapulmonary mixing was greatly abnormal on the diseased side although conventional determination of this mixing index for both lungs together often failed to bring out this defect. The effect of pneumonectomy on the remaining lung could be studied since it was possible to measure all volume compartments of this lung before the other lung had been removed. Overdistention and emphysema after operation at times existed to the same degree before removal of the other lung. A number of collapse procedures used in the treatment of pulmonary tuberculosis were evaluated. Phrenic interruption caused a reduction of the inspiratory capacity which was not limited to the operated side. Extrapleural pneumothorax reduced the lung volume at the expense of the residual volume and expiratory reserve volume and the effect was confined to the operated side. Immobilization of a portion of the chest wall by thoracoplasty caused reduction of all volume compartments. Both the intrapulmonary mixing index and the ratio of residual volume to total lung capacity increased.
|Original language||English (US)|
|Number of pages||21|
|Journal||The Journal of laboratory and clinical medicine|
|State||Published - Oct 1952|
ASJC Scopus subject areas
- Pathology and Forensic Medicine