Studies on pulmonary gas exchang during intermittent positive pressure breathing and voluntary hyperventilation in patients with bronchial asthma and chronic pulmonary emphysema, with special reference to changes in distribution of ventilation and perfusion

Abstract

Since the report of MOTLEY(1952), oxygen, bronchodilators and antibiotics, are inspirated by means of the intermittent positive pressure breathing (IPPB) to obtain a therapeutic effect on the ventilatory impairment due to the obstructive lung disease. This procedure has been proved effective, but it is known that it is less effective upon the chronic pulmonary emphysema than upon the bronchial asthma. The studies were performed on five cases of chronic pulmonary emphysema and six cases of bronchial asthma, to clarify the effectiveness of IPPB itself by comparing the therapeutic effects on the patients with the results during voluntary hyperventilation (VH) of similar ventilatory volume. Analysis of blood gas and expired air and measurements of alveolar gas exchange were made on the subjects at rest, during IPPB and during VH. General pulmonary function was also examined at rest. Right-sided cardiac catheterization was performed on all cases and the measurements were made in each of the states. The results were as follows: 1) Changes of blood gas In chronic pulmonary emphysema, during IPPB, arterial oxygen tension (PaO2) rose from 62.4mmHg ±3.6 to 81.0mmHg ±8.9 (increase of 30%), and arterial CO2 tension (PaCO2) fell from 52.4mmHg ±5.7 to 45.8mmHg ±8.2 (de-crease of 13%). PaO2 increased by 8.2mmHg and PaCO2 decreased by 2.0mmHg during IPPB as compared with those during VH. In bronchial asthma, PaO2 rose from 78.0mm-Hg ±10.7 to 90.3mmHg ±9.9 (increase of 16%) and PaCO2 fell from 45.5mmHg ±3.9 to 38.1mmHg ±7.8 (decrease of 16%). PaO2 increased by 5.0mmHg and PaCO2 decreased by 2.0mm-Hg during IPPB as compared with those during VH. 2) Pulmonary gas exchanges a) The ratio of each space to the total lung capacity (Li/LT) In chronic pulmonary emphysema, the volume fraction of the fast ventilated space increased from 6.0% ±1.6 to 9.2% ±2.6 during IPPB and to 8.4% ±2.5 during VH. In bronchial asthma, it increased from 11.3% ±6.2 to 18.5% ±4.8 during IPPB and to 17.2% ±6.6 during VH. Volume fraction of the normal ventilated space (L2/LT) rose from 18.8% ±2.6 to 24.0% ±2.8 during IPPB and to 26.4% ±8.3 during VH in chronic pulmonary emphysema. In bronchial asthma, it decreased from 37.0% ±4.4 to 35.0% ±13.5 during IPPB and to 36.2% ±14.5 during VH.