摘要：

Observations were made on the effect of visceral elevation of the diaphragm produced by the head-down position in patients with pulmonary emphysema. Striking relief of dyspnea was accompanied by increased diaphragmatic excursion and a marked decrease in the minute volume of ventilation. In twenty-four subjects the average decrease in pulmonary ventilation on tilting from the sitting to the head-down posture was 22 per cent. The average decrease in pulmonary ventilation for this group in the sitting position, when 100 per cent oxygen was substituted for air, was 15 per cent. The arterial oxygen saturation was measured in the lying head-down position after forty-five minutes; in one case with associated cardiac insufficiency a fall of 1.6 volumes per cent took place; in three more cases there was no significant change; in six cases the arterial oxygen saturation increased. In seven of ten patients in whom an average fall of 26 per cent in pulmonary ventilation took place with the head-down position the pH and pCO 2 showed little or no change. In two cases a rise in pCO 2 of 4 and 5 mm. Hg was found, with a fall in pH from 7.43 to 7.39 and from 7.50 to 7.45. In one patient with an associated respiratory acidosis the pH rose markedly, from 7.27 to 7.44. The effect of elevation of the diaphragm by upward pressure of the viscera resulted in increased diaphragmatic excursion, comparable in some respects to raising the resting level of the diaphragm by increase of the intra-abdominal pressure through the use of abdominal belts or by pneumoperitoneum. The increased efficiency of alveolar ventilation of the lower lobes induced by diaphragmatic as compared to costal breathing was illustrated by the blood gas changes in eight of ten subjects tested. In three cases in which the arterial oxygen saturation was unchanged there appeared to be adaptation to an accustomed degree of anoxia which permitted marked lowering of pulmonary ventilation and consequent relief of dypsnea. These observations provide a physiologic basis for the clinical use of viscero-diaphragmatic breathing in patients with pulmonary emphysema.

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