Gaseous diffusion from alveoli into pulmonary arteries

Abstract

In 40 patients, during right heart catheterization a catheter with a platinum tip electrode was wedged in a branch of the pulmonary artery. With the electrode acting as part of a potentiometer, signals were recorded following single inhalations of hydrogen. Similarly signals were recorded following inhalations of oxygen with the electrode acting as part of a polarograph. With either gas, signals were recorded appearing in less than 1 sec after the gas entered the nose. The signals paralleled the changes in the alveolar concentration of the gas. The infusion of dextrose through the wedged catheter or the withdrawal of the catheter a short distance from the wedged position, did not significantly affect the results. The inhaled gas was also shown to appear at the tip of the wedged catheter significantly before it appeared in the descending aorta. It is concluded that the observations made are evidence of diffusion of the inhaled gases from the alveoli directly into the pulmonary arteries. platinum/hydrogen anode; oxygen polarograph; alveolo-arterial oxygen diffusion; alveolo-arterial hydrogen diffusion Submitted on May 29, 1963