Gaseous Diffusion from Alveoli to Pulmonary Vessels of Considerable Size

Abstract

Thirty patients have been presented in whom the appearance of inhaled hydrogen gas at an electrode in the wedge position of a pulmonary artery was seen to occur within two seconds. In 13 of these patients the appearance of hydrogen occurred with equal or nearly equal rapidity in a pulmonary artery at least 3 mm in diameter. In 11 patients increasing alveolar oxygen tension by the inhalation of a single breath of 100% oxygen or by voluntary hyperventilation produced a rapid response at the wedge position as well. It is concluded that the rapid appearance of hydrogen and oxygen is due to direct diffusion of the inhaled gas from the alveoli to the pulmonary arterial blood.