PULMONARY TRANSCAPILLARY EXCHANGE OF Na24 AND P32-LABELED PHOSPHATE IN PULMONARY EMPHYSEMA*

Abstract

In previous studies it was observed that 5 to 20 per cent of intravenously administered Na24 and P32-labeled phosphate and other electrolytes escaped from the circulation during a single transit through the cardiopulmonary pool (1). The relatively small transcapillary exchange of electrolytes in the lungs as compared with skeletal muscle and certain other viscera was attributed to a lesser permeability of the pulmonary capillaries (1). The fraction of intravascular tracer electrolyte transferred across the pulmonary capillaries during pulmonary transit was diminished in the presence of a rapid circulation time and increased in patients with congestive heart failure and a prolonged circulation time (1). The present study extends these observations in patients with pulmonary emphysema where the problem of structural and physiological alterations of the pulmonary vascular tree is of particular interest. METHODS

Pulmonary Transcapillary Exchange of 24Na and 51CrEDTA. An Evaluation of Factors Influencing the Extraction of these Tracers during one Passage through an Isolated Lung Preparation

“…Several investigators have studied the transcapillary exchange of small solute molecules and ions in the pulmonary circulation with the single injection indicator diffusion technique (Chinard and Enns 1954, Bauman et al 1957, Rothschild et al 1959, Chinard, Enns and Nolan 1962) . Chinard et al (1954) and Bauman et al (1957) found that only small amounts of "Na passed out from the pulmonary vessels of dogs and healthy humans, respectively, during one single passage of the tracer through the pulmonary vascular bed.…”