Pulmonary Circulation and Transcapillary Exchange of Electrolytes

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

“…The techniques employed in this laboratory have been described previously (1 terial blood are obtained at two second intervals from an indwelling arterial needle previously inserted in the brachial artery of the opposite arm. The doses of the various isotopes used were as follows: Na", 40 to 80 ,sc.…”

“…; and albumin-I1"', 5 to 40 ,gc. The methods employed in assaying these isotopes have been described previously (1).…”

“…This has been interpreted as being due to the return to the blood stream of some of the tracer electrolyte which has previously diffused out (1). At any time during the first circulation the net loss of the tracer electrolyte may be determined by comparing the areas under the curves up to that time.…”

“…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 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.…”