TRANSCAPILLARY MIGRATION OF HEAVY WATER AND THIOCYANATE ION IN THE PULMONARY CIRCULATION OF NORMAL SUBJECTS AND PATIENTS WITH CONGESTIVE HEART FAILURE 123

Abstract

By rapidly injecting into the afferent pulmonary circulation a mixture of T-1824 dye, D2O, and NaSCN in known proportion and collecting 2 second samples for analysis continuously from the femoral artery during the period of the first circulation, information was obtained about the relative transcapillary migration of these substances. Results indicate complete almost instantaneous transcapillary exchange of heavy water in the lungs of both normal subjects and patients with congestive heart failure - the characteristics of the exchange pattern permitting the calculation of the pulmonary extravascular D2O space. This averaged 190 cc in 6 normal subjects and 290 cc in 7 patients with pulmonary congestion studied. In contrast to the large rapid transcapillary loss of D2O only insignificant amounts of SCN ion migrated. This is compared with a similar study of the forearm circulation previously reported. The comparison suggests an inherent difference in the permeability of the capillary bed of the lung as compared to the forearm with respect to SCN ion.