The Effect of Generalized Hypoxia upon Flow and Composition of Cardiac Lymph in the Dog

Generalized hypoxia lasting 60 seconds more than doubled the cardiac lymph flow in dogs. The number of erythrocytes per mm3 of cardiac lymph increased by about 300%. However, there was no change in total protein or in the concentrations of different lipids following hypoxia. Thus, the transfer of erythrocytes across the myocardial interstitium increased by a factor of ten, and proteins and lipids by 150%. An increase of the capillary surface area probably explained the increased lymph flow. Permeability for macromolecules through the endothelial cells was not increased, since the selectivity for different lipids did not change. The increased transfer of erythrocytes may be explained by an increased permeability through intercellular junctions. The triglyceride content of thoracic duct lymph decreased by about 60% in the corresponding period, but no changes in flow or permeability were observed.