Temperature variations in the venous system of dogs

¹ Departments of Medicine and Physiology, and the Cardiopulmonary Research Laboratory, University of Wisconsin Medical School, Madison, Wisconsin

Respiratory fluctuations in the temperature of blood of the superior and inferior venae cavae and the pulmonary artery of anesthetized dogs are described. Diverse experiments were performed with the objective of elucidating the mechanism of production of these thermal variations. Data obtained were consistent with the hypothesis that changes in the ratio of venous flows draining into the venae cavae related to breathing are the main cause of the observed temperature variations.