Edward J. Baldes

Studies on peripheral blood flow

Abstract Since the beginning of our work on blood flow in animals about ten years ago, we have investigated many problems concerning the peripheral circulation of the dog. In this report a number of studies have been summarized, and, in some instances, additional data only recently obtained have been included. These studies will serve to illustrate the dynamic nature of the peripheral circulation, as reflected in the blood flow in the femoral artery or vein.

THE THERMO‐STROMUHR METHOD OF MEASURING BLOOD FLOW

The purpose of the following article is to bring to the attention of the physicist, who is interested in the application of physics to physiology, a typical problem in biophysics. Rein, a physicist at the University of Freiburg, was confronted with the necessity of knowing accurately the blood supply to a certain organ. Because the various standard methods proved inadequate he developed an ingenious method which he calls the thermo‐stromuhr. This method of determining blood flow has been modified in two respects: in the method of measuring the heating energy applied to the blood vessel, and in the method of construction of the diathermy‐thermoelements. A tuned circuit is used which permits the measurement of resistance by the method of substitution. The diathermy‐thermoelements are made from transparent bakelite and the process of construction is fully described. The theory of the thermo‐stromuhr as well as the experimental application is explained in detail.

Visualization of Intrathoracic Vena Cava, Effect of Respiration on Diameter of the Vessel

Summary and Conclusions A method of visualizing, roentgenologically, blood vessels such as the vena cava is described. Significant changes in the diameter of the thoracic portion of the posterior vena cava were not observed when the dog was lying on its side. Slight changes in diameter occurred during the respiratory cycle when the dog was standing. The changes in diameter were too insignificant, even in the standing position, to interfere with thermal and electric contacts when the thermostromuhr method of measuring blood flow is used.