STUDIES ON THE VELOCITY OF BLOOD FLOW

Abstract

This paper presents the first measurements of the velocity of blood flow through the lungs of man. Thorough understanding of the blood flow through the lungs is of great significance in understanding adapta-tions of the circulation in health and disease. The study of the pulmonary circulation has, therefore, always at-tracted the interest of investigators. The literature is voluminous and was reviewed in 1903 by Tigerstedt (1) and in 1921 by Wiggers (2). In animals the study of the pulmonary circulation necessitates such distortion of the normal physiological conditions that interpre-tation of the results is diflicult. The chest has usually been opened, the negative intrathoracic pressure abolished, and normal inspiration has been replaced by forcible distention of the lungs with positive blasts of air. By such methods Plunier (3) in 1904 first studied the pulmonary circulation time in animals, estimating the time between release of a previously compressed vena cava and the subsequent maximal rise in arterial pressure. G. N. Stewart (4) (19) advanced the knowledge of the pulmonary blood flow by studying the time required for dyes and salt solutions to pass from the great veins through the heart and lungs to the great arteries. The chest was not opened al-though the animals were under general anesthesia. His results will be discussed later. Because such experiments are clinically not feasible, and because I This investigation was aided