Continuous recording of pulmonary blood volume: pulmonary pressure and volume changes

¹ Department of Physiology and Biophysics, University of Mississippi School of Medicine, Jackson, Mississippi

A method for continuous recording of pulmonary blood volume in the intact animal has been devised, utilizing the detection of I¹³¹-tagged blood from a circumscribed portion of lung field. To rule out the interference of blood in the chest wall the counts per minute (cpm) obtained from the chest wall after removing the lung at the end of the experiment were subtracted from the recorded cpm throughout the experiment. The cpm from the chest wall were found to be stable, so that it was concluded that changes in total cpm were caused by changes in pulmonary blood volume. Constriction of the ascending aorta or pulmonary artery by previously placed loops of plastic tubing produced either right or left heart failure. When left heart failure was produced acutely, the pulmonary blood volume increased an average of 79.5%±6.1 S.E. in 23 dogs. Constriction of the pulmonary artery, producing acute right heart failure, decreased the pulmonary blood volume an average of 38%±2.3 S.E. in 23 dogs.

Note:
With the Technical Assistance of Richard L. Yelverton and Carolyn Gill