Pulmonary Arterial Blood Volume and Tissue Volume in Man and Dog

After the injection of an ethyl ether-alcohol solution above the pulmonic valve, the pul-monary arterial circulation time was determined in conscious man by an established body plethysmographic technique and in anesthetized man by a newly developed pneumotacho-graphic method. In the anesthetized dog, estimates of pulmonary arterial circulation time determined by this new method were compared with those simultaneously determined by the plethysmographic method; agreement was good. The usefulness of applying corrective factors for the right-to-left intrapulmonary shunt and the uptake of ether gas from the al-veoli into the blood while the ether gas is being evolved from the initial injection was eval-uated from the dog experiments. In five humans with normal pulmonary arterial pres-sures, pulmonary arterial blood volume estimated by these methods was 172 ± 22 (SD) ml. Estimates of pulmonary tissue volume in both dogs and man were much larger than pre-viously reported values determined from the tritiated water space of the lungs but more in keeping with previously published estimates of the total water content of the lungs deter-mined at postmortem examination