Blood volume distribution in lung injury.

Mild hydrochloric acid was used to induce injury in the caudal section of one lung in each of 10 dogs. 99mTc-red blood cells were injected intravenously. Blood samples were drawn prior to sacrifice. Lung and blood samples were weighed, assayed for radioactivity and dried to constant weight. Assuming a uniform hematocrit, and hence a constant density, we computed blood volumes in terms of mass. The control lung had 4.32 +/- 0.62 g of extravascular lung water (EVLW) per g of bloodless dried weight (BLDW). Injury in the other lung was characterized by an elevated average of 7.08 +/- 0.79 g of EVLW per g of BLDW. The control lung contained 2.49 +/- 0.43 g of blood per g of BLDW and the injured lung contained a reduced amount of 1.69 +/- 0.55 g of blood per g of BLDW. In 8 subjects, injured portions retained the least blood volume per g of BLDW (a limiting value of 1.43 +/- 0.47 g per g). These results support a thesis of a reduction of blood volume in an injured area.