Intrapulmonary systemic to pulmonary bronchial blood flow [Q̇br (s-p)] decreases with administration of cyclooxygenase inhibitors. This effect may be due to a decrease in the production of vasodilating prostaglandins and reflect either a decrease in the total intrapulmonary bronchial blood flow (Q̇br), or a redistribution of the intrapulmonary systemic venous return. In nine open chested dogs the left lower lobe (LLL) was isolated and perfused in situ. Blood flow to the extrapulmonary airways (Q̇ep), and Q̇br were measured by the reference flow technique. Q̇br (s-p) was measured as the overflow from the closed LLL perfusion circuit. After ibuprofen, PG-I2 was infused into the LLL PA and the Q̇br (s-p) was continuously monitored. Q̇br, and Q̇ep were measured before and after ibuprofen, and during and after the PG-I2 infusion. The upstream pressure for Q̇br (s-p) was estimated with and without PG-I2 infusion. After ibuprofen the Q̇ep,Q̇br, and Q̇br (s-p) fell to 45, 22, and 17%, respectively, of the pre-ibuprofen values (P <0.05). PG-I2 increased the Q̇br (s-p) and Q̇br (P <0.05), while Q̇ep was unchanged. During all experimental conditions the simultaneous measurements of Q̇br and Q̇br (s-p) were not different from each other (P <0.001). The upstream pressure for Q̇br (s-p) increased from 30 to 50 cm H2O (P <0.05). Intralobar bronchial blood flow is drained almost entirely through the pulmonary circulation, and PG-I2 in the LLL pulmonary circulation increases systemic blood flow to the LLL, probably acting at the level of a systemic arteriole.
- Bronchial blood flow
- Cyclooxygenase inhibitors
- Left lower lobe, Pulmonary circulation
ASJC Scopus subject areas
- Pulmonary and Respiratory Medicine