title: Pulmonary hemodynamic response to dopamine and dobutamine in hyperoxic and in hypoxic dogs.
abstract: The pulmonary hemodynamic response to dopamine and to dobutamine was investigated in dogs ventilated with hyperoxia (fraction of inspired O2 concentration [FIO2], 0.4 balance nitrogen) and challenged with short periods of inspiratory hypoxia (FIO2 0.125 or 0.1 for 10 min). Dopamine at doses of 5, 10, and 20 micrograms X kg-1 X min-1 (n = 7 dogs) increased cardiac index (CI) and pulmonary artery pressure (PAP) without change in indexed pulmonary vascular resistance (PVRI) at both FIO2 0.4 and 0.125. Hypoxia-induced increases in PVRI were unaffected by dopamine. Dobutamine at doses of 5, 10, and 20 micrograms X kg-1 X min-1 (n = 7 dogs) increased CI, with an increase in PAP without change in PVRI at FIO2 0.4, and at FIO2 0.125 there was no change in PAP and a decrease in PVRI. Hypoxia-induced increases in PVRI were inhibited by dobutamine, partially at 5 and 10 micrograms X kg-1 X min-1, and completely at 20 micrograms X kg-1 X min-1. In two additional groups of seven dogs the effects of reducing FIO2 from 0.4 to 0.1 without and with dopamine or dobutamine either at 10 micrograms X kg-1 X min-1 (n = 7) or at 20 micrograms X kg-1 X min-1 (n = 7) were studied at an unchanged CI obtained by stepwise inflations of a balloon placed in the inferior vena cava. At constant flow both amines increased PVRI at FIO2 0.4 and did not significantly affect hypoxia-induced increases in PVRI.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000818:Animals; D004280:Dobutamine / Q000494:pharmacology*; D004285:Dogs; D004298:Dopamine / Q000494:pharmacology*; D006439:Hemodynamics / Q000187:drug effects*; D000860:Hypoxia / Q000503:physiopathology*; D010100:Oxygen / Q000633:toxicity*; D011652:Pulmonary Circulation; D011669:Pulmonary Wedge Pressure / Q000187:drug effects; D014655:Vascular Resistance / Q000187:drug effects
chemical_list: D004280:Dobutamine; D010100:Oxygen; D004298:Dopamine