Effects of nebulized nitroprusside on pulmonary and systemic hemodynamics during pulmonary hypertension in piglets.
We tested the effects of nebulized nitroprusside (Neb-NP) on pulmonary and systemic hemodynamics during pulmonary hypertension induced by hypoxia or group B streptococci infusion in piglets. Twenty-three anesthetized and mechanically ventilated piglets received Neb-NP under four experimental conditions: 1) normoxia; 2) 15 and 60 min of pulmonary hypertension induced by hypoxia; 3) after pretreatment with dipyridamole; 4) pulmonary hypertension induced by infusion of group B streptococci. In addition, Neb-NP was contrasted to nebulization of tolazoline. During hypoxia-induced pulmonary hypertension, Neb-NP significantly reduced pulmonary artery pressure [PAP; -8.4+/-0.9 (SEM) mm Hg] and pulmonary vascular resistance (-25+/-2.1%) (both p < 0.001), whereas neither systemic arterial pressure nor cardiac output changed significantly. Selective pulmonary vasodilation began within 2 min of the onset of Neb-NP, and did not wane over 1 h. In contrast, within 5 min after Neb-NP was discontinued while hypoxia persisted, PAP rose significantly. Pretreatment with dipyridamole did not enhance the pulmonary vasodilation induced by Neb-NP, but did reduce systemic arterial pressure. Nebulized tolazoline did not reduce PAP significantly, but did lower systemic arterial pressure. Selective pulmonary vasodilation induced by Neb-NP was significantly smaller during group B streptococci-induced versus hypoxia-induced pulmonary hypertension. In sum, Neb-NP produced prompt, significant, selective reduction of PAP in piglets with pulmonary hypertension. Cautious extrapolation of these findings to selected clinical conditions in human infants may be warranted.
Meadow
W
W
Department of Pediatrics, University of Chicago Children's Hospital, University of Chicago, Illinois 60637, USA.
Rudinsky
B
B
Bell
A
A
Hipps
R
R
D000280:Administration, Inhalation; D000336:Aerosols; D000818:Animals; D001784:Blood Gas Analysis; D006152:Cyclic GMP / Q000502:physiology; D004176:Dipyridamole / Q000494:pharmacology; D006439:Hemodynamics / Q000187:drug effects*; D006976:Hypertension, Pulmonary / Q000139:chemically induced / Q000503:physiopathology*; D009569:Nitric Oxide / Q000502:physiology; D009599:Nitroprusside / Q000008:administration & dosage / Q000494:pharmacology*; D010101:Oxygen Consumption; D011652:Pulmonary Circulation / Q000187:drug effects*; D015398:Signal Transduction; D013552:Swine; D014043:Tolazoline / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology
D000336:Aerosols; D014665:Vasodilator Agents; D009599:Nitroprusside; D009569:Nitric Oxide; D004176:Dipyridamole; D014043:Tolazoline; D006152:Cyclic GMP