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.
Department of Pediatrics, University of Chicago Children's Hospital, University of Chicago, Illinois 60637, USA.
W
W
Meadow
B
B
Rudinsky
A
A
Bell
R
R
Hipps
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