title: Inhaled nitric oxide improves oxygenation in piglets with meconium aspiration.
abstract: We hypothesized that nitric oxide (NO) inhalation in a model of meconium aspiration in newborn piglets would decrease pulmonary vascular resistance. Seven neonatal piglets were obtained at less than 48 hr of age and instrumented under fentanyl anesthesia. Inhaled NO (40 parts per million) was administered during normoxia and again after hypoxia was induced by reducing FiO2 to 0.13. During normoxia NO inhalation caused a fall in pulmonary artery pressure from a mean of 3.15 (SD 0.8) kPa to 2.84 (SD 0.7) kPa (P < 0.01). Hypoxia (mean arterial O2 saturation 35%) increased PA pressures to a mean of 5.4 (SD 1.6) kPa and NO administration during hypoxia decreased PA pressures to 3.6 (SD 1.2) kPa (P < 0.001). In order to determine the effects of NO in a model of meconium aspiration, 6 to 7 mL/kg of 20% human meconium in normal saline was instilled into the trachea. This procedure induced hypoxemia (mean SaO2 43.4%, SD 19), respiratory acidosis, (mean PaCO2 12.1 kPa, SD 0.5; mean pH 7.04, SD 0.03), and pulmonary arterial hypertension (mean pulmonary artery pressure 6.0 kPa, SD 1.3) despite ventilation with 90% oxygen. Inhaled NO was then administered in concentrations of 5, 10, 20, 30, 40, 60, and 80 parts per million in random order according to a Latin square design.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000280:Administration, Inhalation; D000818:Animals; D000831:Animals, Newborn; D003326:Coronary Circulation / Q000187:drug effects; D006801:Humans; D006976:Hypertension, Pulmonary / Q000188:drug therapy / Q000503:physiopathology; D000860:Hypoxia / Q000188:drug therapy / Q000503:physiopathology; D007231:Infant, Newborn; D008471:Meconium Aspiration Syndrome / Q000188:drug therapy* / Q000503:physiopathology; D009569:Nitric Oxide / Q000008:administration & dosage*; D011659:Pulmonary Gas Exchange / Q000187:drug effects; D011669:Pulmonary Wedge Pressure / Q000187:drug effects; D013552:Swine; D014655:Vascular Resistance / Q000187:drug effects; D014692:Ventilation-Perfusion Ratio / Q000187:drug effects
chemical_list: D009569:Nitric Oxide