title: Effect of nitric oxide inhalation on gas exchange in acute severe pneumonia.
abstract: Inhaled nitric oxide (NO) causes selective pulmonary vasodilatation and may improve gas exchange. The study was aimed to evaluate the acute effects of inhaled NO on pulmonary gas exchange in severe unilateral pneumonia, where hypoxemia results from increased intrapulmonary shunt. We studied 8 patients without preexisting lung disease (59±18 yr; 4M/4F) with early unilateral severe pneumonia and respiratory failure. Pulmonary and systemic hemodynamics and gas exchange, including ventilation-perfusion (V;A/Q;) distributions, were measured at baseline and while breathing 5 and 40 parts per million (ppm) of NO. Inhaled NO caused a dose-dependent fall in pulmonary vascular resistance (by 12% and 21%, with 5 and 40ppm, respectively; p<0.01, each) and improvement of PaO2 (by 25% and 23%; p<0.05, each), owing to the reduction of intrapulmonary shunt (by 23% and 27%; p<0.05, each), without changes in the amount of perfusion to low V;A/Q; ratio alveolar units. Patients with greater baseline intrapulmonary shunt exhibited greater improvement in arterial oxygenation (r(2)=0.55, p<0.05). We conclude that low doses of inhaled NO improve pulmonary gas exchange in acute severe pneumonia.
authors.affiliation: Department of Pulmonary Medicine, Institut Clínic del Tórax, Hospital Clínic, University of Barcelona, Barcelona, Spain. fp.gomez@gmail.com
authors.forename: Federico P
authors.initials: FP
authors.lastname: Gómez
authors.forename: Veronica M
authors.initials: VM
authors.lastname: Amado
authors.forename: Josep
authors.initials: J
authors.lastname: Roca
authors.forename: Antoni
authors.initials: A
authors.lastname: Torres
authors.forename: Josep M
authors.initials: JM
authors.lastname: Nicolas
authors.forename: Robert
authors.initials: R
authors.lastname: Rodriguez-Roisin
authors.forename: Joan A
authors.initials: JA
authors.lastname: Barberà
mesh_terms: D000280:Administration, Inhalation; D000368:Aged; D000704:Analysis of Variance; D001794:Blood Pressure / Q000187:drug effects; D001993:Bronchodilator Agents / Q000008:administration & dosage*; D047630:Depsipeptides / Q000187:drug effects; D005260:Female; D007839:Functional Laterality; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D006940:Hyperemia / Q000150:complications / Q000628:therapy; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000008:administration & dosage*; D011014:Pneumonia / Q000150:complications / Q000382:microbiology / Q000628:therapy*; D011659:Pulmonary Gas Exchange; D055815:Young Adult
chemical_list: D001993:Bronchodilator Agents; D047630:Depsipeptides; C081425:respirantin; D009569:Nitric Oxide