title: The initial response to inhaled nitric oxide treatment for intensive care unit patients with acute respiratory distress syndrome.
abstract: BACKGROUND
  Inhaled nitric oxide (INO) can improve hypoxemia and reduce pulmonary hypertension, but there is a wide range of response to INO.
  
  
  OBJECTIVE
  The aim of this study was to evaluate the effect of different INO concentrations in acute respiratory distress syndrome (ARDS) patients.
  
  
  METHODS
  Thirty-two adult ARDS patients who were supported by mechanical ventilator were included. INO was given at a concentration of 1, 5, 10, 20 and 40 ppm, sequentially. Arterial blood gas and mean pulmonary artery pressure (MPAP) were measured 30 min after INO concentrations changed.
  
  
  RESULTS
  There was a significant increase in PaO(2)/FiO(2) (p < 0.0001) and a decrease in pulmonary vascular resistance index and MPAP (p < 0.0001) after INO use. INO concentrations required for improving oxygenation were in the range of 1-20 ppm, whereas concentrations required for decreasing MPAP were in the range of 1-40 ppm. PaO(2)/FiO(2) worsened when the INO dose was adjusted above 20 ppm. Sixty-nine percent of ARDS patients were responders; 31% of them were nonresponders. Among responders, 64% of patients responded at 1 ppm, 36% at 5 ppm.
  
  
  CONCLUSIONS
  The optimal doses for improving oxygenation and reducing PAP differ. The maximum PaO(2)/FiO(2) was observed at a lower INO concentration than that required for the minimal MPAP. There was no further improvement in PaO(2)/FiO(2) when the INO dose was adjusted above 20 ppm. Higher doses of INO treatment worsened oxygenation.
authors: Intensive Care Unit, Internal Medicine Department, Veterans General Hospital Kaohsiung, Kaoshiung, Taiwan, ROC. cwhsu2003@yahoo.com
authors: Chien-Wei
authors: CW
authors: Hsu
authors: David Lin
authors: DL
authors: Lee
authors: Shoa-Lin
authors: SL
authors: Lin
authors: Shu-Fen
authors: SF
authors: Sun
authors: Hsueh-Wen
authors: HW
authors: Chang
mesh_terms: D018806:APACHE; D000280:Administration, Inhalation; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004305:Dose-Response Relationship, Drug; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000008:administration & dosage*; D011446:Prospective Studies; D011659:Pulmonary Gas Exchange; D012128:Respiratory Distress Syndrome / Q000188:drug therapy* / Q000453:epidemiology; D012307:Risk Factors; D016896:Treatment Outcome
chemical_list: D009569:Nitric Oxide