title: Response to nitric oxide inhalation in early acute lung injury.
abstract: OBJECTIVE
  To evaluate the dose response of inhaled nitric oxide (NO) on gas exchange and central haemodynamics in patients with early acute lung injury (ALI).
  
  
  METHODS
  Prospective, multicentre clinical study.
  
  
  METHODS
  General ICUs in university and regional hospitals.
  
  
  METHODS
  18 Patients with early ALI according to specified criteria.
  
  
  METHODS
  During controlled ventilation an inhalation system was used to deliver NO (1000 ppm in N2) and O2/air to the low pressure fresh gas inlet of a Siemens 900C ventilator. Haemodynamics and pulmonary gas exchange variables were measured at baseline and at stepwise increased inspiratory NO concentrations of 0.1, 0.3, 1, 3, 10, 30 and 100 ppm, each dose being maintained for 15 min. Dose testing was repeated the next day, and the response to prolonged (2 h) NO inhalation at 1 and 10 ppm was also tested.
  
  
  RESULTS
  Inhalation of NO produced a significant increase in PaO2 (P < 0.0025). The degree of response, as well as the optimal NO dose varied in individual patients and between different days. Venous admixture (QVA/QT) was reduced (P < 0.02) from 38% (31-46%) to 33% (26-41%). In our patients with early acute lung injury and only a moderate elevation in pulmonary arterial pressure NO inhalation did not reduce mean pulmonary artery pressure significantly, being 27.0 (21-30) mmHg at baseline and 26.0 (21-30) mm Hg at 100 ppm.
  
  
  CONCLUSIONS
  This study shows that improvements in arterial oxygenation in response to inhaled NO may show great inter- as well as intraindividual variability, and that improvements in arterial oxygenation occur without any measurable lowering of the pulmonary artery pressure.
authors.affiliation: Department of Anaesthesia and Intensive Care, Sahlgrenska University Hospital, Göteborg, Sweden.
authors.forename: S
authors.initials: S
authors.lastname: Lundin
authors.forename: U N
authors.initials: UN
authors.lastname: Westfelt
authors.forename: O
authors.initials: O
authors.lastname: Stenqvist
authors.forename: H
authors.initials: H
authors.lastname: Blomqvist
authors.forename: A
authors.initials: A
authors.lastname: Lindh
authors.forename: L
authors.initials: L
authors.lastname: Berggren
authors.forename: S
authors.initials: S
authors.lastname: Arvidsson
authors.forename: U
authors.initials: U
authors.lastname: Rudberg
authors.forename: C G
authors.initials: CG
authors.lastname: Frostell
mesh_terms: D000280:Administration, Inhalation; D000328:Adult; D000368:Aged; D004305:Dose-Response Relationship, Drug; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D008875:Middle Aged; D009569:Nitric Oxide / Q000494:pharmacology* / Q000627:therapeutic use; D010100:Oxygen / Q000097:blood; D011446:Prospective Studies; D011659:Pulmonary Gas Exchange / Q000187:drug effects*; D011669:Pulmonary Wedge Pressure / Q000187:drug effects; D012121:Respiration, Artificial; D012128:Respiratory Distress Syndrome / Q000188:drug therapy / Q000503:physiopathology*; D018709:Statistics, Nonparametric
chemical_list: D009569:Nitric Oxide; D010100:Oxygen