title: Effects of pulse-delivered inhaled nitric oxide administration on pulmonary perfusion and arterial oxygenation in dorsally recumbent isoflurane-anesthetized horses.
abstract: OBJECTIVE
  To image the spatial distribution of pulmonary blood flow by means of scintigraphy, evaluate ventilation-perfusion (VA/Q) matching and pulmonary blood shunting (Qs/Qt) by means of the multiple inert gas elimination technique (MIGET), and measure arterial oxygenation and plasma endothelin-1 concentrations before, during, and after pulse-delivered inhaled nitric oxide (PiNO) administration to isoflurane-anesthetized horses in dorsal recumbency.
  
  
  METHODS
  3 healthy adult Standardbreds.
  
  
  METHODS
  Nitric oxide was pulsed into the inspired gases in dorsally recumbent isoflurane-anesthetized horses. Assessment of VA/Q matching, Qs/Qt, and Pao2 content was performed by use of the MIGET, and spatial distribution of pulmonary blood flow was measured by perfusion scintigraphy following IV injection of technetium Tc 99m-labeled macroaggregated human albumin before, during, and 30 minutes after cessation of PiNO administration.
  
  
  RESULTS
  During PiNO administration, significant redistribution of blood flow from the dependent regions to the nondependent regions of the lungs was found and was reflected by improvements in VA/Q matching, decreases in Qs/Qt, and increases in Pao2 content, all of which reverted to baseline values at 30 minutes after PiNO administration.
  
  
  CONCLUSIONS
  Administration of PiNO in anesthetized dorsally recumbent horses resulted in redistribution of pulmonary blood flow from dependent atelectatic lung regions to nondependent aerated lung regions. Because hypoxemia is commonly the result of atelectasis in anesthetized dorsally recumbent horses, the addition of nitric oxide to inhaled gases could be used clinically to alleviate hypoxemia in horses during anesthesia.
authors.affiliation: Department of Animal Environment and Health, Swedish University of Agricultural Sciences, 53223 Skara, Sweden., Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman, WA 99164.
authors.forename: Tamara L
authors.initials: TL
authors.lastname: Grubb
authors.forename: Peter F
authors.initials: PF
authors.lastname: Lord
authors.forename: Mieth
authors.initials: M
authors.lastname: Berger
authors.forename: Christina
authors.initials: C
authors.lastname: Larsson
authors.forename: Anneli
authors.initials: A
authors.lastname: Rydén
authors.forename: Jan
authors.initials: J
authors.lastname: Frendin
authors.forename: Pia
authors.initials: P
authors.lastname: Funkquist
authors.forename: Anna
authors.initials: A
authors.lastname: Edner
authors.forename: Görel
authors.initials: G
authors.lastname: Nyman
mesh_terms: D000280:Administration, Inhalation; D000328:Adult; D018685:Anesthetics, Inhalation / Q000494:pharmacology; D000818:Animals; D001158:Arteries / Q000187:drug effects; D001784:Blood Gas Analysis / Q000662:veterinary; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects; D006736:Horses / Q000502:physiology*; D006801:Humans; D000860:Hypoxia / Q000209:etiology / Q000628:therapy / Q000662:veterinary*; D007530:Isoflurane / Q000494:pharmacology; D008168:Lung / Q000098:blood supply* / Q000000981:diagnostic imaging; D008297:Male; D009569:Nitric Oxide / Q000008:administration & dosage*; D010477:Perfusion / Q000662:veterinary; D001261:Pulmonary Atelectasis / Q000503:physiopathology / Q000662:veterinary; D011877:Radionuclide Imaging; D012119:Respiration / Q000187:drug effects
chemical_list: D018685:Anesthetics, Inhalation; D009569:Nitric Oxide; D007530:Isoflurane