title: Increased expired NO and roles of CO2 and endogenous NO after venous gas embolism in rabbits.
abstract: Venous gas embolism (VGE) is a feared complication in diving, aviation, surgery and trauma. We hypothesized that air emboli in the lung circulation might change expired nitric oxide (FeNO). A single intravenous infusion of air was given (100 mul kg(-1)) to three groups of anaesthetized mechanically ventilated rabbits: (A) one with intact NO production, (B) one with intact NO production and where end-tidal CO(2) was controlled, and (C) one with endogenous NO synthesis blockade (L: -NAME, 30 mg kg(-1)). Air infusions resulted in increased FeNO of the control group from 20 (4) [mean (SD)] ppb to a peak value of 39 (4) ppb within 5 min (P < 0.05), and FeNO was still significantly elevated [27 (2) ppb] after 20 min (P < 0.05). Parallel to the NO increase there were significant decreases in end-tidal CO(2 )(ETCO(2)) and mean arterial pressure and an increase in insufflation pressure. In group B, when CO(2) was supplemented after air infusion, NO was suppressed (P = 0.033), but was still significantly elevated compared with pre-infusion control (P < 0.05). In group C, all animals died within 40 min of air infusion whereas all animals in the other groups were still alive at this time point. We conclude that venous air embolization increases FeNO, and that a part of this effect is due to the concomitant decrease in ETCO(2). Furthermore, an intact NO production may be critical for the tolerance to VGE. Finally, FeNO might have a potential in the diagnosis and monitoring of pulmonary gas embolism.
authors.affiliation: Department of Physiology and Pharmacology, Karolinska Institutet, 17177, Stockholm, Sweden. Per.Agvald@ki.se
authors.forename: Per
authors.initials: P
authors.lastname: Agvald
authors.forename: L Christofer
authors.initials: LC
authors.lastname: Adding
authors.forename: Kristofer F
authors.initials: KF
authors.lastname: Nilsson
authors.forename: Lars E
authors.initials: LE
authors.lastname: Gustafsson
authors.forename: Dag
authors.initials: D
authors.lastname: Linnarsson
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D001944:Breath Tests; D002245:Carbon Dioxide / Q000097:blood / Q000502:physiology*; D004618:Embolism, Air / Q000378:metabolism / Q000503:physiopathology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D006863:Hydrogen-Ion Concentration; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D010100:Oxygen / Q000097:blood; D010313:Partial Pressure; D011659:Pulmonary Gas Exchange / Q000187:drug effects / Q000502:physiology*; D011817:Rabbits; D012121:Respiration, Artificial
chemical_list: D004791:Enzyme Inhibitors; D002245:Carbon Dioxide; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D010100:Oxygen; D019331:NG-Nitroarginine Methyl Ester