title: Perfluorocarbon-associated gas exchange in normal and acid-injured large sheep.
abstract: OBJECTIVE
  We hypothesized that a) perfluorocarbon-associated gas exchange could be accomplished in normal large sheep; b) the determinants of gas exchange would be similar during perfluorocarbon-associated gas exchange and conventional gas ventilation; c)in large animals with lung injury, perfluorocarbon-associated gas exchange could be used to enhance gas exchange without adverse effects on hemodynamics; and d) the large animal with lung injury could be supported with an FIO2 of <1.0 during perfluorocarbon-associated gas exchange.
  
  
  METHODS
  Prospective, observational animal study and prospective randomized, controlled animal study.
  
  
  METHODS
  An animal laboratory in a university setting.
  
  
  METHODS
  Thirty adult ewes.
  
  
  RESULTS
  Five normal ewes (61.0 +/- 4.0 kg) underwent perfluorocarbon-associated gas exchange to ascertain the effects of tidal volume, end-inspiratory pressure, and positive end-expiratory pressure (PEEP) on oxygenation. Respiratory rate, tidal volume, and minute ventilation were studied to determine their effects on CO2 clearance. Sheep, weighing 58.9 +/- 8.3 kg, had lung injury induced by instilling 2 mL/kg of 0.05 Normal hydrochloric acid into the trachea. Five minutes after injury, PEEP was increased to 10 cm H2O. Ten minutes after injury, sheep with Pao2 values of <100 torr (<13.3 kPa) were randomized to continue gas ventilation (control, n=9) or to institute perfluorocarbon-associated gas exchange (n=9) by instilling 1.6 L of unoxygenated perflubron into the trachea and resuming gas ventilation. Blood gas and hemodynamic measurements were obtained throughout the 4-hr study. Both tidal volume and end-inspiratory pressure influenced oxygenation in normal sheep during perfluorocarbon-associated gas exchange. Minute ventilation determined CO2 clearance during perfluorocarbon-associated gas exchange in normal sheep. After acid aspiration lung injury, perfluorocarbon-associated gas exchange increased PaO2 and reduced intrapulmonary shunt fraction. Hypoxia and intrapulmonary shunting were unabated after injury in control animals. Hemodynamics were not influenced by the institution of perfluorocarbon-associated gas exchange.
  
  
  CONCLUSIONS
  Tidal volume and end-inspiratory pressure directly influence oxygenation during perfluorocarbon-associated gas exchange in large animals. Minute ventilation influences clearance of CO2. In adult sheep with acid aspiration lung injury, perfluorocarbon-associated gas exchange at an FIO2 of <1.0 supports oxygenation and improves intrapulmonary shunting, without adverse hemodynamic effects, when compared with conventional gas ventilation.
authors.affiliation: Division of Pediatric Critical Care, Children's Hospital of Buffalo, NY 14222, USA.
authors.forename: L J
authors.initials: LJ
authors.lastname: Hernan
authors.forename: B P
authors.initials: BP
authors.lastname: Fuhrman
authors.forename: R E
authors.initials: RE
authors.lastname: Kaiser
authors.forename: S
authors.initials: S
authors.lastname: Penfil
authors.forename: C
authors.initials: C
authors.lastname: Foley
authors.forename: M C
authors.initials: MC
authors.lastname: Papo
authors.forename: C L
authors.initials: CL
authors.lastname: Leach
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D005466:Fluorocarbons / Q000627:therapeutic use*; D006439:Hemodynamics; D011175:Positive-Pressure Respiration / Q000379:methods; D011446:Prospective Studies; D011659:Pulmonary Gas Exchange / Q000187:drug effects*; D012128:Respiratory Distress Syndrome / Q000503:physiopathology / Q000628:therapy*; D015656:Respiratory Mechanics; D012756:Sheep
chemical_list: D005466:Fluorocarbons