title: Relationship among cardiac index, inspiration/expiration ratio, and perfluorocarbon dose during partial liquid ventilation in an oleic acid model of acute lung injury in sheep.
abstract: BACKGROUND
  The aim of this study was to demonstrate the influence of different inspiration/expiration (I/E) ratios on cardiac index (CI) and hemodynamics during partial liquid ventilation (PLV) using a large animal model of acute respiratory failure in a prospective, randomized controlled animal laboratory trial.
  
  
  METHODS
  After induction of respiratory failure by right atrial injection of 0.09 mL/kg oleic acid, (1) determination of agreement between reversed Fick and pulmonary artery thermodilution (QTD) techniques with progressive doses of perflubron (LiquiVent, Alliance Pharmaceutical Corp, San Diego, Calif) (n = 7 sheep) and (2) comparison of 4 groups with I/E ratios of 3.4:1, 2:1, 1:1, and 1:2 were performed, applying identical ventilatory patterns in all I/E groups (n = 28 sheep). PLV was established with intratracheal instillation of 25 mL/kg perflubron. Cardiac index was assessed at 15-minute intervals for a 120-minute experimental period by QTD.
  
  
  RESULTS
  During progressive doses of PLV, the correlation (r) between Fick and QTD techniques was 0.82. Thermodilution deteriorated after induction of lung injury and recovered after PLV start. Regarding QTD, no significant changes after PLV onset (within-group comparison) and between I/E groups were observed (P < .05).
  
  
  CONCLUSIONS
  The QTD technique is a satisfactory reflector of CI during PLV, and I/E ratio has no significant influence on CI, even using extreme inverse ratio ventilation.
authors.affiliation: Department of Anesthesiology and Intensive Care, Universitätsklinikum Mannheim Fakultüt für Klinische Medizin, Ruprecht-Karls-University, Mannheim 68167, Germany. juergen.meinhardt@anaes.ma.uni-heidelberg.de
authors.forename: Jürgen P
authors.initials: JP
authors.lastname: Meinhardt
authors.forename: Ulrike
authors.initials: U
authors.lastname: Friess
authors.forename: Hans Joachim
authors.initials: HJ
authors.lastname: Bender
authors.forename: Ronald B
authors.initials: RB
authors.lastname: Hirschl
authors.forename: Michael
authors.initials: M
authors.lastname: Quintel
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D005466:Fluorocarbons / Q000008:administration & dosage; D006321:Heart / Q000502:physiology; D006439:Hemodynamics; D021061:Liquid Ventilation; D019301:Oleic Acid; D011446:Prospective Studies; D011651:Pulmonary Artery / Q000502:physiology; D011897:Random Allocation; D012119:Respiration; D012756:Sheep
chemical_list: D005466:Fluorocarbons; D019301:Oleic Acid