title: Effects of partial liquid ventilation with perfluorocarbons on pressure-flow relationships, vascular compliance, and filtration coefficients of isolated blood-perfused rabbit lungs.
abstract: OBJECTIVE
  The density of perfluorocarbons is almost twice that of blood. Therefore, we hypothesized that partial liquid ventilation with these fluids markedly affects pulmonary hemodynamics and filtration coefficients. To test these hypotheses we studied pressure-flow relationships, vascular compliances, capillary pressures, and filtration coefficients in normal and perfluorocarbon-ventilated rabbit lungs.
  
  
  METHODS
  Controlled animal study with an ex-vivo isolated lung preparation.
  
  
  METHODS
  Research laboratory for experimental anesthesiology at the Heinrich-Heine-University of Düsseldorf.
  
  
  METHODS
  Fourteen New Zealand White rabbits.
  
  
  METHODS
  The lungs were perfused under zone 3 flow conditions with autologous blood at various flow rates (50 to 250 mL/min, closed circuit, roller pump, 37 degrees C) and ventilated with 5% CO2 in air (positive end-expiratory pressure: 2 cm H2O, tidal volume: 10 mL/kg, respiratory rate: 30 breaths/min) without (control group, n=7) and with (n=7) perfluorocarbon administered intratracheally (15 mL/kg).
  
  
  RESULTS
  Pulmonary arterial, left atrial, and airway pressures, as well as blood reservoir volume (reflecting changes in pulmonary blood volume) and lung weight, were measured continuously. Inconsistent with our hypothesis, we found no significant differences between both groups in the slopes and intercepts of the pressure-flow relationships. There were no significant differences in capillary pressures determined by double occlusion (6.7+/-1.2 vs. 6.3+/-1.3 cm H2O for control group, p=.53), vascular compliances (0.51+/-0.10 vs. 0.47+/-0.09 mL/cm H2O for control group, p=.38), and filtration coefficients (0.33+/-0.06 vs. 0.37+/-0.07 mL/min/mm Hg/100 g wet weight for control group, p=.80, Mann-Whitney).
  
  
  CONCLUSIONS
  Partial liquid ventilation with perfluorocarbons has no relevant effects on pulmonary filtration coefficients and global hemodynamic variables of isolated zone 3 lungs. These findings suggest that right ventricular afterload is not changed with partial liquid ventilation. It is likely, however, that intrapulmonary blood flow is redistributed toward less-dependent regions, although relevant global hemodynamic changes are absent during partial liquid ventilation.
authors.affiliation: Department of Experimental Anesthesiology, Heinrich-Heine-University of Düsseldorf, Germany.
authors.forename: S A
authors.initials: SA
authors.lastname: Loer
authors.forename: J
authors.initials: J
authors.lastname: Tarnow
mesh_terms: D000818:Animals; D001802:Blood Substitutes / Q000008:administration & dosage / Q000494:pharmacology*; D004353:Drug Evaluation, Preclinical; D005260:Female; D005466:Fluorocarbons / Q000008:administration & dosage / Q000494:pharmacology*; D006439:Hemodynamics / Q000187:drug effects; D066298:In Vitro Techniques; D007322:Instillation, Drug; D008297:Male; D011652:Pulmonary Circulation / Q000187:drug effects*; D011669:Pulmonary Wedge Pressure / Q000187:drug effects*; D011817:Rabbits; D011897:Random Allocation; D012121:Respiration, Artificial / Q000379:methods*; D014655:Vascular Resistance / Q000187:drug effects
chemical_list: D001802:Blood Substitutes; D005466:Fluorocarbons