title: High-frequency oscillatory ventilation of the perfluorocarbon-filled lung: dose-response relationships in an animal model of acute lung injury.
abstract: OBJECTIVE
  To examine dose-response relationships regarding the efficiency of gas exchange and hemodynamic function during high-frequency oscillation and partial liquid ventilation (HFO-PLV) of the perfluorocarbon (PFC)-treated lung in a model of acute lung injury.
  
  
  METHODS
  An animal research laboratory in a university medical center.
  
  
  METHODS
  A prospective, randomized study comparing animals receiving varying doses (0, 5, 15, and 20 mL/kg) of perflubron during high-frequency oscillatory ventilation (HFOV) with mean airway pressure (Paw) optimized to achieve a minimal percutaneous oxygen saturation (Spo2).
  
  
  METHODS
  Nineteen healthy swine (mean weight 28.9 kg) with saline lavage-induced acute lung injury.
  
  
  METHODS
  Animals were treated with repetitive saline lavage to achieve a uniform degree of acute lung injury (Spo2 < or =90% on an Fio2 of 1.0). After lung injury, subjects were converted to HFOV, and lung volume was optimized. HFO-PLV was initiated by instillation of perflubron at a rate of 0.5 mL.kg-1.min-1 to achieve total doses of 5, 15, and 20 mL/kg. After PFC dosing, the only experimental manipulation consisted of adjustment of Paw to achieve an Spo2 of 90% +/- 2% with Fio2 of 0.6. Gas exchange, hemodynamic variables, and pulmonary mechanics data were collected over a 1-hr period. Five control animals were not dosed with perflubron and remained on HFOV for the 1-hr period of data collection.
  
  
  RESULTS
  After lung volume recruitment with HFOV, the initiation of HFO-PLV was best tolerated with the two lower doses in our protocol. There were essentially no changes in Paco2 or pH between groups over the dosing interval. After dosing, analysis of variance demonstrated a PFC dose-dependent effect for oxygenation index (p =.01) only; the lowest oxygenation index was found in the 15 mL/kg group (p =.01). In the 15 mL/kg group, the Paw decreased steadily from 20.6 +/- 3.4 cm H2O at the end of dosing to 18.0 +/- 4.9 cm H2O at 60 mins. The Pao2 increased from 113 +/- 51 torr (15.06 +/- 6.79 kPa) to 134 +/- 49 torr (17.86 +/- 6.53 kPa) during this period and was associated with a decreasing oxygenation index (from 11.4 +/- 2.0 to 9.3 +/- 1.5). The cardiac index and pulmonary vascular resistance did not change significantly during the dosing period and were relatively stable after the completion of dosing.
  
  
  CONCLUSIONS
  The combination of HFOV and perflubron administration was well tolerated hemodynamically and was not associated with deterioration of gas exchange during dosing. Our data suggest that the optimal dose of perflubron to achieve the lowest oxygenation index during HFO-PLV is between 5 and 15 mL/kg. The combination of HFOV and perflubron administration is a novel strategy in the treatment of acute lung injury that shows some promise and merits additional investigation. We hope in future studies to address the histopathologic effects of varying perflubron doses during HFOV in a long-term study of the lung-protective effects of HFO-PLV.
authors.affiliation: Critical Care Research Laboratories and the Department of Anesthesia and Research Computing and Biostatistics, Children's Hospital and Harvard Medical School, Boston, MA, USA.
authors.forename: A
authors.initials: A
authors.lastname: Doctor
authors.forename: B
authors.initials: B
authors.lastname: Price
authors.forename: N
authors.initials: N
authors.lastname: Bhargava
authors.forename: J
authors.initials: J
authors.lastname: DiCanzio
authors.forename: J H
authors.initials: JH
authors.lastname: Arnold
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D005466:Fluorocarbons / Q000008:administration & dosage / Q000627:therapeutic use*; D006439:Hemodynamics; D006612:High-Frequency Ventilation / Q000379:methods*; D006842:Hydrocarbons, Brominated; D021061:Liquid Ventilation; D008171:Lung Diseases / Q000628:therapy*; D011659:Pulmonary Gas Exchange / Q000187:drug effects; D013552:Swine; D007507:Therapeutic Irrigation
chemical_list: D005466:Fluorocarbons; D006842:Hydrocarbons, Brominated; C003072:perflubron