title: High-frequency oscillation and exogenous surfactant administration in lung-injured adult sheep.
abstract: OBJECTIVE
  To evaluate the effects of high-frequency oscillation on the response to exogenous surfactant in lung-injured adult sheep.
  
  
  METHODS
  A prospective, controlled, in vivo, animal laboratory study.
  
  
  METHODS
  Animal research facility of a health sciences university.
  
  
  METHODS
  Twenty-eight adult sheep.
  
  
  METHODS
  Animals were anesthetized and instrumented with a tracheostomy and vascular catheters. Following whole lung saline lavage, animals were randomized to one of four groups: Group S-CMV received surfactant and was ventilated for 4 hrs using a conventional mechanical ventilation strategy, group S-HFOV/CMV received surfactant and was ventilated with a high-frequency oscillation technique for 2 hrs and a conventional mechanical strategy for 2 hrs, group HFOV/CMV underwent the latter ventilatory strategies without receiving surfactant, and group HFOV was ventilated with high-frequency oscillation only for 4 hrs. At the end of the ventilatory period, the distributions of ventilation and surfactant were evaluated in animals that received surfactant.
  
  
  RESULTS
  Animals in the S-CMV group had a significantly greater mean PaO2 value at the end of the experimental period than animals in the S-HFOV/CMV or HFOV/CMV groups. Evaluation of the distribution of ventilation relative to surfactant demonstrated that animals ventilated with high-frequency oscillation followed by conventional mechanical ventilation had a significantly greater disproportionate distribution of ventilation relative to surfactant compared with the CMV-only group.
  
  
  CONCLUSIONS
  A period of high-frequency oscillation, as used in this study, immediately following exogenous surfactant administration mitigates the host's response to surfactant when subsequently switched to conventional mechanical ventilation.
authors.affiliation: Department of Physiology & Pharmacology, Lawson Health Research Institute, St Joseph's Health Centre, The University of Western Ontario, London, Canada.
authors.forename: Carolyn L
authors.initials: CL
authors.lastname: Kerr
authors.forename: Lynda A
authors.initials: LA
authors.lastname: McCaig
authors.forename: Ruud A W
authors.initials: RA
authors.lastname: Veldhuizen
authors.forename: James F
authors.initials: JF
authors.lastname: Lewis
mesh_terms: D000818:Animals; D006612:High-Frequency Ventilation; D011669:Pulmonary Wedge Pressure; D012121:Respiration, Artificial; D012128:Respiratory Distress Syndrome / Q000628:therapy*; D012756:Sheep; D013501:Surface-Active Agents / Q000627:therapeutic use*
chemical_list: D013501:Surface-Active Agents