title: Total liquid ventilation efficacy in an ovine model of severe meconium aspiration syndrome.
abstract: OBJECTIVE
  To test the hypothesis that total liquid ventilation enables a more effective and better tolerated lavage than a bronchoalveolar lavage performed with diluted surfactant in a newborn ovine model of severe acute meconium aspiration syndrome.
  
  
  METHODS
  Prospective, randomized, interventional study.
  
  
  METHODS
  Animal research laboratory at the Faculté de médecine et des sciences de la santé de l'université de Sherbrooke, Sherbrooke, Canada.
  
  
  METHODS
  Twenty-three newborn lambs, <4 days, 2.5-4.0 kg in weight.
  
  
  METHODS
  Animals were intubated, anesthetized, and paralyzed. Catheters were placed in the femoral artery and jugular vein. Severe meconium aspiration syndrome was obtained by instillation of a 25% dilution of human meconium in saline (1 mL/kg × 2). Lambs were then randomized in 12 total liquid ventilation-bronchoalveolar lavage (minute ventilation of 160 mL/kg/min with perfluorodecalin) vs. 11 bronchoalveolar lavage performed with diluted surfactant (conventional ventilation + 30 mL/kg in two aliquots bronchoalveolar lavage with 5 mg/mL BLES surfactant). Surviving lambs were ventilated for a total of 4 hrs and euthanized.
  
  
  RESULTS
  Arterial blood gases, systemic and pulmonary hemodynamic parameters using the thermodilution method, percentage of recovered meconium, and lung histologic scores. Total liquid ventilation bronchoalveolar lavage enabled a significantly higher PaO2 throughout the experiment. PaCO2, pH, and hemodynamic parameters were comparable for both groups except for an increase in mean pulmonary arterial pressure during total liquid ventilation. Total liquid ventilation bronchoalveolar lavage allowed for 43 ± 14% of the instilled meconium to be removed vs. 28 ± 10% for bronchoalveolar lavage performed with diluted surfactant (p = .022). Lung histologic analysis showed no difference between total scores.
  
  
  CONCLUSIONS
  Total liquid ventilation bronchoalveolar lavage is well tolerated and more effective in terms of meconium washout and gas exchange than bronchoalveolar lavage performed with diluted surfactant in this experimental model of severe meconium aspiration syndrome. These positive results open the way to further experiments in our ovine model, ultimately aiming at a clinical trial with total liquid ventilation bronchoalveolar lavage to treat severe meconium aspiration syndrome.
authors.affiliation: Department of Pediatrics, Université de Sherbrooke, Sherbrooke, Canada.
authors.forename: Olivier
authors.initials: O
authors.lastname: Avoine
authors.forename: Dominick
authors.initials: D
authors.lastname: Bossé
authors.forename: Benoit
authors.initials: B
authors.lastname: Beaudry
authors.forename: Alexandre
authors.initials: A
authors.lastname: Beaulieu
authors.forename: Roula
authors.initials: R
authors.lastname: Albadine
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Praud
authors.forename: Raymond
authors.initials: R
authors.lastname: Robert
authors.forename: Philippe
authors.initials: P
authors.lastname: Micheau
authors.forename: Hervé
authors.initials: H
authors.lastname: Walti
mesh_terms: D000818:Animals; D018893:Bronchoalveolar Lavage / Q000379:methods*; D004195:Disease Models, Animal; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D007150:Immunohistochemistry; D007231:Infant, Newborn; D021061:Liquid Ventilation / Q000379:methods*; D008168:Lung / Q000473:pathology*; D008297:Male; D008471:Meconium Aspiration Syndrome / Q000628:therapy*; D011659:Pulmonary Gas Exchange; D011663:Pulmonary Surfactants / Q000494:pharmacology; D011897:Random Allocation; D012307:Risk Factors; D012720:Severity of Illness Index; D012756:Sheep; D018709:Statistics, Nonparametric; D015996:Survival Rate; D016896:Treatment Outcome
chemical_list: D011663:Pulmonary Surfactants