title: An improved porcine model of stable methacholine-induced bronchospasm.
abstract: OBJECTIVE
  To validate an animal model replicating the pathophysiological characteristics of severe induced bronchospasm observed in humans, with a high level of stability permitting measurements such as the assessment of ventilation-perfusion relationships with the multiple inert gas elimination technique.
  
  
  METHODS
  Experimental study in an animal research laboratory.
  
  
  METHODS
  13 piglets (age 3-4 months) were studied and 7 underwent the complete protocol
  
  
  METHODS
  The animals were anesthetized and paralyzed. Mechanical ventilation was initiated in a volume-controlled mode. Ventilatory parameters were adjusted to obtain normocapnia and were maintained constant during the bronchospasm. Methacholine was administered via a synchronized nebulizer and progressively adjusted to obtain a stable twofold increase in peak inspiratory pressure.
  
  
  RESULTS
  Cardiopulmonary physiological data including assessment of lung mechanics and measurement of ventilation-perfusion relationships were obtained before and during the bronchospasm. Peak inspiratory pressure increased from 19.7+/-2.9 to 44.4+/-7.1 cmH(2)O during the bronchospasm. The latter remained stable over 2 h. Respiratory mechanics, gas exchange, and ventilation-perfusion distribution changes typical of those observed in severe bronchospasm in humans were observed in all animals.
  
  
  CONCLUSIONS
  The present experimental model replicates some of the physiopathological characteristics of severe human bronchospasm, and its stability should facilitate studies of the effects of different ventilatory modes in the setting of acute severe asthma.
authors.affiliation: Department of Anesthesiology, Cliniques Universitaires St-Luc, Université Catholique de Louvain, Avenue Hippocrate 10, 1200 Brussels, Belgium.
authors.forename: Christine
authors.initials: C
authors.lastname: Watremez
authors.forename: Jean
authors.initials: J
authors.lastname: Roeseler
authors.forename: Marc
authors.initials: M
authors.lastname: De Kock
authors.forename: Thierry
authors.initials: T
authors.lastname: Clerbaux
authors.forename: Bruno
authors.initials: B
authors.lastname: Detry
authors.forename: Claude
authors.initials: C
authors.lastname: Veriter
authors.forename: Marc
authors.initials: M
authors.lastname: Reynaert
authors.forename: Pierre
authors.initials: P
authors.lastname: Gianello
authors.forename: Philippe
authors.initials: P
authors.lastname: Jolliet
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Liistro
mesh_terms: D000818:Animals; D001249:Asthma / Q000503:physiopathology*; D001986:Bronchial Spasm / Q000139:chemically induced* / Q000503:physiopathology*; D004195:Disease Models, Animal; D016210:Methacholine Chloride / Q000494:pharmacology*; D015203:Reproducibility of Results; D012121:Respiration, Artificial; D015656:Respiratory Mechanics; D013552:Swine; D014692:Ventilation-Perfusion Ratio
chemical_list: D016210:Methacholine Chloride