title: Lung mechanics and histology during sevoflurane anesthesia in a model of chronic allergic asthma.
abstract: BACKGROUND
  There are no studies examining the effects of sevoflurane on a chronically inflamed and remodeled airway, such as that found in asthma. In the present study, we sought to define the respiratory effects of sevoflurane in a model of chronic allergic asthma. For this purpose, pulmonary mechanics were studied and lung morphometry analyzed to determine whether the physiological modifications reflected underlying morphological changes.
  
  
  METHODS
  Thirty-six BALB/c mice (20-25 g) were randomly divided into four groups. In OVA groups, mice were sensitized with ovalbumin and exposed to repeated ovalbumin challenges. In SAL groups, mice received saline using the same protocol. Twenty-four hours after the last challenge, the animals were anesthetized with pentobarbital sodium (PENTO, 20 mg/kg i.p.) or sevoflurane (SEVO, 1 MAC). Lung static elastance (Est), resistive ([DELTA]P1) and viscoelastic/inhomogeneous ([DELTA]P2) pressure decreases were analyzed by an end-inflation occlusion method. Lungs were fixed and stained for histological analysis.
  
  
  RESULTS
  Animals in the OVASEVO group showed lower [DELTA]P1 (38%), [DELTA]P2 (24%), and Est (22%) than animals in the OVAPENTO group. Histology demonstrated greater airway dilation (16%) and a lower degree of alveolar collapse (25%) in the OVASEVO compared with OVAPENTO group. [DELTA]P1 was lower (35%) and airway diameters larger (12%) in the SALSEVO compared with SALPENTO group.
  
  
  CONCLUSIONS
  Sevoflurane anesthesia acted both at airway level and lung periphery reducing ([DELTA]P1 and [DELTA]P2 pressures, and Est in chronic allergic asthma.
authors.affiliation: Division of Anesthesiology, Department of Surgery, Faculty of Medicine, Federal University of Rio de Janeiro, Brazil.
authors.forename: Shirley Moreira
authors.initials: SM
authors.lastname: Burburan
authors.forename: Debora Gonçalves
authors.initials: DG
authors.lastname: Xisto
authors.forename: Halina Cidrini
authors.initials: HC
authors.lastname: Ferreira
authors.forename: Douglas Dos Reis
authors.initials: Ddos R
authors.lastname: Riva
authors.forename: Giovanna Marcella Cavalcante
authors.initials: GM
authors.lastname: Carvalho
authors.forename: Walter Araujo
authors.initials: WA
authors.lastname: Zin
authors.forename: Patricia Rieken Macêdo
authors.initials: PR
authors.lastname: Rocco
mesh_terms: D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D000818:Animals; D001249:Asthma / Q000188:drug therapy*; D004195:Disease Models, Animal; D006967:Hypersensitivity / Q000188:drug therapy*; D008168:Lung / Q000187:drug effects* / Q000473:pathology; D008738:Methyl Ethers / Q000494:pharmacology*; D051379:Mice; D008807:Mice, Inbred BALB C; D010047:Ovalbumin / Q000494:pharmacology; D011312:Pressure; D012119:Respiration / Q000187:drug effects; D015656:Respiratory Mechanics / Q000187:drug effects; D000077149:Sevoflurane; D013997:Time Factors
chemical_list: D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D000077149:Sevoflurane; D010047:Ovalbumin