Lung mechanics and histology during sevoflurane anesthesia in a model of chronic allergic asthma.
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.
Burburan
Shirley Moreira
SM
Division of Anesthesiology, Department of Surgery, Faculty of Medicine, Federal University of Rio de Janeiro, Brazil.
Xisto
Debora Gonçalves
DG
Ferreira
Halina Cidrini
HC
Riva
Douglas Dos Reis
Ddos R
Carvalho
Giovanna Marcella Cavalcante
GM
Zin
Walter Araujo
WA
Rocco
Patricia Rieken Macêdo
PR
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
D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D000077149:Sevoflurane; D010047:Ovalbumin