Respiratory mechanics and lung histology in normal rats anesthetized with
sevoflurane.
Correa, Fatima C. F., Patricia B. Ciminelli, Haroldo Falcão, Bruno J. C. Alcântara,
Renata S. Contador, Aline S. Medeiros, Walter A. Zin, and Patricia R. M. Rocco.
1Laboratory of Respiration Physiology, Carlos Chagas Filho Biophysics Institute, and
2Faculty of Medicine, Federal University of Rio de Janeiro, Ilha do Fundão,
21949«hyphen»900, Rio de Janeiro, Rio de Janeiro, Brazil
APStracts 8:0253A, 2001.
Respiratory system, lung, and chest wall mechanical properties were subdivided into their
resistive, elastic, and viscoelastic/inhomogeneous components in normal rats, to define
the sites of action of sevoflurane. In addition, we aimed to determine the extent to which
pretreatment with atropine modified these parameters. Twenty-four rats were divided into
four groups of six animals each: in the P group, rats were sedated (diazepam) and
anesthetized with pentobarbital; in the S group, sevoflurane was administered; in the AP
and AS groups, atropine was injected 20 min before sedation/anesthesia with
pentobarbital and sevoflurane, respectively. Sevoflurane increased lung
viscoelastic/inhomogeneous pressures and static elastance compared with rats belonging
to the P group. In AS rats, lung static elastance increased in relation to the AP group. In
conclusion, sevoflurane anesthesia acted not at the airway level but at the lung periphery,
stiffening lung tissues and increasing mechanical inhomogeneities. These findings were
supported by the histological demonstration of increased areas of alveolar collapse and
hyperinflation. The pretreatment with atropine reduced central and peripheral airway
secretion, thus lessening lung inhomogeneities.
Received 11 September 2000; accepted in final form 16 April 2001
APS Manuscript Number A0912-0.
Article publication pending J Appl Physiol
ISSN 1080-4757 Copyright 2001 The American Physiological Society.
Published in APStracts on 18 June 2001