BJA Advance Access originally published online on March 24, 2009
British Journal of Anaesthesia 2009 102(5):704-713; doi:10.1093/bja/aep041
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Desflurane but not sevoflurane can increase lung resistance via tachykinin pathways
1 Department of Anesthesiology
2 Department of Cellular Physiology and Signal Transduction, Sapporo Medical University School of Medicine, South 1, West 16, Chuo-ku, Sapporo, Hokkaido 060-8543, Japan
* Corresponding author. E-mail: yamakage{at}sapmed.ac.jp
Background: Although there is evidence that the volatile anaesthetic desflurane directly relaxes preconstricted airway smooth muscle in vitro, the anaesthetic increases the lung resistance in vivo. The constrictive mechanisms of desflurane are, however, still unknown. This study was conducted to clarify the increasing mechanisms of desflurane on lung resistance by examining the vagal nerve reflexes in guinea pigs.
Methods: The effects of desflurane and sevoflurane on total lung resistance (RL) and dynamic lung compliance (CDyn) were investigated in animals that were either untreated, pretreated with atropine or vagotomy, pretreated with the tachykinin receptor antagonists sendide or MEN-10376, or given chronic pretreatment with capsaicin.
Results: Desflurane biphasically and dose-dependently increased RL (by 180% and 230% at the first and second peaks, respectively, at 2 minimum alveolar concentration) concomitant with a decrease in CDyn. However, sevoflurane had little effect on either RL or CDyn. Although vagotomy partially inhibited the first peak of RL by 30%, neither atropine nor vagotomy had any effect on the other respiratory responses to desflurane. Antagonization of tachykinin receptors of airway smooth muscles completely diminished the increase in RL induced by desflurane. Desflurane also had little effect on respiratory parameters after the capsaicin pretreatment, in which tachykinin containing afferent C-fibres was desensitized.
Conclusions: Desflurane but not sevoflurane increased RL concomitant with a decrease in CDyn in guinea pigs. The increase in lung resistance by desflurane might be due to antidromic tachykinin release from afferent C-fibres but not acetylcholine release from parasympathetic efferent nerves.
Keywords: anaesthetics volatile, desflurane; anaesthetics volatile, sevoflurane; lung, resistance, compliance; parasympathetic nervous system, airway, reflexes
These data were presented in part at (i) the Annual Meeting of the American Society of Anesthesiologists, Chicago, IL, USA, October 14–18, 2006, and (ii) the Annual Meeting of the American Society of Anesthesiologists, Orlando, FL, USA, October 18–22, 2008.