[Effect of sevoflurane on respiratory impedance measured by the forced oscillation method with random noise input].
This study was performed to investigate the effect of sevoflurane, a new inhalation anesthetic, on the respiratory impedance measured by forced oscillation method with random noise input. Random noise (1 to approximately 25Hz) oscillated by a loudspeaker was imposed on the respiratory system of dogs through a tracheostomy and the oscillatory pressure wave and flow wave were monitored at the same point with a pressure transducer and a pneumotachograph. This procedure was repeated during inhalation of 100%-oxygen, 2.0%-then 4.0%-sevoflurane-oxygen mixture, respectively. Impedance was calculated with fast Fourier transform by spectrum analyzer and a personal computer. During inhalation of 4.0%-sevoflurane-oxygen mixture, respiratory impedance especially respiratory resistance decreased at the high frequency area (6to approximately 20Hz), but 2.0%-sevoflurane-oxygen mixture did not cause a significant change of respiratory impedance. This study suggests that inhalation of an anesthetic concentration of sevoflurane produces weak bronchodilation compared with halothane or enflurane.
Yasuda
S
S
Sumi
H
H
Masuda
J
J
Sekiguchi
H
H
Nagano
M
M
Morishige
H
H
Minamitani
H
H
D000777:Anesthetics / Q000494:pharmacology*; D000818:Animals; D001696:Biomechanical Phenomena; D004285:Dogs; D004987:Ethers / Q000494:pharmacology*; D008738:Methyl Ethers; D010992:Plethysmography, Impedance; D012143:Respiratory Physiological Phenomena; D012137:Respiratory System / Q000187:drug effects*; D000077149:Sevoflurane
D000777:Anesthetics; D004987:Ethers; D008738:Methyl Ethers; D000077149:Sevoflurane