Effects of minor surgery and endotracheal intubation on postoperative breathing patterns in patients anaesthetized with isoflurane or sevoflurane.
We studied the effects of minor surgery and endotracheal intubation on postoperative breathing patterns. We measured breathing patterns and laryngeal resistance during the periods immediately before intubation (preoperative) and immediately after extubation following minor surgery (postoperative) in eight patients anaesthetized with sevoflurane and eight patients anaesthetized with isoflurane, breathing spontaneously through a laryngeal mask airway at a constant end-tidal anaesthetic concentration (1.0 MAC). In both sevoflurane-anaesthetized and isoflurane-anaesthetized patients, expiratory time was reduced and inspiratory and expiratory laryngeal resistance increased after surgery. In sevoflurane-anaesthetized patients, occlusion pressure (P0.1) increased without changes in inspiratory time (T(I)). Occlusion pressure did not change and T(I) was greater in isoflurane-anaesthetized patients after surgery. Minor surgery may have a small but significant influence on breathing and increased laryngeal resistance following endotracheal intubation may modulate these changes. The difference in breathing pattern between sevoflurane and isoflurane may be a result of different responses of the central nervous system to different anaesthetics in the presence of increased laryngeal resistance.
Tanaka
A
A
Department of Anaesthesiology, Chiba University School of Medicine, Japan.
Isono
S
S
Sato
J
J
Nishino
T
T
D000328:Adult; D000368:Aged; D000403:Airway Resistance / Q000187:drug effects; D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D005260:Female; D006801:Humans; D007442:Intubation, Intratracheal; D007530:Isoflurane / Q000494:pharmacology*; D007830:Larynx / Q000187:drug effects / Q000503:physiopathology; D008297:Male; D008738:Methyl Ethers / Q000494:pharmacology*; D008875:Middle Aged; D013511:Minor Surgical Procedures; D011184:Postoperative Period; D015656:Respiratory Mechanics / Q000187:drug effects*; D000077149:Sevoflurane
D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D000077149:Sevoflurane; D007530:Isoflurane