Quantitative analysis of changes in blood concentrations and 'presumed effect-site concentration' of sevoflurane during one-lung ventilation.
During one-lung ventilation, ventilation-perfusion mismatch decreases the arterial concentration of inhaled anaesthetics due to the arterial-to-venous concentration difference. This study tested the hypothesis that in humans, the 'presumed effect-site concentration' (taken as the mid-point between the arterial and superior jugular venous concentrations) of inhaled anaesthetic falls during one-lung (vs two-lung) ventilation. Four patients scheduled for elective prostatectomy (two-lung ventilation) and four patients for elective thoracotomy (one-lung ventilation) were randomly selected and assigned to receive sevoflurane (vaporiser-dial setting, 1.5%). Sevoflurane concentrations were measured periodically from radial artery and superior jugular vein (via a catheter advanced cephalad from the jugular vein). During one-lung ventilation, the end-expiratory sevoflurane concentration was stable at ∼1.3% but the mean (SD) presumed effect-site concentration declined initially from 58 (6.7) to 43 (4.7) μg.ml(-1) (p=0.011) before slowly recovering. A period of insufficient depth of anaesthesia is thus a risk during one-lung ventilation.
Department of Anaesthesia, Kasukabe-chuo General Hospital, Saitama, Japan. shinjimat@hotmail.com
S
S
Matsuse
Y
Y
Hara
T
T
Ohkura
N
N
Yahagi
D000328:Adult; D000368:Aged; D000768:Anesthesia, General; D018685:Anesthetics, Inhalation / Q000097:blood*; D018686:Anesthetics, Intravenous; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007601:Jugular Veins; D008297:Male; D008738:Methyl Ethers / Q000097:blood*; D008875:Middle Aged; D010880:Piperidines; D011175:Positive-Pressure Respiration; D011446:Prospective Studies; D011468:Prostatectomy; D017534:Radial Artery; D000077208:Remifentanil; D012121:Respiration, Artificial; D000077149:Sevoflurane; D013908:Thoracotomy
D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D008738:Methyl Ethers; D010880:Piperidines; D000077149:Sevoflurane; D000077208:Remifentanil