title: Uptake of desflurane and isoflurane during closed-circuit anesthesia with spontaneous and controlled mechanical ventilation.
abstract: Although theoretical models predict uptake of inhaled anesthetics during closed-circuit anesthesia (CCA), clinical data for most anesthetics are conflicting or non-existent. In addition, the effects of patient characteristics and mode of ventilation on anesthetic uptake are unclear. Forty-one ASA physical status I or II adult patients undergoing a variety of 1-1.5 h surgical procedures were randomly allocated to receive CCA with desflurane or isoflurane with ventilation being either spontaneous or controlled. An end-expired anesthetic concentration of 1.3 minimum alveolar anesthetic concentration (MAC) was maintained by continuous injection of the liquid anesthetic into the circuit using a syringe pump. After an initial 4-min wash-in period, uptake during the first hour of CCA was nearly constant. Uptake was the same whether ventilation was spontaneous or controlled. Patient characteristics (age, height, weight, weight3/4, and body surface area) were comparable between groups and did not correlate with uptake. The virtually constant uptake after wash-in of desflurane and isoflurane contrasts with the square root of time model of Lowe and Ernst. These findings may greatly simplify CCA.
authors.affiliation: Department of Anesthesiology, University of Pittsburgh School of Medicine, Pennsylvania, USA.
authors.forename: J F
authors.initials: JF
authors.lastname: Hendrickx
authors.forename: M
authors.initials: M
authors.lastname: Soetens
authors.forename: A
authors.initials: A
authors.lastname: Van der Donck
authors.forename: H
authors.initials: H
authors.lastname: Meeuwis
authors.forename: F
authors.initials: F
authors.lastname: Smolders
authors.forename: A M
authors.initials: AM
authors.lastname: De Wolf
mesh_terms: D000328:Adult; D000764:Anesthesia, Closed-Circuit; D018685:Anesthetics, Inhalation / Q000493:pharmacokinetics*; D000077335:Desflurane; D005260:Female; D006801:Humans; D007530:Isoflurane / Q000031:analogs & derivatives* / Q000493:pharmacokinetics*; D008297:Male; D012119:Respiration; D012121:Respiration, Artificial
chemical_list: D018685:Anesthetics, Inhalation; D000077335:Desflurane; D007530:Isoflurane