title: The acute and residual effects of subanesthetic concentrations of isoflurane/nitrous oxide combinations on cognitive and psychomotor performance in healthy volunteers.
abstract: A blind, randomized, cross-over trial was conducted to determine the degree of psychomotor/cognitive impairment and the recovery profile produced by combinations of subanesthetic concentrations of isoflurane and nitrous oxide in healthy volunteers. In the experiment, subjects (n = 10) inhaled 100% oxygen-placebo, 30% nitrous oxide in oxygen, and 0.2% and 0.4% isoflurane in oxygen, alone, and in combination with 30% nitrous oxide, in different sessions. Dependent measures included psychomotor and cognitive performance. Impairment was profound with the combination of inhaled anesthetics, and from an analysis of control conditions (the anesthetics alone), it appeared that isoflurane produced more impairment than did nitrous oxide. The time course of recovery was extremely rapid, with subjects returning to control-level functioning 5 min after cessation of the drug inhalation. The drug combination of isoflurane and nitrous oxide appears to be a promising candidate for conscious sedation procedures, although its analgesic and mood-altering effects need to be studied more systematically.
authors.affiliation: Department of Anesthesia and Critical Care, University of Chicago, Illinois.
authors.forename: J P
authors.initials: JP
authors.lastname: Zacny
authors.forename: S
authors.initials: S
authors.lastname: Yajnik
authors.forename: J L
authors.initials: JL
authors.lastname: Lichtor
authors.forename: J M
authors.initials: JM
authors.lastname: Klafta
authors.forename: C J
authors.initials: CJ
authors.lastname: Young
authors.forename: P
authors.initials: P
authors.lastname: Thapar
authors.forename: G
authors.initials: G
authors.lastname: Rupani
authors.forename: D W
authors.initials: DW
authors.lastname: Coalson
authors.forename: J L
authors.initials: JL
authors.lastname: Apfelbaum
mesh_terms: D000328:Adult; D018685:Anesthetics, Inhalation / Q000493:pharmacokinetics / Q000494:pharmacology*; D003071:Cognition / Q000187:drug effects*; D003072:Cognition Disorders / Q000139:chemically induced; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D007530:Isoflurane / Q000493:pharmacokinetics / Q000494:pharmacology*; D008297:Male; D009609:Nitrous Oxide / Q000493:pharmacokinetics / Q000494:pharmacology*; D011596:Psychomotor Disorders / Q000139:chemically induced; D011597:Psychomotor Performance / Q000187:drug effects*; D016037:Single-Blind Method
chemical_list: D018685:Anesthetics, Inhalation; D007530:Isoflurane; D009609:Nitrous Oxide