title: Time course of ethanol and propofol exhalation after bolus injection using ion molecule reaction-mass spectrometry.
abstract: The transit of ethanol from blood to breath gas is well characterised. It is used for intraoperative monitoring and in forensic investigations. A further substance, which can be measured in breath gas, is the phenol propofol. After a simultaneous bolus injection, the signals (time course and amplitude) of ethanol and propofol in breath gas were detected by ion molecule reaction-mass spectrometry (IMR-MS) and compared. After approval by the regional authorities, eight pigs were endotracheally intubated after a propofol-free induction with etomidate. Boluses of ethanol (16 μg/kg) and propofol (4 or 2 mg/kg) were infused alone and in combination. For both substances, breath gas concentrations were continuously measured by IMR-MS; the delay time, time to peak and amplitude were determined and compared using non-parametric statistic tests. IMR-MS allows a simultaneous continuous measurement of both substances in breath gas. Ethanol appeared (median delay time, 12 vs 29.5 s) and reached its peak concentration (median time to peak, 45.5 vs 112 s) significantly earlier than propofol. Time courses of ethanol and propofol in breath gas can be simultaneously described with IMR-MS. Differing pharmacological and physicochemical properties of the two substances can explain the earlier appearance and time to peak of ethanol in breath gas compared with propofol.
authors.affiliation: Department of Anaesthesiology, University of Luebeck, Ratzeburger Allee 160, 23538 Luebeck, Germany. martin_grossherr@hotmail.com
authors.forename: Martin
authors.initials: M
authors.lastname: Grossherr
authors.forename: Balamurugan
authors.initials: B
authors.lastname: Varadarajan
authors.forename: Leif
authors.initials: L
authors.lastname: Dibbelt
authors.forename: Peter
authors.initials: P
authors.lastname: Schmucker
authors.forename: Hartmut
authors.initials: H
authors.lastname: Gehring
authors.forename: Andreas
authors.initials: A
authors.lastname: Hengstenberg
mesh_terms: D018686:Anesthetics, Intravenous / Q000032:analysis*; D000818:Animals; D001944:Breath Tests; D000431:Ethanol / Q000032:analysis*; D045853:Exhalation; D005740:Gases / Q000032:analysis*; D007275:Injections, Intravenous; D007477:Ions; D013058:Mass Spectrometry; D015742:Propofol / Q000032:analysis*; D013552:Swine
chemical_list: D018686:Anesthetics, Intravenous; D005740:Gases; D007477:Ions; D000431:Ethanol; D015742:Propofol