title: Xenon elimination kinetics following brief exposure.
abstract: Xenon is a modern inhalative anaesthetic with a very low solubility in tissues providing rapid elimination and weaning from anaesthesia. Besides its anaesthetic properties, Xenon promotes the endogenous erythropoietin biosynthesis and thus has been enlisted as prohibited substance by the World Anti-Doping Agency (WADA). For effective doping controls, knowledge about the elimination kinetics of Xenon and the duration of traceability are of particular importance. Seventy-seven full blood samples were obtained from 7 normal weight patients undergoing routine Xenon-based general anaesthesia with a targeted inspiratory concentration of 60% Xenon in oxygen. Samples were taken before and during Xenon inhalation as well as one, two, 4, 8, 16, 24, 32, 40, and 48 h after exposure. Xenon concentrations were assessed in full blood by gas chromatography and triple quadrupole tandem mass spectrometry with a detection limit of 0.25 µmol/L. The elimination of Xenon was characterized by linear regression of log-transformed Xenon blood concentrations, as well as non-linear regression. Xenon exposure yielded maximum concentrations in arterial blood of 1.3 [1.1; 1.6] mmol/L. Xenon was traceable for 24 to 48 h. The elimination profile was characterized by a biphasic pattern with a rapid alpha phase, followed by a slower beta phase showing a first order kinetics (c[Xe] = 69.1e-0.26x, R2= 0.83, t1/2= 2.7 h). Time in hours after exposure could be estimated by 50*ln(1.39/c[Xe]0.077). Xenon's elimination kinetics is biphasic with a delayed beta phase following a first order kinetics. Xenon can reliably be detected for at least 24 h after brief exposure. Copyright © 2016 John Wiley & Sons, Ltd.
authors.affiliation: Department of Anaesthesiology, University Hospital Düsseldorf, Germany.
authors.forename: Maximilian S
authors.initials: MS
authors.lastname: Schaefer
authors.affiliation: Center for Preventive Doping Research - Institute of Biochemistry, German Sports University Cologne, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Piper
authors.affiliation: Center for Preventive Doping Research - Institute of Biochemistry, German Sports University Cologne, Germany.
authors.forename: Hans
authors.initials: H
authors.lastname: Geyer
authors.affiliation: Department of Anaesthesiology, University Hospital Düsseldorf, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Schneemann
authors.affiliation: Department of Anaesthesiology, University Hospital Düsseldorf, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Neukirchen
authors.affiliation: Center for Preventive Doping Research - Institute of Biochemistry, German Sports University Cologne, Germany.
authors.forename: Mario
authors.initials: M
authors.lastname: Thevis
authors.affiliation: Department of Anaesthesiology, University Hospital Düsseldorf, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Kienbaum
mesh_terms: D000368:Aged; D018685:Anesthetics, Inhalation / Q000008:administration & dosage / Q000097:blood*; D016903:Drug Monitoring / Q000379:methods; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006801:Humans; D057230:Limit of Detection; D016014:Linear Models; D008297:Male; D053719:Tandem Mass Spectrometry / Q000379:methods; D014978:Xenon / Q000008:administration & dosage / Q000097:blood*
chemical_list: D018685:Anesthetics, Inhalation; D014978:Xenon
keywords: Xenon; doping in sports; kinetics; performance-enhancing substances; pulmonary elimination