title: Drug detection in breath: effects of pulmonary blood flow and cardiac output on propofol exhalation.
abstract: Breath analysis could offer a non-invasive means of intravenous drug monitoring if robust correlations between drug concentrations in breath and blood can be established. In this study, propofol blood and breath concentrations were determined in an animal model under varying physiological conditions. Propofol concentrations in breath were determined by means of two independently calibrated analytical methods: continuous, real-time proton transfer reaction mass spectrometry (PTR-MS) and discontinuous solid-phase micro-extraction coupled with gas chromatography mass spectrometry (SPME-GC-MS). Blood concentrations were determined by means of SPME-GC-MS. Effects of changes in pulmonary blood flow resulting in a decreased cardiac output (CO) and effects of dobutamine administration resulting in an increased CO on propofol breath concentrations and on the correlation between propofol blood and breath concentrations were investigated in seven acutely instrumented pigs. Discontinuous propofol determination in breath by means of alveolar sampling and SPME-GC-MS showed good agreement (R(2)=0.959) with continuous alveolar real-time measurement by means of PTR-MS. In all investigated animals, increasing cardiac output led to a deterioration of the relationship between breath and blood propofol concentrations (R(2)=0.783 for gas chromatography-mass spectrometry and R(2)=0.795 for PTR-MS). Decreasing pulmonary blood flow and cardiac output through banding of the pulmonary artery did not significantly affect the relationship between propofol breath and blood concentrations (R(2)>0.90). Estimation of propofol blood concentrations from exhaled alveolar concentrations seems possible by means of different analytical methods even when cardiac output is decreased. Increases in cardiac output preclude prediction of blood propofol concentration from exhaled concentrations.
authors.affiliation: Department of Anesthesiology and Intensive Care, University of Rostock, Schillingallee 35, 18057 Rostock, Germany.
authors.forename: Svend
authors.initials: S
authors.lastname: Kamysek
authors.forename: Patricia
authors.initials: P
authors.lastname: Fuchs
authors.forename: Henny
authors.initials: H
authors.lastname: Schwoebel
authors.forename: Jan P
authors.initials: JP
authors.lastname: Roesner
authors.forename: Sabine
authors.initials: S
authors.lastname: Kischkel
authors.forename: Kathi
authors.initials: K
authors.lastname: Wolter
authors.forename: Christian
authors.initials: C
authors.lastname: Loeseken
authors.forename: Jochen K
authors.initials: JK
authors.lastname: Schubert
authors.forename: Wolfram
authors.initials: W
authors.lastname: Miekisch
mesh_terms: D018686:Anesthetics, Intravenous / Q000032:analysis*; D000818:Animals; D001944:Breath Tests; D002302:Cardiac Output / Q000187:drug effects*; D045853:Exhalation; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D006439:Hemodynamics; D008297:Male; D015742:Propofol / Q000032:analysis*; D011652:Pulmonary Circulation / Q000187:drug effects*; D013552:Swine
chemical_list: D018686:Anesthetics, Intravenous; D015742:Propofol