title: Continuous real time breath gas monitoring in the clinical environment by proton-transfer-reaction-time-of-flight-mass spectrometry.
abstract: Analysis of volatile organic compounds (VOCs) in breath holds great promise for noninvasive diagnostic applications. However, concentrations of VOCs in breath may change quickly, and actual and previous uptakes of exogenous substances, especially in the clinical environment, represent crucial issues. We therefore adapted proton-transfer-reaction-time-of-flight-mass spectrometry for real time breath analysis in the clinical environment. For reasons of medical safety, a 6 m long heated silcosteel transfer line connected to a sterile mouth piece was used for breath sampling from spontaneously breathing volunteers and mechanically ventilated patients. A time resolution of 200 ms was applied. Breath from mechanically ventilated patients was analyzed immediately after cardiac surgery. Breath from 32 members of staff was analyzed in the post anesthetic care unit (PACU). In parallel, room air was measured continuously over 7 days. Detection limits for breath-resolved real time measurements were in the high pptV/low ppbV range. Assignment of signals to alveolar or inspiratory phases was done automatically by a matlab-based algorithm. Quickly and abruptly occurring changes of patients' clinical status could be monitored in terms of breath-to-breath variations of VOC (e.g. isoprene) concentrations. In the PACU, room air concentrations mirrored occupancy. Exhaled concentrations of sevoflurane strongly depended on background concentrations in all participants. In combination with an optimized inlet system, the high time and mass resolution of PTR-ToF-MS provides optimal conditions to trace quick changes of breath VOC profiles and to assess effects from the clinical environment.
authors.affiliation: Department of Anaesthesia and Intensive Care, University Medical Center Rostock , Schillingallee 35, 18057 Rostock, Germany.
authors.forename: Phillip
authors.initials: P
authors.lastname: Trefz
authors.forename: Markus
authors.initials: M
authors.lastname: Schmidt
authors.forename: Peter
authors.initials: P
authors.lastname: Oertel
authors.forename: Juliane
authors.initials: J
authors.lastname: Obermeier
authors.forename: Beate
authors.initials: B
authors.lastname: Brock
authors.forename: Svend
authors.initials: S
authors.lastname: Kamysek
authors.forename: Jürgen
authors.initials: J
authors.lastname: Dunkl
authors.forename: Ralf
authors.initials: R
authors.lastname: Zimmermann
authors.forename: Jochen K
authors.initials: JK
authors.lastname: Schubert
authors.forename: Wolfram
authors.initials: W
authors.lastname: Miekisch
mesh_terms: D000465:Algorithms; D001944:Breath Tests / Q000379:methods*; D006801:Humans; D057230:Limit of Detection; D013058:Mass Spectrometry / Q000379:methods*; D011522:Protons; D055549:Volatile Organic Compounds / Q000032:analysis*
chemical_list: D011522:Protons; D055549:Volatile Organic Compounds