BJA Advance Access originally published online on November 3, 2009
British Journal of Anaesthesia 2009 103(6):822-827; doi:10.1093/bja/aep312
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Determination of serum propofol concentrations by breath analysis using ion mobility spectrometry
1 Department of Anaesthesiology, Emergency and Intensive Care Medicine, University of Göttingen, Robert-Koch-Str. 40, 37099 Göttingen, Germany
2 ISAS—Institute for Analytical Sciences, Metabolomics Department, Dortmund, Germany
* Corresponding author. E-mail: tperl{at}med.uni-goettingen.de
Background: We aimed to measure propofol concentrations in exhaled air with an ion mobility spectrometer coupled to a multicapillary column for pre-separation (MCC–IMS). In addition, we aimed to compare the values of these measurements with serum propofol concentrations, as determined by gas chromatography–mass spectrometry (GC–MS).
Methods: Thirteen patients, ASA I or II, undergoing elective ENT surgery were studied. Anaesthesia was induced with propofol 2.1 (0.7) mg kg–1, rocuronium 0.5 (0.1) mg kg–1, and remifentanil 0.5 µg kg–1 min–1. After tracheal intubation, anaesthesia was maintained with a continuous infusion of propofol 3.9 (1.8) mg kg–1 h–1 and remifentanil 0.5 µg kg–1 min–1. Simultaneously, a venous blood sample was obtained. Propofol concentrations in serum were determined by GC–MS and compared with the height of the respective propofol signals achieved by MCC–IMS.
Results: Twenty-four pairs of samples were obtained. The comparison of propofol concentrations in exhaled air and serum presented a bias of –10.5% and a precision of ± 12.3%. With these values, the 95% limits of agreement were 14.1% and –35.1%.
Conclusions: MCC–IMS may be a suitable method to determine propofol concentrations in exhaled air, and may be used to predict propofol concentrations in serum.
Keywords: anaesthetics i.v., propofol; measurement techniques, drug concentration, chromatography