Determination of serum propofol concentrations by breath analysis using ion mobility spectrometry.
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 microg 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 microg 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.
Perl
T
T
Department of Anaesthesiology, Emergency and Intensive Care Medicine, University of Göttingen, Göttingen, Germany. tperl@med.uni-goettingen.de
Carstens
E
E
Hirn
A
A
Quintel
M
M
Vautz
W
W
Nolte
J
J
Jünger
M
M
D000293:Adolescent; D000328:Adult; D000368:Aged; D018686:Anesthetics, Intravenous / Q000032:analysis / Q000097:blood*; D001944:Breath Tests / Q000379:methods; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006801:Humans; D008297:Male; D013058:Mass Spectrometry / Q000379:methods; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D013517:Otorhinolaryngologic Surgical Procedures; D015742:Propofol / Q000032:analysis / Q000097:blood*; D015203:Reproducibility of Results; D055815:Young Adult
D018686:Anesthetics, Intravenous; D015742:Propofol