Drugs and brain death diagnostics: determination of drugs capable of inducing EEG zero line.
BACKGROUND
Several drugs may affect the diagnosis of brain death by depressing the electroencephalographic signal. Serum levels of these drugs must be below their respective therapeutic ranges.


METHODS
A high performance liquid chromatography-based fast and simple method was developed for determination of thiopentone, pentobarbitone, phenobarbitone, methohexital and propofol in serum and validated according to international recommendations.


RESULTS
Separation of extracted analytes was performed on a reversed phase column [Agilent Zorbax SB C18, 5 microm, 4.6 x 250 mm; mobile phase 50% 50 mM NaH(2)PO(4) pH 4.6 mixed with 35% (v/v) acetonitrile and 15% (v/v) methanol]. Calibration curves were linear throughout the selected ranges (microg/mL, thiopentone 0.25-50, pentobarbitone 0.25-25, phenobarbitone 2.5-50, methohexital 0.125-2.50, propofol 0.25-5.0). The standard deviations for the regression line, recovery, imprecision and accuracy results were all highly satisfactory. The lower limits of quantification for propofol, thiopentone and pentobarbitone were set at 0.25 microg/mL, for phenobarbitone 2.5 microg/mL, and for methohexital 0.125 microg/mL, which are below the lowest pharmacologically relevant serum concentrations. Intra- and inter-day coefficients of variation were less than 10% throughout as determined with six replicates.


CONCLUSIONS
The method presented is suitable for drug monitoring to help enhance the reliability of the diagnosis of brain death.
Meinitzer
Andreas
A
Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Graz, Austria. andreas.meinitzer@klinikum-graz.at
Kalcher
Kurt
K
Gartner
Gabriele
G
Halwachs-Baumann
Gabriele
G
März
Winfried
W
Stettin
Mariana
M
D018686:Anesthetics, Intravenous; D001926:Brain Death / Q000097:blood / Q000175:diagnosis*; D002492:Central Nervous System Depressants / Q000097:blood*; D002851:Chromatography, High Pressure Liquid / Q000379:methods* / Q000592:standards; D004569:Electroencephalography; D006801:Humans; D006993:Hypnotics and Sedatives; D008723:Methohexital / Q000097:blood; D010424:Pentobarbital / Q000097:blood; D015742:Propofol / Q000097:blood; D011786:Quality Control; D013874:Thiopental / Q000097:blood; D013997:Time Factors
D018686:Anesthetics, Intravenous; D002492:Central Nervous System Depressants; D006993:Hypnotics and Sedatives; D008723:Methohexital; D010424:Pentobarbital; D013874:Thiopental; D015742:Propofol