Accumulation of S(+) enantiomer in human beings after general anaesthesia with isoflurane racemate.
OBJECTIVE
Isoflurane is a chiral, volatile anaesthetic with low metabolic rate (0.17%) that is routinely administered in its racemic form. Knowledge about the distribution of the enantiomers in human beings may give some important information about the understanding of the mechanisms of volatile anaesthetics.


METHODS
Blood samples were drawn immediately after tracheal extubation and daily up to 8 days postoperatively from patients undergoing general anaesthesia with isoflurane racemate. The enantiomer enrichment of isoflurane was determined by headspace gas chromatography-mass spectrometry.


RESULTS
At all time points, there was a statistically significant accumulation of the S(+) enantiomer in blood, especially at days 2 (52.01%) and 7 (52.1%). Separate analysis of obese patients or in a small group of patients with co-existing lung disease did not show any difference to the total population. In addition, duration of anaesthesia did not influence the enantiomer concentrations.


CONCLUSIONS
We suggest that a slower association and dissociation rate is responsible for the S(+) enrichment.
Haeberle
H A
HA
Tuebingen University Hospital, Department of Anaesthesiology and Intensive Care Unit, Germany. helene.haeberle@uni-tuebingen.de
Wahl
H G
HG
Jakubetz
H
H
Krause
H
H
Schmidt
R
R
Schurig
V
V
Dieterich
H J
HJ
D000368:Aged; D000768:Anesthesia, General; D018685:Anesthetics, Inhalation / Q000097:blood* / Q000737:chemistry*; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007442:Intubation, Intratracheal; D007530:Isoflurane / Q000097:blood* / Q000737:chemistry*; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D013237:Stereoisomerism
D018685:Anesthetics, Inhalation; D007530:Isoflurane