Flumazenil improves cognitive and neuromotor emergence and attenuates shivering after halothane-, enflurane- and isoflurane-based anesthesia.
OBJECTIVE
To conduct a randomized, placebo-controlled, double-blinded, clinical experiment testing the hypothesis that flumazenil, a benzodiazepine antagonist, may affect recovery from halothane-, enflurane- and isoflurane-based anesthesia.


METHODS
Patients who underwent surgery under N(2)O/O(2) plus halothane (n=100), enflurane (n=100) or isoflurane (n=70) anesthesia were administered flumazenil 1 mg or placebo upon emergence from anesthesia, and their postanesthesia vital signs, vigilance, neurological recovery, shivering, amnesia reversal, and general subjective feeling were assessed.


RESULTS
A ten-point vigilance score showed better recovery of flumazenil-treated patients compared to those who received placebo (60-min after halothane anesthesia: 9.9 +/- 0.1 vs 9.5 +/- 0.2, P <0.01; after enflurane: 10 +/- 0 vs 9.4 +/- 0.2, P <0.01; after isoflurane: 10.0 +/- 0 vs 9.3 +/- 0.1, P <0.01). Halothane- and enflurane-flumazenil-treated patients (but not isoflurane) reached a better neurological score (2.97 +/- 0.05 or 3 +/- 0) compared to placebo (2.8 +/- 0.4 or 2.6 +/- 0.4, P <0.01), respectively. Reversal of amnesia was superior in the flumazenil group at 60 min and at 24 hr postsurgery, and more flumazenil patients rated recovery as "pleasant". Flumazenil patients shivered less than placebo patients despite their lower core temperature (at 30 min: halothane: 11% vs 28%, P <0.05; enflurane: 11% vs 30%, P <0.05; isoflurane: 17% for both groups).


CONCLUSIONS
Flumazenil improves recovery of high cortical and neuromotor functions following halothane, enflurane and isoflurane anesthesia, reduces shivering and improves the overall quality of emergence, including patients' subjective feeling.
Weinbroum
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AA
Post-Anesthesia Care Unit, The Department Of Anesthesiology Critical Care Tel Aviv Sourasky Medical Center, The Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel. draviw@tasmc.health.gov.il
Geller
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E
D000328:Adult; D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D001569:Benzodiazepines / Q000037:antagonists & inhibitors*; D001921:Brain / Q000187:drug effects; D003071:Cognition / Q000187:drug effects*; D004311:Double-Blind Method; D004347:Drug Interactions; D004737:Enflurane / Q000494:pharmacology; D005260:Female; D005442:Flumazenil / Q000494:pharmacology*; D006221:Halothane / Q000494:pharmacology; D006801:Humans; D007530:Isoflurane / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000187:drug effects; D012018:Reflex / Q000187:drug effects; D012768:Shivering / Q000187:drug effects*
D018685:Anesthetics, Inhalation; D001569:Benzodiazepines; D005442:Flumazenil; D004737:Enflurane; D007530:Isoflurane; D006221:Halothane