[Effect of dexmedetomidine on bispectral index and auditory evoked potential index during anesthesia with target controlled infusion of propofol and remifentanyl].
To evaluate the effect of dexmedetomidine (Dex) on bispectral index (BIS) and auditory evoked potential index (AAI) during anesthesia with target controlled infusion (TCI) of propofol and remifentanyl.



Thirty adult patients (ASA I approximate, equalsII) who were scheduled for elective thyroidectomy were monitored with BIS, AAI, ECG, blood pressure, end-tidal CO(2), and pulse oximeter before and during anesthesia. Anesthesia was induced by TCI with propofol 4 mg/L and remifentanyl 1 mu g/kg. After loss of consciousness the patients were intubated after rocuronium 0.6 mg/kg intravenous injection, remifentanyl was then infused at 0.2 microg/(kg x min)(-1) and propofol infusion (Ct) was titrated to maintain a BIS value at 50 +/- 3. At 10 min after stabilization of anesthesia the patients were randomly and double-blindly divided into 2 groups: Group D (n=15) received Dex 0.4 mu g/kg iv administered over 5 min and Group C (n=15) received equal volume of normal saline. Values of BIS, AAI, MAP, HR were recorded every 2 min within 20 min after the administration of the drugs.



Before anesthesia the BIS index was 90 +/- 2 in Group D and 92 +/- 2 in Group C, AAI was 81 +/- 1 in Group D and 78 +/- 1 in Group C. In anesthesia with target controlled infusion of propofol, BIS index showed a significant decrease with the i.v. administration of Dex 0.4 microg/kg, while AAI remained unchanged. In Group C, both of BIS and AAI remained unchanged after saline injection.



During propofol and remifentanyl anesthesia, after the administration of Dex, BIS value demonstrates a predominant decrease, whereas AAI shows no changes.
Li
Hui-ling
HL
Department of Anesthesiology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China. hzlhl@126.com
She
Shou-zhang
SZ
Yan
Yan
Y
Zhu
Sheng-mei
SM
D000316:Adrenergic alpha-Agonists / Q000008:administration & dosage; D000328:Adult; D000732:Androstanols / Q000008:administration & dosage; D019162:Anesthetics, Combined / Q000008:administration & dosage; D018686:Anesthetics, Intravenous / Q000008:administration & dosage; D020927:Dexmedetomidine / Q000008:administration & dosage* / Q000494:pharmacology; D004311:Double-Blind Method; D005072:Evoked Potentials, Auditory / Q000187:drug effects*; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous / Q000379:methods; D008297:Male; D020926:Medetomidine / Q000494:pharmacology; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D003473:Neuromuscular Nondepolarizing Agents / Q000008:administration & dosage; D010880:Piperidines / Q000008:administration & dosage* / Q000494:pharmacology; D015742:Propofol / Q000008:administration & dosage* / Q000494:pharmacology; D000077208:Remifentanil; D000077123:Rocuronium; D013965:Thyroidectomy
D000316:Adrenergic alpha-Agonists; D000732:Androstanols; D019162:Anesthetics, Combined; D018686:Anesthetics, Intravenous; D003473:Neuromuscular Nondepolarizing Agents; D010880:Piperidines; D020927:Dexmedetomidine; D020926:Medetomidine; D000077208:Remifentanil; D000077123:Rocuronium; D015742:Propofol