Korean J Anesthesiol.  2006 Jan;50(1):60-65. 10.4097/kjae.2006.50.1.60.

Does Epidural Clonidine Decrease the Sevoflurane Concentration for Maintaining the BIS 50?

• Bahn YJ
• Lee HW
• Lim CH
• Lim HJ
• Yoon SM

• KMID: 2237478
• DOI: http://doi.org/10.4097/kjae.2006.50.1.60

Abstract

BACKGROUND: The aim of this study was to investigate the influence of epidural clonidine on the BIS, and its potential dose-sparing effect on the sevoflurane requirement for maintaining the BIS 50.
METHODS
Forty ASA I or II patients aged 20 to 65, undergoing lower abdominal, gynecologic surgery under general anesthesia, were randomly allocated to either a 10 ml epidural normal saline injection group (n = 20) or a 10 ml epidural clonidine 3microgram/kg mixed with normal saline injection group (n = 20). They received 5 mg/kg thiopental sodium and 0.1 mg/kg vecuronium bromide for induction, with no premedication. After surgical incision, the sevoflurane concentration was controlled to maintain the BIS 50. Epidural saline or clonidine was then injected and end-tidal sevoflurane concentration to maintain the BIS 50, the heart rate (HR) and mean arterial pressure (MBP) were measured every 5 min over a 20 minute period.
RESULTS
The end-tidal sevoflurane concentration in the clonidine group decreased by 27.5% after the epidural clonidine injection (1.49 +/- 0.23 vol% vs. 1.08 +/- 0.27 vol%; P<0.05) compared with the saline group (1.36 +/- 0.18 vol% vs. 1.33 +/- 0.21 vol%; P>0.05). There were no changes in the heart rate and mean blood pressure in either group.
CONCLUSIONS
Epidural clonidine causes a significant decrease in the BIS, and lowers the end-tidal sevoflurane concentration required for maintaining the BIS 50.

Keyword

BIS; end-tidal sevoflurane concentration; epidural clonidine

MeSH Terms

Anesthesia, General
Arterial Pressure
Blood Pressure
Clonidine*
Female
Gynecologic Surgical Procedures
Heart Rate
Humans
Premedication
Thiopental
Vecuronium Bromide
Clonidine
Thiopental
Vecuronium Bromide