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

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%; P0.05). 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.

Hypothermia Induced by Incorrect Monitoring of Core Temperature: A case report / 대한마취과학회지

A 55-year-old man was scheduled to undergo revisional total hip arthroplasty under general anesthesia. During the operation, a warm blanket and fluid warmer were applied, with his body temperature maintained at 35oC, as assessed with the use of a temporal-artery thermometer. In the course of the operation, severe bleeding developed, which required a massive transfusion of packed red blood cells and other blood components to correct the electrolyte and pH balances; the infusion of cardiovascular drugs was also preformed. However, the hemodynamic status of the patient deteriorated to severe hypotension, with atrial fibrillation, non-sustaining paroxysmal ventricular tachycardia and ventricular fibrillation. The patient was re-evaluated, and it was realized the temporal-artery thermometer had been incorrectly monitored, causing hemodynamic deterioration, which was assessed as hypothermia from a nasopharyngeal temperature of 29 degrees C. Active warming methods, including a condensed humidifier, and warming of the fluids and blood compounds with a rapid infusion system, were instigated, resulting in stabilization of the patient's hemodynamic status and the disappearance of his dysrhythmia.