The Effect of Epidural Clonidine on Plasma Catecholamine Response during General Anesthesia

Chung, Chong Dal; Moon, Hak Kyu; Lim, Kyung Joon; An, Tae Hun; Lim, Dae Won

Abstract

BACKGROUND: Tracheal intubation and skin incision are potent stimuli that can induce increased sympathetic activity, tachycardia and hypertension. The purpose of this study is to evaluate whether the epidural clonidine pretreatment reduce the sympathetic activity and cardiovascular response. We compared the hemodynamic changes and catecholamine concentration before, during and after general anesthesia with epidural clonidine pretreatment.
METHODS
Forty patients undergoing lower abdominal surgery were randomly allocated into the two groups. In Group 1, 10 ml of 0.9% normal saline was administered epidurally 15 minutes before induction of anesthesia as control. In Group 2, 3 microgram/kg clonidine diluted in 10 ml normal saline was administered epidurally 15 minutes before induction of anesthesia. We measured the blood pressure, heart rate and plasma catecholamine concentration at preinduction, 1 minute after intubation (T1), 1 (T2) and 30 minutes after skin incision (T3), 1 (T4) and 2 (T5) hours after arrival at recovery room and the results were compared between group 1 and group 2.
RESULTS
There was statistically significant difference in systolic pressure at T1 and T2 between the two groups. Heart rate was statistically significant difference at T1 and T4 between the two groups. There was statistically significant difference in epinephrine and norepinephrine concentration at T1 and T2 between the two groups.
CONCLUSION
The elevation of blood pressure, heart rate and plasma catecholamine concentration accompanying tracheal intubation and skin incision may be reduced by administration of epidural clonidine.