Spinal anesthesia with hyperbaric tetracaine has short action duration, therefore it is inappropriate to long term operation. Clonidine has been shown to stimulate central and peripheral alpha two adrenergic receptors. By these central adrenergic
action, clonidine decreases the MAC of anesthetics. Clonidine also has analgesic property following intrathecal administration. These properties may make clonidine as a useful adjunct to extend anesthesia time with spinal anesthesia. This study
was
undertaken to evaluate the effects of clonidine in spinal anesthesia.
Thirty healthy adult patients who were scheduled for orthopedic operation below knee were divided into 3 groups: Group I (hyperbaric tetracaine 10 mg(2 ml)+N/S 1 ml), group II (hyperbaric tetracaine 10 mg with clonidine 75 (g(0.5 ml)+N/S 0.5 ml)
and
Group III (hyperbaric tetracaine 10 mg with clonidine 150 ((1 ml). We investigated the onset and duration of spinal anesthesia and hemodynamic changes (blood pressure and heart rate).
@ES The results were as follows:
@EN 1) There were no significant changes between groups in hemodynamic data.
2) The onset of spinal anesthesia was more rapid in the group II (knee flexion 2.9(0.7, foot dorsiflexion 4.6(0.8 minutes) and III (knee flexion 2.0(0.4, foot dorsiflexion 4.1(0.7 minutes) than group I (knee flexion 4.9(1.6, foot dorsiflexion
9.1(3.4
minutes).
3) The time to recovery of nerve block was more prolonged in the group II (touch 256, pain 295, foot dorsiflexion 276, knee flexion 300 minutes) and III (touch 295, pain 312, foot dorsiflexion 339, knee flexion 385 minutes) than group I (touch
143,
pain 176, foot dorsiflexion 178, knee flexion 195 minutes).
4) There were more sedation and dry mouth in group II and group III. From the above results, clonidine can be used as an effective adjunct in hyperbaric tetracaine spinal anesthesia to make rapid onset and prolonged anesthesia without
significant
hemodynamic changes. (Korean J Anesthesiol 1995; 29: 36~41).
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