Effect of clonidine added to ropivacaine for epidural anesthesia / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the effect of clonidine added to ropivacaine for epidural anesthesia. Methods Sixty ASA Ⅰ - Ⅱ patients aged 24-62 yr, weighing 50-76 kg, scheduled for elective gynecological surgery under epidural anesthesia were randomly assigned to one of four equal groups of 15 patients each, according to the dose of clonidine added to ropivacaine solution group 1 (R) received no clonidine and served as control; group 2-4 in which clonidine 50, 100 or 150 ug was added to 0.75% ropivacaine 25 ml (R-C 50, R-C 100, R-C 150). Epidural anesthesia was performed at L2-3. Epidural catheter was inserted into epidural space and advanced in cephalad direction for 3.5 cm. Ropivacaine solution was prepared and provided by a specially designated person. A test dose of 5 ml of ropivacaine was given. 5 min later when epidural placement of catheter was confirmed, the rest 20 ml of ropivacaine was given in fractions of 5 ml every 2-3 min. At the beginning of operation midazolam 2.5-3.5 mg was given iv. During operation if the patient felt uncomfortable when viscera were being pulled, ketamine 0.5 mg? kg-1 was given iv. The onset and duration of analgesia, the height of black, the degree of motor block as well as adverse effects were recorded. Results The onset time of motor block was significantly shorter, the duration of analgesia was significantly longer, the incidences of visceral pain and shivering were significantly lower and ketamine requirement was significantly reduced in group R-C 100 and R-C 150 as compared with group R. However the incidence of hypotension, the amount of fluid infused and epinedrine requirement were significantly increased in group R-C 150. Conclusion The addition of clonidine 100 ug to 0.75 % ropivacaine 25 ml improves the effect of epidural block without increasing adverse effects.