Introduction.The use of regional anesthetic techniques in children has been increased due to the adequate pain relief offered during intraoperative as well as postoperative period. Bupivacaine is widely used, in pédiatrie age, for continuous infusion even if at various dose regimens in order to reduce possible systemic toxic effects (seizures, hypotension, myocardial depressionXl). Clonidine, largely used for spinal administration in adults, has recently become object of study in pédiatrie age too (2); clonidine, when administered together with a local anesthetic, is able to improve postoperative analgesia, if compared with local anesthetic alone (3,4). Aim of this study is to evaluate wheter the infusion of clonidine - bupivacaine mixture is suitable for pédiatrie postoperative analgesia and if clonidine is able to enhance postoperative analgesia if compared to bupivacaine infusion alone. Methods. After parental informed consent and IRB approval, ASA 1 patients (n=35), aged 2-7 years undergoing hypospadia repairs (mean duration 110 ± 23 min) received premedication with oral diazepam. General anesthesia was induced and maintained with halothane in O2/air; after LMA placement, atracurium was given to facilitate mechanical ventilation during surgery. Lumbar epidural block was performed at L 5-S 1 in a left lateral position with a Tuohy 19G needle (Portex Minipak; Hythe, Kent, England) using an epidural catheter. All patients received an initial bolus of 1.25 mg kg -1 of bupivacaine, followed by a continuous infusion of 0.3 mg kg -1 h -1 starting 60 min after the bolus. At the end of surgery patients were randomized in order to receive (Group A n=18) bupivacaine alone 0.3 mg kg -1 h -1 or (Group B n=17) bupivacaine 0.3 mg kg -1 h -1 and clonidine 2mcg kg -1 /24 hrs by CADD Plus (Pharmacia, Sweden) for a period of 48 hrs. HR,NIBP3tCQ 2,SpQ 2,were recorded intraoperatively while HR,SpQ 2,NIBP and RR in the postoperative period. Postoperative analgesia was assessed using OPS scale. Parents were instructed about the use of infusion pump. Statistical analysis were performed with ANOVA, Student t-test with Bonferroni correction,Mann-Whitney test where appropriated. Ap value <0.05 was considered significant. Results.There was not any significative difference between the two groups in relation to age, weight or duration of surgical procedure or onset of analgesia. Two patients of Group A and 1 patient of Group B were excluded from study due to catheter dislocation (n=1)or filter disconnection(n=2). No statistical differences were observed in respect to hemodynamic and respiratory parameters . The OPS score was lower in group B than in Group A ( 1.5 ± 0.8 and 5.3 ± 1.6 respectively; p <0.05). Less patients of Group B ( n=2) compared with group A ( n=7 ) required postoperative analgesia ( p <0.05 ). First analgesic supplementation ( acetaminophen ) took place after 28 hrs in group B while after 16 hrs in group A;no more analgesic was requested from patients of group B. No motor block was observed in any patient. All patients started NPO six hours after surgery; four patients of group A and three patients of group B had vomiting postoperatively. Due to OPS scale use, we were able to observe that patients in clonidine group were more sedated . All patients had urinary catheter or epicistostomy in the postoperative phase. No toxic effects were observed due to bupivacaine infusion. All epidural catheters have been removed 48 hours after surgery. Discussion.Our study demonstrates that the continuous infusion of clonidine plus bupivacaine by epidural route allows an adequate postoperative analgesia if compared with bupivacaine alone. It means that if continuous infusion of bupivacaine 0.3 mg kg"1 h"1 is not sufficient for a satisfactory analgesia in postoperative period (5), the addition of clonidine provides an adequate analgesia without an increase in local anesthetic dose;as toxic dose limits for bupivacaine are not well defined in children ,clonidine could be able to avoid the potentially toxic effects of local anesthetic . Sedation observed in clonidine treated group was considered useful for our patients. Further studies would be useful for evaluating bupivacaine plasma concentrations during a concomitant clonidine infusion.
|Number of pages||1|
|Issue number||2 SUPPL.|
|Publication status||Published - 1997|
ASJC Scopus subject areas
- Anesthesiology and Pain Medicine