Effect of ondansetron on the duration of caudal block with bupivacaine on children who undergoing infraumbilical surgery

Caudal epidural block is usually performing for pediatric patients whom underwent infraumbilical surgery. for postoperative analgesia. There are some publications showed that 5 HT-3 antagonist drugs like ondansetron, rapids sensorial block regression of neuroaxial anesthesia. We want to evaluate this effect on caudal block on pediatric patients. We include 4-10 years old ASA 1 or 2 patients who will undergo infraumbilical surgery. we will exclude if patients BMI is over 30 kg/m2, have neurological or neuromuscular disease, allergy to sudy drugs, have contrindication for caudal block. After routine monitorisation of patients and standart anesthetic induction for general anesthesia, we divide patients into two groups . We give 0.1 mg/kg ondansetron intravnously during seconds to Group Ondansetron and give same volume of serum physiologic for Group Control patients. After than we will perform caudal block with 1 ml/kg %0.025 bupivacaine at left decubitis position. After operation we will evaluate patients pain level with faces pain scale for 24 hours/ 1 time per hour and sensory level for 8 hours/ 1 time per hour. we will evaluate these findings and want to determine if there is a significant effect of ondansetron administration on the analgesic duration or sensorial level of caudal block.