Title: Efficacy and Safety of Clonidine as an Adjuvant to Bupivacaine for Caudal Analgesia in Paediatric Infra-Umbilical Surgeries
Abstract: Caudal analgesia, in the recent years, is the preferred technique in paediatric pain management both intraoperative and postoperative, for lower abdominal and lower limb surgeries.This is because it is simple, easy to perform and the level of blockade achieved is predictable.The drawback of single shot caudal analgesia is its short duration of action and this necessitates either the insertion of a catheter or the use of an adjuvant with inherent limitations.[2,4], and have been used for caudal block with various results.Clonidine, an alpha2-adrenergic agonist produces analgesia without causing significant respiratory depression after caudal administration in children [5].Using clonidine as an adjuvant enables us to use a lower concentration of the local anaesthetic to achieve the same level of analgesia with the advantages of prolonged duration of analgesia, reduced residual motor blockade and increased margin of safety [6].However, clonidine can cause hypotension and bradycardia [7].Studies have shown that clonidine in a dose of 1 µg/kg added to 0.25% Bupivacaine produced significant prolongation of caudal block in children [8] and was as effective as 2 µg /kg [9,10].Few studies have evaluated the addition of 1 µg/kg Clonidine to 0.125% Bupivacaine for caudal analgesia [11,12]. AImTo evaluate the efficacy and side effects of caudal clonidine in a low dose of 1µg/kg combined with a low concentration of 0.125% solution of bupivacaine. mAterIAls And methOdsA prospective, randomized, double-blind, controlled study was conducted after the approval of the Institutional Ethical Committee and parental informed consent, in 60 patients, over 18 months, from May 2010 to November 2011.They were between 1-10 years of age, of ASA Physical Status I, weighing 5-20 kg, scheduled to undergo infraumbilical operations in a tertiary hospital.Exclusion criteria were: contraindication to caudal blockade, history of allergic reaction to Bupivacaine or Clonidine, ASA Physical Status > I and parental refusal.Sample size was calculated based on a previous study [11] with a minimum requirement of 30 patients in each group and there were no drop outs.Prior to surgery, the children were kept nil per oral according to standard guidelines.They were randomly assigned to either study groups B or BC, for caudal analgesia.Group: B: 1ml/kg of 0.125% Bupivacaine solution.Group: BC: Mixture of 1ml/kg of 0.125% Bupivacaine with preservative free Clonidine 1µ/kg.The solution was prepared by an Anaesthesiologist who was not one of the observers for the study.All the patients were premedicated with midazolam 0.75 mg/kg orally 30 minutes prior to induction of anaesthesia.In the operation theatre, patients were connected to Datex Ohmeda A-5 multipara monitor and Heart Rate (HR), Mean Arterial Blood Pressure (MAP) and oxygen saturation (SpO 2 ) were monitored.General anaesthesia was induced with thiopentone (1.25%) 5 mg/kg via 22-G or 24-G IV cannula and inhalation of oxygen, nitrous oxide and sevoflurane.