A Comparative study on two doses of Clonidine added to Hyperbaric Bupivacaine in Spinal Anaesthesia

INTRODUCTION: Spinal anaesthesia is commonly used for abdominal, perineal, gynaecological and lower limb operations. It offers excellent anaesthesia and fewer side effects than General anaesthesia. It is easy to perform and provides faster onset and effective sensory and motor block. Bupivacaine produces long lasting spinal anaesthesia without Transient neurological symptoms. Recently there has been an interest in using additives to intra thecal local anasesthetics to decrease the dose of local anaesthetics and also provide effective post operative analgesia. Various studies have been conducted to evaluate the addition of clonidine to hyperbaric bupivacaine. The alpha 2 adrenergic agonist clonidine has a variety of actions including the ability to potentiate the effect of local anesthetics. It prolongs sensory blockade and also reduces requirement of post operative analgesics. This study was designed to evaluate the addition of two doses of clonidine( 40 μg and 60μg) added to hyperbaric bupivacaine (0.5%) 2.75ml in spinal anaesthesia for sub umbilical surgeries. AIM OF THE STUDY: To compare the effect of addition of two doses of clonidine (40μg and 60μg) to 0.5% hyperbaric bupivacaine 2.75 ml, intrathecally for sub umbilical surgeries. To evaluate : • Time to onset of sensory and motor block, • Duration of sensory and motor block, • Duration of effective post operative analgesia, • Side effects, MATERIALS AND METHODS: This study was conducted at the Chengalpattu Medical College Hospital, Chengalpattu - between May 2009 to August 2009 on 60 patients of ASA physical status I and II undergoing infra umbilical surgeries. This study was done after Ethical Committee approval and written informed consent obtained from all patients included in the study. Study Design: This study was done in a prospective double blinded randomized manner. Selection of Cases: Inclusion Criteria: 1. Patients in age group of 20 to 50 yrs, 2. ASA –PS I & II, 3. Infra umbilical surgeries. Exclusion criteria: 1. ASA –PS III & IV, 2. Patient refusal, 3. Renal / hepatic dysfunction, 4. Allergy to drugs, 5. Contra indication to sub arachnoid block. 60 patients were included in this double blinded randomized controlled study. patients were divided into 3 groups. Patients in group B received 2.75ml of 0.5% hyperbaric bupivacaine plus 0.4ml saline. Patients in group C1 received 2.75ml of hyperbaric bupivacaine with 40 μg of clonidine . Patients in group C2 received 2.75ml of hyperbaric bupivacaine with 60μg of clonidine. Statistical Analysis: All recorded data were entered using MS Excel software and analysed using STATA software for determining the statistical significance. Analysis of Variance was used to study the significance of mean of various study parameters between the three groups. Student’s ‘t’ test was used to compare the two groups on mean values of various parameters. The p-value taken for significance is 0.05. CONCLUSION: In conclusion the addition of clonidine as an adjuvant to bupivacaine in subarachnoid block prolongs duration of both sensory and motor block. I conclude that 60μg of clonidine hydrochloride added to local anaesthetic in subarachnoid block has proved to be a better adjuvant in prolonging the sensory and motor blockade intra operatively and duration of effective post operative analgesia compared to 40μg, without significant adverse effects