Comparison of Post Operative Analgesia following Epidural Bupivacaine with Clonidine and Epidural Bupivacaine in Orthopaedic Lower Limb Surgeries

INTRODUCTION: Recent advances in neurosciences have demonstrated that peripheral tissue injury may lead to long alterations in central processing with reduction in pain threshold, amplification of response to pain. Comparable alterations may also occur following surgical trauma, resulting in amplification and prolongation of postoperative pain. Postoperative pain treatment should be an integral component of the routine surgical and anaesthetic management not only for humanitarian reasons but also because it can help to reduce morbidity and complications as well as accelerate rehabilitation. Good perioperative analgesia is an important avenue to attenuate the surgical stress response. Post operative pain relief can be provided by pharmacological and nonpharmacological methods. Non pharmacological methods include hypnosis, cold or heat, relaxation therapy, splinting of wounds, Transcutaneous Electrical Nerve Stimulation and pre-operative explanation and education. The pharmacological methods include simple analgesics, Non- steroidal anti- inflammatory drugs, Opioids (oral, intramuscular, intravenous, Patient Controlled Analgesia, Epidural or intrathecal) and Local anaesthetic agents (wound infiltration, nerve blockade, epidural, intrathecal). Epidural anaesthesia is a central neuraxial block technique with many applications. Epidural anaesthesia can be used as sole anaesthetic for procedures involving the lower limbs, pelvis, perineum and lower abdomen. The advantage of epidural over spinal anaesthesia is the ability to maintain continuous anaesthesia after placement of an epidural catheter, thus making it suitable for procedures of long duration. This feature also enables the use of this technique into the postoperative period for analgesia, using lower concentrations of local anaesthetic drugs or in combination with different agents. Clonidine an alpha – 2 agonist drug, which was introduced into clinical practice as an anti-hypertensive medication, can be used as an additive to local anaesthetics in nerve blockade and central neuraxial blockade. Following local anaesthetics and opioids, clonidine is the most studied drug used for human neuraxial analgesia. Although the systemic administration of clonidine can provide analgesia, its primary site of antinociceptive action appears to be at the spinal level. Alpha - 2 receptors at the spinal cord level are thought to be responsible for the analgesic properties of α2-adrenergic agonists. This study was designed to evaluate the analgesic efficacy of bupivacaine and clonidine mixture given through lumbar epidural route in patients undergoing elective orthopaedic lower limb surgeries, comparing the quality of analgesia with epidural plain bupivacaine and also to calculate the number of post-operative aanalgesic doses required. AIMS AND OBJECTIVES: 1. To evaluate the analgesic efficacy of bupivacaine and clonidine mixture given through lumbar epidural route for postoperative analgesia in patients undergoing elective orthopaedic lower limb surgeries, by calculating the number of doses of postoperative analgesics required. 2. To compare the quality and duration of analgesia of epidural bupivacaine - clonidine mixture with epidural plain bupivacaine intra and post- operatively. 3. To evaluate the hemodynamic response of epidural clonidine intra and post-operatively. MATERIALS AND METHODS: Patient selection: The study population consist of ASA I & ASA II patients in the age group of 18 years to 65 years admitted to undergo elective orthopaedic lower limb surgeries at Govt. Stanley Hospital, Chennai during the period of January 2008 to June 2008. After getting approval by the institutional ethical committee and after obtaining written informed consent from each patient, the study was conducted. Inclusion criteria: 1. Age Group 18 – 65 years. 2. ASA I and ASA II. 3. Elective orthopaedic lower limb surgeries. 4. Duration of Surgery between 2:00 to 2:30 hours. Exclusion criteria: 1. Patient refusal. 2. Age 65 years. 3. ASA III and ASA IV. 4. Patient posted for emergency surgery. 5. Ischemic heart disease/ rheumatic heart disease. 6. Sinus bradycardia / heart blocks / conduction defects. 7. Preoperative hypotension. 8. Local infection at lumbar area. 9. Pre-existing neurological disorders. 10. Coagulation defects and patient on anticoagulants. STATISTICS AND ANALYSIS: Forty patients posted for Orthopaedic lower limb surgeries of ASA I and ASA II were taken up for the study. They were allocated randomly into two equal groups of 20 each. Group P receieved 1 ml of placebo along with the first dose of epidural 0.5% bupivacaine and Group C received 50 μg of clonidine diluted with normal saline to 1 ml along with first dose of epidural 0.5% bupivacaine. A standard anaesthetic technique was followed in all patients. The patients were assessed by the same observer in the postoperative period. All the data were expressed as mean ± standard deviation (SD). Qualitative variables were compared with ‘Chi-square test’ and quantitative variables were compared with ‘the student ‘t’ test’. The level of statistical significance was set at P < 0.05. CONCLUSION: 1. Single dose administration of clonidine and bupivacaine mixture given through lumbar epidural route provides effective postoperative analgesia in patients undergoing elective orthopaedic lower limb surgeries, without any hemodynamic instability. 2. Epidural clonidine significantly reduces the postoperative analgesic consumption.