A Comparison of Epidural Bupivacaine and Bupivacaine-Magnesium Sulphate combination in Lower Abdominal Surgeries

INTRODUCTION: Epidural anesthesia was first performed by Spanish military surgeon Fidel Pages in 1921 in lumbar region. In 1949 Curbelo used Tuohy equipment for continuous blockade. The epidural technique became popular as it had some specific advantages over spinal anaesthesia. The feasibility of extended duration and differential blockade extended its application into other fields like post operative analgesia, chronic pain relief and obstetric pain relief. But some inherent negative points of epidural technique like delayed onset and patchy analgesia persist. Various attempts have been made to rectify these negative points. Combined spinal-epidural technique got introduced in an attempt to rectify this and has become popular. Various additive drugs have been tried along with local anaesthetics in an attempt to hasten the blockade to improve the quality of block. Among drugs that have been tried, magnesium sulphate deserves special mention. Even though magnesium sulphate has been used for various other purposes, its entry into anaesthetic arnamentorium is new. Magnesium sulphate has been described to possess various properties. The potentiation of local anaesthetic drugs is one among them. So my study aims to evaluate the effect of its addition to local anaesthetic in epidural blockade. Along with local anesthetic agent other additive drugs are Epinephrine, Clonidine, Dexmedetomidine, Neostigmine, Ketamine, and Benzodiazepines. Magnesium sulphate a potent antagonist of NMDA receptors when used epidurally is claimed to hasten the onset of sensory blockade. Magnesium also causes physiological Calcium channel blockade and decreases the postoperative opioid requirements. AIM OF THE STUDY: Sole epidural Bupivacaine is becoming unpopular due to delayed onset of sensory blockade. The aim of the study is to add magnesium sulphate as an adjunct to epidural Bupivacaine and evaluate 1. The impact of Magnesium sulphate on the quality of the block using the following parameters, a. Onset of sensory blockade, b. Motor blockade quality, c. Two segment regression time, d. Post-Operative analgesia. 2. Impact of Magnesium sulphate on hemodynamic changes. MATERIALS AND METHODS: After approval of the study by our institutional ethics committee, the study was conducted on 50 ASA grade I or II patients undergoing elective lower abdominal surgeries. Lumbar epidural anesthesia was performed to all the patients. The age of the patients ranged from 23- 70 weighing 45-80 kg and height ranging from 150 – 172 cm. all patients were thoroughly examines preoperatively. Informed consent was obtained from all of them. In the assessment room, vital parameters like pulse, blood pressure, and base line investigations like hemoglobin, urine analysis for albumin and sugar, blood sugar ,urea and creatinine and Electrocardiogram were checked. Thorough examination of all the systems and airway assessment was done. Exclusion criteria including significant co-existing diseases , long term analgesic use, and contraindications to regional anaesthesia such as local infection and bleeding diathesis. The patients were randomly allotted to 2 groups each containing 25. Group C: Patients received 19ml of 0.5 % Bupivacaine + 1 ml normal saline. Group S: Patients received 19ml of 0.5 % Bupivacaine + 50 mg of magnesium sulphate at L2-L3 space using 17G Tuohy needle and placing epidural catheter at 8 cm. SUMMARY: We conducted a double blinded randomized controlled study in 50 patients belonging to ASA I and II undergoing elective lower abdominal surgeries to evaluate the effect of adding magnesium sulphate to bupivacaine and bupivacaine alone in epidural anaesthesia in KAPV Govt Medical college hospital. For the same reason, we divided randomly the patients into two groups of 25 each. Group C received 19 ml of 0.5% of bupivacaine (95mg) and 1ml of Normal saline. Group S received 19 ml of 0.5% of bupivacaine (95 mg) and 1ml of Magnesium sulphate (50 mg). The total volume of the injected solution was 20 ml in both groups. The onset of sensory and motor blockade, the duration of post-operative analgesia were noted in the both the groups. Demographic data were similar in both the groups. We found the onset of sensory blockade was faster in the magnesium group. The duration of post-operative analgesia was slightly prolonged in the study group. The incidence of side effects were similar in both the groups. There is no difference in the change in heart rate and the episode of hypotension were also similar in both the groups. CONCLUSION: This study concludes that epidural magnesium sulphate when added to bupivacaine will shorten the onset of sensory blockade significantly in patients undergoing elective lower abdominal surgeries without increasing the incidence of side effects