A Study to Evaluate Magnesium Sulphate in Accelerating the Onset of Action of Injection Bupivacaine used for Epidural Anaesthesia

Manoj Kumar, S (2012) A Study to Evaluate Magnesium Sulphate in Accelerating the Onset of Action of Injection Bupivacaine used for Epidural Anaesthesia. Masters thesis, Madras Medical College, Chennai.


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INTRODUCTION: Jean Athanase Sicard and Fernand Cathelin independently introduced cocaine through sacral hiatus in 1901, thereby becoming the first practitioners of caudal (epidural) anesthesia. Twenty years later, Fidel Pages described the interspinous approach to the epidural space and reported satisfactory anesthesia for intra-abdominal procedures. In 1945, Tuohy introduced the epidural needle but it was Eugene Aburel who introduced a silk ureteral catheter in the epidural space and used it to block the pain of labor in women. By 1962, the first polyvinyl catheter with a closed tip was introduced, making the continuous epidural block much easier to perform in an efficient way. Epidural blockade2 has a unique special feature of segmental blockade where by only the desired segments required for surgical plane are blocked, unlike the uncontrolled level of blockade as occurs in spinal anesthesia. The period of analgesia can be extended to the post-operative period through the continuous catheters. Ever since the administration of local anesthetics in epidural route, there has been many adjuvants (adrenaline, opioids, alpha-2 agonists, ketamine, neostigmine) that are added to shorten the onset of action, improve the quality of analgesia and prolong the duration of analgesia in the post-operative period. Magnesium sulphate has been added as an adjuvant in neuraxial blockade. It has been known to possess anti-nociceptic property in intravenous route in the perioperative and the postoperative period. The site of action of magnesium has been explained by the property of NMDA receptor antagonism which has prevented central sensitisation to peripheral nociceptive stimulation. There are many studies to prove its potency as an analgesic. Its clinical efficacy and safety has been proved in humans in experimental studies. In this Prospective Randomised Double blind controlled study we evaluated the onset of action of magnesium sulphate in epidural anesthesia in patients coming for lower abdominal surgeries. AIM OF THE STUDY: To evaluate the role of Magnesium sulphate as an adjuvant in accelerating the onset of action of injection Bupivacaine in epidural anesthesia in patients coming for lower abdominal surgeries. MATERIALS AND METHODS: After approval of the study by our institutional ethics committee, the study was conducted in 50 ASA grade I or II patients undergoing elective lower abdominal surgeries under epidural anaesthesia. The age, weight, and height, vital parameters like pulse rate, blood pressure, baseline investigations like hemoglobin, blood sugar, urea, creatinine, CXR and ECG were all checked. Thorough examination of all the systems and airway assessment was done. Inclusion Criteria: 1. Patients between the age group 18 to 60 yrs., 2. Patients in ASA I and II physical status, 3. Patients with BMI < 30 kg/m2, 4. Patients coming for elective surgeries, 5. Patients who have given valid informed consent. Exclusion Criteria: 1. Patients with coagulation abnormality, 2. Patients with cardiac or renal failure, 3. Patients with mental illness, 4. Patients with neurological illness, 5. Patients with spinal deformities, 6. Patients with allergy to local anesthetics, 7. Patients coming for emergency surgeries, 8. Patients not fitting into inclusion criteria. The patients who fulfilled the above explained criteria were taken into the study after obtaining written informed consent from them. MATERIALS USED: 1. 18 G or 16 G, 9 cm Tuohy needle, with a 15-20 degrees angulation at the tip (Hueber’s tip), filter. 2. 18 G epidural catheter. 3. 5 ml syringe (for LOR). 4. 2 ml syringe. 5. local anesthetic preparation of 1.5 % lignocaine with 1 in 2 lac adrenaline. Visual Analog Scale (VAS) was explained to the patients. The patients were shown a 10 cm long scale marked 0 – 10 on a blank paper and told that 0 represented ―no pain‖ and 10 represented ―worst possible pain‖. Rectus Abdominis Muscle score was also explained to the patients. A score of 60 % represented adequate blockade. The patients were randomly allocated into two groups of 25 each by using closed envelop method. SUMMARY: We conducted a randomised double blinded control study in a group of 50 patients belonging to ASA I and II undergoing elective lower abdominal surgeries to evaluate the effect of adding magnesium sulphate with injection bupivacaine in epidural anesthesia. Two groups of 25 each were randomly taken and analysed. The groups were comparable in terms of demographic profile. The purpose of the study was to determine the time for onset of action of sensory and motor blockade. Data showed statistical significance of early onset of action in the magnesium group. On the course of the study the time taken for two segment regression from the peak sensory level was found to be prolonged in the magnesium group. The obtained data showed statistical significance. Also on the due course of the study it was found that the incidence of shivering was less in the patients belonging to the magnesium group compared to the control group which showed statistical significance. Also epidural magnesium did not produce significant side effects in the study. CONCLUSION: This study concludes that addition of epidural magnesium sulphate accelerates the onset of action of epidural bupivacaine and also prolongs the duration of action of epidural bupivacaine in patients coming for lower abdominal surgeries without increasing the incidence of side effects.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Magnesium Sulphate ; Accelerating ; Onset ; Injection ; Bupivacaine ; Epidural Anaesthesia.
Subjects: MEDICAL > Anaesthesiology
Depositing User: Subramani R
Date Deposited: 22 Apr 2018 10:38
Last Modified: 22 Apr 2018 10:38
URI: http://repository-tnmgrmu.ac.in/id/eprint/7214

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