Comparing the Effects of Perineural Magnesium Sulphate with Intravenous Magnesium Sulphate as an Adjuvant to Bupivacaine in USG Guided Supraclavicular Block

In present anaesthesia practice to prolong postoperative analgesia use of various adjuvants is routinely done. Magnesium sulphate is one of the widely used adjuvant used in different routes along with regional anaesthesia to prolong postoperative analgesia. We compared perineural magnesium sulphate and intravenous magnesium sulphate when used as an adjuvant with bupivacaine in   supraclavicular block under USG guidance for upper limb surgeries.

We enrolled ninety patients with physical status I or II, age ranging from 20-60 years, scheduled for upper limb surgeries under USG guided brachial plexus block were categorised into 3 groups (n-30). In study all patients were received 28 ml 0.5% injection Bupivacaine in addition patients in Group 1 and 2 were received 2 ml of Normal Saline (NS) and in Group 3 were received 1.5 ml of NS with 250 mg of Magnesium sulphate. Along with this intravenously 30 minutes prior to block patients in Group 1 and 3 were received 100 ml of 0.9% of NS and patients in Group 2 were received 100 ml of 0.9% normal saline with injection Magnesium Sulphate 50 mg/kg. They were evaluated for block characteristics and total dose of rescue analgesic required in post-operative period for 24 hours were noted.

We found that sensory, motor block and postoperative analgesia duration was significantly longer in both study groups (2 and 3) compared to group 1 (control) but significantly prolonged in perineural group compared to intravenous group. Postoperative analgesic consumption was less in both study group with insignificant difference between them.

We concluded that in supraclavicular block magnesium sulphate was more effective when used perineurally  as compared to intravenous route as an adjuvant to Bupivacain 0.5% regarding to provide prolong duration of postoperative analgesia with insignificant side effects.