The effect of adding different doses of Magnesium Sulphate to Bupivacaine in the ultrasound-guided supraclavicular brachial plexus block anesthesia.

Introduction: Pain is characterized as an unpleasant experience linked to the damage to the tissues. 
Perioperative pain management can provide short-term and long-term benefits that may pose a 
challenge to providers of anesthetics. Aim of the work: Aim of this study is to evaluate the effect of 
adding different doses of magnesium sulphate to bupivacaine for supraclavicular brachial plexus 
block anesthesia. Patients and methods: After approval of the university ethical committee and 
obtaining informed consent from all patients, this prospective, randomized, double blinded, and 
placebo controlled study was conducted in Minia University hospital during the period from October 
2019 to May 2020. A total of 60 patients aged between 18 and 40 years with ASA I and II patients 
scheduled to undergo supraclavicular brachial plexus block for upper limb surgeries were included in 
the study. Patients were randomly allocated into 3 equal study groups each contains 20 patients. 
Group (A) received 80mg of .5% bupivacaine. Group (B) received 80mg of 0.5% bupivacaine + 
Magnesium Sulphate 100 mg (2ml). Group (C) received 80mg of 0.5% bupivacaine + Magnesium 
Sulphate 50 mg (1ml). Anesthetic technique was standardized in all the 3 groups. Heart rate 
(beats/min), mean arterial blood pressure (mmHg) and oxygen saturation (%) were assessed just 
before the block as: a baseline value, immediately after the block, every 10 (min) during the operative 
time till the end of operation and every 2 hours till 12 hours after the operation. Pain intensity was 
assessed using VAS 2, 4, 6, 8, 10 and 12 hours postoperatively. Also, quality of the sensory and motor 
block was assessed using different tests. Adverse effects such as hypotension, nausea, vomiting and 
hypoxemia (SpO2 <90%) were recorded during the operation and for 12 hours postoperatively.
Results: Magnesium sulphate as an adjuvant to bupivacaine in supraclavicular brachial plexus blocks 
reduces the time to reach complete sensory and motor block and therefore shortens the time before 
operation. Also, using magnesium sulphate with doses of 100mg and 50mg as an adjuvant to 
bupivacaine in supraclavicular brachial plexus blocks could give satisfactory results that could 
compete vigorously with the high doses used in previous studies.
Key words: supraclavicular block, magnesium sulphate, upper limb surgeries, regional anathesia