The role of magnesium as an adjuvant during general anaesthesia

Abstract

SummaryMagnesium sulphate is used extensively in the treatment of eclampsia, and is also used to treat refractory arrhythmias, asthma, myocardial ischaemia and acute respiratory failure. We studied the interaction between magnesium sulphate and the anaesthetic agents propofol, rocuronium bromide and fentanyl citrate. This randomised, double blind study was conducted in 50 patients. The magnesium group A (n = 25) received 30 mg.kg )1 magnesium sulphate before induction of anaesthesia and 10 mg.kg )1 continuously intra-operatively until the end of surgery. Group B (n = 25) received the same volume of isotonic saline. Propofol, rocuronium and fentanyl infusions were started and the patients lungs' were ventilated with 33% oxygen in nitrous oxide. Anaesthetic depth was maintained at a bispectral index value of between 40 and 60. Muscle relaxation was maintained at a train-of-four count of 1 throughout surgery using neuromuscular monitoring. The fentanyl infusion was titrated to haemodynamic variables: heart rate and blood pressure. We concluded that magnesium sulphate has anaesthetic, analgesic and muscle relaxation effects and significantly reduces the drug requirements of propofol, rocuronium and fentanyl during anaesthesia.

Comparison of quality of the surgical field after controlled hypotension using esmolol and magnesium sulfate during endoscopic sinus surgery

“…However, there are the potential risks of magnesium such as, potentiation of opioids and neuromuscular blockers leading to delayed emergence. [89] Elsharnouby and Elsharnouby[10] concluded that magnesium sulfate leads to a reduction in arterial pressure, HR, blood loss and duration of sinus surgery.…”

Effects of magnesium sulfate and propofol on the minimum alveolar concentration preventing motor movement in sevoflurane-anesthetized dogs

“…30 Results of those studies 29,30 parallel the lack of a sevofluranesparing effect after MgSO 4 administration that was found in the present study. In humans undergoing hysterectomy, MgSO 4 administration at a rate of 30 mg/ kg did not decrease the doses of propofol needed for anesthetic induction, 31 and infusion of MgSO 4 at a rate of 10 mg/kg/h did not result in significant changes in the requirement for sevoflurane in other studies. 32,33 Those studies 31-33 also corroborated findings of the present study, whereby MgSO 4 did not provide a decrease in the requirements for volatile or injectable anesthetics.…”

The Effect of a Preoperative Single Dose of Magnesium Sulfate versus Preoperative Ultrasound Guided Bilateral Transversus Abdominis Plane Block on Hemodynamics and Postoperative Analgesic Requirements in Patients Undergoing Colorectal Surgery

“…Additionally Gupta et al [26] reported that, preoperative administration of magnesium sulfate in patients undergoing spinal surgeries was associated with stable hemodynamics.…”