Magnesium as part of balanced general anaesthesia with propofol, remifentanil and mivacurium: a double-blind, randomized prospective study in 50 patients

Abstract

Background and objective To test the hypothesis that magnesium sulphate reduces the amount of remifentanil needed for general anaesthesia in combination with propofol and mivacurium, we studied 50 patients undergoing elective pars plana vitrectomy in a double-blind, randomized prospective fashion. Methods Magnesium sulphate (50 mg kg ±1 body weight) or placebo (equal volume of NaCl) was given slowly intravenously after induction of anaesthesia with propofol 1±2 mg kg ±1 . Anaesthesia was maintained with propofol (using electroencephalographic control), mivacurium (according to train-of-four monitoring of neuromuscular blockade) and remifentanil (according to heart rate and arterial pressure). Results We observed a signi®cant reduction in remifentanil consumption from 0.14 to 0.09 lg kg ±1 min ±1 (P < 0.01). Mivacurium consumption was also markedly reduced from 0.01 to 0.008 mg kg ±1 min ±1 (P < 0.01), whereas propofol consumption remained

The role of magnesium as an adjuvant during general anaesthesia

“…In our study as in previous reports, the fentanyl requirements were titrated according to haemodynamic changes. Other work using doses of magnesium similar to ours have been shown to produce reductions in analgesic requirements both during and after surgical interventions [13].…”

“…[12] concluded that intravenous administration of magnesium sulphate reduced propofol infusion requirements, whereas Schulz‐Stubner et al . [13] observed that propofol consumption remained unchanged after using magnesium sulphate.…”

“…Similarly, Schulz‐Stubner et al . [13] concluded from his study that mivacurium consumption was markedly reduced in patients receiving magnesium sulphate infusion.…”

“…Their data demonstrated that magnesium could be used as an adjuvant to peri‐operative analgesic management by reducing the fentanyl requirements. Recently, in a study by Schulz‐Stubner [13], magnesium sulphate given as a bolus following induction of anaesthesia produced a significant reduction in remifentanil consumption during general anaesthesia. In our study as in previous reports, the fentanyl requirements were titrated according to haemodynamic changes.…”

“…[11] and Schulz‐Stubner et al . [13] demonstrated that magnesium infusion was well tolerated, with no signs of muscle weakness. In our study, serum magnesium levels rose from 1.99 to 2.17 mg.dl −1 in the magnesium group and were stable at 2.02 (0.04) mg.dl −1 in the control group.…”