Effect of pre-emptive magnesium sulfate infusion on the post-operative pain relief after elective cesarean section

Abstract

Background:The aim of this study was to evaluate the analgesic efficacy of pre-operative single dose of intravenous (I.V.) magnesium sulfate infusion in patients undergoing elective Cesarean section.Materials and Methods:Seventy pregnant women who underwent elective Cesarean section were randomly divided into two groups. Before induction of anesthesia, the magnesium group (Group A) received magnesium sulfate 50 mg/kg I.V. in bolus dose. The control group (Group B) received the same volume of isotonic saline. The pain scores at rest and also upon movement were evaluated up to 24 h post-operatively and analgesic requirement was recorded during the first 24 h after operation.Results:Cumulative analgesic consumption (24 h after operation was 11.2 ± 6.3 mg in group A vs. 13.9 ± 3.9 mg in group B). Post-operative pain scores (24 h after operation was 1.8 ± 2.1 in group A vs. 2.9 ± 1.2 in group B) and shivering incidents (8.57 in group A vs. 14.28 in group B) were significantly lower in Group A (P < 0.05). Mean arterial pressure just after intubation and during the immediate post-operative period was significantly lower in Group A (P < 0.05).Conclusion:Pre-operative intravenous magnesium sulfate infusion decrease post-operation pain and requirement of analgesia in Cesarean section.

Intravenous Magnesium Sulphate for Analgesia after Caesarean Section: A Systematic Review

“…One study used a standard dose of 6 grams as a bolus [ 24 ] which would likely be the highest dose-to-weight studied. 50 mg/kg was the most commonly studied bolus dose, with four trials assessing a group with this dose [ 11 , 20 – 22 ]. Of those with postoperative infusion protocols, two groups received a standard 2 g/hr infusion [ 11 , 24 ], one group received 1 g/hr [ 11 ] and one group received a weight-based infusion of 10 mg/kg/hr for 24 hours [ 25 ].…”

“…Total analgesic requirement in the immediate 24 hours post caesarean was measured in six of the seven trials. Intravenous magnesium resulted in significantly less analgesic consumption than placebo in four of the six, p < 0.01 [ 20 – 22 , 25 ]. Likewise, Elgebaly et al [ 24 ] did not measure total analgesic consumption, though did measure and reveal significantly lower frequency of analgesic intake in their magnesium group (2.5) compared to control (3.0; p < 0.01) [ 24 ] in the first 24 hours post caesarean, which may be a comparable outcome.…”

“…The remaining five trials serially measured VAS scores. Magnesium intervention resulted in significantly lower VAS scores at the 24-hour time point in two trials [ 22 , 25 ] ( p < 0.05) and consistently lower VAS scores at multiple time points in the same trials ( p < 0.05).…”

“…Other authors [ 22 ] have postulated that the superior analgesic efficacy of PCEA may have masked the analgesia effect of magnesium in the study by Paech et al [ 11 ]. In addition, Helmy et al [ 23 ] conceded in their study that failure to reach significant outcome differences from control may have been due to their low magnesium bolus dose (30 mg/kg compared to the most common 50 mg/kg) and lack of an ongoing infusion protocol [ 23 ].…”

The Comparison of Preventive Analgesic Effects of Ketamine, Paracetamol and Magnesium Sulfate on Postoperative Pain Control in Patients Undergoing Lower Limb Surgery: A Randomized Clinical Trial

“…There are also some recent regional studies which support the findings of the previous studies regrinding the effectiveness of magnesium sulfate for postoperative pain in different surgeries. [ 21 22 23 ]…”