Effects of magnesium sulfate administration in attenuating chronic postsurgical pain in rats

Effects of intra-operative magnesium sulfate infusion on orthognathic surgery: A prospective and randomized controlled trial

Purpose

To comprehensively understand the effects of intra-operative infusion of magnesium sulfate on patients who underwent orthognathic surgery, including remifentanil consumption, postoperative pain, postoperative nausea and vomiting (PONV), inflammatory response, and serum magnesium levels.

Methods

Seventy-five adult patients undergoing orthognathic surgery under general balanced anesthesia were randomly divided into two groups. One group (Group M) received 50 mg/kg of magnesium sulfate in 20 mL 0.9 % saline after intubation, followed by a continuous infusion at a rate of 15 mg/kg/h until 30 min before the anticipated end of surgery. The other group (Group C) received an equal volume of isotonic saline as a placebo. (Clinical trial registration number: chiCTR2100045981).

Results

The primary outcome was remifentanil consumption. The secondary outcomes included the pain score assessed using the verbal numerical rating scale (VNRS) and PONV assessed using a Likert scale. Remifentanil comsumption in Group M was lower than Group C (mean ± SD: 0.146 ± 0.04 μg/kg/min vs. 0.173 ± 0.04 μg/kg/min, P = 0.003). At 2 h after surgery, patients in Group C suffered more severe PONV than those in Group M (median [interquartile range, IQR]: 1 [3] vs. 1 [0], mean rank: 31.45 vs. 42.71, P = 0.040). At post-anesthesia care unit (PACU), postoperative pain in Group C was severe than Group M (3 [1] vs. 3 [0], mean rank: 31.45 vs. 42.71, P = 0.013). Changes in haemodynamics and surgical field scores did not differ between the groups (all P > 0.05). The levels of cytokines (IL-4, IL-6, IL-8, IL-10, TNF-a, and MIP-1β) were not significantly different between the groups after surgery (all P > 0.05). Postoperative serum magnesium levels in Group C were lower than those in Group M (0.74 ± 0.07 mmol/L vs. 0.91 ± 0.08 mmol/L, P = 0.000) and the preoperative level (0.74 ± 0.07 mmol/L vs. 0.83 ± 0.06 mmol/L, P = 0.219).

Conclusions

In orthognathic surgery, magnesium sulfate administration can reduce remifentanil requirement and relieve PONV and postoperative pain in the early postoperative phase.

Efficacy of intravenous magnesium sulfate infusion on postoperative pain and quality of recovery for septorhinoplasty: a randomized controlled study

BACKGROUND

The pain that occurs after septorhinoplasty is an important factor affecting the comfort of the patient.

OBJECTIVES

To investigate the effect of perioperative intravenous magnesium sulfate infusion on postoperative pain and quality of recovery in patients underwent septorhinoplasty surgery.

MATERIAL AND METHODS

One hundred twenty patients who underwent septorhinoplasty were randomly divided into two groups. Magnesium group received intravenous magnesium after induction of anesthesia (30 mg/kg), then infused until the end of the surgical procedure (9 mg/kg). The placebo group received the same volume of saline infusion. The VAS score was used for postoperative pain assessment, and the Quality of Recovery-40 (QoR-40) score was used for the assessment of recovery status.

RESULTS

The postoperative 30 min, 1st, 2nd, 4th (p < .001) and 24th hour (p < .05) VAS scores of the patients in the magnesium infusion group were significantly lower compared to the placebo group. Also; in terms of physical comfort (p < .001), emotional state (p < .05), psychological support, pain and total score values (p < .001), patients in magnesium group had significantly higher QoR-40 scores than those in placebo group.

CONCLUSION

Intraoperative magnesium infusion, which is widely used in many surgeries to provide controlled hypotension, also contributes significantly to patient comfort with its positive effect on postoperative pain and recovery scores.

Management of pain using magnesium sulphate: A narrative review

Pain is one of the most complex and unpleasant sensory and emotional human experiences. Pain relief continues to be a major medical challenge. The application of systemic opioid and regional analgesia techniques has facilitated a decrease in the occurrence and gravity of pain. Magnesium has an evolving role in pain management. Magnesium sulphate (MgSO4), the pharmacological form of magnesium, is a physiological voltage-dependent blocker of N-methyl-D-aspartate (NMDA)-coupled channels. In terms of its antinociceptive role, magnesium blocks calcium influx, which inhibits central sensitization and decreases preexisting pain hypersensitivity. These properties have encouraged the research of magnesium as an adjuvant agent for intra- and post-operative analgesia. Moreover, the mentioned magnesium impacts are also detected in patients with neuropathic pain. Intravenous magnesium sulphate, followed by a balanced analgesia, decreases opioid consumption. This review has focused on the existing evidence concerning the role of magnesium sulphate in pain management in situations including neuropathic pain, postherpetic neuralgia, trigeminal neuralgia, migraine, and post-operative pain. Additional studies are required to improve the use of magnesium sulphate for pain to increase the quality of life of patients.