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Effects of perioperative magnesium on postoperative analgesia following thoracic surgery: a meta-analysis of randomised controlled trials Volume 36, numéro 4, December 2023

Illustrations


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Tableaux

Auteurs
1 School of Medicine, National Sun Yat-Sen University. No. 70 Lienhai Road, Kaohsiung 80424, Taiwan
2 Department of Anesthesiology, Chi Mei Medical Center, Tainan 71004, Taiwan
3 Department of Neurology, Chi Mei Medical Center, Tainan 71004, Taiwan
4 Chia Nan University of Pharmacy and Science, Tainan 71710, Taiwan
5 The center for General Education, Southern Taiwan University of Science and Technology, Tainan 71004, Taiwan
6 Department of Nutrition, Chi Mei Medical Center, Tainan 71004, Taiwan
7 Department of Food Nutrition, Chung Hwa University of Medical Technology, Tainan 71703, Taiwan
* Co-First author
* Correspondence: Jen-Yin Chen. School of Medicine, National Sun Yat-Sen University. No. 70 Lienhai Road, Kaohsiung 80424, Taiwan

Objectives

To evaluate the analgesic effects of intravenous magnesium in patients undergoing thoracic surgery.

Methods

Randomised clinical trials (RCTs) were systematically identified from MEDLINE, EMBASE, Google Scholar and the Cochrane Library from inception to May 1st, 2023. The primary outcome was the effect of intravenous magnesium on the severity of postoperative pain at 24 hours following surgery, while the secondary outcomes included association between intravenous magnesium and pain severity at other time points, morphine consumption, and haemodynamic changes.

Results

Meta-analysis of seven RCTs published between 2007 and 2019, involving 549 adults, showed no correlation between magnesium and pain scores at 1-4 (standardized mean difference [SMD]=-0.06; p=0.58), 8-12 (SMD=-0.09; p=0.58), 24 (SMD=-0.16; p=0.42), and 48 (SMD=-0.27; p=0.09) hours post-surgery. Perioperative magnesium resulted in lower equivalent morphine consumption at 24 hours post-surgery (mean difference [MD]=-25.22 mg; p=0.04) and no effect at 48 hours (MD=-4.46 mg; p=0.19). Magnesium decreased heart rate (MD = -5.31 beats/min; p=0.0002) after tracheal intubation or after surgery, but had no effect on postoperative blood pressure (MD=-6.25 mmHg; p=0.11). There was a significantly higher concentration of magnesium in the magnesium group compared with that in the placebo group (MD = 0.91 mg/dL; p<0.00001).

Conclusion

This meta-analysis provides evidence supporting perioperative magnesium as an analgesic adjuvant at 24 hours following thoracic surgery, but no opioid-sparing effect at 48 hours post-surgery. The severity of postoperative pain did not significantly differ between any of the postoperative time points, irrespective of magnesium. Further research on perioperative magnesium in various surgical settings is needed.