The Effect of Systemic Magnesium on Postsurgical Pain in Children Undergoing Tonsillectomies

Abstract

Introduction Tonsillectomy is a frequently performed surgical procedure in children; however few multimodal analgesic strategies have been shown to improve postsurgical pain in this patient population. Systemic magnesium infusions have been shown to reliably improve postoperative pain in adults, but its effects in pediatric surgical patients remains to be determined. In the current investigation our main objective was to evaluate the use of systemic magnesium to improve postoperative pain in pediatric patients undergoing tonsillectomy. We hypothesized that children who received systemic magnesium infusions would have less post-tonsillectomy pain than the children who received saline infusions. Methods The study was a prospective, randomized, double-blinded, clinical trial. Subjects were randomized using a computer-generated table of random numbers to one of the two intervention groups: systemic magnesium infusion (initial loading dose 30 mg/kg given over 15 minutes followed by a continuous magnesium infusion 10 mg/kg/hr) or the same volume of saline. The primary outcome was pain scores in the postanesthesia care unit (PACU) measured by FLACC pain scores. Pain reduction was measured by the decrement in the area under the pain scale versus 90-minute postoperative time curve using the trapezoidal method. Secondary outcomes included opioid consumption in the PACU, emergence delirium scores (measured by the pediatric anesthesia emergence delirium scale) and parent satisfaction. Results Sixty subjects were randomized and 60 completed the study. The area under pain scores (up to 90 minutes) was not different between the study groups, median (IQR) of 30 (0 to 120) score*min and 45 (0 to 135) score*min for the magnesium and control groups, respectively, P= 0.74. Similarly, there was no clinically significant difference in the morphine consumption in the PACU between the magnesium group, median (IQR) of 2.0 (0 to 4.44) mg IV morphine compared to control, median (IQR) of 2.5 (0 to 4.99) mg IV morphine, P= 0.25. The serum level of magnesium was significantly lower in the control group compared to the treatment group at the end of the surgery (P<0.001). Discussion Despite a large number of studies demonstrating the efficacy of systemic magnesium for preventing postsurgical pain in adults, we could not find evidence for a significant clinical benefit of systemic magnesium infusion in children undergoing tonsillectomies. Our findings reiterate the importance of validating multimodal analgesic strategies in children that have been demonstrated to be effective in the adult population.

Magnesium sulfate for postoperative complications in children undergoing tonsillectomies: a systematic review and meta‐analysis

“…As showed in Table 1, only two studies (11,18) used the same pain score scale (mCHEOPS), meta-analysis (Fig 2) of the two studies showed no significant different effect was found between MgSO 4 and control group (MD = −0.15, 95% CI = −0.87 to 0.57, P = 0.56). The other six studies (10,17,19,(21)(22)(23) using other pain score scales also showed no significant different effect between study and control group.…”

“…A total of 334 studies were retrieved through database search. After screening, 10 RCTs with 665 participates published between 2003 and 2015 were included. Of which, four studies administrated magnesium locally and six administrated systemically.…”

“…For systemic magnesium use, cause two included studies, which used a single magnesium bolus, has not been demonstrated to be effective for reducing postoperative pain in adults , Benzon et al. suggest to use a bolus followed by a continuous infusion strategy and, if possible, prolong the infusion into postoperative period which was never been tried in previous studies.…”

“…Magnesium sulfate (MgSO 4 ), by serving as an antagonist of N-methyl-D-aspartate receptors, has been extensively studied in adults with recent systematic reviews supporting its benefits in reducing postoperative pain and other complications by decreasing opioid consumption (12)(13)(14)(15). In contrast, there are only a few studies (10,11,(16)(17)(18)(19)(20)(21)(22)(23) with controversial results investigating the benefit potentials of magnesium sulfate in children and without systematical reviews. Thus, we performed this systematic review of all relevant, published randomized trials to evaluate the impact of magnesium sulfate on postoperative complications in children undergoing tonsillectomies.…”

“…The risk of bias of included RCTs was generally low. Magnesium was administered as local analgesia (11) or analgesic adjuvant (18,22,23) in four studies (40%), systemically in six studies (60%) (10,16,17,(19)(20)(21), as a single bolus in two studies (20%) (10, 17), as a bolus followed by infusion in two trials (20%) (19,21), as an infusion in two trials (20%) (16,20).…”