Effect of magnesium added to local anesthetics for caudal anesthesia on postoperative pain in pediatric surgical patients: A systematic review and meta-analysis with Trial Sequential Analysis

Perioperative Magnesium for Postoperative Analgesia: An Umbrella Review of Systematic Reviews and Updated Meta-Analysis of Randomized Controlled Trials

The purpose of this study was to summarize and evaluate evidence on the effectiveness of perioperative magnesium as an adjuvant for postoperative analgesia. We conducted an umbrella review of the evidence across systematic reviews and meta-analyses of randomized controlled trials (RCTs) on the effect of perioperative magnesium on pain after surgical procedures. Two independent investigators retrieved pain-related outcomes and assessed the methodological quality of the evidence of included studies using the A MeaSurement Tool to Assess systematic Reviews (AMSTAR) tool, and the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system. In addition, an updated meta-analysis of postoperative pain-related outcomes with a trial sequential analysis (TSA) was conducted. Of the 773 articles initially identified, 17 systematic reviews and meta-analyses of 258 RCTs were included in the current umbrella review. Based on the AMSTAR tool, the overall confidence of the included systematic reviews was deemed critically low to low. Pain score, analgesic consumption, time to first analgesic request, and incidence of analgesic request were examined as pain-related outcomes. According to the GRADE system, the overall quality of evidence ranged from very low to moderate. While the updated meta-analysis showed the beneficial effect of perioperative magnesium on postoperative analgesia, and TSA appeared to suggest sufficient existing evidence, the heterogeneity was substantial for every outcome. Although the majority of included systematic reviews and updated meta-analysis showed a significant improvement in outcomes related to pain after surgery when magnesium was administered during the perioperative period, the evidence reveals a limited confidence in the beneficial effect of perioperative magnesium on postoperative pain.

Efficacy and safety of caudal dexmedetomidine in pediatric infra-umbilical surgery: a meta-analysis and trial-sequential analysis of randomized controlled trials

BACKGROUND

Dexmedetomidine is used as a local-anesthetics adjuvant in caudal block to prolong analgesia in pediatric infra-umbilical surgery.

OBJECTIVE

We evaluated the analgesic efficacy and safety of the addition of caudal dexmedetomidine to local anesthetics (vs local anesthetics alone) in pediatric infra-umbilical surgery.

EVIDENCE REVIEW

We searched 10 databases for randomized controlled trials (RCTs) of pediatric patients undergoing infra-umbilical surgery, comparing caudal block with and without dexmedetomidine as local anesthetic adjuvant. We performed a frequentist random-effects meta-analysis (R statistical package). We analyzed continuous outcomes as a ratio of means (ROM) and dichotomous data as relative risk (RR), along with 95% CI. We included 19 RCTs (n=1190 pediatric patients) in the meta-analysis. The primary outcome was duration of analgesia (defined as 'the time from caudal injection to the time at which the study-specific pain score was greater than a cut-off threshold').

FINDINGS

Data from 19 included RCTs (n=1190) suggested that compared with control (mean duration 346 min), the addition of caudal dexmedetomidine significantly prolonged the duration of analgesia (ratio of means 2.14, 95% CI 1.83 to 2.49, p<0.001; 'moderate' evidence). Trial-sequential analysis showed adequate 'information size' for the primary outcome. Caudal dexmedetomidine also reduced the number of analgesic administrations ('low' evidence), total acetaminophen dose ('moderate' evidence) and the risk of emergence delirium ('moderate' evidence). There were no significant differences in adverse effects such as hypotension, bradycardia, post-operative nausea and vomiting, urinary retention and respiratory depression.

CONCLUSIONS

Our results suggest that the addition of dexmedetomidine to local anesthetic in caudal block significantly improves the duration of analgesia and reduces the analgesic requirements, while maintaining a similar risk-profile compared with local anesthetic alone. Further data on neurological safety are needed.

Comparative evaluation of epidural bupivacaine alone and bupivacaine combined with magnesium sulfate in providing postoperative analgesia: a meta-analysis of randomized controlled trials

Background

The comparative efficacy of epidural bupivacaine alone and bupivacaine combined with magnesium sulfate in providing postoperative analgesia remains controversial.

Methods

We searched Mediline (OvidSP), EMBASE (OvidSP) and Cochrane Central Register of Controlled Trials (CENTRAL) to identify trials that compared epidural bupivacaine and magnesium sulfate combination (intervention) with bupivacaine alone (control). Grading of Recommendations, Assessment, Development and Evaluations (GRADE) framework was used to assess the quality of evidence.

Results

Eleven studies fulfilled our inclusion criteria after screening. We found that epidural bupivacaine combined with magnesium sulfate could prolong the time for first rescue analgesics (SMD 4.96; 95% CI [2.75, 7.17], P < 0.00001, I² = 98%), reduce the number of patients who need rescue analgesics (RR 0.38; 95% CI [0.20, 0.74], P = 0.004, I² = 75%) and requirement for rescue analgesics (SMD -2.65; 95% CI [− 4.23, − 1.06], P = 0.001, I² = 96%).

Conclusions

Magnesium suifate as an adjuvant of epidural bupivacaine improved postoperative analgesia. However, we rated the quality of evidence to be very low because of high heterogeneity, imprecise of results and small sample sizes. Furthermore, further large high-quality trials are still needed to confirm the effects of magnesium sulfate on postoperative analgesia.

Clonidine and Morphine as Adjuvants for Caudal Anaesthesia in Children: A Systematic Review and Meta-Analysis of Randomised Controlled Trials

Objective

The aim of this systematic review and meta-analysis is to compare the outcomes of morphine vs. clonidine use as adjuvants in caudal anaesthesia. We are specifically focused on analgesic and side effect profiles.

Methods

We searched databases and trial registration sites and include here randomised controlled trials that compare the analgesic effects of caudal clonidine vs. morphine as adjuvants on postoperative pain. The risk ratio for evaluating pain scores, the need for rescue analgesia and all adverse effects were assessed. The i2 statistic was used to assess heterogeneity. We also assessed risk of bias with Cochrane’s Collaboration tool. The quality of evidence was assessed with Grading of Recommendations Assessment, Development and Evaluation (GRADE) system.

Results

Four randomised controlled trials (including 166 patients) that evaluated the use of clonidine vs. morphine as adjuvants in caudal block were included in this systematic review and meta-analysis. The pooled estimate for postoperative analgesia revealed no statistically significant differences between the clonidine group compared to morphine group (MD=2.90; 95% CI 4.05 to 9.85; i2 93%). Significantly less postoperative nausea and vomiting were reported among the patients that received clonidine vs. those that were treated with morphine (RR 0.57, 95% CI −0.36 to −0.90, i2 26%). There were no statistically significant differences between the two groups in assessments that included urinary retention, pain scores or need for rescue analgesia at 24 hours.

Conclusion

Clonidine is just as effective as morphine when used an adjuvant to local anaesthetic for caudal block, and has a more desirable side effect profile, particularly with respect to postoperative nausea and vomiting.

Dexmedetomidine versus Magnesium as Adjuvants to Bupivacaine-Induced Caudal Block in Children: A Randomized, Double-Blinded, Placebo-Controlled, Trial

BACKGROUND

Caudal block remains fundamental in pediatric anaesthetic practice. It is very useful in a wide range of surgical procedures and has proved to have a remarkable safety record, But one of the major limitations of the single-injection technique is the relatively short duration of postoperative analgesia. Prolongation of caudal analgesia using single-shot technique has been achieved by the addition of various adjuvant.

AIM

This work aims to compare magnesium and dexmedetomidine as adjuvants to bupivacaine-induced caudal block in children undergoing lower limb orthopaedic surgery.

STUDY DESIGN

Randomized, double-blind trial.

SETTINGS

Pediatric or of a tertiary care centre.

METHODS

A double-blinded, randomised controlled trial included 36 children, aged between 1 and 7 years, scheduled for lower limb orthopaedic surgery. Patients received general anaesthesia in addition to the caudal block. Patients were divided into three groups: Dexmedetomidine group (n = 12): received 0.5 mL/Kg bupivacaine + 2 mcg/Kg dexmedetomidine, Magnesium group (n = 12): received 0.5 mL/Kg bupivacaine + 50 mg magnesium, and control group (n = 12): received 0.5 mL/Kg bupivacaine + normal saline. Patients were compared according to the duration of analgesia, pain scores, sedation scores, mean arterial pressure, and heart rate.

RESULTS

Both magnesium group and dexmedetomidine group showed better analgesic profile (duration of analgesia and pain scores) compared to the control group without significant difference between the two former groups. Dexmedetomidine group showed higher sedation score, lower mean arterial pressure and lower heart rate compared to other groups.

CONCLUSIONS

Both magnesium (50 mg) and dexmedetomidine (2 mcg/Kg) improved the analgesic profile of bupivacaine-induced caudal block in children. Dexmedetomidine administration was accompanied with higher sedation score and negative hemodynamic profile.