Evaluation of the efficacy of magnesium sulphate as an adjuvant to lignocaine for intravenous regional anaesthesia for upper limb surgery

The Use of Magnesium Sulfate and Peripheral Nerve Blocks: An Updated Meta-analysis and Systematic Review

OBJECTIVES

With the popularization of ultrasound, nerve blocks have been widely implemented in current clinical practice. Although, they have seen limited success due to their shorter duration and suboptimal analgesia. Magnesium sulfate as a local anesthetic adjuvant for peripheral nerve blocks could enhance the effects of local anesthetics. However, previous investigations have not thoroughly investigated the analgesic efficacy of magnesium sulfate as an adjunct to local anesthetics for peripheral nerve blocks. Thus, we attempted to fill the gap in the existing literature by conducting a meta-analysis.

MATERIALS AND METHODS

We performed of a quantitative systematic review of randomized controlled trials published between May 30, 2011 and November 1, 2018. Inclusion criteria were: (1) magnesium sulfate used as adjuvant mixed with local anesthetic for nerve blockade, (2) complete articles and published abstracts of randomized controlled trials, (3) English language.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome measures were time of onset, total duration of the sensory blockade, and Visual Analog Scale pain scores. The secondary outcomes were postoperative oral and intravenous analgesics consumption and the incidence of nausea and vomiting.

RESULTS

The 21 trials analyzed in this study included 1323 patients. Magnesium sulfate effectively prolonged the total duration of sensory blockade (mean difference [MD]=114.59 min, 95% confidence interval [CI]: 89.31-139.88), reducing Visual Analog Scale pain scores at 6 hours (MD=1.36 points, 95% CI: -2.09 to -0.63) and 12 hours (MD=1.54 points, 95% CI: -2.56 to -0.53) postsurgery. Magnesium sulfate also effectively reduced postoperative analgesic use within 24 hours postsurgery (standard MD=-2.06, 95% CI: -2.67 to -1.35). Furthermore, adjuvant magnesium sulfate significantly reduced the incidence of nausea and vomiting after transversus abdominis plane blockade (odds ratio: 0.39, 95% CI: 0.18-0.81).

CONCLUSION

Adjuvant magnesium sulfate enhanced the anesthetic effects of local anesthetics and improved postoperative analgesia following the perineural blockade.

Post-operative analgesia of 2% lignocaine with or without magnesium sulfate for inferior alveolar nerve block in symptomatic mandibular molars - a randomized double blind controlled clinical trial

Background

Single inferior alveolar nerve block is ineffective in achieving adequate pulpal anesthesia in 30-80% of patients due to anatomical variations, local tissue pH, central sensitization, and several factors. Various supplementary techniques and combination of adjuvants with lignocaine are used to overcome these failures. Magnesium sulfate (MgSO₄), one such adjuvant, acts at the N-methyl-D-aspartate glutamate receptor resulting in effective anesthesia. The aim of this prospective, randomized, double-blind, clinical controlled trial was to evaluate the onset, anesthetic efficacy, duration and post-operative analgesia of 2% lignocaine with and without the addition of MgSO₄ in patients with symptomatic irreversible pulpitis and apical periodontitis.

Methods

Fourty-two patients were randomly divided into three groups: 2% lignocaine (group 1) and 2% lignocaine with MgSO₄ (75 mg) and (150 mg) in groups 2 and 3, respectively. Pre-operative vitals and Heft Parker-Visual Analogue Scale (HP-VAS) pain scores were recorded. The onset of anesthesia, anesthetic efficacy, and duration of anesthesia were evaluated post administration of the local anesthetic solution. The post-operative analgesia was examined at intervals of 2, 6, 12, 24, and 48 h.

Results

Administration of 150 mg MgSO₄ hastens the onset of anesthesia (1.29 min) and produces better anesthetic efficacy (3.29 HP-VAS) compared to group 2 (2.07 min and 9.14 HP-VAS) and group 1 (3.29 min and 35.79 HP-VAS), respectively. The duration of anesthesia was significantly higher in group 3 (247.07 min) compared to that of groups 2 and 1 (190 min and 110.21 min) with P < 0.05.

Conclusion

Combining 75 mg or 150 mg of MgSO₄ with lignocaine is more effective than 2% lignocaine and 75 mg of MgSO₄ is adequate for endodontic procedures.

Efficacy and Safety of Magnesium versus Dexmedetomidine as Additives to Local Anesthetic Mixture Using Single Injection Percutaneous Peribulbar Anesthesia in Vitreoretinal Surgeries

Background:

Peribulbar block for vitreoretinal surgery is rather associated with delayed onset of globe anesthesia, akinesia and short duration of analgesia.

Objective:

To compare the effect of addition of Magnesium sulphate vs dexmedetomidine to standard local anesthetics mixtures on the time of onset of Globe Anesthesia, Akinesia & analgesia duration.

Patients and Methods:

Ninety patients of both sexes, aged 25- 75 years, ASA I-III scheduled for vitreoretinal surgery. They were randomly allocated into 3 equal groups each received peribulbar block a mixture of Levo- bupivacaine 0.5% (3 ml) + lidocaine 2% (3 ml) +120 IU hyaluronidase + Control group (C): 0.5 ml of Normal saline. Group (M): 50 mg of Magnesium sulphate in 0.5 ml normal saline. Group (D): 50 μic of dexmedetomidine in 0.5 ml normal saline. The duration of sensory, motor block, Sedation level, Intra-ocular Pressure (IOP) and surgeon satisfaction were assessed.

Results:

The onset of globe anesthesia and akinesia was significantly shorter in M group in comparison with D and C Groups, with a significant increase in the duration of globe analgesia and akinesia in the D Group when compared to both M & C groups. Groups D and M showed a statistically significant decrease in the IOP at 5 min and 10 min when compared to the baseline measurement of the same groups & to C Group, no complications or adverse effects related to the drug or technique were recorded.

Conclusion:

Magnesium sulphate as a local anesthetic adjuvant in peribulbar block is safe and comparable to dexmedetomidine regarding the sensory and motor block duration with better cost-effectiveness and availability.

Comparison of Magnesium Sulfate and Dexmedetomidine as an Adjuvant to 0.5% Ropivacaine in Infraclavicular Brachial Plexus Block

Background:

Magnesium sulfate and dexmedetomidine were used as adjuvants to local anesthesia to improve the quality of regional anesthesia.

Aims:

The aim of this study is to evaluate and compare the effects of magnesium sulfate and dexmedetomidine when added to ropivacaine on the quality of infraclavicular brachial plexus block (BPB).

Settings and Design:

This was a prospective randomized double-blinded controlled study.

Patients and Methods:

A total of 105 adult patients undergoing surgery in hands, wrist, and forearm using infraclavicular BPB were randomly assigned into three groups. Ultrasound-guided infraclavicular BPB was performed using 35 ml ropivacaine 0.5% diluted with 4 ml normal saline 0.9%. Magnesium sulfate 150 mg and dexmedetomidine 100 μg were added in the magnesium sulfate group and dexmedetomidine group, respectively. Duration of analgesia, onset times and durations of sensory block (SB) and motor block (MB), patient's satisfaction, and complications were recorded.

Statistical Analysis:

Statistical software SPSS 16 was used for statistical analysis.

Results:

Dexmedetomidine and magnesium sulfate provided longer duration of analgesia and lesser consumption of postoperative rescue analgesia than the control group (P = 0. 000); dexmedetomidine provided the longest duration of analgesia versus control and magnesium sulfate groups (P = 0.000). Dexmedetomidine provided the quickest onset times and the longest durations of both SB and MB than control and magnesium sulfate groups (P = 0.000). Dexmedetomidine group had higher incidences of bradycardia and hypotension.

Conclusions:

Magnesium sulfate or dexmedetomidine is a useful adjuvant to ropivacaine for infraclavicular BPB in lengthening the duration of analgesia. Dexmedetomidine provided quicker onset and longer duration of both SB and MB and longer duration of analgesia with lesser consumption of postoperative rescue analgesia; however, it showed a higher incidence of intraoperative hypotension and bradycardia than magnesium sulfate.

Comparative efficacy of clonidine versus magnesium sulfate as an adjunct to lignocaine in intravenous regional anesthesia for postoperative analgesia: A prospective, randomized, double-blind study

Background and Aims:

Intravenous regional anesthesia (IVRA) is a very good technique to be used in unstable patients. Various adjuvants have been added, but till date, there is no ideal adjuvant. Clonidine is one of the most widely used adjuvants in IVRA. However, it has many side effects. Hence, the search continues for a better adjuvant. The aim of the present study was to compare the efficacy of clonidine versus MgSO₄ as an adjunct to lignocaine in IVRA for postoperative analgesia and to compare their side effect profile.

Material and Methods:

This prospective double-blind randomized controlled study was conducted in a tertiary care institute. Forty adult patients were included. Patients were assigned into two groups; Group 1 (n = 20) received 3 mg/kg of 2% lignocaine + 50% MgSO₄ 1.5 g diluted with normal saline to 40 ml. Group 2 (n = 20) received 3 mg/kg of 2% lignocaine + clonidine 150 μg diluted with normal saline to 40 ml. Pain score, time to first rescue analgesic (TTFA), total number of rescue analgesics required, and the side effects of the two drugs were compared for 24 h postoperatively.

Results:

The mean TTFA was significantly longer in Group 1 (193.9 ± 38.4 min) than in Group 2 (169.5 ± 33.3 min); P < 0.05. The mean number of rescue analgesics required was 1.6 ± 0.7 in Group 1 as compared to 2.1 ± 0.8 in Group 2 (P < 0.05). More serious side effects such as hypotension and bradycardia were noted with clonidine, although all patients experienced transient pain during intravenous injection of MgSO₄.

Conclusion:

MgSO₄ provides better postoperative analgesia as compared to clonidine when used as an adjunct to lignocaine in IVRA with fewer side effects.

Effect of addition of magnesium to local anesthetics for peribulbar block: A prospective randomized double-blind study

Background:

Magnesium sulphate has been used along with local anesthetics in different regional blocks and found to be effective in decreasing the time of onset of the block and increasing the duration of the block.

Objective:

To evaluate the effect of addition of magnesium sulfate to standard local anesthetics mixture on the time for onset of the globe and lid akinesia for peribulbar block in ophthalmic surgeries.

Materials and Methods:

Sixty patients with American Society of Anesthesiologists status I to III undergoing ophthalmic surgery under peribulbar block were included in this study. Patients were randomized into two groups. Both the groups received 4.5 ml of 2% lidocaine, 4.5 ml of 0.5% bupivacaine with150 IU hyaluronidase. Group NS received normal saline 1 ml in the peribulbar block and Group MS, magnesium sulfate 50 mg in 1 ml normal saline. The onset of akinesia, satisfactory block and complications were observed by an independent observer.

Results:

Demographic data was statistically similar. In the Group NS at 3, 5, 10 and 15 min after the block, complete akinesia was seen in 0, 2, 11 and 28 patients respectively. In the Group MS, at 3, 5, 10 and 15 min after the block, complete akinesia was seen in 13, 23, 27 and 28 patients respectively. Patients received magnesium sulfate showed the statistically significant rapid onset of lid and globe akinesia than the control group till 10 min (P < 0.000). None of the patients needed a supplementary block and had complications during the surgery.

Conclusion:

Addition of 50 mg of magnesium sulfate to the lidocaine-bupivacaine mixture for peribulbar block decreases the onset of akinesia without any obvious side effect.

The effect of magnesium sulfate on motor and sensory axillary plexus blockade

Background:

Magnesium is a physiologic cation that blocks neuromuscular transmission and does not allow the nerve to be stimulated.

Objectives:

This study investigates the effect of adding magnesium sulfate to lidocaine to extend the duration of sensory and motor blocks of the axillary plexus in orthopedic surgeries of the upper extremities.

Patients and Methods:

This controlled randomized double-blind study was performed on patients who were candidates for orthopedic surgery of the upper extremities. A total of 60 patients between 18–60 years with ASA Class 1 or 2 participated in the study. One group received lidocaine (5 mg/kg) with magnesium sulfate 20% (3 mL) as the case group, while the second group received lidocaine (5 mg/kg) with normal saline (3 mL) as a placebo to block the axillary plexus using the trans-arterial technique. The duration of the sensory and motor block of the axillary plexus was monitored and evaluated using the pinprick and modified Bromage scale.

Results:

A total of 60 patients were included in the study with 30 patients having received lidocaine plus magnesium and the other 30 patients having received lidocaine plus normal saline. The mean sensory block duration in the case group was 248.83 ± 18.36 and in control group was 204.67 ± 22.62. The mean motor block duration in the case group was 207.0 ± 16.64 and in control group was 147.33 ± 21.52 (both P < 0.0001). The mean onset of sensory block in case group was 15.5 ± 3.79 and the onset block in control group was 10.33 ± 4.13 (P < 0.0001). The mean onset of motor block in case group was 20.66 ± 4.09 and the onset block in control group was 19.73 ± 26.18 (P < 0.848).

Conclusions:

The addition of magnesium sulfate to lidocaine increased the duration of motor and sensory axillary block in the upper extremities during surgeries when compared to the use of lidocaine alone.

Tourniquets in orthopedic surgery

Tourniquets are commonly used in limb surgeries, be it orthopedic or plastic surgeries. But the inflation pressures, the duration, and release guidelines are still not clear. According to a survey, majority of orthopedic surgeons inflate the tourniquet to fixed pressures for the upper and the lower limbs without considering the baseline blood pressure of the patient on whom the tourniquets are being applied. This review was designed to recall and review the safe use of tourniquets and the various techniques that can be employed to minimize the complications of tourniquet use. Google, science direct, and pubmed were searched for appropriate literature and relevant articles were identified.

An ultra-low dose of naloxone added to lidocaine or lidocaine-fentanyl mixture prolongs axillary brachial plexus blockade

INTRODUCTION

In this prospective, randomized, double-blind study, we evaluated the effect of an ultra-low dose of naloxone added to lidocaine and fentanyl mixture on the onset and duration of axillary brachial plexus block.

METHODS

One hundred twelve patients scheduled for elective forearm surgery under axillary brachial plexus block were randomly allocated to receive 34 mL lidocaine 1.5% with 3 mL of isotonic saline chloride (control group, n = 28), 34 mL lidocaine 1.5% with 2 mL (100 microg) of fentanyl and 1 mL of isotonic saline chloride (fentanyl group, n = 28), 34 mL lidocaine 1.5% with 2 mL saline chloride and 100 ng (1 mL) naloxone (naloxone group, n = 28), or 34 mL lidocaine 1.5% with 2 mL (100 microg) of fentanyl and 100 ng (1 mL) naloxone (naloxone + fentanyl group, n = 28). A multiple stimulation technique was used in all patients. After performing the block, sensory and motor blockades of radial, median, musculocutaneous, and ulnar nerves were recorded at 5, 15, and 30 min. The onset time of the sensory and motor blockades was defined as the time between the last injection and the total abolition of the pinprick response and complete paralysis, respectively. The duration of sensory and motor blocks was considered as the time interval between the complete block and the first postoperative pain and complete recovery of motor functions.

RESULTS

Sensory and motor onset times were longer in the naloxone (sensory onset time: 15 +/- 3, and motor onset time: 21 +/- 4) and naloxone + fentanyl group than control or fentanyl groups (sensory onset time: 10 +/- 3 min in control group, 10 +/- 4 min in fentanyl group, and 17 +/- 3 min in naloxone + fentanyl group, motor onset time: 15 +/- 5 min in control group, 14 +/- 7 min in fentanyl group, and 17.3 +/- 3.4 min in naloxone + fentanyl group) (P < 0.001). The duration of time to first postoperative pain and motor blockade was significantly longer in the naloxone (92 +/- 10 and 115 +/- 10 min) and naloxone + fentanyl groups (98 +/- 12 and 122 +/- 16 min) than control (68 +/- 7 and 89 +/- 11 min) and fentanyl groups (68 +/- 11 and 90 +/- 12 min) (P < 0.001). The time to first postoperative pain was significantly longer in the naloxone and naloxone + fentanyl groups than in the control or fentanyl groups (P < 0.001).

CONCLUSIONS

The addition of an ultra-low dose of naloxone to lidocaine 1.5% solution with or without fentanyl solution in axillary brachial plexus block prolongs the time to first postoperative pain and motor blockade but also lengthens the onset time.