To compare the efficacy of ropivacaine alone versus ropivacaine with magnesium sulphate for postoperative analgesia in peripheral nerve stimulator-guided supraclavicular plexus block in upper limb surgeries

Introduction

When opposed to general anaesthesia, regional anaesthesia is becoming a more popular option because it temporarily reduces pain and nerve transmission in particular body parts while maintaining awareness through the use of local anaesthetic medications.¹ The brachial plexus block, a method that provides anaesthesia from the shoulder to the fingertips, is frequently used in upper limb procedures, which is where this tendency is most noticeable. The best method for blocking the brachial plexus will rely on a number of variables, such as the specific surgical indication, the patient’s attributes, anatomical variations, and medical concerns.² The introduction of ultrasonography-guided techniques has greatly improved the accuracy and efficiency of these treatments. These developments have helped to increase success rates, enhance pharmacodynamics, and lessen systemic side effects, which has led to the acceptance of regional anaesthesia as a crucial part of contemporary surgical care.³

Important ramifications of managing postoperative pain include early mobilisation, reduced risk of deep vein thrombosis, cardiac and pulmonary problems, swift recovery, fewer healthcare costs, and higher patient satisfaction. Peripheral nerve blocks have therefore become an essential tool for achieving these goals as part of a more comprehensive multimodal analgesic approach.

When compared to other drugs such as bupivacaine, ropivacaine, a well-known aminoamide local anaesthetic, has gained favour due to its relative cardiac and neurologic safety profile. One benefit is that it produces a less severe motor block and takes less time, so patients can be mobilised and discharged sooner.⁴

Local anaesthetics by nature have a short half-life. Researchers have experimented with adding adjuvants to local anaesthetic solutions in order to produce denser blocks, accelerate onset, and prolong analgesia. By lowering the overall amount of local anaesthetic utilised and minimising systemic side effects, these adjuvants seek to improve analgesic effects.⁵ Magnesium sulphate is a naturally occurring intracellular cation that has gained interest among these adjuvants. It is essential for controlling nerve activity and may have effects akin to those of medications that limit calcium entry. Because of its capacity to control calcium influx into cells and inhibit N-methyl-D-aspartate receptors, magnesium is thought to have antinociceptive qualities. These effects lessen the need for anaesthesia and the amount of postoperative analgesics used.⁶ Numerous clinical investigations have documented the advantages of magnesium administration, including its use during general anaesthesia, which has resulted in a drop in the amount of opioids used and a reduction in the total dose needed for analgesia. Magnesium has shown the ability to improve analgesic characteristics when used as an adjuvant in perineural injection with local anaesthetic in the supraclavicular block.⁷

The main goal of the research is to make a contribution to the current discussion on the best ways to manage pain after upper limb procedures. Through a thorough investigation of the safety and effectiveness of ropivacaine in combination with magnesium sulphate, this study aims to offer important knowledge to medical practitioners, which will ultimately lead to better patient outcomes and increased delivery efficiency in this crucial clinical area.

Aim

To assess the safety and effectiveness of utilising magnesium sulphate in addition to ropivacaine alone for postoperative analgesia in patients having upper limb surgeries under peripheral nerve stimulator guided supraclavicular plexus block.

Objectives

Methods

Sampling size

The sample size was calculated in openepi.com using the duration of motor block in minutes as criteria from the study by Gupta et al.⁸ as seen in Figure 1. The study will be conducted on 50 patients with 25 patients in each group, to account for any possible dropouts.

Figure 1. Sample size for comparing two means.

Discussion

For upper limb procedures, the decision to use a peripheral nerve stimulator-guided supraclavicular plexus block is important because it may provide better pain management without having the systemic adverse effects that are frequently connected to general anaesthesia. Given the increasing amount of evidence bolstering the use of adjuvants to improve analgesia, the choice to look into the possibility of adding magnesium sulphate as an adjuvant to ropivacaine is followed in this study.⁹

Numerous clinical studies have shown that giving magnesium during general anaesthesia lowers the need for anaesthesia and the amount of analgesics used after surgery. Ropivacaine is less neurotoxic and cardiotoxic than other aminoamides, such as bupivacaine. Ropivacaine causes a shorter-lasting and less severe motor block than bupivacaine, allowing for speedier mobilisation and discharge.¹⁰ Mukherjee et al. found that although there was a slight delay in the onset time of sensory and motor blockade, adding 150 mg of magnesium sulphate to ropivacaine 0.50% in supraclavicular brachial plexus block resulted in a longer duration of sensory and motor blockade and a reduced need for rescue analgesics.¹¹ Conversely, Shridevi et al. noticed positive results when magnesium sulphate was used as an adjuvant, showing both a quicker start and a longer duration of motor and sensory anaesthesia.¹² Similarly, Kaur et al. discovered that postoperative analgesia was enhanced by adding 250 mg MgSO₄ and 2 mg.kg⁻¹ ketamine to 0.5% ropivacaine as opposed to ropivacaine alone. In the setting of supraclavicular brachial plexus block, MgSO4 demonstrated superiority in terms of block features and a lower frequency of adverse effects.¹³ In their comparison of dexmedetomidine and MgSO₄ as adjuvants to ropivacaine, Shukla et al. found that while both were helpful, dexmedetomidine offered prolonged analgesia, an earlier onset of sensory and motor block, and a longer duration of block. The investigation also emphasised variations in adverse event patterns, wherein dexmedetomidine demonstrated a greater frequency of bradycardia, sedation, and hypotension.¹⁴ According to Chadha et al.’s study, the volume of 0.5% ropivacaine utilised in ultrasound-guided supraclavicular brachial plexus block decreased from 35 mL to 20 mL, which led to a 21% reduction in the length of analgesia. This highlights the significance of determining the lowest effective ropivacaine volume needed to achieve a full sensory and motor block with the least amount of IV analgesia needed.¹⁵ As adjuvants to ropivacaine, Kumari et al. examined dexmedetomidine and clonidine and discovered that dexmedetomidine produced a noticeably longer duration of postoperative analgesia and an earlier sensory block. The combination of ropivacaine and dexmedetomidine showed promise in this trial, especially for orthopaedic surgeries.¹⁶

The purpose of this study is to examine how well magnesium sulphate works with ropivacaine to prevent post-operative analgesia following upper limb procedures. A thorough research approach to address the critical problem of postoperative pain management in patients undergoing upper limb procedures is outlined in the study protocol that is being presented. Effective postoperative pain management is vital due to its significant influence on patient outcomes, recovery, and the healthcare system as a whole. Through a comparison of the two anaesthesia approaches’ efficacy and safety, this study protocol aims to give clinicians evidence-based counselling and shed light on the advantages of mixing magnesium sulphate with ropivacaine. By doing this, the study hopes to improve patient satisfaction, lower healthcare costs, accelerate recovery, and optimise patient outcomes. Although the study has great potential, there will likely be difficulties, such as finding patients, adhering to protocol, possible variation in surgical techniques, and ethical issues. Careful management of these obstacles is necessary to guarantee the validity and generalizability of the study.

To sum up, the study protocol offers a methodical and well-organized research strategy that tackles an important clinical concern in anesthesiology. This research has the potential to greatly improve postoperative pain management and, in turn, improve patient care in the setting of upper limb procedures by comparing the efficacy of various anaesthetic approaches. Attaining this goal will require meticulous protocol execution, ethical standards observance, and in-depth data analysis.