Postoperative Analgesia of Magnesium Sulfate in Suprascapular Nerve Block Following Shoulder Arthroscopy

Study Overview
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Brief Summary
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Arthroscopic shoulder surgeries in adults are accompanied with severe immediate postoperative pain reported in approximately 45% of patients. For quicker recovery and rehabilitation of these patients, postoperative analgesia is mandatory. Different analgesic modalities have been proposed including parenteral opioids, intra-articular injection of local anesthetics, interscalene brachial plexus block (ISB), and a suprascapular nerve block (SSNB), with varying degrees of effectiveness and multiple reported side effects. A recent meta-analysis demonstrates that suprascapular block results in 24-h morphine consumption and pain scores similar to ISB, so, it may be considered an effective and safe alternative for interscalene block in shoulder surgery, with less motor restriction, and fewer complications. Different agents are used as adjuvants to local anesthetics during peripheral nerve block to prolong its analgesic action including magnesium sulfate. A meta-analysis by Mengzhu et al., concluded that magnesium sulfate combined with local anesthetics in perineural nerve blocks provided better analgesic efficacy and may be a promising analgesic for perineural nerve blocks. Antinociceptive effects of magnesium are due to the regulation of calcium influx into the cell and a non-competitive antagonism of the NMDA receptors

Detailed Description
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The aim of this study is to evaluate the effects of magnesium sulfate as an adjuvant to bupivacaine in suprascapular nerve block on the duration and quality of postoperative analgesia following shoulder arthroscopy, postoperative pain VAS scores, intraoperative fentanyl requirements, sedation scores, respiratory depression, postoperative 24 hours cumulative morphine consumption.

Official Title
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Efficacy of Magnesium Sulfate Added to Bupivacaine in Suprascapular Nerve Block on Duration of Analgesia Following Shoulder Arthroscopy: a Prospective Randomized Controlled Study

Conditions
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Arthroscopic Shoulder Surgery

Intervention / Treatment
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* Drug: Bupivacaine
* Drug: Bupivacaine-magnesium
* Drug: Propofol
* Device: Ultrasound
* Drug: Sevoflurane
* Drug: Rocuronium


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ASA physical status I-III Exclusion Criteria: Patient's refusal Significant cardiac diseases Significant hepatic diseases Significant renal diseases (serum creatinine ˃ 1.5 mg/dl) Cardiac conduction abnormalities Drug abuse Pregnancy Allergy to study medications Mental disease Communication barrier Coagulopathy Local skin infection Traumatic nerve injury of upper limb Patients receiving opioid analgesics Patients receiving magnesium sulfate Patients receiving beta blockers Patients receiving calcium channel blockers Previous shoulder surgery

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Bupivacaine<br>Ultrasound-guided suprascapular nerve block using bupivacaine will be performed before induction of general anesthesia | Drug: Bupivacaine<br>* Ultrasound-guided suprascapular nerve block will be performed using 7 mL of 0.5% bupivacaine plus 3 mL of 0.9% saline<br>Drug: Propofol<br>* Using propofol 1.5-2.5 mg/kg<br>Device: Ultrasound<br>* Ultrasound-guided suprascapular nerve block<br>Drug: Sevoflurane<br>* Sevoflurane 0.7-1.5 MAC in 40% oxygen<br>Drug: Rocuronium<br>* Rocuronium 0.6 mg/kg<br>|
| Active Comparator: Bupivacaine-magnesium<br>Ultrasound-guided suprascapular nerve block using bupivacaine in conjunction of magnesium sulfate will be performed before induction of general anesthesia | Drug: Bupivacaine-magnesium<br>* Ultrasound-guided suprascapular nerve block will be performed using 7 mL of 0.5% bupivacaine plus magnesium sulfate 10% (3 ml) (total 10mL)<br>Drug: Propofol<br>* Using propofol 1.5-2.5 mg/kg<br>Device: Ultrasound<br>* Ultrasound-guided suprascapular nerve block<br>Drug: Sevoflurane<br>* Sevoflurane 0.7-1.5 MAC in 40% oxygen<br>Drug: Rocuronium<br>* Rocuronium 0.6 mg/kg<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Duration of postoperative analgesia | time from administering the study solution in the suprascapular block till the time for the first rescue morphine request | For 8 hours after suprascapular nerve block | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pain score at rest | Pain score as assessed using visual analogue scale to assess the severity of postoperative pain (0 mm for no pain and 100 mm for worst imaginable pain) | time 0 (after extubating) and at 30 minutes, 1 hour , 2 hours, 4hours, 6hours, 8hours,12 hours , 16hours, 20 hours and 24 hours postoperatively | 
| Pain score on shoulder abduction | Pain score as assessed using visual analogue scale to assess the severity of postoperative pain (0 mm for no pain and 100 mm for worst imaginable pain) | time 0 (after extubating) and at 30 minutes, 1 hour , 2 hours, 4hours, 6hours, 8hours,12 hours , 16hours, 20 hours and 24 hours postoperatively | 
| Systolic arterial blood pressure |  | At baseline, immediately after induction of anaesthesia, at skin incision, every 15 minutes till the end of surgery, on arrival to PACU, then at 30, 60 minutes after surgery , every 6 hours up to 24 hours postoperatively | 
| Diastolic arterial blood pressure |  | At baseline, immediately after induction of anaesthesia, at skin incision, every 15 minutes till the end of surgery, on arrival to PACU, then at 30, 60 minutes after surgery , every 6 hours up to 24 hours postoperatively | 
| Heart rate |  | At baseline, immediately after induction of anaesthesia, at skin incision, every 15 minutes till the end of surgery, on arrival to PACU, then at 30, 60 minutes after surgery ,every 6 hours up to 24 hours postoperatively | 
| Intraoperative fentanyl requirements |  | For 5 hours after suprascapular nerve block | 
| Sedation scores | Sedation: will be assessed using a sedation scale (awake and alert= 0; quietly awake= 1; asleep but easily roused= 2; deep asleep= 3). | at 1 hour, 2 hours, and 6 hours postoperatively | 
| The degree of nausea and vomiting | Nausea will be measured using a numerical rating system (none= 0; mild= 1; moderate= 2; severe= 3) | For 24 hours after surgery | 
| Number of vomiting episodes |  | For 24 hours after surgery | 
| Number of antiemetics received |  | For 24 hours after surgery | 
| Postoperative cumulative morphine consumption |  | For 24 hours after surgery |