Effect of Dexamethasone Dose and Route on Duration of Interscalene Block After Outpatient Shoulder Surgery

Study Overview
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Brief Summary
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In this factorial design study, 280 participants having outpatient, arthroscopic shoulder surgery will be randomized into 4 equal sized groups. All participants will receive a standardized interscalene brachial plexus block and 4mg or 8mg of dexamethasone given by the intravenous or perineural (by the nerve with the nerve block) route just prior to their surgery. The purpose of this study is to determine which dose and route of dexamethasone provides the longest duration of pain control and the fewest side effects after surgery. The investigators hypothesize that giving dexamethasone by the perineural route, and by higher doses, will result in the longer durations of pain control, without increased side effects.

Detailed Description
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BACKGROUND & RATIONALE Interscalene brachial plexus blockade (ISB) has emerged as the choice method of analgesia for arthroscopic shoulder surgery performed on an outpatient basis. The ISB is typically administered as a single injection of local anesthetic prior to surgery. Benefits include reduced pain, opioid consumption and postoperative nausea and vomiting on the first postoperative day. However, the limited duration of analgesia with a single injection of local anesthetic, typically 12 to15 hours, is inadequate for many patients. Recent interest in prolonging the analgesic duration of single injection ISB has been focused on the addition of various adjuncts to the local anesthetic, with varying degrees of success. Dexamethasone is the most promising of these adjuncts, with both perineural and intravenous administration consistently resulting in increased analgesic duration, by as much as two-fold. Nevertheless, it would seem prudent to administer perineural adjuncts at the lowest effective dose and only if they offer significant benefit over other routes of administration. The multiple small clinical studies published to date have used dexamethasone doses between 4 and 10mg for both intravenous and perineural routes. Attributing differences in results between any of these studies to the dose and route of dexamethasone administered is not possible due to differences in drugs, doses, study populations and methodology. Most importantly, no study has compared two different doses of dexamethasone and the only two studies that compared the intravenous and perineural routes arrived at different conclusions. Thus, the effect of dexamethasone dose and route on the analgesic duration of interscalene block remains unclear, with multiple recent editorials and meta-analyses calling for further study. In light of these gaps in the evidence, a trial elucidating the effect of dose and route of administration of dexamethasone on analgesic duration of ISB is required. This is the focus of our proposed study. OBJECTIVES AND HYPOTHESES In this factorial design study of outpatients undergoing elective arthroscopic shoulder surgery with interscalene brachial plexus block (ISB), the investigators will compare perineural and intravenous administration of dexamethasone at high (8mg) and low (4mg) doses. The investigators hypothesize that high doses and the perineural route will provide significantly longer duration of analgesia, without significant statistical interaction between dose and route of administration. METHODS This single-centre, factorial design, double-blinded, randomized controlled superiority trial has four parallel groups and 1:1:1:1 randomization. Consenting and eligible adult ambulatory patients undergoing arthroscopic shoulder surgery will receive preoperative, ultrasound guided ISB with 30 millilitres (mL) of 0.5% bupivacaine and 4mg or 8mg of preservative free dexamethasone either intravenous or perineural. The remainder of the intraoperative and postoperative care is at the discretion of the attending anesthesiologist and surgeon. Based on previous work, with 70 patients per group, the study is at least 90% powered to detect a 3 hour difference in analgesia for dose or route, and a 4 hour synergistic interaction, even with a 5% attrition rate. Outcomes will be assessed by chart review and telephone follow up on postoperative day one, postoperative day 2 (if necessary), and postoperative day 14. An interim analysis of group standard deviations only will occur after 100 patients have completed the study to determine if the original power calculations were accurate, and if testing for the interaction effect is feasible within the planned sample size of 280 participants. If testing for the interaction of dose and route is not feasible, a new study sample size will be determined, based on the number of participants needed to have 90% power to test the two main effects. The primary outcome analysis will analyze by intention to treat only those patients who were randomized and did receive an attempt at an interscalene block. A secondary analysis will exclude patients who had a failed inter scalene block in the post anesthesia care unit. A tertiary analysis will be a multivariable analysis adjusted for demographics, preoperative naproxen use, use of general anesthesia, cumulative analgesic use and failed inter scalene block.

Official Title
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Effect of Dexamethasone Dose and Route on Duration of Interscalene Brachial Plexus Block for Outpatient Arthroscopic Shoulder Surgery - A Randomized Controlled Trial

Conditions
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Pain, Postoperative, Disorder of Shoulder

Intervention / Treatment
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* Drug: Dexamethasone
* Drug: Bupivacaine
* Procedure: Interscalene brachial plexus block


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Elective ambulatory surgery patients undergoing arthroscopic shoulder surgery Including rotator cuff repair Stabilization procedures Acromioplasty Debridement and distal clavicle excision Exclusion Criteria: Patient refusal, diabetes Pregnancy Coagulopathy significant enough to be a contraindication to regional anesthesia as determined by the attending anesthesiologist Sensitivity to local anesthetics or dexamethasone Severe chronic obstructive pulmonary disease Contralateral vocal cord paralysis Contralateral diaphragmatic paralysis Surgical limb brachial plexus neuropathy Interscalene block site infection Systemic glucocorticoids in the last 2 weeks Epidural or intraarticular steroid injection in the past 3 months Chronic opioid use defined as daily use for the last two weeks International normalized ratio (INR) > 1.5 Active peptic ulcer disease End-stage renal disease Cirrhotic liver disease Previous participation in the study.

Ages Eligible for Study
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Minimum Age: 18 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: Treatment
Allocation: Randomized
Intervention Model: Factorial Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Low dose intravenous dexamethasone<br>4 milligrams dexamethasone administered once intravenously with a 30 millilitres 0.5% bupivacaine interscalene brachial plexus block | Drug: Dexamethasone<br> <br> Drug: Bupivacaine<br> <br> Procedure: Interscalene brachial plexus block<br>* Performed with real time ultrasound guidance.<br>|
| Active Comparator: High dose intravenous dexamethasone<br>8 milligrams dexamethasone administered once intravenously with a 30 millilitres 0.5% bupivacaine interscalene brachial plexus block | Drug: Dexamethasone<br> <br> Drug: Bupivacaine<br> <br> Procedure: Interscalene brachial plexus block<br>* Performed with real time ultrasound guidance.<br>|
| Active Comparator: Low dose perineurial dexamethasone<br>4 milligrams dexamethasone administered once perineurally with a 30 millilitres 0.5% bupivacaine interscalene brachial plexus block | Drug: Dexamethasone<br> <br> Drug: Bupivacaine<br> <br> Procedure: Interscalene brachial plexus block<br>* Performed with real time ultrasound guidance.<br>|
| Active Comparator: High dose perineurial dexamethasone<br>8 milligrams dexamethasone administered once perineurally with a 30 millilitres 0.5% bupivacaine interscalene brachial plexus block | Drug: Dexamethasone<br> <br> Drug: Bupivacaine<br> <br> Procedure: Interscalene brachial plexus block<br>* Performed with real time ultrasound guidance.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Duration of analgesia after interscalene block | Time from block performance to the first time shoulder pain was experienced after the surgery, rounded to the nearest 0.1 hours, as reported by the participant at telephone follow-up on postoperative day one, or if necessary, postoperative day 2. | Time-to-event outcome measure, assessed up to the end of postoperative day 2 (approximately 60 hours from performance of the block). | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Block Success or Failure | The block will be considered failed if the patient required opioid analgesia for surgical site pain during their stay in the post anesthesia care unit, as determined by the patient's nurse. At our facility, patients are discharged home directly from the post anesthesia care unit. | Assessed at discharge from the post anesthesia care unit, an expected average of 5 hours after the performance of the block. | 
| Severity of pain at the time the primary outcome occurred, measured on an 11-point numerical rating score. | 11-point numerical rating score, with integers from 0 to 10 where 0 represents no pain and 10 represents worst imaginable pain. As reported by telephone follow up. | Assessed at the time that the primary outcome occurs, an expected average of 20 hours after performance of the block. | 
| Cumulative Analgesic Consumption in the post anesthesia care unit, measured as equivalent milligrams of morphine. |  | Change outcome measure: From admission to the post anesthesia care unit (an expected average of 3 hours after performance of the block), to discharge from the post anesthesia care unit (an expected average of 5 hours after performance of the block). | 
| Cumulative Analgesic Consumption from post anesthesia care unit discharge until the time the primary outcome occurred, measured as equivalent milligrams of morphine. |  | Change outcome measure: From discharge from the post anesthesia care unit (an expected average of 5 hours after performance of the block), to the occurrence of the primary outcome (an expected average of 20 hours after performance of the block). | 
| Postoperative Nausea and/or vomiting measured on an 11-point numerical rating score. | 11-point numerical rating score, with integers from 0 to 10 where 0 represents the symptom was completely absent and 10 represents the symptom was present the entire time since arrival to the post anesthesia care unit. | Assessed at telephone follow up on postoperative day one. | 
| First postoperative night Sleep Quality, measured on an 11-point numerical rating score. | 11-point numerical rating score, with integers from 0 to 10 where 0 represents a very poor sleep and 10 represents a very restful night's sleep. | Assessed at telephone follow up on postoperative day one. | 
| Observed postoperative Dyspnea, as recorded in the post anesthesia care unit record. | As observed and recorded by the post anesthesia care unit nurse during the patient's stay in the post anaesthesia care unit. | Assessed at discharge from the post anesthesia care unit, an expected average of 5 hours after performance of the block. | 
| Subjective postoperative Dyspnea, measured on an 11-point numerical rating score. | 11-point numerical rating score, with integers from 0 to 10 where 0 represents the symptom was completely absent and 10 represents the symptom was present the entire time since admission to the post anesthesia care unit. | Assessed at telephone follow up on postoperative day one. | 
| Restlessness and/or Anxiety, measured on an 11-point numerical rating score. | 11-point numerical rating score, with integers from 0 to 10 where 0 represents the symptom was completely absent and 10 represents the symptom was present the entire time since admission to the post anesthesia care unit. | Assessed at telephone follow up on postoperative day one. | 
| Motor and/or Sensory Block Dissatisfaction, measured on an 11-point numerical rating score. | 11-point numerical rating score, with integers from 0 to 10 where 10 represents complete dissatisfaction and 0 represents no dissatisfaction. | Assessed at telephone follow up on postoperative day one | 
| Likelihood of choosing this method of analgesia again, measured on an 11-point numerical rating score. | 11-point numerical rating score, with integers from 0 to 10 where 10 would for sure choose this method again, and 0 represents would for sure not choose this method again. | Assessed at telephone follow up on postoperative day one | 
| Unplanned Postoperative Hospital Admission, as reported at telephone follow up or chart review. | Transfer or admission to hospital during the postoperative period between admission to the post anesthesia care unit and telephone follow up on postoperative day one. | Assessed at telephone follow up and chart review on postoperative day one. | 
| New Persistent Neurologic Symptoms | Patient will be asked whether they are experiencing any tingling, numbness or weakness in the surgical limb, or hoarseness or dyspnea. Patients answering yes to any of the above will be reassessed at 6 months postoperatively. | Assessed at postoperative day 14. | 
| Post anesthesia care unit length of stay in minutes | Amount of time between admission and discharge from the post anesthesia care unit. | Assessed at discharge from the post anesthesia care unit, an expected average of 5 hours after performance of the block. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Shoulder Joint, Arthroscopy, Ambulatory surgical procedures, Pain, Postoperative, Brachial Plexus Block, Corticosteroid, Dexamethasone, Bupivacaine, Perineural