Ultrasound Guidance for Interscalene Brachial Plexus Block

Study Overview
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Brief Summary
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This study has been designed to assess the possible advantages of using ultrasound imaging to block the brachial plexus (i.e., nerves of the upper limb) in patients undergoing shoulder surgery. The ultrasound technique will be compared with the current gold standard, electrical nerve stimulation. The aim of this study is to define which technique is better in terms of time to onset of anesthesia.

Detailed Description
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The study will compare real-time ultrasound (US) guidance and electrical nerve stimulation (ENS) in terms of onset time for interscalene brachial plexus anesthesia. The main hypothesis is that direct visualization of neural structures under US guidance will grant better local anesthetic (LA) disposition around the roots of the plexus, thus improving onset times. Perineural catheters will be used to maintain regional analgesia for 48 hours after surgery. We hypothesize that US guidance may also help physicians place perineural catheters more precisely, thus improving analgesia in the following hours to days. Finally, we will investigate for possible differences in minor adverse events such as vascular puncture, pain during the anesthetic procedure.

Official Title
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Ultrasound Guidance or Electrical Nerve Stimulation for Interscalene Brachial Plexus Block: a Randomized, Controlled Trial

Conditions
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Shoulder, Orthopedic Surgery, Nerve Block

Intervention / Treatment
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* Procedure: Ultrasound-guided continuous interscalene brachial plexus block
* Procedure: Continuous interscalene brachial plexus block using electrical nerve stimulation
* Drug: Ropivacaine
* Drug: Paracetamol
* Drug: Morphine
* Drug: Fentanyl
* Procedure: General anesthesia


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ASA Physical Status Class I-III Elective surgery of the shoulder Informed consent to regional anesthesia Exclusion Criteria: Inability to effectively communicate Chronic opioid use Absence of informed consent to participation to the study Ipsilateral upper limb neurological deficits Known allergy to study medications Contraindications to continuous block placement

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 85 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: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: US Group<br>In this group, the continuous block will be performed under real-time ultrasound (US) guidance. | Procedure: Ultrasound-guided continuous interscalene brachial plexus block<br>* With patients in the supine position, a high-frequency (10-12 MHz) ultrasound transducer in a sterile sheath will be applied to explore the interscalene region and locate the brachial plexus. The transducer will be positioned so as to image the C5 and C6 roots in a single view. Visualization of the C7 root in the same scan will be sought, but will not be required. A 50-mm, 20 G needle will be advanced in-plane from the postero-lateral side of the transducer. Injection of the local anesthetic will be performed in small aliquots while repositioning of the needle in order to optimize spread of the injectate around the nerve roots. At the end of the injection, a catheter will be threaded through the needle. The catheter will be positioned to lie deep and close to the imaged nerve roots.<br>* Other names: Regional anesthesia;Drug: Ropivacaine<br>* Block induction [1% (wt/vol) solution]: 20 ml (200 mg) Postoperative analgesia [0.2% (wt/vol) solution]: Background infusion: 4 ml/h (8 mg/h) Incremental on-demand dose: 2 ml (4 mg) Lockout time: 15 min<br>* Other names: Amide local anesthetic;Drug: Paracetamol<br>* 1 g iv q8h<br>* Other names: Analgesic;Drug: Morphine<br>* 5 mg im prn q1h (in the postoperative period)<br>* Other names: Analgesic;Drug: Fentanyl<br>* 50 µg iv prn (in the intraoperative period)<br>* Other names: Analgesic;Procedure: General anesthesia<br>* Will be given in case of block failure and/or patient discomfort intractable with fentanyl during the procedure. The technique will be left at the discretion of the attending anesthesiologist. Monitored anesthesia care will also be acceptable; the block will be considered as failed in that case as well.<br>* Other names: Monitored anesthesia care;|
| Active Comparator: ENS Group<br>In this group, the continuous block will be performed with an electrical nerve stimulation (ENS) technique. | Procedure: Continuous interscalene brachial plexus block using electrical nerve stimulation<br>* With patients in the supine position, the head will be rotated to the contralateral side. The interscalene groove will be palpated. A 35-mm, 20 G needle will be inserted at the estimated C6 level (cricoid cartilage) with a 30-45° angle to the skin. The needle will be advanced along a line joining the insertion site to the axilla. An electrical nerve stimulator will be used at an initial intensity of 1.0 mA (frequency: 2 Hz, pulse width: 0.2 ms). A musculocutaneous or axillary-nerve mediated twitch will be sought Injection of the local anesthetic will start with a visible motor response at a current <0.5 mA. The catheter will be positioned to as to elicit a motor response at ≤0.4 mA.<br>* Other names: Regional anesthesia;Drug: Ropivacaine<br>* Block induction [1% (wt/vol) solution]: 20 ml (200 mg) Postoperative analgesia [0.2% (wt/vol) solution]: Background infusion: 4 ml/h (8 mg/h) Incremental on-demand dose: 2 ml (4 mg) Lockout time: 15 min<br>* Other names: Amide local anesthetic;Drug: Paracetamol<br>* 1 g iv q8h<br>* Other names: Analgesic;Drug: Morphine<br>* 5 mg im prn q1h (in the postoperative period)<br>* Other names: Analgesic;Drug: Fentanyl<br>* 50 µg iv prn (in the intraoperative period)<br>* Other names: Analgesic;Procedure: General anesthesia<br>* Will be given in case of block failure and/or patient discomfort intractable with fentanyl during the procedure. The technique will be left at the discretion of the attending anesthesiologist. Monitored anesthesia care will also be acceptable; the block will be considered as failed in that case as well.<br>* Other names: Monitored anesthesia care;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Onset time of brachial plexus anesthesia |  | ≤30 min | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Successful brachial plexus anesthesia |  | ≤30 min | 
| Additional analgesic requirements during surgery |  | Duration of surgery | 
| Incidence of paresthesiae during the anesthetic procedure |  | ≤30 min | 
| Incidence of blood aspiration during the anesthetic procedure |  | ≤30 min | 
| Number of needle redirections for the performance of the block |  | ≤30 min | 
| Pain during performance of the block |  | ≤30 min | 
| Pain at rest and on movement (visual analog scale) |  | q8h until 48 h after surgery | 
| Local anesthetic consumption on patient-controlled pump |  | ≤48 h | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Analgesia, Patient-controlled, Anesthesia, Regional, Ultrasound, Postoperative Pain, Brachial Plexus