Ultrasound Guidance for Interscalene Brachial Plexus Block
Condition: Shoulder; Orthopedic Surgery; Nerve Block
Study type: Interventional
Phase: Phase 4

Summary: 
      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: 
      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.
    

Intervention name(s): Ultrasound-guided continuous interscalene brachial plexus block; Continuous interscalene brachial plexus block using electrical nerve stimulation; Ropivacaine; Paracetamol; Morphine; Fentanyl; General anesthesia
Intervention type(s): Procedure; Procedure; Drug; Drug; Drug; Drug; Procedure
Intervention description(s): 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.; 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.; 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; 1 g iv q8h; 5 mg im prn q1h (in the postoperative period); 50 µg iv prn (in the intraoperative period); 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.
Other intervention name(s): Peripheral nerve block; Ultrasound; Regional anesthesia; Peripheral nerve block; Electrical nerve stimulation; Regional anesthesia; Naropin; Local anesthetic; Amide local anesthetic; Acetaminophen; Perfalgan; Analgesic; Opioid; Narcotic; Analgesic; Opioid; Narcotic; Analgesic; Monitored anesthesia care
Intervention MeSH terms: Acetaminophen; Fentanyl; Morphine; Analgesics, Opioid; Narcotics; Analgesics; Anesthetics; Ropivacaine; Anesthetics, Local
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Treatment
Keywords: Analgesia, Patient-controlled; Anesthesia, Regional; Ultrasound; Postoperative Pain; Brachial Plexus