Intra- Versus Extraplexic Catheter Placement for Continuous Interscalene Brachial Plexus Block
Condition: Shoulder Pain; Regional Anesthesia Morbidity; Shoulder Arthritis
MeSH terms: Shoulder Pain
Study type: Interventional
Phase: Phase 4

Summary: 
      Continuous interscalene brachial plexus block consists of inserting a catheter directly
      within the brachial plexus in the interscalene groove, between the middle and anterior
      scalene muscles, which is then infused with local anesthetic. This technique provides potent
      and site-specific analgesia for several days after major shoulder surgery, along with
      increased shoulder range of motion. A major side-effect of this procedure is the paralysis of
      the ipsilateral diaphragm, which is the main muscle of the respiration. This paralysis occurs
      at a rate of 90 to 100%, and is due to the spread of the local anesthetic towards the phrenic
      nerve, lying anteriorly to the plexus, between the sternocleidomastoid and anterior scalene
      muscles. Therefore, many patients suffering from respiratory syndromes, such as chronic
      obstructive pulmonary disease, will not have a continuous interscalene brachial plexus block,
      thus forfeiting some, or all, of the aforementioned benefits associated regional anesthesia.

      It is conventionally taught to place the needle tip between the nerve roots of the brachial
      plexus to obtain an effective block (intra-plexic injection). Recently, we have published a
      new technique of single-shot injection for interscalene brachial plexus block where the
      needle tip was positioned at a distance of 4 mm of the lateral part of the brachial plexus
      (extra-plexic injection) and resulted in a reduction rate of 70% of hemidiaphragmatic paresis
      and a preservation of spirometric values, while providing similar analgesia, when compared to
      a conventional injection. Contrary to single-shot injections where high volume and high
      concentration of local anesthetics are injected (eg, ropivacaine 0.5%, 20 mLs), continuous
      blocks required low volume and low concentration (eg, ropivacaine 0.1-2%, 2-6 mLs/h) and
      therefore the aforementioned concept of extra-plexic technique might not be suitable.

      Recently, new catheter-over-the needle (Contiplex® C; B. Braun Melsungen AG, Germany) have
      been released on the market and allows the physician to place the catheter tip exactly where
      he desires, contrary to the previous generations where the catheters were inserted blindly,
      despite the use of ultrasound.

      The first objective of that randomised controlled trial is to demonstrate that an
      extra-plexus catheter placement produces less respiratory complications than an intra-plexus
      catheter placement. The second objective is to confirm that both techniques provide similar
      analgesia.
    

Detailed description: 
      Patients will be brought to the block room theatre. Before nerve blockade, standard
      monitoring including non-invasive blood pressure, electrocardiogram, and pulse oximetry will
      be applied and IV access established. Sedation and anxiolysis will be achieved with IV
      midazolam (incremental doses of 1 mg) and IV fentanyl (incremental doses of 25 µg).

      Continuous interscalene brachial plexus block will be performed with the patient lying
      lateral on the non-operative side. The ultrasound probe will be placed in the interscalene
      region to visualize the carotid artery and brachial plexus in the transverse sectional view
      as is routine in our institution. The C5-C6-C7 roots will be identified following the
      description of Martinolo et al. After sterilization and injection of local anesthetic (1-2%
      lidocaine) into the skin, a catheter-over-the-needle (Contiplex® C; B. Braun Melsungen AG,
      Germany) will be placed on the lateral side of the probe and advanced along the long axis of
      the probe in the same plane as the ultrasound beam. For patients in the intra-plexus group,
      the catheter tip will be positioned beyond the sheath, between C5 and C6 roots. In the
      extra-plexus group, the catheter tip will be positioned 2 mm away from the lateral sheath of
      the brachial plexus. After the injection of dose-test to exclude an intravascular placement,
      twenty milliliters of local anesthetic containing ropivacaine 0.5% will be injected over 3-5
      min under ultrasound visualization.

      Intraoperative and postoperative procedure After application of routine monitors in the
      operating theatre, patients will receive a standard general anesthetic. Anesthesia will be
      induced using fentanyl 1-2 µg/kg IV and propofol 2-4 mg/kg IV with endotracheal intubation
      facilitated by rocuronium 0.6 mg/kg IV. Maintenance of anesthesia will be ensured via inhaled
      sevoflurane 1.6-2.5% in a 40:60 mixture of oxygen and air. Positive pressure ventilation will
      be initiated with tidal volume and rate adjusted to maintain an end-tidal PCO2 of 30-40 mmHg.
      Fentanyl will be administered as needed to treat increases in blood pressure and/or heart
      rate of more than 15% above pre-induction baseline values. Prophylaxis of postoperative of
      nausea and vomiting will be performed with dexamethasone 0.15 mg/kg after the induction,
      droperidol 1 mg and ondansetron 4 mg at the end of the surgery, as per routine practice in
      our institution. Muscle relaxation will be antagonized with neostigmine 50 µg/kg and
      glycopyrrolate 5-10 µg/kg routinely.

      During postoperative recovery in hospital, pain (Numeric rating scale [NRS] ≥ 4 or patient
      request for analgesia) will be treated with morphine 2 mg every 10 min as needed, and the
      ropivacaine 0.2% infusion will be set at a rate of 2 ml/h with bolus of 4 ml available every
      30 minutes, as per our routine institutional practice. Once oral intake will be initiated,
      patients will receive acetaminophen 1000 mg PO every 6 h and breakthrough oxycodone 5 mg per
      os (PO) as needed, max 8 times. On the ward, infusion rate of ropivacaine will be increased
      to 4 ml/h and then 6 ml/h in case of pain scores ≥ 4. The catheter will be removed on the
      morning of postoperative day 3.

      On postoperative day 1, 2, 3, and 4 a blinded research assistant will visit patients and
      record data. Patients will also be contacted on postoperative day 30 to capture any
      block-related complications such as persistent paresthesia, weakness, bruising, or
      non-surgical pain in the operative extremity.

      All these managements represent the current standard of care at Centre Hospitalier
      Universitaire Vaudois.

      Measurement of respiratory outcomes Diaphragmatic movement will be assessed by real-time
      M-mode ultrasonography on each side using a curvilinear 2 - 5 MHz US probe, following
      previous published descriptions. Patients will be examined in the lying position and scanned
      from a low intercostal or subcostal approach using the liver or spleen as an acoustic window.
      The range of diaphragmatic movement from the resting expiratory position (functional residual
      capacity) to deep and quiet inspiration (sigh test) will be recorded as will the range of
      diaphragmatic movement from resting expiratory position when quickly inspirating through the
      nose (sniff test). The movement of the diaphragm will be measured in centimeters.

        -  diaphragmatic movement reduction of more than 75%, no movement, or paradoxical movement
           will be considered to be " complete paresis " ;

        -  diaphragmatic movement reduction of both sigh and sniff test between 25% and 75% will be
           considered to be " partial paresis " ;

        -  diaphragmatic movement of less than 25% will be considered to be " no paresis ".

      Normal caudad movement will be designated as positive, whereas paradoxical cephalad movement
      will be designated as negative. Each test will performed 3 times, and values will be
      averaged. All measurements will be performed before the surgery (baseline), after the surgery
      in phase 1 recovery (postanesthetic care unit) and on postoperative day 1.

      A bedside spirometer (EasyOneTM Spirometer; ndd Medical Technologies, Andover, UK) will be
      used to assess ventilatory function (pulmonary function tests). After instructions, the full
      vital capacity (VC) in lying and sitting upright positions will be measured. Other
      measurements performed in patients in upright sitting position will be forced expiratory
      volume at 1 sec (FEV1), forced vital capacity (FVC), and peak expiratory flow (PEF); the
      tests will be repeated 3 times. The best value will be recorded.

      All measurements will be performed before the surgery (baseline), after the surgery in phase
      1 recovery (postanesthetic care unit) and on postoperative day 1, 2, 3 and 4.

      The percent fall of vital capacity from sitting to supine position will be considered as an
      index of diaphragmatic dysfunction.
    

Intervention name(s): Intraplexic catheter location (Contiplex® C, B. Braun Melsungen, AG); Extraplexic catheter location (Contiplex® C, B. Braun Melsungen, AG)
Intervention type(s): Procedure; Procedure
Intervention description(s): The catheter tip will be placed with the aid of the ultrasound within the brachial plexus between C5 and C6; The catheter tip will be placed with the aid of the ultrasound 2 mm away from the lateral part of the brachial plexus
Other intervention name(s): Contiplex® C, B. Braun Melsungen, AG; Contiplex® C, B. Braun Melsungen, AG
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Primary purpose: Treatment