Supraclavicular Brachial Plexus Block Using Ropivacaine Alone and With Dexmedetomidine
Condition: Brachial Plexus Anesthesia
Study type: Interventional

Summary: 
      80 American Society of Anesthesiologists (ASA) grade I-II patients, 18-60 years old,scheduled
      for elective upper limb orthopaedic surgery under supraclavicular brachial plexus block, were
      included in this prospective study. The patients were randomly assigned to group R
      (Ropivacaine alone) and group RD (Ropivacaine and dexmedetomidine) (40 patients in each
      group). Group R received Ropivacaine 0.50% (30 cc) + placebo and group RD received
      Ropivacaine 0.50% (30 cc) + dexmedetomidine 1 µg/kg.
    

Detailed description: 
      After Institutional Ethical Committee approval and written informed consent, a prospective,
      randomized, double-blinded study was carried out on 80 ASA Grade I and II patients of either
      sex, aged 18-60 years, undergoing various orthopaedic surgeries on the upper limb under
      supraclavicular brachial plexus block. A power analysis was performed to determine the
      necessary number of patients for each group based on duration of analgesia. With a 2-sided
      type I error of 5% and study power at 80%, it was estimated that 38 patients would be needed
      in each group in order to detect a difference of 35 min in the duration of analgesia between
      the 2 groups. The study was conducted in two groups of 40 patients each. Patients were
      randomly chosen by computer-generated random selection to one of the following groups:

      Group R: Ropivacaine 0.50% (30 cc) + Placebo Group RD: Ropivacaine 0.50% (30 cc) +
      Dexmedetomidine 1 µg/kg Randomization was performed by an independent statistician and
      concealed from patients and investigators until completion of statistical analysis. Patients
      were instructed preoperatively about use of the verbal rating scale (VRS) for pain assessment
      (VRS: 0 = no pain, 10=worst pain possible). On arrival in the operation room, baseline heart
      rate, blood pressure and oxygen saturation were recorded. An intravenous line was secured in
      the unaffected limb and Ringer's lactate was started. Patients were given midazolam
      intravenous (IV) (0.03 mg/kg) as premedication 10-15 min before beginning each blocks
      technique. Subcutaneous injection with 2 mL of 2% lidocaine was administered at the needle
      insertion site. All the patients received brachial plexus block through the supraclavicular
      approach by an experienced anesthesiologist different from the one assessing the patient
      intra- and post-operatively. Both were blinded to the treatment groups. Neural localization
      was achieved by using a nerve locator (Stimuplex® Dig RC, B.Braun, Melsungen AG, Melsungen,
      Germany) connected to a 22 G, 50-mm-long stimulating needle (Stimuplex, Braun, Germany). The
      location end point was a distal motor response with an output lower than 0.5 milliampere
      (mA).

      Following negative aspiration, 30 mL of a solution containing local anesthetic combined with
      placebo or dexmedetomidine as mentioned above was injected and the use of Dexmedetomidine was
      off-label. A 5-min compression was performed to facilitate an even drug distribution. Sensory
      blockade was assessed every 3 min and motor block was evaluated every 5 min within the first
      30 min following completion of drug administration. Sensory block was confirmed by pinprick
      sensation using a 23-G needle in all dermatomes of the brachial plexus (C5-T1) i.e. median
      nerve, radial nerve, ulnar nerve and musculocutaneous nerve. Sensory onset was considered
      when there was a dull sensation to pin prick along the distribution of any of these nerves
      (Grade 1). Complete sensory block was considered when there was complete loss of sensation to
      pin prick.

      Sensory block was graded as- Grade 0 Sharp pin felt Grade 1 Analgesia, dull sensation felt
      Grade 2 Anesthesia, no sensation felt

      Motor blockade was evaluated by the ability to flex the elbow and hand against gravity as
      follows :

      Grade 1 Ability to flex and extend the forearm Grade 2 Ability to flex or extend only the
      wrist and fingers Grade 3 Ability to flex or extend only the fingers Grade 4 Inability to
      move the forearm, wrist, and fingers Onset of motor block was defined as the time from
      injection of local anesthetic mixture until achieving a reduction in motor power to grade 3
      or less. The block was considered incomplete when any of the segments supplied by median,
      radial, ulnar and musculocutaneous nerve did not have analgesia even after 30 min of drug
      injection. These patients were supplemented with intravenous fentanyl (2 μg/ kg) and
      midazolam (0.03 mg/kg). When more than one nerve remained unaffected, it was considered a
      failed block. In this case, general anesthesia was given intraoperatively. Patients were
      monitored for hemodynamic variables such as heart rate, blood pressure and oxygen saturation.
    

Intervention name(s): Ropivacaine; Ropivacaine with Dexmedetomidine
Intervention type(s): Drug; Drug
Intervention description(s): Ropivacaine 0.5% 30 ml was used to block brachial plexus; Dexmedetomidine 1 microgram per kilogram bodyweight was added with 30 ml 0.5% Ropivacaine to block brachial plexus
Other intervention name(s): Ropin; Ropin with Dextomid
Intervention MeSH terms: Dexmedetomidine; Ropivacaine
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Investigator)
Primary purpose: Supportive Care