Effect of Intravenous Dexmedetomidine on Analgesic Duration of Infraclavicular Block
Condition: Postoperative Pain
MeSH terms: Pain, Postoperative
Study type: Interventional

Summary: 
      The study will evaluate the effect of Dexmedetomidine sedation on the duration of
      infraclavicular block in patients scheduled for surgery of elbow, forearm and/or hand. All
      patients will receive infraclavicular block before the surgery and then they will be
      randomized to receive either Dexmedetomidine or Propofol sedation. Duration of the sensory
      block will be evaluated in recovery room, 24 and 48 hours after the surgery.

      Hypothesis:

      Primary: Dexmedetomidine sedation increases the duration of sensory infraclavicular block in
      patients scheduled for upper limb surgery.

      Secondary: Dexmedetomidine sedation

        -  Gives an adequate level of sedation during the surgical procedure

        -  Reduces the requirements of postoperative opioids

        -  Improves the quality of sleep on the night of the surgery

        -  Increases patients satisfaction regarding the anesthesia technique

        -  Dexmedetomidine sedation is safe and easy to use

        -  Dexmedetomidine sedation provides less respiratory depression during the procedure.
    

Detailed description: 
      Methodology:

      Study design A randomized, prospective, double blind study.

      Patient groups Group 1 (control group) This group will have infraclavicular block and
      sedation during surgery with intravenous Propofol.

      Group 2 (intervention group) This group will have infraclavicular block and sedation with
      intravenous Dexmedetomidine.

      Recruitment and Informed consent: Recruitment will take place in the preoperative clinic or
      surgical day care unit.

      Duration of study: We estimate that 3 patients per week will be eligible and agree to
      participate. One year should therefore provide adequate time for study completion.

      Data analysis:

      Descriptive statistics will be used to present baseline characteristics for the two groups.

      T-test or Mann-Whitney U- test will be used to compare these baseline values between the two
      groups. Quantitative data like pain scores and narcotic consumption will be compared using
      repeated measures ANOVA within the groups and two tailed unpaired t-test between groups (or
      Mann- Whitney-U test if skewed distribution). The nonparametric data will be analyzed using
      Chi squared test. P less than 0.05 will be considered statistically significant. Continuous
      variables will be assessed for normality and will be presented as mean (SD) or median with
      interquartile range (IQR) as appropriate. Categorical variables will be assessed using
      frequency tables and Fisher's exact test. The interval between the onset of the sensory block
      and first analgesic request will be analyzed by Kaplan-Meier survival analysis.

      Protocol: The study will be performed on patients undergoing ambulatory hand, forearm or
      elbow surgery. After informed consent, the patients will be randomized to a study group using
      a computer generated random number table and sealed envelope technique. Following this the
      patients will be taken to the block room for performing the infraclavicular block, using
      standard monitors that will include non-invasive blood pressure, electrocardiogram and pulse
      oximetry.

      All patients will receive ultrasound guided infraclavicular block with the standard protocol
      of the Block Room in St. Joseph Hospital. After the block, the patient will be moved to the
      operating room for the surgery where sedation with Dexmedetomidine or Propofol will be
      started as per the randomization. In order to blind the patient, the syringe and tubing will
      be covered with towels. The patients will be allocated to one of the two groups:

      Group 1: Patients will receive intravenous Dexmedetomidine sedation bolus 0.5mcg/kg in 10
      minutes and then 0.2-0.5 mg/kg/hr infusion. The infusion will be stopped 15 minutes before
      the end of surgery.

      Group 2: Patients will receive intravenous Propofol sedation 50-100 mcg/kg/min infusion. The
      infusion will be stopped 15 minutes before the end of surgery.

      Sedation score and hemodynamic profile during the surgery will be recorded every 15 minutes.
      Oxygen will be provided through facial mask. Total dose of narcotic used will be recorded.

      After the surgical procedure, patients will be moved to the Post Anesthetic Care Unit (PACU),
      where an independent blinded observer not involved in the performance of the block or
      intraoperative care of the patient, will follow up the patients in the postoperative period.

      The patients will be assessed for the site and severity of pain at rest at the arrival in the
      PACU. Pain score will be the Numerical Rating Score (NRS) on a scale of 0 to 10 where 0 is no
      pain and 10 the worst pain ever experienced. Data regarding duration of surgery and the
      duration of stay in PACU will also be collected from the nursing records. Opioids requirement
      in PACU will also be collected from these records. Complications, if any will be noted.

      The patients will be assessed for pain at the surgical site at the time of discharge from
      PACU. They will also be given a diary to take home. Patient will be educated regarding the
      NRS and asked to record in the diary after discharge from the PACU until 20:00 hours. They
      will also be asked to record when they require first analgesic dose, the time of return of
      sensation in dorsal area of the hand/finger and also the time when they are able to extend
      the wrist.

      Patients will be instructed to take their oral rescue analgesic once the pain is score >5/10.

      Patients will be contacted by phone 24 hours and 48 hours after their time of arrival in PACU
      (time 0). They will be reminded regarding entry in the diary. They will also be asked about
      quality of sleep.

      Patient satisfaction will be documented at 24 and 48 hours on a visual analogue scale where 0
      is totally dissatisfied and 100 is totally satisfied.

      The total participation time for the patients is for 2 days.

      Sample size estimation The sample size is calculated for the primary outcome measure, which
      is the duration of the sensory block.

      The duration of sensory infraclavicular block when the local anesthetic is Ropivacaine is 402
      (± 183) minutes (Abdallah et al. Anesthesiology 2016; 124:683-95). With an equivalence limit
      (d) of 180 minutes and the calculation of the sample size with the following formula:

      n = f(α, β) × 2 × σ2 / d2 (non-inferiority) and n = f(α/2, β) × 2 × σ2 / (μ1 - μ2)2
      (superiority) This showed 27 patients per group (non-inferiority) and 32 patients per group
      (superiority), were required to ensure adequate sample size with an α of 2.5% and 95% power.
      We plan to have 50 patients per group, considering a high non-compliance rate.

      Randomization: This will be performed using a computer generated randomization and closed
      envelope system. Patients will be randomized on the day of the surgical procedure. This study
      will be double blind because patients, anesthesiologist performing the infraclavicular block
      and the evaluator in the postoperative setting will not know the allocation group. The
      anesthesiologist providing the sedation in the Operating Room will prepare the sedative
      agents (Propofol and/or Dexmedetomidine) and will cover the infusions with drapes (Propofol
      is a white solution, the only way to hide it is to cover it with drapes). This person will
      not be blinded but will also not be part of the study.
    

Intervention name(s): Dexmedetomidine; Propofol; Infraclavicular block
Intervention type(s): Drug; Drug; Procedure
Intervention description(s): Intravenous sedation with dexmedetomidine; Intravenous sedation with propofol; All patients will receive ultrasound guided infraclavicular block with the standard protocol of the Block Room in St. Joseph Hospital.
Other intervention name(s): Precedex
Intervention MeSH terms: Dexmedetomidine; Propofol
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Primary purpose: Treatment
Keywords: Dexmedetomidine sedation; Regional Anesthesia; Infraclavicular block