Can Dexmedetomidine For Procedural Sedation In Knee Arthroplasty Reduce Postoperative Pain? A Randomized Control Study
Condition: Total Knee Arthroplasty
MeSH terms: Pain, Postoperative
Study type: Interventional
Phase: Phase 4

Summary: 
      Dexmedetomidine has been often used for procedural sedation. It has also has been shown to
      have a pain sparing effect. Therefore the investigators propose that if Dexmedetomidine is
      used for sedation in total knee replacements done under spinal anesthetic, the patients will
      have less pain up to 24 hours after the procedure.
    

Detailed description: 
      Randomization will occur prior to patient being brought into operating room (by pharmacy or
      by the anesthesia research coordinator). A third anesthetist not involved in the project will
      mix up the syringe based on instructions in an opaque envelope, and provide the syringe to
      the attending anesthetist.

      The current standard of care entails patients receiving a midazolam bolus for sedation during
      the operation. The investigators propose to substitute a syringe of dexmedetomidine or saline
      to be run as an infusion throughout the case for sedation. A midazolam bolus will be
      available at anesthetist discretion to achieve a moderate sedation score as defined by the
      American Society of Anesthesia.

      Standardized Medication Protocol

      Pre-op:

      Tylenol and Naproxen

      Spinal:

      Marcaine .75%, 1.7cc (12.75mg) Fentanyl 10 micrograms

      Sedation

        1. st arm- Dexmedetomidine, drawn up into a 50cc syringe of saline, thereby making it
           5ug/ml.

        2. nd arm- Receives Normal Saline syringe

      Plan for bolus of 0.5microgram/kg over 10 minutes, and then infusion of 0.5 microgram/kg/hr
      (Can be titrated from 0.2-0.7 microgram per kg per hr to achieve moderate sedation as defined
      by the ASA

      Both groups will have a midazolam 0.5mg prn q 5minutes to be used as a rescue to achieve
      moderate sedation.

      Post op- Initial setting of patient-controlled-analgesia pump to be set at morphine 1 mg,
      lockout of 8 minutes, to be increased to 1.5 mg with lockout of 6 minutes if pain not
      controlled. The investigators will increase the pump dose by 0.5 mg/dose/1 hr until pain
      controlled.

      Risks The most common treatment-emergent adverse reactions for dexmedetomidine, occurring in
      2% of patients in both ICU and procedural sedation studies, include- Hypotension, Bradycardia
      and Dry mouth. To minimize the risks to participants, an anesthesiologist will always be
      present in the room while the infusion is running, will monitor the patient, and will be
      allowed to treat as they see fit any of these risks.

      Data Collection Data collection will be performed primarily by Ian Chan, anesthesiology
      resident.

      Primary Outcome:

      Total morphine consumption in the first 24 hours
    

Intervention name(s): Dexmedetomidine; Normal Saline Placebo
Intervention type(s): Drug; Drug
Intervention MeSH terms: Dexmedetomidine
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Treatment