Dexmedetomidine Versus Propofol in Vitreoretinal Surgery
Condition: Retinal Detachment
MeSH terms: Retinal Detachment
Study type: Interventional
Phase: Phase 4

Summary: 
      The investigators would like to determine if using Dexmedetomidine alone or in a reduced dose
      can prevent or reduce the incidence of adverse effects, while providing adequate sedation,
      and respiratory stability as compared to propofol.
    

Detailed description: 
      Alpha2 adrenergic receptor agonist have been used increasingly as a new armamentarium to
      provide sedative/hypnotic, analgesic, anxiolytic and sympatholytic effects in the
      perioperative settings. Dexmedetomidine, a selective and specific alpha2- adrenoceptor
      agonist has unique properties that makes it an almost ideal sedative drug for monitored
      anesthesia care in procedures under local or regional block. Unlike other drugs use for
      sedation, dexmedetomidine induces sedation that is similar to natural sleep (readily
      arousable) without causing respiratory depression. It attenuates the stress-induced
      sympathoadrenal response seen with laryngoscopy and intubation. It has anesthetic and opioid
      sparing effects, hence it may be a useful adjunct to general anesthesia and monitored
      anesthesia care in patients susceptible to narcotic induced respiratory depression. Another
      unique property of dexmedetomidine is that its sedative effect is reversible with
      Atipamezole. A previous study wherein dexmedetomidine has been used in procedures under local
      and regional block had shown that it provides effective sedation and better operating
      condition without significant respiratory depression. As a supplement to general anesthesia,
      it has been shown to provide stable hemodynamics. However, it is associated with some adverse
      events such as hypertension, hypotension and bradycardia, these commonly occur during bolus
      administration of the recommended dose of 1ug/kg. Post-operatively it can cause nausea and
      vomiting. Vitreoretinal surgery requires either an injection of local anesthetic within the
      muscle cone (retrobulbar block),or into the periorbital space (peribulbar block). This can be
      done individually or in combination. This surgery can also be done under a safer technique of
      retrobulbar block that is given using a sub-tenon's approach through a snip peritomy; a blunt
      cannula can be used with this technique mitigating the complications of retrobulbar
      hemorrhage or inadvertent injection into the optic nerve sheath or perforation of the globe
      using a sharp needle. The anesthetic goal is to provide an immobile and uncongested operative
      field. Hemodynamic stability of the patient is also important since some patients that
      require this procedure are elderly with co-morbid conditions such as hypertension, diabetes
      mellitus and Coronary Artery Disease (CAD). In our study we would like to investigate if
      Dexmedetomidine alone and in a reduced dose can prevent or reduce the incidence of adverse
      effects, provide hemodynamic and respiratory stability, provide adequate sedation with
      patient and surgeon satisfaction and compare it with Propofol.

      Objectives:

      Primary:

        1. Adequate sedation

        2. Hemodynamic and respiratory stability intraoperatively

      Secondary:

        1. surgeon satisfaction

        2. Time to achieved " street fitness " status

        3. subject satisfaction

        4. Hemodynamic stability in PACU
    

Intervention name(s): Dexmedetomidine infusion; propofol
Intervention type(s): Drug; Drug
Intervention description(s): bolus of 0.5ug/kg intravenously over a period of 10-15 minutes, followed by an infusion of 0.2-0.7ug/kg/hr of drug; propofol 1mg/kg intravenously as a bolus followed by 25-100ug/kg/min
Other intervention name(s): Precedex infusion; Diprivan
Intervention MeSH terms: Dexmedetomidine; Propofol
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Triple (Participant, Care Provider, Outcomes Assessor)
Primary purpose: Treatment
Keywords: sedation for vitreoretinal surgery