Dexmedetomidine and Desflurane Consumption
Condition: Anesthesia
Study type: Interventional

Summary: 
      The aim of this study is to calculate desflurane consumption when combined with
      intraoperative dexmedetomidine infusion guided by bispectral index (BIS)
    

Detailed description: 
      Forty patients will be randomly allocated into two equal groups as Group 'D' (Dexmedetomidine
      group) and Group 'P' (Placebo group) using computer generated random numbers. After arrival
      in the operating room, ondansetron 0.15 mg/kg intravenous (IV) will be given as a
      pre-medication. Ringer's acetate solution (500 ml) will be infused as a preload then at a
      rate of 6-8 ml/kg/h during surgery for supplying maintenance and deficit. Monitoring
      consisted of continuous electrocardiogram (EKG), non-invasive blood pressure (NIBP), pulse
      oximetry (SpO2), CO2 expired fraction (ETCO2), desflurane inspired fraction (FIdes), and
      desflurane expired fraction (ETdes) (Infinity Kappa, Dräger, Lübeck, Germany) will be
      attached to the patient. BIS module (InfinityR BISxTM SmartPodR, smoothing rate: 15 or 30
      seconds, software revision: VF5) will also be attached for detection of consciousness level.

      All patients will be preoxygenated with 100% oxygen for 3 minutes. The patients in group D
      will receive dexmedetomidine (2 ml diluted in 18 ml of saline) IV in a dose of 1 mcg/kg
      over10 minutes through infusion pump prior to induction. Group P patients will receive
      similar volume of normal saline over 10 min. The study drug and placebo infusions will be
      prepared by an anesthesiologist who is not involved in the study and the anesthesiologist
      recording the details is unaware of the type of infusion patients received. Anesthesia will
      be induced with IV fentanyl 1.5 μg/kg and propofol in a dose of 10 mg every 5 seconds until
      the BIS level dropped below 60 and confirmed with loss of response to verbal commands. In
      both groups, Atracurium 0.5 mg/kg IV will be administered, and trachea will be intubated.
      Fresh gas flow oxygen in air 30-40% at a rate of 3 L/min for 10 minutes will be administered
      then the flow will be decreased at a rate of 1 L/min using a closed system (Fabius GS,
      Dräger, Lübeck, Germany) and ventilation will be adjusted to maintain end-tidal carbon
      dioxide at 30-35 mmHg. Patients in study groups will receive the volatile agent at a
      concentration of 1 MAC (Minimum Alveolar Concentration). The MAC of desflurane is defined as
      an expired fraction of 6.0 vol%. Then the dial-up desflurane percentage will be adjusted to
      establish a BIS value between 40- 50. A maintenance dose of Dexmedetomidine infusion at 0.5
      mcg/kg/hour made to 20 mL with normal saline will be administered in group D patients and a
      similar volume of normal saline will be administered in Group P, till the end of surgery. Top
      up doses of Atracurium will be given as needed. When heart rate and blood pressure exceeds
      20% of baseline in spite of adequate level of anesthesia guided by BIS, boluses of 0.5 μg/kg
      will be given. While decrease in heart rate and blood pressure more than 20% of baseline,
      will be treated by ephedrine 5 mg.

      In both groups, dexmedetomidine or saline will be stopped approximately 15-20 minutes before
      completion of surgery, diclofenac sodium 1 mg/kg will be given IM at the time of skin
      closure. Desflurane will be discontinued after skin closure in both groups. Reversal of
      neuromuscular blockade will be achieved with neostigmine 0.05 mg/kg and atropine 0.02 mg/kg.
      Tracheal extubation will be done when respiration is satisfactory and adequate muscle tone is
      achieved
    

Intervention name(s): Dexmedetomidine; Placebo; Ondansetron; fentanyl; propofol; Atracurium; diclofenac sodium; desflurane
Intervention type(s): Drug; Drug; Procedure; Procedure; Procedure; Procedure; Procedure; Procedure
Intervention description(s): A maintenance dose of Dexmedetomidine infusion at 0.5 mcg/kg/hour made to 20 mL with normal saline will be administered; A maintenance dose of 20 mL with normal saline will be administered at a rate similar to that of dexmedetomidine; 0.15 mg/kg intravenous (IV) will be given as a pre-medication; 1.5 μg/kg intraoperative; 10 mg every 5 seconds until the BIS level dropped below 60 for induction of anesthesia; 0.5 mg/kg IV for endotracheal intubation; 1 mg/kg for postoperative analgesia; 1 MAC concentration (expired fraction of 6.0 vol%) for maintenance of anesthesia
Other intervention name(s): Precedex; Dexdor; placebo effect; Zofran; Sublimaze,Actiq, Durogesic, Duragesic; Diprivan; Atracurium besilate; Voltaren; Suprane
Intervention MeSH terms: Diclofenac; Fentanyl; Dexmedetomidine; Ondansetron; Propofol; Desflurane; Atracurium
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Care Provider)
Primary purpose: Treatment
Keywords: Dexmedetomidine; Desflurane; Bispectral Index BIS