Automated Closed Loop Propofol Anaesthesia Versus Desflurane Inhalation Anaesthesia In Bariatric Surgery
Condition: Anesthesia; Bariatric Surgery
MeSH terms: Respiratory Aspiration
Study type: Interventional
Phase: Phase 4

Summary: 
      Complete recovery from anaesthesia is absolutely desirable in the obese patients to avoid
      postoperative airway, oxygen ventilation or sleep apnea related complications. Over the
      years, Desflurane has emerged as the anaesthetic agent of choice for maintenance of
      anaesthesia in obese patients for its efficient elimination profile and ability to facilitate
      early recovery from anaesthesia. Alternatively, Propofol is a commonly used intravenous
      anesthetic agent administered as a part of total intravenous anesthesia (TIVA) regimen.
      However, it is a lipid soluble drug and there are concerns that it may accumulate in obese
      patients due to their increased proportion of body fat Therefore, Propofol TIVA is likely to
      result in a prolonged duration of action and consequently, delayed emergence from anaesthesia
      and a protracted recovery time. A recent advance in the delivery of Propofol to the patient
      is the development of computer-controlled anesthesia delivery systems. These devices deliver
      Propofol based on feedback from patient's frontal cortex electrical activity as determined by
      monitoring bispectral index (BIS). Evaluation of anesthesia delivery by these systems has
      shown that Propofol and maintain depth of anesthesia with far more precision as compared to
      manual/simple infusion administration. This, in turn, holds promise that recovery from
      Propofol anaesthesia can also be favourable in the obese patients. An indigenously developed
      computer-controlled anesthesia delivery sytem is the closed loop anaesthesia delivery system
      (CLADS), which has been extensively evaluated in patients belonging to different surgical
      settings. The evidence generated with Propofol anaesthesia delivered by CLADS has shown
      significant improvement in recovery outcome.The performance of CLADS has not yet been
      evaluated in obese surgical patients. We hypothesise that in the obese patients undergoing
      bariatric surgery, automated delivery of Propofol using CLADS would allow precision control
      of anaesthesia depth, intra-operative haemodynamics, and rapid recovery from anaesthesia. We
      plan to conduct a randomised controlled investigation to compare patient recovery profile
      following Desflurane anaesthesia versus CLADS empowered Propofol anaesthesia.
    

Detailed description: 
      After Institutional Ethics Committee approval and written informed consent,
      forty-participants (20 per group) aged 18-65 years, ASA physical status I/III, BMI >35-kg/m2,
      of either sex, and undergoing laparoscopic/robotic bariatric surgery (sleeve gastrectomy or
      gastric bypass) will be included in this single center (Sir Ganga Ram Hospital, New
      Delhi-110060, India) prospective, double-blinded, two-arm, randomised controlled study.

      The patients who qualify inclusion criteria and consent for recruitment will be randomly
      divided into one of the two groups:

      Group-1 [CLADS Group, n=20]: Anaesthesia will be induced and maintained with Propofol
      administered using the automated CLADS.

      Group-2 [Desflurane Group, n=20]: Anaesthesia will be induced with Propofol administered
      using the automated CLADS and will be maintained with Desflurane.

      Sample-size Estimation

      In a previous study, the time-to-eye opening with Desflurane and Propofol was 4.2 minutes and
      10.7 minutes, respectively. Based on above, a samples size of 15-patients will be required
      per group to provide 90% power with a bilateral α-risk value of 0.05 to posit a significant
      difference in time-to-eye opening. We plan to recruit a total of 40-patients to cover up for
      unanticipated losses after the recruitment.

      Randomization, Allocation Concealment

      The patients will be randomly allocated to one of the two groups based on a
      computer-generated random number table
      (url:stattrek.com/statistics/random-number-generator.aspx). Randomization sequence
      concealment will include opaque-sealed envelopes with alphabetic codes whose distribution
      will be in control of an independent analyst. The envelopes will be opened; patient's
      data-slip will be pasted on them, and will be sent back to the control analyst.

      Blinding Strategy

      The attending anaesthesiologist will not be blinded to the technique utilized to administer
      GA and recovery immediately after extubation inside the OR. However, the postoperative
      patient recovery profile will be evaluated by an independent assessor blinded to the
      technique of GA.

      Management of Anesthesia

      Two peripheral venous lines (18G/20G catheter) will be secured. Standard monitoring (EKG,
      NIBP, pulse oximeter, EtCO2) will be applied. A BIS sensor (Covidien IIc, Mansfield, USA)
      will be applied over the patient's forehead according to manufacturer's instruction prior to
      induction of anaesthesia for monitoring depth of anaesthesia. The BIS monitoring module
      (Model DSC-XP, Aspect medical system, USA) will facilitate monitoring of anaesthesia depth.

      Anaesthesia Technique

      All the patients will be administered pre-induction fentanyl-citrate analgesia as per a
      predefined strategy (total 2-µg/kg IV: 1-µg/kg at 0 minute and 3-minute time point).
      Pre-oxygenation will be initiated at 3-minute time point or prior to that if there is a fall
      in oxygen saturation (< 94 percent). In both the groups, at 6-minute time point, anesthesia
      will be induced with Propofol administered by CLADS. In both the groups CLADS will be set to
      deliver Propofol according to lean body weight (LBW). A BIS-value of 50 will be used as the
      target for induction of anesthesia. After induction of anesthesia, atracurium besylate
      0.05-mg/kg will be administered for skeletal muscle relaxation to facilitate tracheal
      intubation. Ventilator settings of CMV, tracheal tube size [7.5-mm I.D (male), 6.5-mm I.D
      (female)], and breathing circuit (circle-CO2 absorber system) will be the standardized in all
      the patients. Thereafter, the patients in the CLADS group will receive anaesthesia
      maintenance with Propofol, with the dosing based on adjusted body weight (ABW), and
      administration controlled with CLADS tuned to consistent anaesthetic depth (BIS-50) feedback
      from the patients. The patients in Desflurane group will receive anaesthesia maintenance with
      Desflurane dial concentration titrated to maintain a BIS of 50-55 in all the patients.
      Oxygen-air mixture (FiO2 0.50) will be used for ventilation in both the groups.

      In addition, starting post-intubation, all the patients will receive 1.0-µg/kg/hr fentanyl
      infusion for intraoperative analgesia. Intraoperative muscle relaxation will be maintained
      using atracurium boluses controlled by train-of-four response on peripheral neuromuscular
      monitor (Infinity TridentNMT Smartpod, Draeger Medical Systems, Inc Telford, USA).

      Thirty minutes before the end of surgery, non-opioid analgesics, such as paracetamol 1-gm,
      and tramadol 100-mg will be administered to the patient. The Propofol or Desflurane delivery
      will be stopped at the point of completion of skin closure. Residual neuromuscular blockade
      (assessed with train-of-four response) will be reversed with neostigmine (50-µg/kg) and
      glycopyrrolate (20-µg/kg).

      Thirty minutes before the end of surgery, non-opioid analgesics, such as paracetamol 1-gm,
      and tramadol 100-mg will be administered to the patient. The Propofol or Desflurane delivery
      will be stopped at the point of completion of skin closure. Residual neuromuscular blockade
      (assessed with train-of-four response) will be reversed with neostigmine (50-µg/kg) and
      glycopyrrolate (20-µg/kg).
    

Intervention name(s): Propofol; Desflurane
Intervention type(s): Drug; Drug
Intervention description(s): Propofol delivery will be controlled using automated closed loop anaesthesia delivery system which will control propofol delivery rate to consistent anaesthetic depth (BIS-50) feedback from the patient.; Desflurane delivery will be controlled using a agent specific vaporiser. The dial concentration of the vaporiser will be adjusted to maintain a BIS of 50-55 in the patients.
Intervention MeSH terms: Propofol; Desflurane
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: 40 patients belonging to ASA physical patients status II and III of either sex, scheduled to undergo laparoscopic/robotic bariatric surgery (sleeve gastrectomy, Rouxen- Y gastric bypass) under general anaesthesia. The patients will be randomly allocated by computer generated numbers to one of the following two groups of 20 patients each.
Group-1 [CLADS Group, n=20]: Anaesthesia will be induced and maintained with Propofol administered using the automated CLADS.
Group-2 [Desflurane Group, n=20]: Anaesthesia will be induced with Propofol administered using the automated CLADS and will be maintained with Desflurane.
Masking: Double (Participant, Outcomes Assessor)
Primary purpose: Basic Science
Keywords: propofol; CLADS; Desflurane; Obesity