Effect of Intraoperative Lidocaine Infusion on Intraoperative Isoflurane Requirements
Condition: Anesthesia
Study type: Interventional

Summary: 
      Fifty patients were included in the study, divided into two equal groups (25 in each),
      underwent spinal fusion surgery.Control group: received normal saline.

      Lidocaine group: received lidocaine 2.0 mg/kg slowly IV before induction of anesthesia,
      followed by lidocaine IV infusion at a rate of 2.5 mg/kg/hr until the end of surgery. We
      evaluated the end-tidal isoflurane concentration required to maintain AAI index in the range
      of 20-25 during adult spinal fusion surgery.
    

Detailed description: 
      This prospective, double-blinded, randomized study was carried out in Assiut University
      Hospitals, after approval by the local research ethics committee of Assiut Faculty of
      Medicine, Egypt. Informed consent was taken from each patient.

      Patients were randomly allocated into two groups of equal size to receive either 0.9% sodium
      chloride infusion group 1 (CG), or lidocaine infusion group 2 (LG). Randomization was
      performed using G1 and G2 registers, which was placed in sealed envelopes prior to study
      initiation and opened prior to anesthesia by a physician who prepared the intravenous
      solution and identified it with the patient number, according to the envelope drawn. The
      solution was handed to another physician, blind to the prepared solutions' content, who was
      responsible for the anesthesia. The solution volume was equal. The responsible investigator
      was remained blind to the chosen group until the end of the study. G1 patients (n = 25) were
      received 10 mL of 0.9% sodium chloride slowly IV just before induction of anesthesia, then
      infused through 50 mL syringe as lidocaine, and G2 patients (n = 25) were received a loading
      dose of lidocaine 2 mg ̸ kg (maximally 200 mg) slowly IV just before induction of anesthesia,
      then the lidocaine infusion started immediately after positioning at a rate of 2.5 mg ̸ kg/h
      until the end of the procedure (50 mL syringe contained 25 mL 2.0% lidocaine i.e., 500 mg
      lidocaine plus 25 mL normal saline). Both syringes (10 mL for loading dose and 50 mL for
      maintenance IV infusion) were labelled by the case number and prepared by another
      anesthesiologist who did not share in anesthesia.

      Anesthesia technique: Patients were monitored with continuous electrocardiography, pulse
      oximetry and intermittent non-invasive blood pressure measurements every 5 min. Capnography,
      end-tidal isoflurane concentration (Et-Iso) via AVANCE CS2 Datex-Ohmeda, Inc. USA, and
      auditory evoked potential monitor (AEP monitor 2 Dia Trade medical engineering) also attached
      to the patient (one AEP electrode was placed on the center of the forehead, one on the
      temple, and one behind the left ear over the mastoid bone).

      General anesthesia was induced by propofol 2.5 mg ̸ kg and cisatracurium 0.15 mg ̸ kg to
      facilitate endotracheal intubation. Patients were then assigned to two groups by
      closed-envelope randomization. In both groups, anesthesia was maintained with isoflurane in
      oxygen/air mixture at sufficient concentration to maintain AAI index in the range 20-25, and
      mean blood pressure within 25% of the baseline value. All patients were received 60 mg
      ketorolac (ketolac) slowly IV after induction of anesthesia, and fentanyl 1.5 µg ̸ kg IV
      before skin incision and 0.5 µg ̸ kg given IV after 45 min. Reversal of residual muscle
      relaxant was done using neostigmine and atropine at the end of the operation.

      Data collection: Demographic and surgical data include: Age, gender, weight, height, duration
      and type of surgery, in addition to Et-Iso.
    

Intervention name(s): sodium chloride solution; Lidocaine
Intervention type(s): Drug; Drug
Intervention description(s): intraoperative IV infusion; intraoperative IV infusion
Other intervention name(s): normal saline solution; xylocaine
Intervention MeSH terms: Lidocaine; Pharmaceutical Solutions
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Care Provider)
Primary purpose: Prevention