Comparison of Licorice Versus Sugar-water Gargle for Prevention of Postoperative Sore Throat and Postextubation Coughing
Condition: Sore Throat
MeSH terms: Pharyngitis
Study type: Interventional

Summary: 
      The investigators propose to test the hypothesis that pre-operative gargling with licorice
      reduces the incidence of sore throat in rest after intubation with double-lumen endotracheal
      tubes compared to placebo after surgery through the first four post-extubation hours.
    

Detailed description: 
      Patients will be premedicated with up to 7.5 mg p.o. midazolam, per routine. They will be
      told that the study involves two different solutions for prevention of post-extubation sore
      throat.

      Patients will be randomly assigned to gargle 5 minutes before induction of general anesthesia
      with: 1) licorice (0.5 g); or, 2) sugar (5 g). Randomization will be based on a
      computer-generated table of random numbers. Licorice or sugar (placebo) will be diluted in 30
      ml water and filled in a small bottle by an independent apothecary of our university. All
      bottles will look similar and will not be opened until just before use. Investigator and
      patient will be blinded to the preparation used for gargle. Patients will be asked to gargle
      for two minutes, but not to swallow the solution.

      General anesthesia will be induced with fentanyl ≈3 µg/kg, propofol ≈1.5 mg/kg, and
      rocuronium ≈0.6 mg/kg. Complete muscle relaxation will be confirmed by absence of palpable
      twitches in response to supra-maximal train-of-four stimulation of the ulnar nerve at the
      wrist. The trachea will then be intubated as gentle as possible. Intubation will be attempted
      with a Macintosh laryngoscope, but the anesthesiologists may subsequently use any other
      intubation equipment as necessary. Initial tube size will be 37 cm left in women and 39 cm
      left for men; however, other sizes can be used if clinically necessary. Endotracheal tube
      cuffs will be inflated with air to 20-25 mmHg as necessary to maintain an adequate seal.

      General anesthesia will be primarily be maintained with sevoflurane. Patients lungs will be
      ventilated with O2 in air, usually with an inspired oxygen fraction (FiO2) of ≈40%. However,
      additional oxygen will be provided as clinically necessary, especially during one-lung
      ventilation. End-tidal CO2 will be maintained between 32 and 35 mmHg as clinically practical.
      Deep of anesthesia will be monitored by using bispectral index BIS, kept between 40 and 50.
      Small amounts of opioid will be permitted during surgery and in preparation for extubation.
      At the end of surgery, an intercostal plexus block -using up to 20 ml Ropivacaine 0.1% - will
      be performed by the surgeons. 1000 mg paracetamol will be given intravenously ten minutes
      before end of surgery. Post operative pain will be treated with fractional piritramid
      (Dipidolor) 3 mg IV as required.
    

Intervention name(s): licorice solution; sugar solution
Intervention type(s): Other; Other
Intervention description(s): licorice (0.5 g); sugar (5 g).
Intervention MeSH terms: Pharmaceutical Solutions
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Investigator)
Primary purpose: Supportive Care
Keywords: Thoracic surgery; double-lumen endotracheal tube; intubation; extubation; sore throat; prevention of post-extubation sore throat