Impact of Blades Used for Scheduled Orotracheal Intubation on Postoperative Sore Throat
Condition: Tracheal Intubation Morbidity; Sore Throat
MeSH terms: Pharyngitis
Study type: Interventional

Summary: 
      Orotracheal intubation following general anesthesia requires blades to be performed. The risk
      of patients contamination with infectious agents related to reusable metal blades leads to
      promote single-use blades. Some of these latter are plastic and this material may need more
      strength to lift the jaw and expose the larynx before orotracheal intubation. Sometimes,
      change of blade, from plastic to metal, during the procedure is necessary to increase the
      larynx exposure. This change of blade may increase the frequency of sore throat following
      orotracheal intubation.

      Consequently, the study hypothesis is an increase of both sore throat intensity and frequency
      with the plastic blades compared with the metal blades.

      The primary purpose of the present study is to compare the impact of these two types of
      blades, metal versus plastic, on sore throat intensity and frequency following scheduled
      orotracheal intubation for general anesthesia
    

Detailed description: 
      Trial design :

      This will be a multicenter, prospective, randomized and single-blind controlled study

      Material and Methods :

      The obtaining of the Ethic Committee approval allows the enrolment of 712 patients scheduled
      for surgery performed under general anesthesia with orotracheal intubation. Adult patients,
      18 to 70 years-old, with grade I-II of ASA (American Society of Anesthesiology) status will
      be enrolled after clear information and obtaining, at the anesthesia visit, of the
      non-opposition to be enrolled in the trial.

      At the anesthesia visit, the anesthesiologist will explain the purpose and protocol to the
      patients and then will propose them to participate to the study. The decision to be enrolled
      will be known at the pre-anesthesia visit, one day before the surgery. Therefore, the
      patients will have a delay between the anesthesia and pre-anesthesia visits to make a
      decision. The non-opposition to participate to the trial will be clearly mentioned in the
      medical file.

      A randomization list will be established by a statistician. Informed and non-opposed patients
      will be allocated both a randomization number and a plastic or metal blade in the operating
      theatre via the Clean Web software.

      The evaluation and measure of the primary outcome will be made in a single-blind way. The
      patients will evaluate the sore throat intensity being unaware of the type of blade used for
      the orotracheal intubation. An independent research assistant in each centre will collect
      data evaluated in both the operating room during the orotracheal intubation procedure and the
      post-operative period.

      The duration of tracheal intubation will be defined as the time elapsing from the mouth
      insertion of the blade to the passage of the tube throughout the vocal cords announced by the
      operator. The intra-tracheal position of the tube will be confirmed by three squared cycles
      of capnography.

      Protocol :

      Anesthesia and monitoring:

      Patients will be premedicated by hydroxyzine 1 mg kg-1 the previous evening and one hour
      before the transfer to the operating room.

      The randomization is performed in the operating room just before the anesthesia induction.

      The monitoring will be standard with:

        -  An electrocardiogram (lookout of cardiac rhythm modifications)

        -  A pulse oxymetry to lookout arterial oxygen saturation

        -  A non-invasive blood pressure monitoring

        -  A capnograph to lookout carbon dioxide elimination in the expired gas and to confirm the
           intra-tracheal position of the tube

        -  A gas analyser to control the concentration of administered halogenated volatile agents

        -  A neuromuscular blockade monitor to lookout the depth of the neuromuscular blockade
           required to perform tracheal intubation in optimal conditions. The monitoring will
           consist of stimulating the facial nerve 1 cm near the external eyelid corner by a train
           of four electric charges (30 mA). The muscular responses will be evaluated on the
           corrugator Supercilia by counting the number of contractions.

        -  A bispectral index (BIS) or entropy to monitor the hypnosis depth. The expected values
           will be 40-60 and 25-35, respectively.

        -  A manometer to control the tracheal tube cuff pressure Before anesthesia induction,
           patients will breathe 100% oxygen till expired oxygen concentration reach 90%.
           Intravenous anesthesia will be then performed with propofol (1.5-2.5 mg kg -1) as
           hypnotic, sufentanil (0.2 mcg kg-1) and atracurium (0.5 mg kg-1) as muscle relaxant.
           Cis-atracurium or vecuronium as middle acting muscle relaxant or SUNCCYNILCHOLINE as
           short acting muscle relaxant will be authorized. According to the randomization, the
           blade used for orotracheal intubation will be metal or plastic. The metal blade is
           reusable and the plastic blade is disposable. When the BIS or the entropy will reach
           40-60 and 25-35, respectively, with efficient face mask ventilation (good thoracic
           amplitude following by capnography cycles), no response to the TOF at the corrugator
           Supercilia, the laryngoscopy will be performed according to the orotracheal intubation
           algorithm. Tracheal tube sizes will be 7 mm for female and 7.5 for males. Tracheal tube
           cuff will be standard.

      After tracheal intubation, the anesthesia will be maintained with inhaled halogenated gas or
      intravenously. Inhaled gas will be moistened. Postoperative analgesia will be anticipated in
      the operating room with paracetamol 1 g, ketoprofen 100 mg and nefopam if necessary. In the
      absence of contraindication, the three analgesics will be administered during laparotomies.
      Wound and abdominal holes for laparoscopy will be infiltrated with ropivacaine. At the end of
      the surgery, the tracheal tube will be withdrawn according to the standard procedure
      recommended by the French Anesthesiology Society. Mouth secretions will be suctioned
      delicately. In the PACU, analgesia will be continued with according to a protocol adapted to
      the type of surgery. Morphine will be administered if pain VAS reaches 4/10. Pharyngeal and
      laryngeal morbidity evaluation will begin at the discharge of the PACU and will last 48
      hours. If signs persist more than 48 hours, an ENT examination will be performed to make a
      diagnostic.

      Statistics :

      Sample size: The literature reports a 30% incidence of postoperative sore throat with metal
      blades. The hypothesis is that this incidence could increase from 30% to 40% if plastic
      blades are used. Un sample size of 356 patients per group is required to detect this increase
      of 10% with a Chi2 test, a statistic power (1-beta) of 0.80 and alpha type I error
      probability of 0.05.
    

Intervention name(s): metal reusable blades MacIntosh; Single use plastic blades HEINE XP®
Intervention type(s): Device; Device
Intervention description(s): laryngoscope blades; laryngoscope blades
Other intervention name(s): Sign use plastic blades HEINE XP®
Intervention MeSH terms: Pyrithione zinc
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Participant)
Keywords: Intubation; Sore throat; Blades; Laryngoscopy; Morbidity