Comparison of video laryngoscope-guided D-blade and adult-blade versus standard digital technique for Proseal Laryngeal Mask Airway placement in patient under general anesthesia : a randomized controlled trial

- Participants will be randomly allocated to 1 of 3 groups for Proseal LMA insertion: Group S (control group) - standard digital technique Group D - under C-MAC laryngoscopic guidance using a D-blade Group A - under C-MAC laryngoscopic guidance using an adult blade - In the operating room, standard anesthetic monitoring was applied with electro- cardiogram, non-invasive blood pressure, and peripheral oxygen saturation monitoring. - Participants will breathe 100% oxygen gas through a face mask for 3 minutes. Induction of anesthesia was carried out with propofol 1.5-2.5 mg/kg intravenous bolus, succinylcholine 0.5 mg/kg intravenous bolus and fentanyl 0.5-1 mcg/kg intravenous bolus. The patients were ventilated with a facemask until conditions were suitable for laryngeal mask airway(LMA) insertion (loss of eyelash reflex, jaw relaxation, and the absence of movement). Additional boluses of 0.5 mg/kg intravenously propofol were given as required until an adequate level of anesthesia was achieved for LMA placement. - A lubricated LMA was inserted by experienced anaesthetist (who experienced LMA insertion more than 3- times) using the standard digital technique in Group S .under C-MAC laryngoscopic guidance (D-blade) in Group D and under C-MAC laryngoscopic guidance (adult-blade) in Group A. Selection of the LMA size was based on the body weight of the patient. Laryngoscope blade was placed in the vallecula and the epiglottis was identified; then, both the tongue and epiglottis were lifted anteriorly. It was not necessary to visualize the tracheal opening or vocal cords. The LMA was pressed with the index finger and forwarded around the palatopharyngeal curve until the resistance was felt - After the LMA was inserted, the cuff was inflated with air based on the amount of air proposed by the manufacturing company. With the cuff manometer pressure was set to 60 cmH2O. - A well-lubricated gastric tube (14 French) was inserted along the drainage tube. - A fiberoptic scope was passed through the LMA tube and the fiberoptic position was evaluated using the fiberoptic scoring system: 4, only the vocal cords seen; 3, vocal cords plus posterior epiglottis seen; 2, vocal cords plus anterior epiglottis seen; 1, vocal cords not seen. - During the procedures, anaesthesia was maintained with sevoflurane in air in oxygen keep end-tidal gas (Etgas) 1-1.2 minimum alveolar concentration (MAC) - At the end of the surgery, all patients received ondansetron 4-8 mg intravenously and removed the LMA after the patient gained consciousness, and collected data on the following adverse events: sorethroat, hoarseness, dysphagia - Monitor adherence to the intervention by review of anaesthesia records.