Comparison of Videolaryngoscope, McCoy laryngoscope and Intubating Laryngeal Mask Airway for oro-tracheal intubation in simulated cervical spine immobilization: A Prospective Randomized Comparative Study

All the patients will be kept nil per oral overnight andpremedicated with tablet pantoprazole 40 mg and tab ondansetron 4mg orally 2hrs prior to the surgery. In the operation theater, electrocardiogram, noninvasive blood pressure, and pulse oximeter will be attached and baseline readings will be noted. An adequate gauge intravenous (i.v.) cannula will be secured and i.v. fluid started. The patient will bepreoxygenated with 100% oxygen for 3 min. General anesthesia will be induced with fentanyl 2 µg.kg −1 body weight followed by propofol 2–2.5 mg.kg −1 body weight and vecuronium bromide 0.1 mg.kg −1 body weight to facilitate endotracheal intubation. Mask ventilation will be done with oxygen (FiO2 1) and isoflurane (MAC 0.6). Patient’s head and neck will be immobilized in the neutral position using appropriate size rigid Philadelphia cervical collar. [3]

After 3 min, oral intubation will be performed using the assigned device by anexperienced anesthesiologist, who has conducted at least 100 successful intubations using these devices.

As per group allocation intubation will be performed using one of the three devices. In group VL, blade will be inserted in the midline in the oral cavity and advanced under its monitor vision till its tip reached vallecula. The epiglottis is then lifted to visualize the glottic opening. A cuffed reinforced endotracheal tube (ETT) of internal diameter 7.0–7.5 mm for females and 8.0-8.5 mm for males will be introduced. Correct placement of ETT is confirmed by the appearance of square wave capnographic trace, bilateral equal breath sounds, and absence of epigastric sounds.

In group MC, MAC COY blade will be inserted in the midline in the oral cavity and advanced till its tip reached vallecula. The epiglottis is then lifted to visualize the glottic opening. A cuffed reinforced endotracheal tube (ETT) of internal diameter 7.0–7.5 mm for females and 8.0-8.5 mm for males will be introduced.

Stylet or bougie will be used for intubation if needed in the above two groups, and will be noted.

In group IL, the correct size of ILMA will be selected according to patient’s body weight: 30–50 kg: ILMA number 3, ILMA tube 7.0 mm; 50–80 kg: ILMA number 4, ILMA tube 7.5 mm. The cuff of ILMA is partially deflated using deflator and upper surface of its mask is lubricated. Mouth is opened using nondominant hand and ILMA inserted by dominant hand. The cuff of ILMA is inflated with the requisite amount of air (size 3: 20 ml, size 4: 40 ml, and size 4: 50 ml) and adjusted to get optimal ventilation. [6] After confirming the presence of bilateral equal entry and a square wave capnograph, intubation will be done with lubricated ILMA ETT. The cuff of ILMA ETT is inflated and intubation confirmed by visualizing square wave capnograph and bilateral air entry. The ILMA cuff is deflated, and ILMA is swung out of the pharynx into the oral cavity while applying counter pressure to the tracheal tube using the stabilizing rod. The ETT connector is replaced and tube placement reconfirmed using a square wave capnograph. Either of the following maneuvers is used for troubleshooting any difficulty in intubation through the ILMA: rotation of ILMA ETT, reinsertion of ILMA ETT, and reinsertion of ILMA of same or smaller or larger size. [6]

Hypoxemia is defined as fall in SpO2 up to or below 92%. In case of failure to intubate with the given device in any of the group within two attempts, patient’s trachea is intubated using macintosh laryngoscope after removing the cervical collar and will be excluded from the study. After rechecking the ETT position, patient is ventilated mechanically, and anesthesia will be maintained with isoflurane (0.6–0.8 MAC) in oxygen and nitrous oxide (FiO2 0.4).