Learning Curve of Endobronchial Intubation Using Video Laryngoscopes

The use of video laryngoscopes for endobronchial intubation has its own potential benefits particularly in case of airway difficulty. It is not clear how many cases are required to show competency in successful endobronchial intubation using McGrath and King Vision video laryngoscopes in simulated "easy" and "difficult" airways by novices.

The here proposed randomized crossover clinical trial will test the learning curve of using each of McGrath and King Vision video laryngoscopes in simulated "easy" and "difficult" airways with respect to the number of intubation trials for successful endobronchial intubation

Surgeries that require lung isolation have been using double-lumen tubes (DLT) for endobronchial intubation as the preferred method due to its numerous advantages.

However, the larger diameter of the DLT compared to the single-lumen tube can be more difficult to insert during intubation. \[1\] The use of video laryngoscopes (VL), which were found to have lower rates of intubation failure, reduced incidences of tracheal and laryngeal trauma, improved glottic view, and increased ease of use, are gaining interest for its use in endobronchial intubation. \[2, 3\]

The use of McGrath® VL systems for DLT endobronchial intubation has been studied and compared to that of conventional laryngoscopy, as well as that of other VL systems. When compared to the conventional Macintosh laryngoscope, McGrath® VL has been consistently associated with a better glottic visualization. \[4 - 6\] Other advantages include reduced need for external laryngeal manipulation and a lower rate of intubation-associated complications, such as bronchospasm and trauma to the oral mucosa. \[7\] However, results regarding time to intubation have been controversial.

The use of King Vision® VL for DLT endobronchial intubation has not been studied as much as the McGrath® video laryngoscope. Two studies compared the King Vision® VL system to the conventional Macintosh laryngoscope and to other VL systems. When comparing King Vision® to Macintosh laryngoscope, the time to intubation was comparable between the two devices. \[8, 9\] However, one study found that in a simulated easy airway, a significantly longer time to intubation was shown with King Vision® VL. \[9\] King Vision® VL and Macintosh laryngoscope were also comparable in terms of glottic visualization, intubation difficulty, first-pass success rates, need for optimizing maneuvers, and postoperative symptoms indicative of pharyngeal or laryngeal trauma. \[8, 9\]

Therefore, competency in endobronchial intubation using video aided laryngoscopes is built through continuous and regular hands-on training. \[10\] The learning curve of the novice is usually monitored aiming to detect when satisfactory performances are reached. This is widely done using the cumulative sum analysis (CUSUM) test, which provides an objective evaluating method of skill learning via ongoing monitoring. \[11\]

* Educational Course.

  * All participants will attend a 30-minutes didactic virtual training course on the Zoom platform equipped with a slide presentation including a demonstrative video on the endobronchial intubation and the tips and tricks for using the two study devices.
  * Additionally, a 5-minute hands-on practice session would be provided on each simulated airway model under close supervision by the investigators (AK, MK, SS, and TAG).
* Before each DLT intubation attempt, the manikin, laryngoscope blade, and DLT will be lubricated.
* After completing the DLT intubation, participants should have a 15-minute break before performing intubation using another laryngoscope.
* All intubations will be performed with a 35-Fr left-side DLT.
* The participants will not be allowed to watch each other to avoid any learning effect through observation.

DATA ANALYSIS

Updated and finalized statistical analysis plan will be written, before closing the database.

Eligibility Criteria:
Inclusion Criteria:

* Novice medical school students in using the devices tested.
* Are not familiar with double-lumen tube (DLT) insertion.
* Having no previous experience with the two tested video laryngoscopes for tracheal intubation.

Exclusion Criteria:

* Decline consent to participate.
* No written informed consent.