DirEct Versus VIdeo LaryngosCopE Trial

Clinicians frequently perform tracheal intubation of critically ill patients in the emergency department (ED) or intensive care unit (ICU). In 10-20% of emergency tracheal intubations, clinicians are unable to intubate the trachea on the first attempt, which increases the risk of peri-intubation complications. Successful laryngoscopy and tracheal intubation requires using a laryngoscope to [1] visualize the larynx and vocal cords and [2] create a pathway through which an endotracheal tube can be advanced through the oropharynx and larynx and into the trachea.

In current clinical practice, two classes of laryngoscopes are commonly used by clinicians to view the larynx while intubating the trachea: a video laryngoscope (equipped with a camera and a video screen) and a direct laryngoscope (not equipped with a camera or video screen). Clinicians use either a video laryngoscope or a direct laryngoscope as standard of care for every laryngoscopy and intubation procedure performed in current clinical practice.

Direct Laryngoscope: The Macintosh direct laryngoscope consists of a battery-containing handle and a blade with a light source. The operator achieves a direct line of sight -from the operator's eye through the mouth to the larynx and trachea - by using the laryngoscope blade to displace the tongue and elevate the epiglottis.

Video Laryngoscope: Video laryngoscopes consist of a fiberoptic camera and light source near the tip of the laryngoscope blade, which transmits images to a video screen. The position of the camera near the tip of the laryngoscope blade facilitates visualization of the larynx and trachea.

Use of a video laryngoscope and use of a direct laryngoscope are both common, standard-of-care approaches the clinicians use to perform tracheal intubation in the ED and ICU in current clinical care.

Currently, it is unknown whether use of a video laryngoscope or use of a direct laryngoscope has any effect on successful intubation on the first attempt or any other outcome. Some prior research has raised the hypothesis that using a video laryngoscope would increase clinicians' rate of successful intubation on the first attempt by facilitating the view of the larynx. Some prior research has raised the hypothesis that using a direct laryngoscope would increase clinicians' rate of successful intubation on the first attempt by facilitating a clear pathway for placement of the tube through the mouth into the trachea.

To date, 8 small single-center randomized trials and one 371-patient multicenter randomized clinical trial have been conducted under waiver of or alteration of informed consent to compare use of a video vs a direct laryngoscope in the setting of emergency tracheal intubation in the ED or ICU. Two of these trials provide the most direct preliminary data for this proposal. The "Facilitating EndotracheaL intubation by Laryngoscopy technique and apneic Oxygenation Within the ICU (FELLOW)" randomized clinical trial, conducted under waiver of informed consent, compared these two standard-of-care approaches during 150 emergency tracheal intubations at Vanderbilt University Medical Center, finding no difference in the rate of successful intubation on the first attempt between use of a video and use of a direct laryngoscope. The "McGrath Mac Videolaryngoscope Versus Macintosh Laryngoscope for Orotracheal Intubation in the Critical Care Unit (MACMAN)" randomized clinical trial among 371 critically ill adults found no difference between use of a video vs direct laryngoscope in the rate of successful intubation on the first attempt. However, a hypothesis-forming post-hoc exploratory analysis of peri-intubation complications suggested that use of a video laryngoscope may be associated with a higher rate of complications than direct laryngoscope (9.5% vs 2.8%, respectively, p=0.01). These trials were underpowered to rule out small but clinically significant differences in first pass success, and were limited to intubations performed by inexperienced trainees in one practice setting (intensive care units), but they demonstrated hypothesis-generating findings requiring validation in larger trials that reflect the full spectrum of settings, operator specialties, and operator experience levels in which emergency tracheal intubation is routinely performed.

Because of the imperative to optimize emergency tracheal intubation in clinical care, the common use of both video and direct laryngoscopes in current clinical practice, and the lack of definitive data from randomized trials to definitively inform whether use of a video laryngoscope or a direct laryngoscope effects the rate of successful intubation on the first attempt, examining whether one approach increases the odds of successful intubation on the first attempt represents an urgent research priority. To address this knowledge gap, the investigators propose to conduct a large, multicenter, randomized clinical trial comparing use of a video laryngoscope versus use of a direct laryngoscope with regard to successful intubation on the first attempt among critically ill adults undergoing tracheal intubation in the ED or ICU.