Video Laryngoscopy



Video Laryngoscopy


John C. Sakles

Brian E. Driver

Calvin A. Brown III



INTRODUCTION

In the past, direct laryngoscopy (DL) was the primary laryngoscope for performing tracheal intubation. When performing DL, the goal is to compress and displace the tissues of the upper airway so that a direct line of sight can be achieved between the intubator’s eye and the laryngeal inlet. The ease of exposure varies greatly between patients and it can be difficult or impossible to achieve an adequate view of the larynx with DL. Video laryngoscopes (VLs) were developed to allow intubation without achieving a direct line of sight between the mouth and larynx.1

The first commercially available VL, the GlideScope, was introduced in 2001. A micro video camera was placed on the distal portion of a hyperangulated blade and provided an indirect view of the airway and allowed intubation to be performed using a video monitor. Since that time, numerous VLs have been developed by a variety of manufacturers and are now in clinical practice. These devices differ considerably in their design, including differences in blade shape (standard geometry vs. hyperangulated), tube delivery (freehand vs. built-in channel guide), monitor placement (on the handle vs. connected to a monitor on a tower), and reusability (single use vs. reusable). A common feature of each VL, however, is the ability to achieve an indirect video view of the laryngeal inlet. This allows intubation to be performed without having to move obstructing tissue out of the way. In addition, the viewing angle is increased over what is usually experienced with DL (10 degrees with DL vs. up to 60 degrees with hyperangulated VL).

VL is now commonly used for emergency intubations and the current literature indicates that it outperforms DL.2,3,4 A recently published pragmatic multicenter randomized control trial (DEVICE trial) compared VL and DL in critically ill patients in the ED and ICU and found that VL had a 85% first-attempt success rate while DL had a 71% first-attempt success rate (14% difference, 95% CI 9.9-18.7%).2 The trial was stopped early, given the improved performance of VL. An updated Cochrane review of VL versus DL analyzed 222 studies of adult patients undergoing tracheal intubation and found numerous benefits of VL over DL.4 VLs of all designs (standard geometry, hyperangulated, and channeled devices) were found to have higher first-attempt success rates and reduced rates of esophageal and failed intubations. In addition, standard geometry VLs and channeled VLs were found to have lower rates of hypoxemia during intubation. Hyperangulated VLs were found to have lower rates of inadvertent esophageal intubation. The authors concluded that VL provides a better safety profile than DL in adult patients undergoing tracheal intubation. VL should thus be used routinely for intubation in the critically ill and not reserved for patients with anticipated difficult airways. This chapter will discuss a general overview of the use of VLs, followed by specific instructions for each class of VL.


ADVANTAGES OF VIDEO LARYNGOSCOPES

VL has numerous advantages over DL:



  • Obviates the need for a direct line of sight to airway


  • Magnifies the view of the airway


  • Requires less force to intubate


  • Allows the whole team to see and assist with the procedure


  • Allows supervising practitioners to supervise intubation, even remotely


  • Allows for recording of photos and videos which can be used for documentation and teaching



CLASSIFICATION OF VIDEO LARYNGOSCOPES

VLs can be fundamentally classified by blade shape: standard geometry or hyperangulated.1 Standard geometry, traditional geometry, and Macintosh geometry are all used interchangeably in the literature, and even througout this book to describe a blade shape that mirrors a Macintosh direct laryngoscope blade. In addition to curved blade geometry, some systems also offer small Miller (straight) blades for use in pediatric patients. Most standard geometry VLs have nearly identical geometry to standard Macintosh DLs but have a micro video camera at the distal aspect of the blade. Hyperangulated blades have a very acute (60 degrees) viewing angle. This angle was selected purely to optimize laryngeal visualization; however, tube delivery can be more difficult compared to blade shapes with less acute distal angles. Hyperangulated blades can be further divided into those that have a tube guide channel and those that do not.

The two major VL manufacturers, Karl Storz (C-MAC) and Verathon (GlideScope), and some other smaller companies now have VL systems that include both standard geometry and hyperangulated blades. Since blade shape is no longer the defining difference between systems, this simplifies the decision of which system to purchase. Figure 24.1 shows examples of standard geometry and hyperangulated blades. Table 24.1 shows various types of commercially available VLs and their characteristics.














WHEN TO USE VIDEO LARYNGOSCOPY COMPARED TO DIRECT LARYNGOSCOPY

Since VL is becoming more affordable, provides superior laryngeal views, demonstrates superior first-attempt success, and is associated with lower complication rates, there is little reason to use a DL. The potential advantages of DL—that it is simpler, suffers from technical failure less often, is not soiled by body fluids, and has easier tube delivery—are reasons to maintain DL skills, but are not reasons to use a DL as the default device. Although not a perfect mimic, DL skills can be maintained by using a standard geometry VL, which allows the intubator to perform DL with recourse to a video screen should intubation prove difficult.

Technical failure and soiling of the camera occur rarely, and even when these difficulties are factored in, the success of VL is higher than DL. Soiling of the camera, an oft-cited concern for VL,

is estimated to occur in just 1% of emergency intubations. In addition, first-attempt success for both DL and VL are lower when body fluids are present in the mouth, with DL having significantly lower success rates.5

Some advocate for using DL for straightforward airways, and video VL for anticipated difficult airways. This is problematic for a couple of reasons. First, the difficulty of a patient’s airway is not always known before laryngoscopy and our ability to identify difficult airways is limited. Second, for a device to be useful in difficult airways, the operator must have skill with that device. Like nearly every procedure, an operator’s skill improves with repetition. For a VL to be used to successfully intubate a patient with an anatomically difficult airway, the operator should have substantial practice with that particular device. While technical aspects of VL differ based on blade shape, success is dictated more by regular use than blade shape. When comparing standard geometry to hyperangulated VLs, success is similar provided that each one is used with high frequency.6 This practice should not occur solely in difficult airways since the incidence of a truly difficult airway is low enough that a clinician might not gain sufficient practice.


DIFFERENCES IN TECHNIQUES FOR VIDEO LARYNGOSCOPY COMPARED TO DIRECT LARYNGOSCOPY

Since VL provides a clearer view of the larynx but does not provide a straight tube delivery path, the technique differs from DL. Specific instructions for use of standard geometry VLs and hyperangulated VLs will be discussed later in the chapter. Key differences in technique for VL compared to DL include:

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Feb 1, 2026 | Posted by in CRITICAL CARE | Comments Off on Video Laryngoscopy

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