The purpose of the laryngoscope is to retract the mandible and soft tissues of the anterior oropharynx upward, allowing visualization of the glottis. In cross section, the blade of the laryngoscope typically consists of a flat portion (spatula) and a vertical portion (flange), along with a light source. These components are arrayed in a large variety of shapes and configurations to meet the challenge of elevating soft tissues during retraction and keeping them out of the line of sight of the laryngoscopist, while at the same time permitting the necessary manipulations to insert an endotracheal tube (ETT). Since the origins of laryngoscopy in the late 19th century, laryngoscopes have undergone an evolution in shape. Early versions had a “C” shape configuration but did not have either detachable blades or an intrinsic light source. By the middle of the 20th century, laryngoscopes incorporated with these innovations had been developed. More modern laryngoscopes contain a light source in the handle with fiberoptic bundles in the blades. The older-style laryngoscopes remain in use by ear-nose-throat (ENT) surgeons today for diagnostic and therapeutic procedures involving the airway.

Many different types of retraction blades for direct laryngoscopy are available today. Although many variations of the straight and curved blade exist, the Miller and Macintosh blades, introduced in the 1940s, remain the most commonly used blades in clinical practice (Figs. 4-1 and 4-2).¹,² Conventionally, the straight blade is inserted beneath the epiglottis and is used to directly lift it, exposing the glottis (Fig. 4-3). The curved blade, on the other hand, fits into the vallecula, exerting upward traction on the glossoepiglottic ligament as it is lifted, thereby indirectly raising the epiglottis superiorly and allowing the operator to visualize the exposed glottis (Fig. 4-4). The choice of laryngoscope blade is largely based on the personal preference of the operator, with both Macintosh and Miller blades being a reasonable choice for a “normal” airway. In general, the advantages of the Macintosh blade include more room for passage of the ETT, whereas the Miller blade may provide better visualization in patients with a small mandibular space, large incisor teeth, or a large epiglottis (see also Chapter 5).³

Some variants of the Miller blade, such as the Phillips (Fig. 4-1) or Wisconsin blade, have a higher vertical profile, answering one of the deficiencies of the Miller blade: inadequate space for ETT manipulation in the pharynx despite an adequate view of the glottis. A variant of the Macintosh blade, the Bizzarri-Giuffrida blade, incorporates the curved design but eliminates the vertical flange, allowing insertion into small mouth openings or in patients with prominent or fragile teeth (Fig. 4-5). The McCoy blade is an articulating blade that allows the user to lift its distal tip in order to improve the view of the glottis if the epiglottis remains downfolded and impedes visibility.⁴

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