These procedures are generally reserved for paramedics and EMS physicians. However, SGAs are included at the AEMT level in the 2019 National EMS Scope of Practice model, and in some areas EMTs may use SGAs as well [18, 19].
Tracheal intubation
ETI is the most widely recognized method of advanced airway management. Paramedics have performed endotracheal intubation in the United States for over 30 years [20–23]. ETI has many theoretical advantages, including isolation of the airway from secretions or gastric contents and the provision of a direct conduit to the trachea without separate airway opening maneuvers.
Orotracheal intubation
Direct orotracheal intubation is the most common method of ETI (Figure 3.2). The most common laryngoscope blades used for orotracheal intubation include Macintosh (curved) and Miller (straight) blades, which require slight variations in laryngoscopy technique [24]. The rescuer places the curved Macintosh blade into the vallecula (the space immediately anterior to the epiglottis) to facilitate indirect lifting of the epiglottis and exposure of the vocal cord structures. In contrast, the rescuer uses the broad side of the straight Miller blade to displace the oropharyngeal structures, using the tip of the blade to lift the epiglottis directly. Blade selection is a matter of personal preference; there are no data indicating the superiority of either blade during prehospital ETI.
Orotracheal intubation optimally requires the absence or near‐absence of protective airway reflexes. It is extremely difficult in patients who are awake or have intact airway reflexes. In these situations, drug‐facilitated intubation techniques are often necessary.
In scenarios with potential cervical spine fracture or injury, EMS personnel must perform orotracheal intubation with “manual in‐line stabilization” of the cervical spine, without hyperextension of the head or neck during laryngoscopy (Figure 3.3). This approach requires a second rescuer to hold the cervical spine “in‐line” during laryngoscopy attempts. However, a critical review questions the value of manual in‐line stabilization, suggesting that it significantly impairs laryngoscopy while not affording adequate spinal cord protection [25]. Video laryngoscopy may improve visualization of the glottis while minimizing cervical spine movement during ETI [26].
Figure 3.2 Orotracheal intubation
Figure 3.3 Manual in‐line stabilization for intubation of the patient with suspect cervical spine injury
Video laryngoscopy
Video laryngoscopy uses a camera with a view from the end of the laryngoscope blade, providing video images of the airway that are displayed on a screen. Newer generation video laryngoscopes include portable and disposable configurations that are suited to the prehospital setting. While video laryngoscopy has demonstrated equal or improved ETI success rates when compared to traditional laryngoscopy in nearly all clinical settings, its cost is higher than conventional laryngoscopy [27–29]. Some studies suggest that proficiency with video laryngoscopy may be obtained in as few as five intubations [30]. Some video laryngoscopes also allow clinicians to record their efforts for offline review for quality improvement or educational initiatives [31].
Video laryngoscopy technique may be similar to or different from direct laryngoscopy, depending on the specific device. For example, the video laryngoscope blade may be similar to a Macintosh blade, requiring the same approach. In that case, the real‐time advantages of video laryngoscopy are the enhanced perspective and views of airway anatomy and abilities of others to see what the principal operator sees, better enabling them to be helpful. Some video laryngoscopes include angulated blades. Instead of facilitating alignment of airway structures to provide direct visualization, angulated blades follow the resting anatomic contour of the oropharynx to the glottis (Figure 3.4). The patient’s tongue is not manipulated as it is for direct laryngoscopy, and less patient movement or repositioning may be required. A special stylet for the endotracheal tube is generally necessary so that the angle of the blade can be followed. Some curved blades incorporate an integrated channel to direct the endotracheal tube, obviating the need for a stylet.
Figure 3.4 GlideScopeTM video laryngoscope
Nasotracheal intubation
Nasotracheal intubation involves insertion of an endotracheal tube through the nose and into the trachea. It is possible only on patients with intact respiratory efforts: for example, individuals with congestive heart failure or acute pulmonary edema. The approach may be possible for patients who cannot lay supine: for example, patients entrapped after a motor vehicle collision. In contrast with orotracheal methods, nasotracheal intubation is often possible in awake patients and those with intact gag reflexes or trismus.
Successful nasotracheal intubation requires a skilled and experienced operator. The rescuer chooses an endotracheal tube one‐half size smaller than customary for orotracheal intubation, inserting the tube into the nares without a stylet, and directing the endotracheal tube inferiorly and anteriorly toward the vocal cords. We recommend first entering the right nostril, which is often larger than the left nostril. The rescuer coordinates insertion of the tube through the vocal cords with patient inhalation. The nasal passage may be dilated by initially inserting a nasal airway for several minutes prior to attempting tracheal tube placement. The nasal airway is then removed prior to placing the tube.
The Endotrol endotracheal tube has a special trigger device that provides directional control of the tip, flexing it to facilitate its correct trajectory toward the larynx as the tube is advanced [32]. A potentially helpful adjunct is the Beck Airway Airflow Monitor (BAAM®; Great Plains Ballistics, Lubbock, Texas). When placed on the connector end of the endotracheal tube, the device “whistles” as air is exhaled though the endotracheal tube approaching vocal cords. Important complications associated with nasotracheal intubation include nasal trauma and epistaxis, sinusitis (which may cause sepsis), and perforation of the cribiform plate with subsequent intracranial placement [33–37].
Other intubation techniques
Digital intubation is one of the original methods of endotracheal intubation [38]. For this procedure, the rescuer places his or her second and third fingers into the patient’s pharynx, forming a cradle extending to the epiglottis and the vocal cords. The rescuer then uses the other hand to guide an endotracheal tube along the cradle and through the vocal cords. Some clinicians recommend twisting the endotracheal tube into a corkscrew shape to facilitate the technique (Figure 3.5). Digital intubation may be a useful approach to an unresponsive patient where EMS personnel have limited access to the airway. The technique could result in rescuer injury should the patient bite down during the procedure [39].
