to perform laryngoscopy. However, the right arm is free to facilitate tube placement in a conventional fashion.
Kneeling. The rescuer kneels at the patient’s head. The left elbow and forearm may be supported by the rescuer’s knee. In this position, the rescuer assumes a slightly more vertical position over the patient’s head, and thus the angle for glottis visualization may be steeper than usual (Figure 4.3).
Sitting. The rescuer sits at the patient’s head with legs either crossed or extended to each side of the patient’s head. The left arm may be braced against the rescuer’s leg (if sitting with crossed legs) (Figure 4.4).
Straddling the patient. The rescuer straddles the patient in a face‐to‐face position. The rescuer holds and inserts the laryngoscope with the right hand, and passes the tube with the left hand (Figure 4.5).
Because EMS patients are frequently found and treated at ground level, clinicians should learn each of these techniques. Note that compared with traditional positioning, the rescuer’s face is closer to the patient’s oropharynx with ground‐level intubation, and thus visualization of glottic structures may differ from conventional approaches. (There may also be greater risk of exposure of the clinician to aerosolized respiratory secretions.) In some cases, tilting the patient upward by using the stretcher back or a backboard may improve airway visualization and access [1].
Limited studies suggest that the position may result in higher intubation success rates than the other ground‐level techniques. When compared to kneeling with a simulated patient on the ground, the left lateral decubitus position provided better glottic exposure [2]. In actual patient situations, laryngoscopy difficulty was lower in this position: 11.1% versus 26.9% for the kneeling group. Subsequently, there were a higher number of intubation attempts in the kneeling position than for the left lateral decubitus position [3]. It may be a better position for three reasons: the operator has better visual alignment with the larynx in the left lateral decubitus position; the left forearm acts as a lever during exposure, which minimizes operator effort; and the right arm is completely free during the procedure for tube placement and suctioning [3].
Figure 4.1 Prone intubation.
Figure 4.2 Left lateral decubitus intubating position.
The rescuer’s ability to visualize the glottis during ground‐level intubation may be challenged. Video laryngoscopy can be an adjunct for facilitating ground‐level intubation. In an evaluation of intubation success for patients lying on the ground, video laryngoscopy resulted in a 17‐second faster intubation than direct visualization with a Macintosh blade. In this study, both were highly successful, 98% and 100%, respectively [4].
Face‐to‐face intubation
A patient may require intubation while positioned upright, for example, when trapped in a car. One described approach is to perform intubation while directly facing the patient. With this technique, the operator holds the laryngoscope with the right hand, inserting the laryngoscope blade in an inverted fashion (“tomahawk” or “ice axe” approach) and passing the tracheal tube with the left hand (Figure 4.6).
Figure 4.3 Kneeling intubation.
Figure 4.4 Sitting intubation.
A study using mannequins in a model of a victim trapped in a motor vehicle compared face‐to‐face intubation with five types of video laryngoscopes and traditional Macintosh laryngoscopy [5]. Interestingly, the fastest time to intubation was with traditional Macintosh laryngoscopy, although the video laryngoscopes provided a better view of the glottis. Of the five video laryngoscopes studied, the two with integrated tube guides were associated with shorter times to intubation. Numerous studies have compared various video laryngoscopes, providing insight to their relative strengths and validating their appropriateness for in‐field deployment [6, 7].
Figure 4.5 Straddle intubation.
Figure 4.6 Face‐to‐face “tomahawk” intubation position.
When face‐to‐face intubation is the only available option, the EMS clinician should evaluate whether immediate airway intervention or patient extrication is most appropriate. The estimated time of extraction combined with patient condition may influence the decision‐making process. High‐flow oxygen devices and supraglottic airways may provide suitable alternatives in these situations.
Intubating under low light conditions
Optimal lighting is important during airway procedures. Increased ambient lighting allows for better equipment preparation and procedure execution. However, EMS clinicians often need to perform airway interventions in suboptimal lighting conditions, such as at night, while conducting military operations, in a confined space rescue, or in indoor areas with poor lighting. A common pitfall of intubation is equipment failure resulting in suboptimal airway illumination; for example, broken laryngoscope bulbs, dead laryngoscope batteries, or damaged airway equipment. Regular equipment checks and use of protective carrying cases are essential aspects of practice. Spare bulbs and batteries should always be part of the standard airway kit. Simple procedures, such as rotating batteries on a regular basis, might have a big effect on airway illumination.
Studies have identified that there is variation in light output among different laryngoscopes. When the light output of curved laryngoscope handles at 19 emergency departments in the Philadelphia area was evaluated, the median luminance varied widely from 11 lux to 5,627 lux (lux is the SI unit of illuminance equal to 1 lumen per square meter) [8]. Factors that may influence illumination brightness include bulbs/laryngoscope type (fiber optic versus regular), condition of batteries, and equipment condition (e.g., multiple sterilizations potentially causing damage to light output).
The influence of laryngoscope illumination grade on time to successful mannequin intubation has been assessed [9]. Intubations were conducted on mannequins with three clinically plausible intensities of light: high (600 lux), medium (200 lux), and low (50 lux). At perceived suboptimal intubation lighting conditions (50 lux), there was no difference in time to intubation on mannequins in this study. Clinicians
