Proper positioning is critical in emergency airway management and especially with rapid sequence intubation, given the short safe apnea times and deleterious effects of repetitive laryngoscopy. Maximal of mouth opening for direct laryngoscopy is a function of jaw distraction and head and neck positioning. Positioning that facilitates jaw distraction and mouth opening are important in all patients, but it is particularly critical in obese patients. In patients who do not have cervical spine immobilization, or known cervical pathology, the ideal laryngoscopy position is with the external auditory meatus and sternal notch horizontally aligned when viewed from the patient’s side. This is called “ear-to-sternal notch positioning,” and also the “ramped position”. This is the position patients adopt themselves when in respiratory distress. Along with “ear-to-sternal notch positioning”, Dr. Levitan also coined the term, Head Elevated Laryngoscopy Positioning (a.k.a. HELP) which emphasizes the importance of head elevation as part of an overall first-pass laryngoscopy strategy.
Imagine the patient in respiratory distress from congestive heart failure, or epiglottis, leaning forward, with the neck flexed on the chest and the head extended (at the atlanto-occipital joint). This position maximizes upper airway dimensions (space behind the base of the tongue and epiglottis) and also allows for optimal jaw distraction. In an upright orientation, the jaw “drops” open in this position when the masseter muscle is relaxed; there is no mechanical restriction to jaw opening and no tension on the front of the neck.
Compared to standard “sniffing” position–8-10 centimeters elevation under the occiput–ear-to-sternal notch positioning is generally much more head elevation. This is especially true for individuals who are obese and morbidly obese. In such patients a ramp may be several feet high and incorporates support under the upper torso and shoulders as well as the head to achieve proper alignment. Head elevation and ramping in this manner optimizes laryngoscopy, and it also extends the safe apnea period and facilitates mask ventilation. Even following intubation, head elevation is beneficial because it improves the mechanics of ventilation.
When performing laryngoscopy with the patient supine, along with ear-to-sternal notch positioning, the face plane of the patient should be parallel to the ceiling. A common error is to over-extend or tilt the head backwards. Atlanto-occipital extension pushes the base of tongue and epiglottis against the posterior hypo-pharyngeal wall. Not only does this make recognition of the epiglottis more difficult upon blade insertion, but this also narrows the space available to pass the laryngoscope and restricts laryngeal exposure. Extension creates an opposing tension on the anterior neck muscles as a simultaneous effort is made to distract the jaw open.
For the operator to be able to perform laryngoscopy, assuming the patient is in ear-to-sternal notch position and the face plane parallel, it is necessary to keep the head of the patient relatively low. Some texts recommend raising the patient to the operator’s xiphoid process. A lower position is needed when the patient’s face plane is parallel to the ceiling, and this lower position also permits increasing head elevation dynamically during laryngoscopy if laryngeal exposure is inadequate. Dynamic head elevation cannot be done on the morbidly obese and these patients must be ramped into a proper position in advance.
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