When face mask ventilation is inadequate to provide necessary airway support, or when long-term positive pressure ventilation is required, an endotracheal tube (ETT) should be placed. In most circumstances, direct laryngoscopy (DL) is the simplest and most readily applied means of placing the ETT. Indications for DL and endotracheal intubation are summarized below (Table 5-1).

When difficulty is unlikely and when conditions are optimized prior to the attempt at intubation (for instance, during elective cases in the operating room), the standard sniffing position is an efficient starting position for experienced practitioners to intubate unassisted.

On the other hand, various factors weigh toward optimizing conditions to ensure “first pass success.” Preparation for successful intubation on the first attempt is indicated by urgency, anatomic predictors of difficulty (see Chapter 9), cardiopulmonary instability, a likely full stomach, possible gastric insufflation by first responders in codes, overly large body habitus, and (especially) limited operator experience.

The case for first pass success has been well summarized by Levitan.¹ In emergent or unplanned situations requiring intubation, maneuvers to cope with unpredicted difficulty are planned into the approach rather than added sequentially as might occur in a conventional approach. Once familiar with the maneuvers that maximize first pass success, the operator may choose a simpler approach. Keys to first pass success include (1) manipulation of the axial anatomy (ie, head, neck, torso positioning) to achieve optimal rather than adequate glottal exposure, (2) retention of fine motor control, through the use of assistants or physical supports for optimal position of the upper torso and head/neck, (3) effective navigation to find and control the epiglottis, and (4) early use of bimanual laryngoscopy. Each key requires practice until it is automated. Integrated performance to complete intubation within 30 seconds, as recommended for unstable patients, requires more practice.

Careful preparation for intubation requires a mental checklist. Of many helpful pneumonic devices, the authors prefer “STOP MAID,” to remember the following (Fig. 5-1):

Effective airway management requires careful planning so that back up plans can be executed when the primary technique fails

Positioning can facilitate both blade insertion and glottic exposure. The sniffing position, most clearly defined by Horton et al³ is atlanto-occipital extension, and elevation of the head to achieve “lower neck flexion [of] 35°,” which in normal volunteers required head support of 31 to 71 mm. Further head elevation may facilitate DL and may be essential for intubation in difficult cases.²,³,⁴,⁵,⁶,⁷ Clinical and geometric observations show flexing the thoracic spine to elevate the head may facilitate DL more than flexion of the cervical spine (Figs. 5-2, 5-3, 5-4).