Blind Intubation Techniques

DESCRIPTION

Blind intubation techniques are those methods of airway management that result in passage of an endotracheal tube (ETT) through the larynx and into the trachea without any visualization of the glottic structures. Pertinent examples of such procedures include blind nasotracheal intubation (BNTI), digital tracheal intubation (DTI), and blind passage of an ETT through an extraglottic device (EGD).

BNTI relies on visual and auditory cues to distinguish tracheal versus esophageal tube passage, whereas DTI depends on the provider’s ability to use tactile senses to distinguish airway anatomy as the tube is inserted. Blind passage of an ETT through an EGD is discussed in Chapter 10.

BLIND NASAL INTUBATION

Historical Perspective

Whereas BNTI was once a commonplace procedure for emergency intubation, it has now been relegated to a novelty in many settings. With the advent of medication-facilitated airway management (MFAM) and technologies such as video laryngoscopes, flexible intubating endoscopes, extraglottic airways, and noninvasive positive-pressure ventilation (NIPPV), the need for performing BNTI has virtually vanished. In addition, ICUs are generally unwilling to manage nasally intubated patients because the smaller tubes required for passage make ventilation and pulmonary toilet more difficult, and there is an increased risk of sinusitis. The “original” indication for BNTI in emergency airway management was for the patient in whom intubation was deemed necessary but who still had intact airway protective reflexes and MFAM was not available. Today, such patients would likely be managed with rapid sequence intubation (RSI) or NIPPV. There was also a long-held but now debunked belief that BNTI was preferable in the setting of confirmed or suspected cervical injury because of less perceived periprocedural cervical spine movement.

Indications and Contraindications

BNTI may still be considered in those situations where intubation is clearly indicated and either (1) RSI is not permitted by scope of practice or (2) RSI is contraindicated because of predicted airway difficulty, and the equipment or expertise for awake oral or visualized nasal intubation is not available. Unfortunately, success rates for BNTI never came close to those for RSI even when it was commonly performed; it is undoubtedly even lower now. Therefore, providers who are attempting BNTI must be ready to perform a surgical airway if unsuccessful.

BNTI is achieved by using some cue to recognize that the patient’s spontaneous airflow is traveling through the ETT after blind passage, and therefore, the procedure should not be attempted in the apneic patient or the chemically paralyzed patient. It is relatively contraindicated in combative patients; in those with anatomically disrupted or distorted airways (e.g., neck hematoma, upper airway tumor); in the context of severe facial trauma with suspected basal skull fracture; in upper airway infection, obstruction, or abscess (e.g., Ludwig’s angina, epiglottitis); and in the presence of coagulopathy. It is also a poor choice for patients with hypoxemic respiratory failure who cannot be adequately oxygenated during a protracted nasal intubation attempt.

Technique

1. Preoxygenate the patient with 100% oxygen.

2. If the patient is awake, explain the procedure. This is a crucial step that is often neglected. If the patient becomes combative during intubation, the attempt must cease because epistaxis, turbinate damage, or even pharyngeal perforation may ensue. A brief, reassuring explanation of the procedure, its necessity, and anticipated discomfort may avert this undesirable situation.

3. Choose the nostril to be used. Inspect the interior of the naris, with particular reference to the septum and turbinates. It may help to occlude each nostril in turn and listen to the flow of air through the orifices. If there appears to be no clear favorite, the right naris should be selected because it better facilitates passage of the tube, with the leading edge of the bevel laterally placed.

4. Instill a topical vasoconstrictor (i.e., phenylephrine or oxymetazoline) spray into each nostril. This may reduce the risk of epistaxis and make tube passage easier, though the evidence is limited. Atomization with a commercially available device may be the most desirable method of application. It may also be helpful to soak two or three cotton-tipped applicators in the vasoconstrictor solution and place them gently and fully into the naris until the tip touches the nasopharynx; this provides vasoconstriction at the area that is often most difficult to negotiate blindly with the ETT.

5. Insert a nasal airway lubricated with 2% lidocaine jelly into the selected naris. This helps to dilate the nasal passage and distribute the anesthesia. If there is ample time, some providers prefer to start with a smaller size and then sequentially replace these with larger diameter nasopharyngeal airways (NPAs) to “dilate up” to the size of the ETT to be used.

6. Consider anesthesia of the posterior oropharynx if time permits. The posterior cavity may be sprayed with 4% lidocaine or a similar spray; a commercially available “wand-style” atomization device may be the best choice for this application. An alternative is to nebulize 3 mL of 4% aqueous lidocaine solution in a standard small-volume nebulizer (see Chapter 23).

7. Select the appropriate ETT. A specialized ETT such as the Endotrol (Covidien; Mansfield, MA) tube may be extremely helpful. These tubes have a “pulley-like” apparatus built into them to allow anterior deflection of the tip of the tube at the will of the operator (Fig. 18-1A, B). In general, the tube should be the largest one that will fit through the nostril without inducing significant trauma, or 6.0 to 7.0 mm in most adults. Test the ETT cuff for leaks in the usual manner. You may consider warming the tube as for a standard endoscopic nasal intubation only if you are using an Endotrol-type ETT. If you are using a standard ETT, warming may make it too floppy to deflect far enough anteriorly.

8. Prepare capnography that will be used for tube guidance (Fig. 18-2).

9. Lubricate the tube generously using any appropriate ETT lubricant.

10. Position the patient appropriately. The awake patient will usually be seated while the unconscious patient will usually be supine. In either situation, a sniffing or ramped position should be assumed unless contraindicated. Positioning the head as for oral intubation is worthwhile, if possible. The so-called “ear to sternal notch” position, with the neck flexed on the body and the head extended on the neck, optimizes the alignment of the mouth and pharynx (in the adult patient) with the vocal cords and trachea (see Chapter 13). A small folded towel may be placed behind the patient’s occiput to help maintain this relationship. Care must be taken to avoid overextension of the atlanto-occipital joint, however, which can cause the tube to pass anteriorly to the epiglottis.