Nasotracheal intubation (NTI) is an essential psychomotor skill that may be useful in many difficult situations. Operators adept at both NTI and rapid-sequence intubation (RSI) are in the best position to assess and act on the following two prime considerations. What are the potential risk-benefits to having spontaneous respirations preserved versus ablated? Is there a safe alternative in this patient that may avoid precipitating the need for a potentially unnecessary surgical airway? 5
Nasal intubation is helpful in situations where laryngoscopy or cricothyrotomy may be difficult and neuromuscular blockade hazardous. Severely dyspneic patients with congestive heart failure (CHF), chronic obstructive pulmonary disease (COPD), or asthma who are awake often cannot remain supine but do tolerate nasotracheal intubation in the sitting position. Nasotracheal tubes are better tolerated by some patients than oral tubes. There is often less intratracheal tube movement against the tracheal muscosa with head motion.
It may be impossible to align the oropharyngeolaryngeal axis in patients with arthritis, masseter spasm, temporomandibular dislocation, or recent oral surgical procedures. Patients with a peculiar body habitus may be difficult to intubate orally. Other considerations for NTI include trismus from seizures, facial trauma, infection, tetanus, or decorticate-decerebrate rigidity.
To minimize epistaxis, spray both nares with a topical vasoconstrictor anesthetic. While waiting briefly, select a cuffed ET tube 0.5 to 1 mm smaller than optimal for oral intubation. Check the integrity of the cuff and ensure snug fitting of the tube adapter. Since secretions and blood may be expelled into the air and onto the intubator's face, observe universal precautions. An option in addition to a face shield includes the use of a protective filtering adapter such as the Humid-Vent 1, which can be attached to the proximal end of the ET tube (Gibeck Respiration, Sweden).
Advance the tube, lubricated with a water-soluble (2% lidocaine or K-Y) jelly along the nasal floor on the more patent side. If the nares appear equal, initially try the right side. It helps to prevent abrasions of the Kiesselbach plexus by having the bevel face the septum. Steady, gentle pressure or slow rotation of the tube usually bypasses small obstructions. Passage of the tube is straight back toward the occiput. If the right side is not passable, try the other side before resorting to a smaller tube.
In patients with intact protective airway reflexes, directed transoral or translaryngeal anesthesia often facilitates intubation. Translaryngeal anesthesia, although not widely utilized in the ED, should be considered when the initial intubation attempt is unsuccessful. After palpating the superior border of the cricoid cartilage in the midline, puncture the cricothyroid membrane with a 22- to 25-gauge 0.5- to 1-in. needle ( Fig 15-2). The needle should be perpendicular to the membrane in the midline, with the point of injection just cephalad to the cricoid cartilage. Aspirate air, then swiftly inject 1.5 to 2.0 mL of 4% lidocaine (sterile for injection) and press the site firmly with a finger for a few seconds. This prevents small degrees of subcutaneous emphysema that would erroneously suggest a laryngeal injury.
FIG. 15-2. Translaryngeal anesthesia via cricothyroid puncture. A. Anatomy—anterior view. B. Anatomy—cross-sectional view.
The literature would suggest a complication rate of less than 0.5 per 1000 procedures. Translaryngeal anesthesia is contraindicated if the landmarks are obscured by thyroid or tumor impingement on the cricothyroid membrane and in obese or combative patients.
An assistant should immobilize the patient's head and initially maintain it in a neutral or slightly extended position ("sniffing position"). Stand to the side of the patient, with one hand on the tube and with the thumb and index finger of the other hand straddling the larynx. Advance the tube while rotating it medially 15 to 30° until you hear maximal airflow through the tube. Then gently but swiftly advance the tube. The best time for advancement is at the initiation of inspiration. Entrance into the larynx may initiate a cough, and most expired air should exit through the tube even though the cuff is uninflated. "Fogging" of the tube, while not foolproof, is usually a good sign. The presence of any vocal sounds indicates a failed attempt.
The advancement of the tube toward the carina can be observed externally. The normal distance from the external nares to the carina is 32 cm in the adult male and 27 to 28 cm in the adult female. Therefore, prior to obtaining a chest x-ray, the optimal initial depth of tube placement in NTI of adults, measured at the naris, is 28 cm in men and 26 cm in women.6 Preformed nasal tracheal tubes are also available, with an acute angle bent at the 29-cm mark. Auscultate to verify bilateral lung expansion and cuff inflation and perform tube confirmation techniques. Secretions or blood in the tube should be removed prior to initiating positive-pressure ventilation.
If intubation is unsuccessful, carefully inspect the neck to determine malposition of the tube. Most commonly, the tube is in the pyriform fossa on the same side as the nostril used. A bulge will be seen and can be palpated laterally. Withdraw the tube into the retropharynx until breath sounds are again heard. Then redirect while manually displacing the larynx toward the bulge. If there is no contraindication, flexion and rotation of the neck to the ipsilateral side while the tube is rotated medially will often help.
The other most common tube misplacement is posteriorly in the esophagus. There will be no breath sounds through the tube, and the trachea will be slightly elevated. The intubator should attempt redirection after extending the patient's head and performing a Sellick maneuver. When cervical spine pathology is suspected, consider the use of a directional tip control tube (Endotrol) or a fiberoptic laryngoscope. Endotrol tubes smaller than 7.5 mm (ID) tend to soften and obstruct and can be difficult to suction. The use of these directional-tip tubes may improve the success rate of the first attempt at NTI.7
When the tube hangs up on the vocal cords, shrill, turbulent air noises will be heard. Rotate the tube slightly to realign the bevel with the cords or squirt 2 mL of 4% lidocaine (80 mg) down the tube onto the cords if transoral or translaryngeal anesthesia was omitted. There have been anecdotal reports that if NTI is unsuccessful with passage of the tube into the esophagus, leaving the original tube in place may facilitate passage of the tube using the other nostril. This technique may also afford some protection from aspiration.
Nasal intubation with a fiberoptic laryngoscope may be required when neoplastic lesions, lymphoid tissue, Ludwig angina, peritonsillar abscess, or epiglottitis obstructs the pharynx.
The presence of facial trauma does not appear to be a contraindication to NTI intubation. 8 Complex nasal and massive midfacial fractures as well as bleeding disorders are relative contraindications to NTI. Oral intubation, on the other hand, can impede prompt reduction and stabilization of some maxillary fractures. Since a LeFort I fracture does not extend to the cribriform plate, this is not a contraindication. Fiberoptic guidance or RSI is preferable for LeFort II and III fractures.
The risk of inadvertent intracranial passage of a nasotracheal tube is extremely low, unlike nasogastric tube insertion. Very poor technique in the setting of obvious massive head trauma would be required. Severe traumatic nasal or pharyngeal hemorrhage may necessitate orotracheal intubation or cricothyrotomy. Contamination of the spinal fluid is a hazard with some basilar skull fractures.
Serious complications of nasotracheal intubation are rare. In a number of large series, there was no permanent laryngeal damage. Epistaxis will occur with inadequate topical vasoconstriction, excessive tube size, poor technique, or anatomic defects. Excessive force can damage the nasal septum or turbinates.
Frequent suctioning, especially if epistaxis or other upper airway hemorrhage is present, will help to prevent thrombotic occlusion of the tube or a mainstem bronchus. Retropharyngeal lacerations, abscesses, and nasal necrosis are reported.
Paranasal sinusitis, especially occurring with prolonged nasotracheal intubation or severe cranial trauma, can be an unrecognized source of sepsis. The risk of postintubation sinusitis correlates with the duration of intubation, which often reflects the neurologic insult. In the setting of craniofacial trauma, any subsequent computed tomography (CT) scans should include views of the paranasal sinuses. Other factors causing sinusitis include presence of a nasogastric tube, sinus hemorrhage or fracture, and administration of glucocorticoids.
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