Chapter 30: Surgical Airways

Establishing an airway by means of a surgical approach—incision or percutaneous insertion—is a challenging procedure deployed at high-risk and high-stress moments when basic airway maneuvers have failed. The key is preparation and practice, which means having all equipment ready and available (often in a common cart to ensure consistency) and prior practice in laboratory settings if not recently performed in clinical care. Knowing what options are available and then choosing one and implementing it before respiratory collapse will improve the outcome. The success rates depend largely on the preparedness of the ED and the training of the staff.^1,2

Surgical cricothyrotomy refers to incision of the cricothyroid membrane under direct visualization and insertion of a tracheostomy tube either directly through the incision or by using the Seldinger technique. Needle cricothyrotomy is a dated term referring to insertion of a 12- to 16-gauge needle catheter into the trachea and connected to either a bag-valve device or wall oxygen. We do not recommend needle cricothyrotomy. Percutaneous transtracheal jet ventilation uses a 12- to 16-gauge catheter inserted into the cricothyroid membrane and connected to a high-pressure (35 to 50 psi) oxygen source for both oxygenation and ventilation.

The primary indication for surgical airway placement is a "can't intubate, can't ventilate" scenario. Most emergency surgical airways follow a failed attempt to establish an oral endotracheal airway. Cricothyrotomy or jet ventilation can be used before laryngoscopy and direct glottic intubation if the latter is likely to fail because of anatomic impingement or any other cause that impedes visualization, notable blood, secretions, swelling, or foreign matter. It is not necessary to try to intubate once before moving to cricothyrotomy; this often simply enhances the risk of harm.

Difficulty in establishing an airway may be due to anatomy (short, obese neck), a disease state (epiglottitis, laryngeal edema, paralyzed vocal cords, or retropharyngeal abscess), trauma from distortion of the neck by hematoma (cervical fracture or major vessel injury), aspiration of blood (facial trauma), or loss of supporting structures (mandibular fractures). Assess for these factors before any laryngoscopic attempts, have a surgical airway plan in mind, and have equipment ready at the bedside to manage impending or actual respiratory failure.

In a patient with a failed intubation attempt, the best course of action is to use bag-valve mask ventilation to restore or maintain gas exchange while regrouping. If bag mask ventilation is successful, try another attempt at laryngoscopy with a different operator and approach, rather than performing immediate cricothyrotomy. Clinical signs and symptoms of airway obstruction—one common reason to choose a surgical airway—are listed in Table 30-1.

Most children do not require advanced airway management, especially a surgical airway. In children under 12 years, the larynx is more easily damaged by cricothyrotomy, and placement is challenged by compressible structures and less distinction between cartilages. Late airway complications, especially stenosis, occur more often in children.³ For children under 12 years old, especially those under 8 years, tracheotomy is preferred; the difficulty is that few emergency physicians have experience performing this successfully, making it an unavailable practical option. Alternatively, a 14- to 16-gauge catheter inserted percutaneously through the cricothyroid membrane to either oxygenate (temporizing for minutes, done by connecting the catheter to high-flow wall oxygen) or jet ventilate (connecting to 0.5 psi/kg compressed gas source, using a 1:3 second insufflation/expiration ratio) is an option while awaiting tracheotomy. Neither technique is well studied, although jet ventilation offers wider capabilities but requires specific equipment ready in advance. Again, the key to success is advance thought, planning, and equipment preparation coupled with training for this specific event. Needle/jet approaches are discussed in more detail later.

Penetrating trauma to the neck affecting a major artery (carotid, vertebral, or thyroid) may create an expanding hematoma and obstruct the airway. If free blood spills into the oro- or hypopharynx, direct visualization for intubation is often not possible. Placing a cuffed tracheostomy tube after cricothyrotomy is the best option to restore gas exchange and limit aspiration. Difficulty in establishing an airway occurs in approximately 10% of patients with penetrating cervical trauma.⁴

Blunt trauma to the neck or face may cause hemorrhage of the soft tissues or injury to the trachea/larynx, including rupture. If the trachea or larynx is disrupted, do not attempt cricothyrotomy; in this rare setting, an emergency tracheostomy is needed. In blunt facial trauma, the principal cause of death is airway obstruction from bleeding (often from fractures) or soft tissue swelling; a surgical airway can prevent death and harm if deployed quickly and with skill.

Cricothyrotomy is preferred over percutaneous approaches (except for children <12 years old). The most skilled provider should perform this procedure to optimize success and limit harm.

Although any large-bore tube is adequate, we suggest using a tracheostomy tube because it has an obturator to ease insertion, is shorter and easier to suction, and secures well by using the flanges on each side and a cloth ribbon around the neck or suturing to nearby skin (Figure 30-1). When an endotracheal tube is placed during cricothyrotomy, the tube is difficult to secure and may be advanced too deeply; it also may be inadvertently directed cephalad (the wrong way) when placed through the cricothyrotomy incision. To avoid this, many use a gum elastic bougie to ensure tracheal placement and the correct tube direction.⁵ If a standard endotracheal tube is used and then designated for change to a tracheostomy tube, use the Seldinger (change over a guide device) technique. Use a suction catheter with the suction vent cut off at one end as an obturator for endotracheal tube removal and tracheostomy tube insertion.

The diameter of the tube inserted is crucial. A common choice for an adult is a 6-mm tracheostomy or 6- to 7-mm endotracheal tube. Do not choose a larger (≥7 mm) tube or one smaller than 4 mm. Larger tubes are difficult to insert in the narrow space between the cricoid and thyroid cartilages. If airway pressures are high with the small-diameter tube or ventilation is inadequate, consider changing to a larger diameter tube. Ventilation problems may occur when a smaller tube is used (3-mm internal diameter or less.) Any tube with a 4- or 5-mm internal diameter will allow adequate volume ventilation in most patients, although at 4 mm there is limited area for suctioning and aggressive minute ventilation; for that reason, select a 4- to 5-mm size only if a 6-mm tube is unavailable or cannot be placed.

ANATOMY

The cricothyroid membrane is located between the thyroid and cricoid cartilages (Figure 30-2A). Both structures are easily palpated but are not directly seen because they are covered with the pretracheal fascia. In men, the thyroid cartilage is prominent and creates the "Adam's apple"; in women and children, the thyroid and cricoid cartilages can be hard to distinguish from each other.

The cricothyroid membrane is found approximately one-third the distance from the manubrium to the chin in the midline in patients with normal habitus (Figure 30-2B). In a patient with a short, obese neck, the membrane may be hidden at the level of the manubrium. In a patient with a thin, long neck, it may be midway between the chin and the manubrium. The thyroid gland overlies the trachea; both structures are difficult to palpate. One easy way to find the cricoid membrane is to slowly palpate the trachea as you move up toward the head from the sternal notch; when your fingers "fall off" after a firm structure, you have palpated the thyroid cartilage. Next, slowly palpate downward toward the feet, and the first "soft spot" after that thyroid cartilage is the cricoid membrane.

The vascular structure potentially injured during the course of a properly performed cricothyrotomy is a thyroid artery, a branch of the aorta running up to the thyroid gland in the midline. This vessel infrequently reaches the level of the cricothyroid membrane. A carotid injury is potential when landmarks are not seen or not adhered to or when technique is poor; this can be catastrophic and requires immediate direct pressure to avoid harm.

EQUIPMENT

The equipment needed to perform a surgical cricothyrotomy is listed in Table 30-2.

PATIENT PREPARATION AND POSITIONING

Place the patient supine, with the neck slightly hyperextended if no cervical trauma is present (neutral if there is suspected trauma) so neck structures can be palpated and identified. If time permits, apply antiseptic solution to the skin. Ventilate with a bag-valve mask connected to 100% oxygen while preparing.

PROCEDURE

The procedure for performing a surgical cricothyrotomy is summarized in Table 30-3.

SURGICAL CRICOTHYROTOMY USING SELDINGER TECHNIQUE

This method uses the Seldinger technique (Figure 30-8). Make a small vertical incision through the skin at the cricothyroid membrane. Insert the needle and aspirate air to make sure the needle is in the trachea. Next, pass the guide wire through the needle, directing the guide wire caudally. Place a tracheostomy tube over the dilator, and make a "nick" in the skin to ease penetration. Then pass the dilator, with the tracheostomy tube, over the guide wire into the trachea. Once the dilator is in the trachea, remove the guide wire, direct the tracheostomy tube into the trachea, and verify correct placement. Indications and complications are similar to the open method, and direct comparisons in real use do not exist. Multiple commercial kits exist, but proper use requires deliberate, repetitive training.

COMPLICATIONS

Acute complications after emergency cricothyrotomy occur in up to 15% of cases.⁶ Venous bleeding usually occurs from small veins and stops spontaneously. Using a vertical neck incision that is not too long decreases the chance of ongoing bleeding. Arterial bleeding can be from the thyroid artery or from a small artery at the base of the cricothyroid membrane. The first step in controlling ongoing bleeding is to apply gentle pressure. If bleeding persists, topical hemostatic agents or ligation may be necessary. A small amount of bleeding usually creates no hemodynamic concerns, but it can make the procedure more challenging.

In an obese patient, it is possible to place the tube anterior to the larynx and trachea into the mediastinum, making ventilation impossible. Signs of an incorrectly positioned tube are high airway pressures, absent breath sounds, and massive subcutaneous emphysema. If this complication is suspected, remove the tube and make a second attempt at insertion. Endotracheal tubes passed through the cricoid membrane may curl toward the mouth, making ventilation impossible. A gum elastic bougie can help direct the endotracheal tube.⁵

Laceration of the trachea, esophagus, or recurrent laryngeal nerves is rare and is more likely to occur if one is unfamiliar with the neck anatomy. Pneumothorax is usually secondary to barotrauma caused by ventilation initiated immediately after tube placement.

A tube left in the narrow space between the cricoid and thyroid cartilages can erode both cartilages, and bacterial chondritis may occur. The cartilages will be destroyed and eventually scar, leading to stenosis and loss of the function of the larynx. Because cricothyrotomy has a high incidence of airway stenosis,⁶ a change to tracheostomy is common after 2 to 3 days.

We do not recommend "needle cricothyrotomy"—defined as a 12- to 16-gauge needle catheter inserted into the trachea and connected to either a bag-valve device or wall oxygen—as a rescue technique. Although many texts and general guidelines discuss this approach, it will not reverse ventilation gaps and will only modestly aid oxygen delivery.^7,8 In addition, the use of needle cricothyrotomy requires rapid reestablishment of a proper airway.

The only small catheter option is correctly performed jet ventilation. The proper equipment must be procured and maintained and the procedure must be practiced, because many physicians lack the proper equipment and knowledge of the procedure.⁹ Do not perform jet ventilation without the correct high-pressure equipment ready in advance and without antecedent practice; one cannot simply "put this together" at the time of critical need.

Jet ventilation uses a small catheter but also a pressured oxygen source—35 to 50 psi (much high than exiting standard bag-valve devices and oxygen wall outlets) to deliver 500 to 12,000 cc of gas. In jet ventilation, the catheter and high-pressure gas provide volume inhalation, and the native airway is the passive exhalation route. With proper jet ventilation, adequate oxygenation and ventilation occur.¹⁰ Duration is limited only by airway desiccation from nonhumidified gas, an effect that takes hours to a day to occur. Properly performed jet ventilation does not create hypercarbia or the need for rapid reestablishment of another airway; only poorly performed or "needle cricothyrotomy" low-pressure techniques create that situation.

Jet ventilation does not harm the lower airways because the high pressure dissipates rapidly; it also allows some aspiration control as the expelled gas clears the upper airway. The only absolute contraindication is complete, including expiratory, airway obstruction; this is exceptionally rare because most upper airway obstruction is inspiratory, including obstruction from masses. Relative contraindications are unfamiliarity, not having the equipment ready, and local infection at puncture site.

ANATOMY, INDICATIONS, AND CONTRAINDICATIONS

The anatomy and general indications are listed in earlier in "Surgical Cricothyrotomy."

EQUIPMENT NEEDED

Equipment needed for transtracheal jet ventilation is listed in Table 30-4. The key is having this prepared in advance; trying to use standard oxygen tubing, three-way stopcocks, or bag-valve devices or attaching to wall outlets turned to highest liter flow will not allow for proper jet ventilation.

PROCEDURE

The steps of performing jet ventilation are summarized in Table 30-5. Optimize preprocedural oxygenation and ventilation if possible (although often failure is the reason for the procedure).

COMPLICATIONS

Complications from the jet ventilation procedure are infrequent. Failure to properly secure the catheter can lead to displacement. Bleeding at the puncture site and infection may occur. Inadvertent perforation of the esophagus or back wall of the trachea or larynx is rare. Massive subcutaneous emphysema can develop during ventilation. The catheter also may be misplaced in the soft tissues of the neck. Even if the cricoid membrane is not used (from misidentification), jet punctures rarely cause long-term airway complications, an advantage over cricothyrotomy.

DEVICE REMOVAL

Jet ventilation allows a more controlled approach to airway management; plan the next step(s) carefully and without fear of ventilation failure if done properly, avoiding any rush to another procedure. Often, a better laryngoscopic attempt or a formal tracheostomy can occur once time pressures are abated with jet ventilation.