INTRODUCTION

Surgical airway management is defined as the creation of an opening to the trachea by invasive, surgical means, to provide ventilation and oxygenation. However, there may be some confusion engendered by use of the term surgical airway management. In some contexts the discussions are limited to open surgical techniques. For the purposes of discussion in this chapter, surgical airway management includes cricothyrotomy (both open and wire-guided techniques), percutaneous transtracheal ventilation (PTV), and placement of a surgical airway using a cricothyrotome (a device intended to place a surgical airway percutaneously, usually in one or two steps, without performance of a formal cricothyrotomy). Each category of surgical airway technique is described in detail in the sections that follow.

Description

Cricothyrotomy is the establishment of a surgical opening through the cricothyroid membrane with placement of a cuffed tracheostomy tube or endotracheal tube (ETT) into the trachea.

A cricothyrotome is a kit or device that is intended to establish a surgical airway without resorting to formal cricothyrotomy. These kits use two basic approaches. One approach relies on the Seldinger technique, in which the airway is accessed through a small needle through which a flexible guide wire is passed. The airway device, with a dilator, is then passed over this guide wire and into the airway in a manner analogous with that of central line placement by the Seldinger technique. The other technique relies on the direct percutaneous placement of an airway device without the use of a Seldinger technique. There have been no clinical studies to date demonstrating the superiority of one approach over another or of any of these devices over formal surgical cricothyrotomy. However, certain attributes of the devices make them intuitively more, or less, hazardous for insertion (see the “Evidence” section).

Indications and Contraindications

The primary indication for cricothyrotomy is when a failed airway has occurred (see Chapters 2 and 3) and the patient cannot be adequately oxygenated despite optimal attempts with BMV or an extraglottic device. A second indication is a method of primary airway management in patients for whom intubation is contraindicated or believed to be impossible with another available device (e.g., fiber optic scope, lighted stylet, intubating laryngeal mask airway) that otherwise would have been likely to successfully secure the airway. Thus, cricothyrotomy should be thought of as a rescue technique in most circumstances, and only infrequently will it be used as the primary method of airway management. An example of a circumstance in which cricothyrotomy is the primary method of airway management is the patient with severe facial trauma in whom access through the mouth or nose would be too time consuming or impossible. This patient requires immediate airway management because of the risk of aspiration of blood and secretions, and cricothyrotomy is indicated.

1. Will accessing the cricothyroid membrane be effective? In other words, will an incision at the level of the cricothyroid membrane bypass the obstruction and solve the problem? If the obstructing lesion is significantly distal to the cricothyroid membrane, performing a cricothyrotomy is a critical waste of time (see Chapter 36).

2. Will the patient’s anatomy or pathologic process make cricothyrotomy difficult to perform? Placement of the initial skin incision is based on palpating the pertinent anatomy. If adiposity, burns, trauma, or infection make this procedure difficult, then the strategy should be adjusted accordingly. A mnemonic for difficult cricothyrotomy (SMART) is shown in Box 19-1 and is discussed in Chapter 2.

3. Which type of invasive technique is best in the particular circumstances (i.e., open surgical or percutaneous)? This consideration takes into account provider preference based on previous experience, equipment availability, and patient characteristics. Needle cricothyrotomy (PTV) is preferred in children <10 years of age (see Chapter 26). In obese patients, subcutaneous tissue may obscure landmarks, making needle localization difficult (see Chapter 40). For these patients, often an open surgical cricothyrotomy is a better choice.

Contraindications to surgical airway management are few and, with one exception, are relative. That one exception is young age. Children have a small, pliable, mobile larynx and cricoid cartilage, making cricothyrotomy extremely difficult. For children 10 years of age or younger, needle cricothyrotomy is the surgical airway technique of choice (see Chapter 26). Relative contraindications include preexisting laryngeal or tracheal pathology such as tumor, infections, or abscess in the area in which the procedure will be performed; hematoma or other anatomical destruction of the landmarks that would render the procedure difficult or impossible; coagulopathy; and lack of operator expertise. Cricothyrotomy has been performed successfully after systemic thrombolytic therapy. Cricothyrotomy has a high success rate when performed in the emergency department (ED) setting. The presence of an anatomical barrier, in particular, should prompt consideration of alternative techniques that might result in a successful airway. However, in cases in which no alternative method of airway management is likely to be successful or timely enough, cricothyrotomy should be performed. The same principles apply for both the cricothyrotome and PTV.

The cricothyrotomes have not been demonstrated to improve success rates or time to completion, or to decrease complication rates when compared with surgical cricothyrotomy. As with formal cricothyrotomy, experience, skill, knowledge of anatomy, and adherence to proper technique are essential for success when a cricothyrotome is used.

TECHNIQUE

Anatomy and Landmarks

The cricothyroid membrane is the anatomical site of access in the emergent surgical airway, regardless of the technique used. It has several advantages over the trachea in the emergent setting. The cricothyroid membrane is more anterior than the lower trachea, and there is less soft tissue between the membrane and the skin. There is less vascularity and therefore less chance of significant bleeding.

The cricothyroid membrane is identified by first locating the laryngeal prominence (notch) of the thyroid cartilage. Approximately one fingerbreadth below the laryngeal prominence, the membrane may be palpated in the midline of the anterior neck, as a soft depression between the inferior aspect of the thyroid cartilage above and the hard cricoid ring below. The relevant anatomy may be easier to appreciate in males because of the more prominent thyroid notch. The thyrohyoid space, which lies high in the neck between the laryngeal prominence and the hyoid bone, should also be identified. This will prevent the misidentification of the thyrohyoid membrane as the cricothyroid membrane, which would lead to misplacement of the incision. We would emphasize that recent literature suggests that identification of the cricothyroid membrane may be more difficult than previously assumed (see “Evidence” section). As landmark identification is critical in any of these approaches, it merits learning and practicing proper landmark identification. The cricothyroid membrane is disproportionately smaller in children because of a greater overlap of the thyroid cartilage over the cricoid cartilage, which is one reason cricothyrotomy is not recommended in children 10 years or younger.

Unfortunately, the same anatomical or physiologic abnormalities (i.e., trauma, morbid obesity, and congenital anomalies) that necessitated surgical airway may also hinder easy palpation of landmarks. One way of estimating the location of the cricothyroid membrane is by placing four fingers on the neck, oriented longitudinally, with the small finger in the sternal notch. The membrane is approximately located under the index finger and can serve as a point at which the initial longitudinal incision is made. Except as described later in the technique for the rapid four-step technique (RFST) of cricothyrotomy, a vertical skin incision is preferred, especially if anatomical landmarks are not readily apparent. Palpation through this vertical incision can then confirm the location of the cricothyroid membrane. Alternatively, identification may be facilitated by using a locator needle, attached to a syringe containing saline or lidocaine. Aspiration of air bubbles suggests entry into the airway, but it will not distinguish between the cricothyroid membrane and a lower tracheal placement.

The No-Drop Technique

The cricothyrotomy instrument set should be simple, consisting of only the equipment necessary to complete the procedure. A sample listing of recommended contents of a cricothyrotomy tray is shown in Box 19-2. Commercial kits that also contain the instruments required for a cricothyrotomy (Fig. 19-1) are available.

• FIGURE 19-1. A: Universal Emergency Cricothyrotomy Catheter Set (Cook Critical Care, Bloomington, IN). B: Opened set containing cuffed tracheostomy tube, as well as equipment for both open surgical and Seldinger techniques.

1. Identify the landmarks. The practitioner moves to their dominant hand side of the patient (i.e., a right-handed practitioner moves to the right of the patient). The cricothyroid membrane is then identified by the nondominant hand using the landmarks described previously (Fig. 19-2). Be aware that the cricothyroid membrane might not be clearly identifiable by palpation. If in doubt, it is better to err by starting lower (more inferiorly) in the neck.

2. Prepare the neck. If time permits, apply appropriate antiseptic solution. Local anesthesia is desirable if the patient is conscious. Infiltration of the skin and subcutaneous tissue of the anterior neck with 1% lidocaine solution will provide adequate anesthesia. If time permits and the patient is conscious and responsive, anesthetize the airway by injecting lidocaine by transcricothyroid membrane puncture (see Chapter 23). The patient will cough briefly, but the airway will be reasonably anesthetized and further cough reflexes suppressed.

3. Immobilize the larynx. Throughout the procedure, the larynx must be immobilized (Fig. 19-3). This is best done by placing the thumb and long finger of the nondominant hand on opposite sides of the superior laryngeal horns, the posterior superior aspect of the laryngeal cartilage. With the thumb and long finger thus placed, the index finger is ideally positioned anteriorly to relocate and reidentify the cricothyroid membrane at any time during the procedure.

4. Incise the skin. Using the dominant hand, a 2-cm vertical midline skin incision is performed (Fig. 19-4). Care should be taken to avoid cutting the deeper structures of the neck. The cricothyroid membrane is separated from the outside world only by skin, subcutaneous tissue, and anterior cervical fascia. An overly vigorous incision risks damage to the larynx, cricoid cartilage, and the trachea. The practitioner should expect venous bleeding at this point in the procedure, which will obscure the view of the cricothyroid membrane. Once the skin is opened, safely withdraw the scalpel blade away from the immediate area so as not to injure yourself or other personnel.

5. Reidentify the membrane. With the thumb and long finger maintaining immobilization of the larynx, the index finger can now palpate the anterior larynx, the cricothyroid membrane, and the cricoid cartilage without any interposed skin or subcutaneous tissue (Fig. 19-5). With the landmarks thus confirmed, the index finger can be left in the wound by placing it on the inferior aspect of the anterior larynx, thus providing a clear indicator of the superior extent of the cricothyroid membrane.

• FIGURE 19-2. Anatomy of the Larynx. The cricothyroid membrane (arrow) is bordered above by the thyroid cartilage and below by the cricoid cartilage.

• FIGURE 19-3. A: Surface anatomy of the airway. B: The thumb and long finger immobilize the superior cornu of the larynx; the index finger is used to palpate the cricothyroid membrane.

• FIGURE 19-4. With the index finger moved to the side but continued firm immobilization of the larynx, a vertical midline skin incision is made, down to the depth of the laryngeal structures.

6. Incise the membrane. The cricothyroid membrane should be incised in a horizontal direction, with an incision at least 1 cm long (Fig. 19-6A). It is recommended to try to incise the lower half of the membrane rather than the upper half because of the relatively cephalad location of the superior cricothyroid artery and vein; however, this may be unrealistic in the emergent setting (Fig. 19-6B).

7. Insert the tracheal hook. With the scalpel blade still inside the cricothyroid membrane incision, the tracheal hook is rotated so that it is oriented in the transverse plane, passed through the incision, and then rotated again so the hook is oriented in a cephalad direction. The hook is then applied to the inferior aspect of the thyroid cartilage, and gentle upward and cephalad traction is applied to bring the airway immediately out to the skin incision (Fig. 19-7). If an assistant is available, this hook may be passed to the assistant to maintain immobilization of the larynx. At this point in the procedure, the scalpel blade can be put down and away from the immediate area so as not to injure yourself or other personnel.

8. Insert the Trousseau dilator. The Trousseau dilator may be inserted in one of two ways. One method is to insert the dilator well in through the incision, directing the blades of the dilator longitudinally down the airway. The second method, which is preferred, is to insert the dilator minimally into the anterior wound with the blades oriented superiorly and inferiorly, allowing the dilator to open and enlarge the vertical extent of the cricothyroid membrane incision, which is often the anatomically limiting dimension (Fig. 19-8). When this technique is used, care must be taken not to insert the dilator too deeply into the airway because it will impede subsequent passage of the tracheostomy tube.

• FIGURE 19-5. With the skin incised, the index finger can now directly palpate the cricothyroid membrane.

• FIGURE 19-6. A: A horizontal membrane incision is made near the inferior edge of the cricothyroid membrane. The index finger may be moved aside or may remain in the wound, palpating the inferior edge of the thyroid cartilage, to guide the scalpel to the membrane. B: A low cricothyroid incision avoids the superior cricothyroid vessels, which run transversely near the top of the membrane.

9. Insert the tracheostomy tube. The tracheostomy tube, with its inner cannula in situ, is gently inserted through the incision between the blades of the Trousseau dilator. An alternate approach is to first insert the tracheostomy tube with the blunt obturator in situ and then replace it with the inner cannula after the tube is in its final position. The blunt obturator can provide smooth insertion during placement. As the tube is advanced gently following its natural curve, the Trousseau dilator is rotated to allow the blades to orient longitudinally in the airway (Fig. 19-9). The tracheostomy tube is advanced until it is firmly seated against the anterior neck. The Trousseau dilator is then carefully removed. If a tracheostomy tube is not readily available, a small gauge endotracheal tube (size 6.0 – 6.5) can be advanced over a bougie inserted into the opening in the cricothyroid membrane. Care must be taken to advance each only a few centimeters, as the tendency will be to advance to the depth one would usually advance through the mouth.

10. Inflate the cuff, and confirm tube position. With the cuff inflated and while the practitioner holds the tracheostomy tube in place, proper tracheal tube position can be confirmed by the same methods as for oral ETT position. Carbon dioxide (CO₂) detection will reliably indicate correct placement of the tube and is mandatory, as for endotracheal intubation. Immediate subcutaneous emphysema with bagging suggests probable paratracheal placement. If doubt remains, rapid insertion of a nasogastric tube through the tracheostomy tube will result in easy passage if the tube is in the trachea and obstruction if the tube has been placed through a false passage into the tissues of the neck. Auscultation of both lungs and the epigastric area is also recommended, although esophageal placement of the tracheostomy tube is exceedingly unlikely. Once these measures confirm placement, secure the tube to the neck either by tracheal tube tape or by suturing it into position. Chest radiography should then be performed to assist in the assessment of tube placement and to evaluate for the presence of barotrauma. Pneumothorax is also possible, but far less likely than the placement of the tube paratracheally.

• FIGURE 19-7. A: The tracheal hook is oriented transversely during insertion. B and C: After insertion, cephalad traction is applied to the inferior margin of the thyroid cartilage.

• FIGURE 19-8. A: The Trousseau dilator is inserted a short distance into the incision. B: In this orientation, the dilator enlarges the opening vertically, the crucial dimension.

• FIGURE 19-9. A: Insertion of the tracheostomy tube. B: Rotation of the Trousseau dilator to orient the blades longitudinally in the airway facilitates passage of the tracheostomy tube. C: Tracheostomy tube fully inserted, instruments removed.

1. Palpate and identify landmarks. The cricothyroid membrane should be identified as described previously (Fig. 19-10). If the key landmarks are unable to be identified by palpation through the soft tissue, then a vertical skin incision is required to permit accurate identification.

2. Make skin incision. Once the pertinent palpable anatomy is identified, the cricothyroid membrane is incised. If the anatomy is fully appreciated through the intact skin, and there is certainty about landmarks and location, then incise the skin and cricothyroid membrane simultaneously with a single horizontal incision of approximately 1.5 cm in length (Fig. 19-11A). For this type of incision, a no. 20 scalpel yields an incision that requires little widening. The intention of the initial incision is to puncture the skin and cricothyroid membrane simultaneously. If the anatomy is not readily and unambiguously identified through the skin, then an initial 2 cm vertical incision should be created to allow more precise palpation of the anatomy and identification of the cricothyroid membrane. In either situation, the cricothyroid membrane is incised with the no. 20 blade that is maintained in the airway, while a tracheal hook (preferably a blunt hook) is placed parallel to the scalpel on the caudad side of the blade (Fig. 19-11B). The hook is then rotated to orient it in a caudad direction to put gentle traction on the cricoid ring. The scalpel is then removed from the airway. At no time during this procedure is the incision left without instrument control of the airway. This detail is particularly important in a scenario where the patient still has the ability to respond or swallow. The newly created opening could be irretrievably lost if the airway is uncontrolled and moves relative to the skin incision. This is a technique that relies exclusively on palpation of key structures. Bleeding will inevitably obscure visualization of the anatomy. No time should be wasted using suction or gauze or manipulating the overhead lighting.

3. Apply traction. The tracheal hook that has been rotated caudally and is controlling the cricoid ring is now used to lift the airway toward the skin incision. This action provides modest stoma dilation. The direction of traction should be “up and away” and should feel reminiscent of laryngoscopy. Importantly, at this time the whole larynx should be lifted and controlled by the hook. If the hook placement is incorrect, it will often be apparent as the hook will simply be tenting the skin and not lift the larger underlying larynx (Fig. 19-12). The amount of traction force required for easy intubation (18 N or 4 lb force) is significantly lower than the force that is associated with breakage of the cricoid ring (54 N or 12 lb force). Use of the hook in this direction generally provides sufficient widening of the incision, and a Trousseau dilator is usually not required. The technique of pulling the airway upward in this way also minimizes the possibility of intubating the pretracheal potential space.

4. Intubate. With adequate control of the airway using the hook placed on the cricoid ring, ETT is readily placed into the airway and secured (Fig. 19-13). Confirmation techniques proceed as described in the no-drop technique. A bougie can also be inserted at this point to aid passage of a small caliber standard ETT.

• FIGURE 19-10. Palpation. The operator’s thumb is on the hyoid bone, while the cricothyroid membrane is identified using the index finger.

• FIGURE 19-11. Incision. A: A horizontal incision is initiated while stabilizing the larynx. B: Before removing the scalpel from the airway, a hook is placed on the caudal side of the scalpel, parallel to the blade.

Complications

Because of the high success rate of RSI, cricothyrotomy is infrequently performed in EDs, so reports of complications are difficult to evaluate. In the National Emergency Airway Registry (NEAR III) study, only 0.3% of more than 17,500 adult ED intubations required a rescue cricothyrotomy.

• FIGURE 19-12. Traction. The hook is applied to the cricoid ring and lifted.

• FIGURE 19-13. Intubation. The tracheostomy tube is passed into the incision as the hook stabilizes the cricoid ring.

There is insufficient evidence to determine whether the overall complication rate is lower when the traditional no-drop technique of cricothyrotomy is used versus the RFST. Box 19-3 lists complications of surgical airway management.

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