Chapter 13. Surgical Airway

In 1799, as George Washington lay dying of life threatening upper airway obstruction, one of his physicians, Elisha Cullen Dick, argued against further bloodletting and for tracheotomy. In retrospect this was the only lifesaving option available. It was not attempted and the President succumbed.1

Indications for surgical airway access vary from the elective through to impending airway compromise, and finally to the true emergency cannot intubate, cannot oxygenate scenario. This chapter will deal primarily with techniques of surgical airway access that the practitioner can use to deal with the difficult airway that presents either in the form of impending airway compromise or, the life-threatening emergency.

13.1.1 Why Cricothyrotomy and Not Tracheotomy?

The higher complication rate of emergency tracheotomy, compared to cricothyrotomy,2 results from the fact that the trachea is situated deeper in the neck, the posterior tracheal wall lacks the protection of a circumferential cricoid cartilage (increasing the risk of esophageal perforation), there is a greater abundance of adjacent vascular structures, and there is a proximity of the thyroid gland and lung. The palpable, often visible, surface landmarks of the thyroid and cricoid cartilages and the ability to accomplish the task faster, with a minimum of equipment, make emergency cricothyrotomy more attractive than tracheotomy, for the surgeon and nonsurgeon alike.3

As a consequence, all of the techniques to be discussed with the exception of percutaneous dilational tracheotomy (see Chapter 31) and possibly needle insufflation in children will involve access to the airway through the cricothyroid membrane (CTM).

13.1.2 What Is the History of Cricothyrotomy?

Surgical access to the airway has its origins in ancient times but it was the pandemic of morbus strangulatorius in Europe at the beginning of the 19th century that began its modern evolution. The French surgeon, Pierre Bretonneau, first attempted to relieve the laryngeal obstruction of this infectious laryngo-tracheal bronchitis by tracheotomy in 1818, finally meeting with success in 1825.4 His paper, published in 1826, gave the disease entity the name diphtheria,5 from the Greek diphthera meaning leather. This was in recognition of the thick, leathery, blue-white upper respiratory tract membranes characteristic of the disease.6 In the 20 years that followed, Armand Trousseau, Joseph Récamier, and MP Guersant, honed the technical aspects of bronchotomy7—laryngotomy and tracheotomy—and by 1851 Trousseau published his experience in 222 cases, 127 of whom survived.8

In the United States, Chevalier Jackson published further refinements to the technique in 1909.9 Ten years later (1921), he published a paper attributing the devastating complication of subglottic stenosis to high tracheotomy, concluding that the only acceptable point of access to the airway was below the first tracheal ring and that high tracheotomy should be abandoned.10 Jackson was a figure of immense authority11 and it is not surprising that high tracheotomy, or cricothyrotomy, was relegated to almost total obscurity for close to five decades.

Brantigan and Grow3 renewed interest in the approach following publication of their 1976 paper. The impetus for the study came from anecdotal experience during the early days of cardiac surgery. Grow, a student of Chevalier Jackson, looked to cricothyrotomy as a way to avoid contamination of median sternotomy wounds by pathogens tracking down the shared mediastinal tissue planes from open tracheotomy sites. He began performing cricothyrotomy, initially in emergency situations, and later electively when it was evident to him that subglottic stenosis did not appear to be a problem.

Grow and Brantigan reported their experience in 655 cricothyrotomies performed over an 8-year period. Duration of intubation ranged from 1 to less than 40 days, with an average of 7 days. Their results showed minimal complications and no cases of subglottic stenosis. Subsequently, several authors,12-14 including a recent prospective study,15 reported similar findings in patients not previously subjected to prolonged endotracheal intubation, or suffering from any acute laryngeal pathology. Talving et al reviewed 30 years (between 1978 and 2008) of published literature to determine the rates of subglottic stenosis following emergency cricothyrotomy.16 Twenty studies (17 retrospective reports and 3 prospective, observational series) with a total of 1124 patients, including 368 trauma patients, were reviewed. With follow-up periods ranging between 2 and 60 months, the rate of subglottic stenosis among survivors was 2.2 % and 1.1% among emergency trauma patients.16 While acknowledging that a well-designed prospective investigation is needed, the authors concluded that no study to date has demonstrated any benefit of routine conversion to tracheotomy.

The discrepancy between the observations of Jackson in the 1920s and the modern authors results from several factors that reflect the two eras, separated by over half a century. Most of the surgical indications for a surgical airway in Jackson's era were inflammatory in nature; cricothyrotomy in the presence of inflammation is now well recognized to predispose to subglottic stenosis. In addition, high tracheotomy was a much more complex procedure than the modern cricothyrotomy, involving division of the cricoid or thyroid cartilages. The lack of antibiotics, and the primitive design of the tracheostomy tubes available in the 1920s, undoubtedly compounded the situation.17

As cricothyrotomy is more advantageous for its speed, safety, and simplicity,18 access through the CTM is the technique of choice in emergency surgical airway management.

In spite of literature to the contrary, the devastating complication of subglottic stenosis associated with cricothyrotomy still compels most clinicians to convert to tracheotomy as soon as possible.

13.1.3 What Anatomy Do I Have to Know to Perform These Procedures?

Access to the airway through the CTM requires a practical knowledge of the anatomy of the larynx, particularly the surface landmarks, as well as the important adjacent structures in the neck.

In most adult males, the thyroid notch (Adam's apple) is a prominent feature, which identifies the superior aspect of the thyroid cartilage. With the neck extended, palpation inferiorly from this point will often allow the practitioner to identify the inferior margin of the thyroid cartilage and the ring-shaped cricoid cartilage below (Figure 13-1). Between the inferior margin of the thyroid and the cricoid cartilages is the CTM. The size of the membrane in adults is 22 to 33 mm wide and 9 to 10 mm high.19 The vocal cords are attached to the internal anterior surface of the thyroid cartilage, approximately 1 cm above the upper border of the cricothyroid membrane.20 Care should be exercised in placing instruments superior to the cricothyroid incision for this reason. The only important vascular structure in the vicinity of the CTM is the superior thyroid artery, which, in 54% of people, courses on its lateral border.21 The left and right cricothyroid arteries, branches of their respective superior thyroid arteries, course medially and traverse the upper half of the CTM,21 anastomosing in the midline. Injury to this vessel can be avoided by entering the CTM in its inferior half. Caution also dictates that the incision should not extend laterally greater than 1 cm.17

Other important anatomical structures include the hyoid bone and the thyroid gland and isthmus. The airway itself is suspended by the hyoid bone lying superior to the thyroid cartilage. Identifying the hyoid bone is important to avoid mistaking the thyrohyoid space for the cricothyroid membrane. In patients with poorly palpable surface anatomy, the location of the hyoid bone can be estimated by extending a line from the mentum posteriorly, half the distance between the mentum and the angle of the mandible.22

The thyroid gland has a pyramidal lobe, in 40% of patients23 that may extend as high as the hyoid bone and could be at risk of injury during cricothyrotomy.

13.1.4 How Can I Predict Whether Access through the CTM Will Be Difficult?

Although there is no formal evidence, it is intuitive that anything interfering with either physical access to the larynx, or the ability to appreciate the landmarks of the larynx, will make CTM puncture difficult. This includes factors such as previous surgery, fixed cervical spine flexion deformity, hematoma, obesity, radiation to the neck, laryngotracheal malignancy, or tumor. SHORT (Surgery/Spine, Hematoma, Obesity, Radiation, and Tumor) is a useful mnemonic to remind practitioners of the factors that may be associated with a difficult surgical airway (see Section 1.6.4).

13.1.5 So, What Do I Need to Do to Get Ready?

The following are common to all techniques of surgical access by way of the CTM:

1. Antisepsis and local anesthetic infiltration: If time permits, every effort should be made to use aseptic technique and infiltrate the proposed surgical site with local anesthetic.

2. Positioning the patient: The patient is ideally placed in the supine sniffing position, with the head extended to best expose the surface landmarks of the larynx. In an emergency situation, particularly in the setting of severe upper airway obstruction, it may be necessary to position the patient semi-recumbent, or fully erect.

3. Immobilization of the larynx and identification of the CTM: Immobilization of the larynx and identification of the CTM is most effectively accomplished by the right-handed practitioner standing on the right side of the patient. The left (nondominant) hand is used to stabilize the larynx by grasping the body of the thyroid cartilage between the thumb and middle finger, leaving the index finger free to palpate the cartilaginous structures (Figure 13-2). If the laryngeal notch is palpable, the index finger is moved caudad along the thyroid cartilage, in the midline, until the fingertip dips off its inferior aspect. Should surface landmarks be difficult to appreciate, the level of the cricothyroid membrane can be estimated as follows: with the head in neutral position, the fifth finger is placed in the suprasternal notch; with all fingers in juxtaposition, the location of the index finger will approximate the level of the CTM.24 In addition, skin creases in the anterior neck may represent a useful visual landmark for estimating the level of the CTM. Hung et al demonstrated that with the head in the neutral position, in patients with two neck creases inferior to the mentum, the second skin crease was a median distance of 2.0 mm above the cricoid cartilage (Figure 13-3).25

For transtracheal catheter and Seldinger techniques, some right-handed practitioners will choose to stand over the right shoulder or at the head of the patient, immobilizing the larynx and identifying the CTM, as described earlier. Others will choose to stand on the left side of the patient for these techniques, immobilizing the larynx and identifying the CTM with the left hand from below. This permits the practitioner to use the right hand to pass implements through the CTM in a caudad direction and in a more dextrous fashion. Primary immobilization of the larynx by the left hand, from below, also minimizes trauma to the thyroid cartilage by promoting retraction of the cricoid ring inferiorly, rather than superior retraction on the thyroid cartilage.

Five methods of surgical access to the airway will be outlined:

1. Open cricothyrotomy

2. Seldinger cricothyrotomy

3. Transtracheal catheter ventilation

4. Percutaneous dilational tracheotomy

13.2.1 Can You Walk Me through Each Method…Step by Step?

13.2.1.1 Open Cricothyrotomy

• Equipment: The instruments required are a scalpel with a #11 blade; a tracheal hook; Armand Trousseau dilator; and a 5.0 mm ID cuffed endotracheal tube, or a small, cuffed tracheotomy tube (Figure 13-4).
• Technique: It should be clearly appreciated by the practitioner that the technique of emergency cricothyrotomy is primarily a tactile and not a visual technique. With the patient positioned and landmarks identified, the following are steps to a successful standard surgical cricothyrotomy technique:

  1. A 4.0 cm vertical, midline skin incision (Figure 13-5)

  2. A transverse incision of the CTM at the superior border of the cricoid cartilage

  3. Retraction with a tracheal hook (Figure 13-6) either superiorly, with potential trauma to the vocal cords or thyroid cartilage, or inferiorly, with less risk and perhaps better exposure

  4. Insertion of the Trousseau dilator (Figure 13-7)

  5. Caudal placement of a 5.0 mm ID cuffed endotracheal tube, or a small, cuffed tracheotomy tube (Figure 13-8)

  6. Inflation of the cuff, ensuring the proper position and removal of the hook and dilator

Prior to securing the tube, it is important to confirm proper placement by ETCO2 and/or by auscultation. A chest X-ray should be obtained, as soon as conveniently possible, to determine adequate tube position and to rule out any parenchymal lung injury, or pneumothorax. Current recommendations view a cricothyrotomy as a temporizing, lifesaving measure. The patient should undergo conversion to a traditional tracheotomy once stabilized.

13.2.1.2 Seldinger Cricothyrotomy Technique

The majority of practitioners are familiar with the Seldinger technique and most will be more comfortable with this approach.

• Equipment: There are several cricothyrotomy kits designed with this technique in mind and all with similar contents. They contain a scalpel blade, a syringe, an 18-gauge catheter over needle and/or a thin-walled introducer needle, a guidewire, a dilator, and a cuffed airway catheter (Figure 13-9).
• Technique: As access to the airway is achieved through the cricothyroid membrane, the anatomic considerations and patient positioning are the same as for open cricothyrotomy. The technique is summarized as follows:

  1. Vertical midline stab incision through the skin overlying the CTM.

  2. Caudal insertion of an 18-gauge needle attached to a syringe (Figure 13-10).

  3. Confirmation of needle placement by aspirating air, followed by removal of the needle and syringe.

  4. Insertion of the guidewire (Figure 13-11) and removal of the catheter, leaving the guidewire in the trachea.

  5. After making a small cut of the CTM along the guidewire (Figure 13-12), the cuffed airway catheter loaded onto the dilator is advanced as a single unit, over the wire and into the airway (Figures 13-13 and 13-14).

  6. Removal of the dilator and securement of the tube.

  7. Confirmation of proper tube placement by ETCO2 and/or by auscultation.

It should be noted that the Universal Cook Critical Care Melker Cricothyrotomy kit contains equipment to perform both open and Seldinger techniques. Once again, current teaching recommends securing a formal tracheotomy, once the patient is stabilized.

13.2.1.3 Transtracheal Catheter Ventilation

The passage of a 12 to 14 gauge catheter through the CTM for the purposes of establishing an emergency airway is a temporizing method at best. It provides short-term oxygenation until a definitive airway can be established. Many variations of this technique have been used in general relation to availability of equipment. One such technique is summarized as follows:

1. Caudal insertion of 14 g IV catheter, with syringe attached, through the CTM

2. Confirmation of position by aspiration air, and advancement of the catheter to its hub, while removing the needle and syringe

3. Oxygenation utilizing one of several options

4. Ensuring that there is sufficient time for egress of gas, in order to prevent hypercapnea/hypoxia and air trapping

Options that are available for delivery of O2 include jet ventilation, the O2 flush valve on the anesthetic machine, and the anesthesia circuit itself. As mentioned, it is essential that there is sufficient time and an available route for egress of gas. An assistant should be instructed to manage the upper airway with all necessary maneuvers, including LMA, or other airway, and appropriate airway maneuvers.

Gaufberg and Workman recommend that ventilation with this technique should not exceed 20 minutes in adults and 40 minutes in children.26 It is also the only recommended emergency surgical airway, other than tracheotomy, in children under the age of 12 years.

13.2.1.3.1 Transtracheal Jet Ventilation

For the purposes of simplicity, only classic transtracheal jet ventilation (TTJV) and TTJV with the ENK modulator will be considered here.

Many operating rooms have access to a commercially available jet ventilator, consisting of a high-pressure connector, high-pressure hosing, an in-line regulator, a jet ventilation toggle switch, and a Luer-Lock connector. This device is powered by central wall oxygen at 50 psi (15 L·min−1) and subject to an in-line regulator. Activation of the toggle switch, in a controlled fashion, allows oxygen to be safely jetted through the transtracheal catheter into the airway.

An O2 tank regulator powers another form of TTJV system, with similar high-pressure hosing, jet injector, and Luer-Lock connector. A low flow tank regulator, as on the E cylinder O2 transport tanks, can achieve a maximum pressure of 120 psi with the flow meter set at 15 L·min−1. When the jet is activated briefly, very high flows are generated and can result in satisfactory tidal volumes through 14-gauge catheters over 0.5 second.27

For all systems, chest rise and fall, and the pulse oximeter response, are noted as a measure of ventilatory adequacy.

13.2.1.3.2 ENK Flow Modulator

The ENK flow modulator (Figure 13-15) permits transtracheal ventilation by tubing connected to the O2 flush valve on an anesthesia machine, or on a wall-mounted flow meter. The device is equipped with a series of five holes that can be occluded in a measured fashion to direct flow through the device to the patient. As with TTJV, chest rise and fall is noted as a measure of ventilatory adequacy.

13.2.1.4 Percutaneous Dilational Tracheotomy

There is an increase in popularity of using percutaneous dilational tracheotomy (PDT) following Ciaglia's28 1985 publication. Limited to elective, bedside procedures, the current widespread use of this technique has revealed it to be safe, rapid, with minimal overall procedural morbidity.15 In fact, the overall complication rate is low and comparable to traditional surgical tracheotomy.29

The procedure was initially performed as a blind technique relying on knowledge of surface landmarks. Adjuncts, such as the lightwand30 (Trachlight™, Laerdal Medical Inc., Wappingers Falls, NY) and the flexible bronchoscope (FFB), can enhance the ease of performing the procedure while minimizing complications, such as paratracheal placement of the tracheotomy tube, pneumothorax, and loss of airway control upon withdrawal of the ETT.31

A summary of the Seldinger-based procedure with the Ciaglia Blue Rhino (Cook Inc., Bloomington, IN) is as follows:

1. Skin incision and palpation of cricoid and proximal tracheal rings

2. Flexible bronchoscopic (FB) visualization to retract the ETT and monitor insertion of a catheter over needle device between the second and third, or third and fourth, tracheal rings

3. Application of the Seldinger technique with J-guidewire and a single tapered dilator

4. Insertion of a size-appropriate tracheostomy tube

5. Confirmation of the intratracheal placement with the FB

PDT should be performed by a team of experienced practitioners familiar with the use of the FB and with the traditional surgical approach. Avoidance of the obese patient with poorly defined neck anatomy, acute laryngeal pathology, complete airway obstruction, previous neck surgery, or C-spine flexion deformity will increase the overall success rate of the procedure. For a complete review, and application of the technique, please refer to Chapter 31.

13.3.1 Are There Any Contraindications to Performing a Surgical Airway?

In the emergency situation when gas exchange cannot be established, a surgical airway is mandatory to prevent catastrophe. As such, there are no contraindications to a surgical airway. There are, however, certain issues that deserve consideration.

In acute or chronic inflammatory laryngeal pathology, and neoplastic disease, cricothyrotomy will likely be more difficult to perform and be subject to a greater incidence of subglottic stenosis. Obesity, injuries, and deformities of the neck may either distort the anatomy and/or render surface landmarks difficult to palpate; and uncontrolled hemorrhage may complicate the situation in the anticoagulated patient. Cricotracheal separation is an absolute contraindication to any procedures that utilize the CTM.

13.3.2 What Are the Concerns in Establishing a Surgical Airway in Patients with a Deep Neck Infection?

Deep space neck infections are most common in the extremes of age. Underlying medical problems often accompany the afflicted elderly patient. Deep space infections can either variably occlude, or shift the airway, rendering what should be an easily managed airway into an emergency. Caution dictates that airway management should be performed in a controlled environment, preferably the operating room. A CT scan, if feasible, would greatly facilitate understanding of the altered anatomy, but this may not be feasible in the severely compromised airway.

In the moderately affected airway, topical anesthesia and awake FB-assisted intubation is the method of choice. If the airway is severely compromised, with total airway obstruction a possibility, an awake surgical airway is the procedure of choice—to ensure a secure airway until the infection and its source can be treated.

13.3.3 Do You Have Any Concerns in Establishing a Surgical Airway in Children?

In children, as the laryngeal prominence does not develop until adolescence, surface landmarks are more difficult to palpate. The vertical dimension of the cricothyroid membrane is considerably smaller in children than adults, with the result that an endotracheal tube may permanently damage the cartilaginous structures. There is an increased risk that the cricoid cartilage, the only completely circumferential supporting laryngeal structure, and the narrowest part of the airway in the child, may be damaged. In addition, the airway of the child is more malleable, making posterior perforation a greater risk and the laryngeal mucosa more vulnerable to injury and subglottic stenosis.17 For all of these reasons, in an emergency situation, if transglottic tracheal tube placement cannot be accomplished, needle cricothyrotomy, or tracheotomy, is the method of choice in children 12 years of age or younger.32

13.3.4 What Are the Pros and Cons of Using Noncuffed and Cuffed Tracheal Tube for Surgical Airway?

The greatest risk of prolonged cricothyrotomy intubation is the development of subglottic stenosis (SGS). Underlying medical illness and/or an element of gastro-esophageal reflux, in conjunction with the mechanical disruption of intubation, may contribute to the development of SGS. Modern tracheostomy tubes are less likely to produce an inflammatory response in the mucosal airway, while low-pressure cuffs reduce mechanical trauma and its sequelae.

Cuffed tubes provide a seal in the airway to allow delivery of larger tidal volumes with lower airway pressures. However, cuffed tubes may be more difficult to insert in an emergency situation, due to their bulk and the risk of snagging the cuff on the edge of the surgical incision. This may tear the cuff and prevent an effective seal. It is critical that the simplest, safest, speediest, and most effective technique be used to reestablish an airway. Thus, a small, noncuffed tube would be adequate for the primary goal of salvage and provision of oxygenation.

As patients requiring a surgical airway may have decreased lung compliance, positive pressure ventilation through a noncuffed ETT can result in gas escaping from the proximal airway, resulting in inadequate ventilation. For this reason either the Cook cuffed airway catheter or #5 cuffed ETT are the tracheal tubes of choice when establishing an emergency surgical airway.

13.4.1 What Immediate and Delayed Complications Should I Be Aware of?

In most studies, complication rates are higher for emergency than elective cricothyrotomy. In a series of 38 emergency cricothyrotomies, McGill et al22 reported an overall complication rate of 40%. The most-frequent complication identified by this group was misplacement of the endotracheal tube through the thyrohyoid membrane (ie, above the larynx), instead of through the CTM. Other complications included execution time greater than 3 minutes, unsuccessful tube placement, and significant hemorrhage. One patient suffered a longitudinal fracture of the thyroid cartilage, due to attempted placement of an 8.0 mm ID tube, resulting in significant long-term morbidity. In a similar series in 1989, Erlandson33 reported a complication rate of 23%, related primarily to incorrect tube placement (10%) and hemorrhage (8%). Miklus et al34 reported on 20 patients requiring emergency cricothyrotomy in the field. In this study, there were no complications of tube misplacement, significant hemorrhage, or long-term morbidity in survivors. Gillespie et al reviewed 35 patients requiring emergency surgical airway over a 6-year period and noted no differences in the overall complication rate between emergency tracheotomy and cricothyrotomy. Of particular note was that there were no long-term complications in the patients that received cricothyrotomy and were not subsequently converted to tracheotomy.35

Although rare, fatal hemorrhages have been reported as a result of laceration of the cricothyroid artery.36 As this artery courses closer to the thyroid cartilage, there is a greater risk of hemorrhage if the incision is made in the upper half of the CTM.

Other complications include subglottic stenosis, dysphonia due to laryngeal damage, tracheal cartilage fracture, endobronchial intubation, pulmonary aspiration, recurrent laryngeal nerve injury, esophageal perforation, and tracheo-esophageal fistula.17

Tissue emphysema (including subcutaneous and mediastinal emphysema) and barotrauma (including tension pneumothorax) have been reported as complications of jet ventilation and establishment of a surgical airway.37,38 Weymuller39 cautions that only practitioners experienced with TTJV should attempt it in emergency airway management. He describes kinked or displaced transtracheal catheters, incoordination of respiratory effort, outlet obstruction, and distal airway secretions as the major problems encountered.

When confronted with the difficult airway, it should be recognized that there are a multitude of techniques available to the practitioner. The wise practitioner is intimately familiar with the noninvasive techniques of difficult airway management and avoids the temptation to unnecessarily substitute surgical methods for the less invasive approaches.

Even within the parameters of the techniques of surgical airway access, it is evident that the practitioner needs to decide which is most appropriate for the clinical situation at hand. Dilational percutaneous tracheotomy is an elective technique, whereas cricothyrotomy is a technique designed to address the true airway emergency. Some catheter insufflation techniques have the advantage of simplicity but all are temporizing at best. This remains the procedure of choice in children under 12 years, where cricothyrotomy is considered a relative contraindication.

What is of vital importance for the practitioner is to recognize that cannot intubate, cannot oxygenate scenario can occur in a variety of clinical settings. As such, the practitioner needs to have in place the necessary knowledge, the necessary equipment, and the clinical confidence to act.

As it is unlikely that sophisticated gadgetry will be available in all circumstances, it is vital for the practitioner to be familiar with the technique that will most likely be successful with the minimum of equipment; this technique is undoubtedly cricothyrotomy. Commercial kits are now available that can be used for either open, or Seldinger techniques, packaged as one. These kits, or a suitable facsimile, should be available in all areas where the expert airway practitioner may be called upon to provide airway management, whether in the operating room, the emergency department, the Intensive Care Unit, or the hospital ward.