INTRODUCTION — Cricothyrotomy (also called cricothyroidotomy) is a procedure that involves placing a tube through an incision in the cricothyroid membrane (CTM) to establish an airway for oxygenation and ventilation. Because cricothyrotomy is a rarely performed but potentially life-saving procedure of last resort in the patient with a failed airway, clinicians responsible for airway management must retain familiarity with the necessary equipment and relevant anatomy. While debate continues regarding the relative merits and risks of various methods for performing the procedure, it remains clear that skill acquisition and maintenance are vital. We suggest that emergency clinicians responsible for airway management review the anatomy and practice with the equipment needed for cricothyrotomy several times each year.
Performance of cricothyrotomy in adults is reviewed here. Needle cricothyrotomy for children and other aspects of difficult airway management are discussed in a number of topics, including those listed below:
●Needle cricothyrotomy in children (see "Needle cricothyroidotomy with percutaneous transtracheal ventilation")
●Rapid sequence intubation and difficult airway management in adults (see "Rapid sequence intubation for adults outside the operating room" and "Approach to the anatomically difficult airway in adults outside the operating room" and "Devices for difficult emergency airway management in adults outside the operating room")
●Rapid sequence intubation and difficult airway management in children (see "Emergency endotracheal intubation in children" and "The difficult pediatric airway" and "Supraglottic airway devices in children with difficult airways" and "Devices for difficult endotracheal intubation in children")
FREQUENCY — Cricothyrotomy is infrequently performed, but rates vary among different providers and settings. A paper from the National Emergency Airway Registry (NEAR) found that, of the 17,583 adult intubations performed in emergency departments over a 10-year period, 0.14 percent (about 25 patients) received a primary surgical airway and 0.31 percent (about 55 patients) received a rescue surgical airway [1]. An emergency medical services-based study reported that, of the 57,209 patients requiring advanced airway management in the prehospital setting, 0.5 percent (286 patients) underwent cricothyrotomy [2].
INDICATIONS — Cricothyrotomy is most commonly performed when a "can't intubate, can't oxygenate" (CICO) situation is encountered during advanced airway management and nonsurgical upper airway techniques have been unsuccessful in restoring oxygenation. Sometimes, during emergency airway management, cricothyrotomy is performed as a primary technique when other nonsurgical options are not felt to be appropriate due to clinical circumstances.
When the clinician encounters a CICO scenario, swift establishment of an airway is crucial. Failure to provide oxygen to the brain can lead to anoxic encephalopathy within minutes and ultimately death. In a CICO scenario, placement of an extraglottic airway device (eg, laryngeal mask airway) may be attempted as a rescue maneuver or as a bridge to provide ventilation while preparations are made to perform a cricothyrotomy (see "Extraglottic devices for emergency airway management in adults"). However, if oxygenation cannot be maintained, cricothyrotomy is required. Management of the difficult and failed airway is discussed separately. (See "Approach to the anatomically difficult airway in adults outside the operating room" and "Approach to the failed airway in adults outside the operating room".)
Conditions associated with a difficult airway that may necessitate cricothyrotomy include massive hemorrhage, profound emesis, trismus, obstructing lesions (eg, tumor, polyp), upper airway occlusion (foreign body, edema, anaphylaxis), and a broad array of traumatic and congenital deformities. One study found that of all clinical conditions requiring cricothyrotomy, 32 percent involved facial fractures, 32 percent blood or vomitus in the airway, 7 percent traumatic airway obstruction, and 11 percent failed intubation in the absence of other specified problems [3]. A multicenter study found that trauma was the most likely indication for a cricothyrotomy, accounting for over 50 percent of the cases [4].
CONTRAINDICATIONS AND PRECAUTIONS
Absolute contraindications — There are no absolute contraindications to emergency cricothyrotomy in adults. Failure to rapidly perform a cricothyrotomy in a "can't intubate, can't oxygenate" (CICO) situation will result in the death of the patient.
Relative contraindications — Fracture of the larynx, laryngotracheal disruption, or transection of the trachea with retraction of the distal trachea into the mediastinum are relative contraindications to cricothyrotomy. In such cases, tracheotomy or stabilization of the distal tracheal segment followed by direct intubation is likely to be the best approach. (See "Penetrating neck injuries: Initial evaluation and management", section on 'Airway management'.)
Surgical cricothyrotomy is relatively contraindicated in young children for several reasons. The airway of a child is funnel-shaped, with the narrowest part located at the cricoid ring rather than at the vocal cords. This narrowing increases the risk for developing subglottic stenosis following cricothyrotomy.
Some believe that surgical cricothyrotomy can damage the cricoid cartilage of young children. Since the tracheal cartilages are C-shaped, soft, and pliable in a child, the cricoid cartilage is the only circumferential support for the trachea and thus the principal structure maintaining airway patency [5]. A child's airway is smaller in diameter than an adult's, and even a small amount of stenosis may cause significant impairment of air flow [6].
The preferred surgical airway technique in a young child is transtracheal oxygenation using a 14-gauge needle. The age at which one can safely perform a cricothyrotomy on a child is not well established, and recommendations vary from 5 to 12 years old. (See "Needle cricothyroidotomy with percutaneous transtracheal ventilation" and "The difficult pediatric airway".)
When determining whether to perform a cricothyrotomy, consider not only age, but other variables such as the child's size and physical maturity, state of health, external landmarks of the neck (eg, is the cricothyroid membrane [CTM] palpable?), clinical findings, and presence of trauma.
Surgical cricothyrotomy is relatively contraindicated in a patient with a bleeding diathesis, but in a life-threatening circumstance, the need to establish an airway supersedes this concern.
PREPARATION
Fundamental considerations for the clinician — Once a failed airway is recognized and a cricothyrotomy is contemplated, the clinician must quickly address a few fundamental considerations:
●Will a cricothyrotomy effectively bypass the airway obstruction? As an example, if the obstruction is in the distal trachea, performing a cricothyrotomy becomes a critical waste of time that will render any noninvasive ventilation technique ineffective.
●Which cricothyrotomy technique is to be used? In most cases, the emergency clinician should be familiar with the tools available in their institution to perform cricothyrotomy and should have selected and practiced a preferred technique ahead of time.
●Will the patient's anterior neck anatomy make the procedure particularly difficult or time consuming?
A mnemonic for difficult cricothyrotomy is presented in the accompanying table (table 1). Management of the difficult and failed airway is discussed separately. (See "Approach to the anatomically difficult airway in adults outside the operating room" and "Approach to the failed airway in adults outside the operating room".)
While addressing the considerations above, the clinician should avail themselves of all potentially helpful resources, including colleagues from emergency medicine, surgery, and anesthesia.
Patient counseling and informed consent — The emergency conditions under which this procedure is performed generally preclude the discussion of risks, benefits, and complications with the patient or family. Ideally, these discussions are held with patients with predicted difficult airways before airway management is required.
Materials — Successful performance of a cricothyrotomy depends on familiarity with the necessary equipment. Keep the cricothyrotomy equipment tray simple (picture 1), in contrast to the typical tracheostomy tray, which may contain dozens of instruments. Only a few instruments are required. Practice using the equipment several times a year so it will be familiar during an emergency.
●Intravenous (IV) catheter – Be certain that an IV is in place and flushing easily.
●Oxygen – Administer high-flow oxygen. In the setting of a failed airway, this will likely be via a bag-valve mask.
●Mechanical ventilator and tubing – Be sure the ventilator is set up and ready for use.
●Yankauer and DuCanto suction catheter, tubing, and canister – Check that all connections are tight and suction is adequate.
●Scalpels – Preferred sizes include numbers 10 and 20 blades. However, in an emergency, any blade size available can be used. Use the same blade for both the skin incision and the cricothyroid membrane (CTM) incision.
●Tracheal hook – Handle the tracheal hook carefully when inserting and removing it. The hook's tip is sharp and can puncture the balloon on the tracheal tube, causing a leak and necessitating replacement. The tip of the hook can also puncture a glove and skin.
●Tracheal dilator (Trousseau dilator) – The dilator is used to widen the opening through the CTM [7]. Unlike standard surgical instruments like scissors or needle drivers, the dilator is opened by squeezing the handles together.
●A cuffed tracheostomy tube – Note that tracheostomy tubes vary. A standard tracheostomy tube kit often includes a tube with an inner cannula as well as a solid obturator (picture 2). Place the obturator in the tracheostomy tube and use it to insert the tube into the trachea. After the tube is placed, remove the obturator and replace it with the inner cannula for air exchange. In an adult, a number 4 cuffed Shiley tube is the preferred device.
Remember that a smaller diameter increases the work of breathing and is more easily obstructed by secretions. However, the CTM averages only 9 mm vertically by 30 mm horizontally, so whenever possible, the outer diameter of the tube should not exceed 9 mm to avoid damage to surrounding cartilage [8,9].
A number 4 Shiley tube with an inner diameter of 5 mm and an outer diameter of 9.4 mm is a good choice for most adults. However, recognize that the outer diameter of the tube is what determines whether the tube fits properly. There is significant product variability even among Shiley brand tubes.
●Alternative tube (modified tracheal tube) – If a tracheostomy tube is not available, use a standard tracheal tube cut to an appropriate length. We suggest a size 6.0 tracheal tube. Tracheal tubes are numbered based on their internal diameter (6.0 tube has an internal diameter of 6 mm), but the outer diameter varies somewhat by manufacturer [10]. The outer diameter of a 6.0 tracheal tube generally ranges from 8 to 9 mm.
To shorten the tube, remove the adaptor and cut just above the take-off of the pilot balloon tubing. Reattach the adaptor to the newly cut end and insert the tube into the trachea, as you would a tracheostomy tube. The tube can be shortened after it is inserted, but take care not to cut the balloon inflation port. Shortening the tube reduces the risk of inadvertent placement in a mainstem bronchus. Eventually, it may be helpful to replace the modified endotracheal tube with a tracheostomy tube, as the design of the tracheostomy tube makes it more stable in the airway.
●Tracheal tube introducer ("bougie") (see 'Scalpel-finger-bougie (author's preferred technique)' below).
●10-mL syringe – Test the balloon on the tracheostomy or endotracheal tube for leaks by injecting 10 mL of air.
●Cloth tie – The cloth tie included with the tracheostomy kit is used to secure the tube by making a circumferential tie around the neck.
CLINICAL ANATOMY AND IDENTIFICATION OF THE CRICOTHYROID MEMBRANE — Proper performance of a cricothyrotomy depends upon an understanding of the relevant anatomy and the ability to identify the cricothyroid membrane (CTM). This requires regular practice on the part of clinicians expected to perform the procedure.
One way to improve familiarity with the anatomy is to regularly palpate the structures of the anterior neck when examining patients (figure 1 and figure 2 and figure 3 and figure 4). Begin by palpating the laryngeal prominence, which forms the superior edge of the thyroid cartilage. There is often a prominent V-shaped notch palpable. It is often more prominent in men [11]. The vocal cords are housed within and protected by the thyroid cartilage. The hyoid bone lies cephalad to the thyroid cartilage. In patients where the thyroid cartilage is not prominent, be aware that the hyoid might be mistaken for the thyroid prominence.
Palpate the trachea and note that it is the caudal continuation of the larynx and no longer palpable as it enters the mediastinum. The trachea is comprised in large part by a row of C-shaped cartilaginous rings that are deficient posteriorly where the trachea rests against the anterior esophagus.
Next, identify and palpate the cricoid cartilage, which is a complete cartilaginous ring, shaped like a signet ring, with its widest part found posteriorly. It is located caudal to the thyroid cartilage. The thyroid cartilage, cricoid cartilage, and tracheal rings support and protect the airway.
The boundaries of the CTM are the thyroid cartilage superiorly, the cricoid cartilage inferiorly, and the cricothyroideus muscles laterally on both sides (figure 1). Palpate the CTM. It is located about 2 cm caudal to the laryngeal prominence and can be identified by a slight depression in this area. The anatomical relationship between the thyroid and cricoid cartilages and the CTM is the most important landmark when performing cricothyrotomy.
The cricothyroid arteries are branches of the superior thyroid arteries that course along both sides of the CTM and anastomose in the midline, closer to the superior border of the membrane. If possible, try to avoid these arteries when performing a cricothyrotomy by incising the inferior portion of the CTM.
Some authors imply that identification of the CTM is relatively straightforward due to its superficial location in the anterior neck. However, lack of familiarity can make it difficult to find the CTM quickly, particularly in the setting of an airway emergency. Obesity compounds this problem, as can edema, hematoma, and subcutaneous air. Misidentification can lead clinicians to make incisions in the thyrohyoid space, which is fraught with potential complications. (See 'Complications' below and "Emergency airway management in the morbidly obese patient".)
Several studies highlight the potential difficulty of identifying the CTM [11-14]. In one prospective observational study, anesthesiologists and obstetricians were asked to identify the CTM in 56 women patients, 15 of whom were obese [11]. The CTM was correctly identified in 10 of 41 nonobese patients (20 percent) and 0 of 15 obese patients (0 percent). A similar study involving six patients reported that anesthesiologists correctly identified the CTM 30 percent of the time [12]. A study of three widely promulgated techniques for identifying the CTM performed in 50 volunteer adult patients reported that none was sufficiently accurate (accuracy ranged from 50 to 62 percent) [15].
ULTRASOUND FOR CRICOTHYROTOMY — Bedside ultrasound has been proposed as a method for identifying the cricothyroid membrane (CTM). Ultrasound has been used to guide tracheostomy, and the results of several observational studies in cadavers and patients suggest that, when used by experienced practitioners, it is a rapid and accurate means of identifying the CTM [16-22]. However, once a "can't intubate, can't oxygenate" (CICO) situation is encountered, it is too late to use ultrasound to identify the CTM as this will waste precious time. Before it becomes necessary to manage an airway predicted to be difficult, ultrasound identification of the CTM is a reasonable approach. When doing this, it is important to mark the CTM using the same position in which the cricothyrotomy will be performed, as the larynx is fairly mobile and can move considerably with movement of the head and neck or change in the angle of the head of the bed [23].
PROCEDURE
Standard precautions against infection — Use standard precautions to protect against blood and body fluid exposure. This includes gloves, face mask, protective eyewear, gown, and shoe covers. Do not break, bend, or recap needles used in the procedure.
Patient positioning — Place the patient in the supine position on the stretcher. Unless there is a cervical spine injury (known or suspected), extend the patient's neck to help identify the procedural landmarks and to obtain the widest exposure of the cricothyroid membrane (CTM). However, it is important to keep in mind that cricothyrotomy is guided by palpation rather than direct visualization.
Preoxygenation — While assembling the equipment for the procedure, ask an assistant (preferably the respiratory therapist) to preoxygenate the patient by administering high-flow oxygen most likely via bag-valve mask. Be aware that once the incision is made through the CTM, positive-pressure ventilation should be paused to avoid blowing a mist of blood into the face of the operator. The role of preoxygenation is reviewed separately. (See "Rapid sequence intubation for adults outside the operating room", section on 'Preoxygenation'.)
Analgesia and sedation — Under emergency circumstances, there may not be time to administer sedative or analgesic medications. The most important goal is to secure the airway. In the case of respiratory depression or arrest, sedation may make matters worse and is not advised. However, if the patient is agitated and struggling, and this behavior is impeding the progress of the procedure, a sedative or analgesic medication can be given to help control the patient. Ketamine is an excellent choice in this situation.
Skin preparation — If time permits, prepare the skin of the anterior neck with an antiseptic solution (eg, povidone-iodine). If the patient is conscious, anesthetize the skin, subcutaneous tissues, and the CTM with a local anesthetic such as 1 percent lidocaine administered through a 27- or 30-gauge needle. Lidocaine with epinephrine may decrease some superficial bleeding.
Monitoring — Monitor heart rate and rhythm, blood pressure, respiratory rate, oxygen saturation, and end-tidal carbon dioxide (EtCO2) throughout the procedure. Remove the patient's gown or sheet from the torso to observe the rise and fall of the chest with respiration.
Methods — Several techniques for cricothyrotomy are in common use. Performance of the scalpel-finger-bougie (ie, bougie-assisted), standard, rapid four-step, and Seldinger techniques are described below:
Scalpel-finger-bougie (author's preferred technique) — The author prefers the scalpel-finger-bougie technique because it is relatively simple, effective, and requires no special tools (picture 3) [24,25]. The scalpel-finger-bougie method is also referred to as "bougie-assisted cricothyrotomy." While it is difficult to perform randomized trials comparing uncommonly performed, emergency airway procedures, a number of observational studies support the scalpel-finger-bougie method [26-28]. The technique is performed as follows:
●Step 1: Immobilize the larynx and palpate the CTM – Stand at the patient's right side if you are right-handed, or at the patient's left side if you are left-handed. Immobilize the larynx with the nondominant hand and perform the procedure with the dominant hand.
The procedure is largely tactile, so proper finger position is essential. Place the thumb and long finger of the nondominant hand on either side of the thyroid cartilage to immobilize the larynx (picture 4). Palpate the laryngeal prominence at the midline of the cephalad rim of the thyroid cartilage with the index finger and then move caudally 1 to 2 cm until a small depression inferior to the thyroid cartilage is encountered. This is the CTM. Palpate the cricoid cartilage, which is at the inferior border of the CTM. Maintain manual control and immobilization of the larynx throughout the procedure to preserve the anatomic relationships (ie, don't let go!).
●Step 2: Incise the skin vertically, repalpate the CTM, then incise the CTM horizontally – Make a generous vertical incision (at least 4 cm) in the skin overlying the CTM (picture 5). The midline skin incision avoids vascular structures located laterally. The vertical orientation allows the incision to be extended superiorly or inferiorly should the initial location be too low or too high or provide inadequate access to the CTM.
Next, insert your index finger into the incision (picture 6) and dissect bluntly to the CTM. Remove your finger and make a stab incision horizontally through the CTM (picture 7).
●Step 3: Insert the bougie through the incision into trachea – Using the scalpel to stent open the incision (picture 8), insert the bougie through the stoma in the CTM and advance it caudally down the trachea (picture 9). Alternatively, you can withdraw the scalpel and immediately insert your index finger through the horizontal incision, dilate the opening in the CTM, and then use the tip of your finger to direct the bougie caudally down the trachea.
Confirmation of tracheal placement is suggested by feeling "tracheal clicks" as the bougie passes over each tracheal ring, or by encountering resistance if the bougie reaches the carina or bronchus. It is best to avoid intentionally advancing the bougie until resistance is felt, as there is a risk of perforating the mainstem bronchus, especially if too much force is used. Of note, as emergency cricothyrotomy is performed rarely and during crisis situations, the clinician may not appreciate "tracheal clicks."
●Step 4: Pass the tracheal tube over the bougie into trachea – Pass a 6-mm tracheal tube over the bougie and advance it into the trachea while maintaining control of the bougie with the other hand (picture 10). Be careful not to advance the tracheal tube too far as it can easily pass into the right mainstem bronchus. The mean distance from the vocal cords to the carina is about 13 cm; the tracheal tube should be advanced about 6 to 8 cm, which would place it mid trachea in most adults and avoid the right mainstem bronchus.
●Step 5: Remove the bougie and secure tracheal tube – While securing the tracheal tube in place with one hand, remove the bougie with the other (picture 11). Inflate the cuff of the tube with air from a 10-mL syringe. Inflate the balloon until the balloon indicator is full but not tense. Confirm tracheal placement with capnography or capnometry. Secure the tracheal tube. Begin positive-pressure ventilation and obtain a radiograph to check tube placement. (See 'Follow-up care' below.)
Rapid four-step technique
Basic technique — The rapid four-step technique can be done quickly and requires only a scalpel (number 11 or 20 blade if available), hook, and cuffed tracheostomy tube [9]. For this technique, stand at the head of the patient in the same position as when performing endotracheal intubation. Next, perform the following four steps in sequence:
●Step 1: Identify the CTM by palpation (figure 5).
●Step 2: Make a single horizontal stab incision through the skin, subcutaneous tissue, and CTM with the scalpel (figure 6). The size of the skin incision is approximately 3 cm.
●Step 3: Place the hook – Prior to removal of the scalpel, the hook is placed and directed inferiorly to engage the cricoid cartilage. Caudal traction is used to stabilize the larynx (figure 7). This marks a significant change from the standard method, in which the tracheal hook is placed under the thyroid cartilage. Also in contrast with the standard technique, this step does not require an assistant to manage the hook.
●Step 4: Insert the tracheostomy tube into the trachea (figure 8).
Modified four-step technique with introducer (bougie) — The rapid four-step technique can be modified by using a tracheal tube introducer (often referred to as a "bougie"). This is done by inserting the introducer through the incision into the trachea following step 3 above and then sliding a tracheal tube over the introducer.
In a small randomized trial performed in anesthetized sheep by inexperienced clinicians, this modified approach increased the speed of performance (median time 67 versus 149 seconds) and was considered easier to perform than the standard technique [29].
Seldinger technique — Cricothyrotomy using a Seldinger technique has been described [30]. Commercial cricothyrotomy kits are available that contain all essential equipment to perform the Seldinger technique. As an example, the Cook Melker kit includes the following: a 6-mL syringe, an 18-gauge needle with overlying catheter, a guide wire, a tissue dilator, a modified airway catheter (picture 12), and tracheostomy tape. Alternatively, a tracheal tube introducer (ie, "bougie") can be used to perform the technique, as described above [29]. (See 'Rapid four-step technique' above.)
The procedure described here is based upon the Melker kit, which involves a guidewire. Perform the procedure as follows (picture 13):
●Step 1: Equipment check – Be certain that all equipment is present and functioning. Insert the dilator into the airway catheter. Palpate the CTM with the index finger of the nondominant hand while immobilizing the larynx with the thumb and middle finger (figure 5).
●Step 2: Needle insertion – Attach the introducer needle to the syringe. Apply a small amount of negative pressure on the syringe and insert the needle carefully into the CTM at a 45-degree angle with the needle oriented caudad (figure 9). Placing a small amount of saline in the syringe can help to identify when the trachea is entered, as air bubbles appear in the syringe during aspiration.
Be careful not to insert it too far as this may damage the posterior wall of the trachea. Watch for free flow of air into the syringe, indicating the needle is in the airway.
●Step 3: Guidewire insertion through catheter – When free flow of air is achieved, remove the syringe and then remove the needle, leaving the catheter in place, with its distal tip in the trachea. Thread the guidewire through the catheter into the trachea (figure 10). Remove the catheter, sliding it over the guidewire.
●Step 4: Incision of skin and CTM – At the entrance point of the guidewire, make a 1- to 2-cm incision through the skin and CTM with a number 15 scalpel blade (figure 11).
●Step 5: Airway catheter insertion over guidewire – Thread the airway catheter with the dilator inside it over the guidewire and advance it through the skin incision (figure 12). Following the curve of the dilator, advance the dilator-catheter unit through the subcutaneous soft tissue and into the trachea until the cuff of the catheter is flush against the skin of the neck. A slight twisting motion may be needed.
●Step 6: Dilator and guidewire removal – Remove the tissue dilator and guidewire as a unit, leaving the airway catheter in the trachea (figure 13).
●Step 7: Secure airway catheter – Secure the airway catheter to the neck with the "trach tape" provided in the kit or other appropriate means.
Prefabricated tools — Percutaneous trocar-type devices that consist of a catheter over a large-bore needle are commercially available. They are designed to be rapidly inserted percutaneously as a single unit without the need for a surgical incision. Newer versions (eg, Quicktrach II) include a protective blocker on the needle intended to reduce the risk of perforating the posterior airway. Literature about these devices is limited, with most studies involving plastic airway or animal models. Available studies report similar success rates and times to insertion compared with other cricothyrotomy techniques [31,32]. Clinicians who choose to use one of these prefabricated devices should be familiar with the equipment and technique, and practice the procedure in a non-clinical setting on a routine basis.
Traditional technique
●Step 1: Immobilize the larynx and palpate the CTM (figure 5) – Stand at the patient's right side if you are right-handed, or at the patient's left side if you are left-handed. Immobilize the larynx with the nondominant hand and perform the procedure with the dominant hand.
The procedure is largely tactile, so proper finger position is essential. Place the thumb and long finger of the nondominant hand on either side of the thyroid cartilage to immobilize the larynx. Palpate the laryngeal prominence at the midline of the cephalad rim of the thyroid cartilage with the index finger and then move caudally 1 to 2 cm until a small depression inferior to the thyroid cartilage is encountered. This is the CTM. Palpate the cricoid cartilage, which is at the inferior border of the CTM. Maintain manual control and immobilization of the larynx throughout the procedure to preserve the anatomic relationships (ie, don't let go!).
Proper stabilization and continuous palpation of the immobilized larynx serves as the foundation for the procedure, from which all other anatomic relationships are established. While immobilizing the larynx, palpate the CTM and complete the entire procedure by feel. Do not waste time attempting to visualize the CTM.
●Step 2: Incise the skin vertically (figure 14) – After palpating the CTM, make a midline, vertical incision roughly 4 cm long through the skin overlying the membrane. The midline skin incision avoids vascular structures located laterally. The vertical orientation allows one to extend the incision superiorly or inferiorly should the initial location be too high or too low or provide inadequate access to the CTM.
●Step 3: Incise the CTM horizontally (figure 15) – Make a 3 cm horizontal incision in the CTM. Make the incision with care; excessive force can lead to injury of the posterior wall of the trachea (note that the posterior portion of the cricoid ring is quite broad, which helps to prevent the incision going through the posterior wall into the esophagus). Aim the scalpel in a caudad direction to avoid the vocal cords. The cords, although surrounded by the thyroid cartilage and partially protected, are located only 0.5 to 2 cm above the CTM [6]. While separating the thyroid cartilage from the cricoid cartilage, be careful not to incise or fracture either one.
Once you have made the incision in the CTM, keep the tip of the index finger of the nondominant hand in the entry to the incision so as not to lose the opening. Continue to immobilize the larynx firmly, maintaining a triangle formed by the thumb and middle finger on opposite sides of the larynx and the index finger in the incision in the CTM. It is crucial not to let go at this point because there is often significant bleeding that obscures the view of the membrane.
If you are unable to stabilize the larynx because of obesity, edema, trauma, aberrant anatomy, or other reasons, you may wish to leave the scalpel in the incision until you place the tracheal hook in order not to lose the opening. In this case, be careful not to injure the back wall of the trachea with the scalpel.
●Step 4: Insert the tracheal hook (figure 16) – Place the tracheal hook under the thyroid cartilage and ask an assistant to provide traction anteriorly and superiorly.
●Step 5: Insert the Trousseau dilator and open it to enlarge the incision vertically (figure 17) – Squeeze the handles of the Trousseau dilator to open its jaws. The membrane is naturally wider in the horizontal direction, which makes the vertical direction the hardest to dilate. Overcome the resistance from the thyroid cartilage as it retracts downward and the cricoid cartilage as it retracts upward against the dilator. Leave the dilator in until the tube is placed; the thyroid and cricoid cartilages will spring back into place if the dilator is removed.
●Step 6: Insert the tracheostomy tube (figure 18) – After dilating the opening, rotate the dilator 90 degrees so that the handles are pointing towards the patient's feet and insert the tube between the jaws of the Trousseau dilator. If the dilator remains in its original horizontal position, its inferior blade will prevent the tube from passing into the trachea. Once past the blades, advance the tube into the trachea. Remove the tracheal hook and Trousseau dilator. Pay particular attention not to puncture the balloon of the tube during insertion and when withdrawing instruments.
●Step 7: Remove the obturator (as needed, depending on type of tube used) (figure 19) – This is the solid object with a rounded tip.
●Step 8: Insert the inner cannula (as needed, depending on type of tube used) and inflate the balloon (figure 20) – Inflate the cuff of the tube with air from a 10-mL syringe. Inflate the balloon carefully until the balloon indicator is full but not tense; overinflation increases the risk of pressure-related injury to the tracheal mucosa.
●Step 9: Attach the tracheostomy tube to the mechanical ventilator or a bag valve device (figure 21) – After confirming proper placement, secure the tube with a circumferential cloth tie around the neck. Use flexible connector tubing to avoid tugging and pressure on the tracheal wall.
Time and ease of completion — The time to completion and ease of performing cricothyrotomy depend upon the surgical technique, patient, setting, and the training and experience of the clinician. Emergency clinicians must be facile with at least one approach.
Studies of cricothyrotomy techniques are limited by the absence of high-quality clinical trials. Available studies consist largely of cadaver reports and animal studies and report disparate findings. Therefore, it is not known which technique is best in which clinical circumstance. A surgical airway data-gathering application for smartphones (The Airway App) has been released and may provide data to help determine which cricothyrotomy technique is most effective [27].
Studies suggest that clinicians can perform cricothyrotomy reasonably quickly using the standard open technique, but that the rapid four-step technique or the bougie-assisted technique may be faster:
●An observational study reported that experienced physicians needed a median of 73 seconds (range 53 to 255 seconds), while inexperienced clinicians required a median of 180 seconds, to complete a cricothyrotomy using the standard technique in unfixed cadavers [33].
●An observational study of 44 paramedic students found that an average of 46 seconds (range 29 to 63 seconds) was needed to complete a standard cricothyrotomy [34].
●Studies performed on preserved human cadavers found that clinicians were 88 percent successful in performing both the standard technique and the rapid four-step technique, but that the rapid four-step technique was faster with a mean time of 43.2 seconds compared with 133 seconds for the standard technique [30]. Other cadaver studies have also reported the rapid four-step technique to be faster [35].
●A randomized trial found that inexperienced residents and students were able to perform a bougie-assisted cricothyrotomy in sheep significantly faster than a standard open cricothyrotomy (median time 67 versus 147 seconds) [27,29].
Studies comparing cricothyrotomy using open versus the Seldinger technique report conflicting results:
●A study of 20 emergency physicians performing cricothyrotomy on 200 human cadavers found that the time to tracheal puncture and first ventilation were significantly faster when cricothyrotomy was performed using the Seldinger technique compared with the open surgical method [30]. Other cadaver studies have found the Seldinger approach to be effective with relatively low complication rates [36,37].
●An observational study involving 63 medical students performing cricothyrotomy on human cadavers reported greater success, increased speed, and fewer complications among those using open versus percutaneous techniques [38].
Variations in technique for a given approach may affect performance. A study evaluating variations of percutaneous techniques in a pig trachea model found that a vertical incision preceding the needle placement-guidewire insertion decreased the time needed for completion of the procedure [39].
COMPLICATIONS — Complication rates vary widely and depend upon the patient population, the clinical scenario, the clinician's level of training, and the location of the procedure (eg, emergency department, prehospital). Published reports cite complication rates between 0 and 54 percent [30,35,40-46]. A systemic review found that, among 1219 patients who underwent emergency cricothyrotomy, the mean early complication rate was 13.4 percent [47]. The most frequent early complication was incorrect performance of the procedure resulting in damage to the cartilaginous structures or failure to achieve airway access.
Bleeding occurs early and is usually not severe. If bleeding does occur, it can usually be controlled by packing the site with gauze [35].
Other early complications include [40-42,44]:
●Laceration of the thyroid cartilage, cricoid cartilage, or tracheal rings
●Perforation of the posterior trachea
●Unintentional tracheostomy
●Passage of the tube into an extratracheal location (ie, false tract); subcutaneous air that develops with ventilation raises concern for such injury
●Infection
Performance of the rapid four-step technique involves lifting the cricoid cartilage, instead of the thyroid cartilage, with the tracheal hook. The cricoid cartilage is vulnerable to injury with this technique because the tracheal hook is placed under the anterior portion where it is weakest and thinnest [33]. However, a cadaver-based study reported that the cricoid ring was able to tolerate the degree of manipulation required for intubation without cartilage fracture [48]. A cadaver study reported that cartilage fracture was eliminated by switching from a standard tracheal hook to a Bair Claw tracheal hook [49].
In one study comparing complications of the rapid four-step technique and the standard technique, the same overall rate of complication (38 percent) was observed for both, but the incidence of major complications (eg, complete transection of the cricoid cartilage, posterior tracheal or esophageal perforation) was 6 percent higher for the rapid four-step technique [35]. Other researchers studied complications rates when both techniques were performed on cadavers [50]. They observed no complications with the standard technique but a 16.7 percent complication rate with the rapid four-step technique. Four of these injuries were to the cricoid cartilage. The remaining complication was a ruptured cuff, which may be attributable to the caudal placement of the tracheal hook beside the cuff, and highlights the importance of removing the hook carefully or using a blunt hook for the rapid four-step technique.
Long-term complications include subglottic stenosis and voice changes. Subglottic stenosis has been associated with prolonged intubation, underlying laryngeal disease, and younger age [51]. Other possible long-term complications include dysphagia, infection, and a persistent stoma.
There are limited data regarding the safety of cricothyrotomy in patients with known or suspected cervical spine injury. A study using a cadaver model of an unstable injury at the level of the fifth cervical vertebra observed 1 to 2 mm of anterior-posterior (AP) displacement and less than 1 mm of axial compression by fluoroscopy during the performance of a standard open cricothyrotomy [52]. The amount of movement considered safe is undetermined, making interpretation of these results difficult. Studies report a low risk of neurologic deterioration with less than 3 mm of AP displacement [53-56]. No case of neurologic deterioration or exacerbation of injury has been reported following cricothyrotomy in trauma patients.
FOLLOW-UP CARE — Appropriate ventilator settings are made for the patient. Adequate sedation and analgesia should be provided as needed. Follow-up care for the tracheostomy tube is provided by the admitting service in consultation with surgery or otolaryngology as the case dictates. (See "Mechanical ventilation of adults in the emergency department".)
SUMMARY AND RECOMMENDATIONS
Emergency cricothyrotomy (or cricothyroidotomy) is an infrequently performed but potentially life-saving procedure of last resort in the patient with a failed airway. We suggest that all clinicians responsible for airway management review the anatomy, choose a preferred technique, and practice with the equipment needed for cricothyrotomy several times per year.
Indications and contraindications – Cricothyrotomy is indicated when an emergency airway is required and orotracheal or nasotracheal intubation is either unsuccessful or contraindicated and other nonsurgical rescue airways are ineffective or not plausible. Relative contraindications include complete transection of the trachea and laryngotracheal disruption with retraction of the distal trachea into the mediastinum. (See 'Indications' above and 'Contraindications and precautions' above.)
Equipment – The equipment necessary for cricothyrotomy is described in the text. The cricothyrotomy equipment tray should be kept simple (picture 1). (See 'Materials' above.)
Anatomy and performance – Emergency cricothyrotomy is a tactile procedure; the field can become bloody following the initial incision, obscuring the view of any landmarks, and clinicians must be prepared to perform the procedure without direct visualization. Clinicians must be familiar with the relevant anatomy (figure 1 and figure 2). (See 'Clinical anatomy and identification of the cricothyroid membrane' above.)
Methods – Four methods for performing emergency cricothyrotomy have been described. We prefer the scalpel-finger-bougie (ie, bougie-assisted) technique because it is relatively simple and effective, and it requires no special tools. (See 'Scalpel-finger-bougie (author's preferred technique)' above.)
Clinicians should choose at least one method in which to become proficient. Text and images showing the step-by-step performance of each technique are provided in the text. (See 'Methods' above.)
Alternative methods include:
Standard open technique (See 'Traditional technique' above.)
Rapid four-step technique (See 'Rapid four-step technique' above.)
Seldinger technique (See 'Seldinger technique' above.)
ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges Aaron E Bair, MD, MSc, FAAEM, FACEP, now deceased, who contributed to an earlier version of this topic review.
