Chapter 24. Percutaneous Transtracheal Jet Ventilation

Percutaneous transtracheal jet ventilation (PTTJV) provides emergency ventilatory support in patients who cannot be adequately ventilated with a bag-valve-mask device (with oral or nasal airways), a laryngeal mask airway (LMA), or endotracheally intubated.1,2,10 This includes patients with upper airway foreign bodies or neoplasms, maxillofacial trauma, laryngeal edema, or infection.2,3 It is also used electively with general anesthesia for surgery involving the larynx and subglottic areas.4 PTTJV involves placement of a percutaneous catheter into the trachea and ventilation via a cyclic delivery of tidal volume to the lungs.5

Early studies of transtracheal ventilation used transtracheal catheters connected to 4 to 5 L/min of oxygen.6 Oxygenation with this apparatus was adequate, but patients quickly developed hypercarbia due to lack of ventilation.5 This “apneic oxygenation” also occurs in ventilation through a catheter attached to a bag-valve device.7 The low pressure and flow of oxygen generated by the bag-valve device result in increases in PaCO2 of 4 mmHg/min and the rapid development of respiratory acidosis.1,8 Numerous studies have since demonstrated that intermittent jets of pressurized 100% oxygen at 50 pounds per square inch (psi) allows for both oxygenation and adequate ventilation.8,9

The anterior neck provides direct access to the airway via the trachea as it extends from the larynx into the lungs (Figure 24-1). At the top of the laryngeal skeleton is the thyroid cartilage, which lies at the level of the fourth and fifth cervical vertebrae. The laryngeal prominence of the thyroid cartilage (more prominent in men) is easily palpated with the thumb and index finger. The cricoid cartilage lies just inferior to the thyroid cartilage at the level of the sixth cervical vertebra. It serves as the junction of the larynx and trachea. Multiple cartilaginous rings support the trachea. Between the cricoid and thyroid cartilages lies the cricothyroid membrane. The cricothyroid membrane is a palpable membranous depression just inferior to the laryngeal prominence and is the access site for PTTJV.11 The cricothyroid artery is a branch of the superior thyroid artery. It travels transversely across the cricothyroid membrane just below the thyroid cartilage. Placement of the catheter through the lower half of the cricothyroid membrane will prevent injury to this small artery.22

Once the catheter is placed and appropriately connected to an oxygen source, oxygen is delivered via bulk flow through the cannula into the trachea and lungs. Entrainment of room air translaryngeally via the Venturi principle is negligible, even with minimal upper airway obstruction.1 Therefore, near 100% O2 is delivered with each insufflation.

Inhalation occurs through the catheter via a pressurized flow of oxygen. Exhalation occurs passively through the elastic recoil of the lungs and chest wall.10 The minute ventilation delivered during PTTJV is proportional to the volume of air injected, the driving air pressure, and the degree of upper airway obstruction.2,12 Animal studies demonstrate that PTTJV delivers more tidal volume than positive-pressure mask ventilation with the same tracheal and transpulmonary pressures despite delivery of oxygen from a pressurized source.2

PTTJV is indicated as a backup emergent airway in any patient who cannot be endotracheally intubated or ventilated with a bag-valve-mask device despite the use of a jaw-thrust maneuver, oropharyngeal airway, or nasopharyngeal airway or LMA.1,2,5 It serves as a simple, relatively safe, and effective alternative to cricothyroidotomy.1,6 This is especially true in pediatric patients below 5 years of age, in whom a cricothyroidotomy is contraindicated. PTTJV is the procedure of choice in the pediatric age group for establishing an emergent airway when endotracheal intubation fails.7 PTTJV can serve as a quick alternative to a difficult intubation. It is especially valuable in cases of maxillofacial trauma, suspected cervical spine injury, or when nasal intubation is contraindicated or unsuccessful.5,6,13 PTTJV is also used routinely by Anesthesiologists in the operating room. Electively, transtracheal catheters are placed in patients undergoing surgery of the upper airway, including the larynx and subglottic structures.7

This procedure is also indicated in cases of partial upper airway obstruction due to foreign bodies, laryngeal edema, neoplasm, or infection.2,3 In cases of upper airway foreign bodies, PTTJV not only serves as an emergent airway but can also assist in dislodging the foreign body.6,7 Animal studies have demonstrated that the expulsion of foreign bodies from the hypopharynx and upper trachea is possible with high-frequency jet ventilation, in effect similar to the Heimlich maneuver.13 Approximately 30% of the air flow from transtracheal jet ventilation is directed cephalad and can therefore assist in the expulsion of airway foreign bodies.14

PTTJV has a large number of advantages when compared to an emergent cricothyroidotomy.1–21 It is easier and faster to perform. The technique is simpler to learn. The need for a large number of instruments, surgical preparation and technique, and an assistant is eliminated. The complications of bleeding, glottic stenosis, subglottic stenosis, and tracheal erosion are significantly lessened. If the patient survives, PTTJV causes less cosmetic disfigurement. Finally, PTTJV can direct secretions and foreign bodies out of the proximal trachea.

PTTJV is contraindicated in patients who can be orally or nasally intubated. Anterior neck trauma may be a contraindication to PTTJV. Damage to the larynx or cricoid cartilage is a contraindication to PTTJV. If laryngeal trauma is suspected, catheter placement may result in laryngeal disruption.5,12 It should not be performed in patients with partial or complete transection of the trachea. Lower tracheal or proximal bronchial tree disruption can result in an increased risk of pneumothorax and pneumomediastinum with high-pressure ventilation.5,7,12

Complete airway obstruction is also an absolute contraindication to PTTJV.5,8,12 Exhalation requires passive recoil of the lungs and chest wall, and a patent airway for outflow of gas. A patient with a complete upper airway obstruction is at an increased risk for barotrauma (i.e., pneumothorax and pneumomediastinum). Numerous studies have been performed to evaluate PTTJV with varying degrees of upper airway obstruction. Ward et al. found that progressively increasing airway obstruction up to 80% did not cause barotrauma.20 With upper airway obstruction, less air is allowed to escape and more volume is forced into the lungs. Therefore, tidal volume increases with increasing airway obstruction. Once a patient develops complete upper airway obstruction, auto-PEEP (end-expiratory alveolar pressure above the set level of positive end-expiratory pressure) will develop as air is trapped within the thoracic cavity with no outlet and insufflation of air under pressure continues. This will ultimately result in barotrauma and decreased mean arterial pressure.19

• Pressurized oxygen source, wall source or tank at 50 psi
• Povidone iodine solution or Chlorhexidine prep
• Commercially available PTTJV kit or a self-assembled kit from available components
• 12 to 16 gauge, 2 to 3 in catheter-over-the-needle (angiocatheter)
• Noncompressible high-pressure oxygen tubing
• Valve device (manual push valve, Y connector, T piece)
• 10 mL syringe
• Sterile saline
• Sterile drapes
• Local anesthetic solution (1% lidocaine)
• 3-0 nylon suture
• Needle driver
• Bag-valve device
• 3 mL syringe
• Adult endotracheal tube connector

A PTTJV system can be purchased from a commercial company. It may also be assembled with individual parts.1 Examples of PTTJV systems are shown in Figures 24-2, 24-3, & 24-4. The components of a PTTJV system are quite simple (Figure 24-5). The oxygen source may be a wall supply or tank. It should have a pressure regulator that can provide 100% O2 at 50 psi through noncompressible and high-pressure tubing. Along the tubing there must be a valve (Y connector or manual push valve) to allow intermittent flow of oxygen.5 The flow into the trachea is regulated by manual control of this valve. Ventilations should be delivered at a rate of 12 to 20 breaths per minute. Oxygen flow rates will vary with catheter size. Flow rates for 20, 16, and 14 gauge catheters at 50 psi are 400, 500, and 1600 mL/s, respectively.9 The inspiratory time is brief compared to the expiratory time by a ratio of 1:2 to 1:9 seconds.2,10,15

If a high-pressure system is unavailable, the patient may still be temporarily oxygenated through a transtracheally placed catheter.23 Attach a 3 mL syringe without the plunger to the catheter. Insert a standard endotracheal tube connector, from a size 5 to 9 mm i.d. endotracheal tube, into the barrel of the syringe. Connect the bag-valve device to the connector and begin ventilation while preparing for more definitive airway control.6,7,24,25

The commercially available PTTJV kits are designed to provide 100% oxygen at 50 psi which has been shown to provide both adequate oxygenation and ventilation.8,9 Several recent studies have compared the effectiveness of a self-made apparatus with the commercial kits. They have shown that flow rates of >15 L/min (regulator wide open) are needed to produce equivalent flow rates.26 Using flow rates less than 15 L/min will result in failure of ventilation within 60 seconds. Therefore, if a high pressure system is unavailable and a more definitive airway cannot be obtained, a surgical cricothyroidotomy should be performed.27

The establishment of PTTJV requires not only proper insertion of the transtracheal catheter, but also a proper setup of the ventilatory equipment. The required equipment should be prepackaged and placed where it is readily accessible. Ensure that the fittings are secure and the tubing is not damaged. Place the patient supine and in the “sniffing” position if no contraindications exist. The patient is most likely already in the proper position, as this technique is most often performed on apneic patients in whom other intubation techniques have failed. Place a rolled towel behind the middle of the neck to hyperextend the neck and allow for better access. Identify by palpation the hyoid bone, thyroid cartilage, cricoid cartilage, and cricothyroid membrane. Clean the anterior neck of any dirt and debris. Apply povidone iodine solution or chlorhexidine prep to the anterior neck. Prepare the needed equipment. Attach a 12 to 16 gauge catheter-over-the-needle (angiocatheter) to a 10 mL syringe containing 5 mL of sterile saline.

Stand at the side of the bed and adjacent to the patient's head and neck. Reidentify the anatomic landmarks. This is crucial to perform this procedure. Using the nondominant hand, place the thumb on one side of the thyroid cartilage and the middle finger on the other side. Use these fingers to stabilize the larynx. Use the index finger to identify the anatomic landmarks.5,10 Start at the laryngeal prominence (Adam's apple) and work inferiorly. The soft membranous defect inferior to the laryngeal prominence is the cricothyroid membrane. Below this is the firm cartilaginous ring of the cricoid cartilage.

Insert the catheter-over-the-needle (angiocatheter) through the skin, subcutaneous tissue, and inferior aspect of the cricothyroid membrane. The inferior aspect of the cricothyroid membrane is the preferred site as it avoids injury to the cricothyroid arteries.7 Direct the catheter-over-the-needle inferiorly and at a 30° to 45° angle (Figure 24-6A). Maintain constant negative pressure within the syringe as it is advanced (Figure 24-6B). Continue to advance the catheter-over-the-needle while maintaining negative pressure until air bubbles are visible in the syringe and a loss of resistance is felt.5,10 These both signify that the angiocatheter is within the trachea.

Once placement within the trachea is confirmed, securely hold the needle and advance the catheter until the hub is against the skin (Figure 24-6C). Remove the needle and syringe (Figure 24-6C). Reattach the syringe without the needle to the catheter. Aspirate once again to reconfirm placement of the catheter within the trachea. The 2 to 3 cm catheter should be long enough to pass into the tracheal lumen without sitting against the posterior wall. If the catheter tip directly touches or faces the posterior tracheal wall, there is the risk of forcing air submucosally.12 Firmly grasp and hold the catheter hub at the skin of the neck. Remove the syringe. Attach the oxygen tubing to the catheter (Figure 24-6D). Begin ventilation and continue until a more permanent and secure airway is established.5 Watch for adequate chest rise with ventilation and allow for complete elastic recoil of the chest wall before giving the next breath to avoid air trapping and barotrauma.

PTTJV requires continuous cardiac and pulse oximetry monitoring to evaluate oxygenation. Continuous capnography can be used to assure adequate ventilation. Arterial blood gas samples should be obtained periodically to look for hypoxia and hypercarbia. Careful attention must be paid to maintaining a patent upper airway to allow for passive expiration and avoid barotrauma. Oropharyngeal and/or nasopharyngeal airways, or a jaw-thrust maneuver, are often adequate.

The catheter, oxygen tubing, and patient must be continually assessed during PTTJV. Check the catheter tubing at regular intervals for signs of dislodgement or kinking. Examine the patient for crepitus in the neck and torso. If crepitus is present, the catheter tip is most likely directly against or directed toward the mucosa of the posterior tracheal wall. Oxygen is being forced into the submucosal tissues and tracking subcutaneously. Remove the catheter and reinsert a new one. Obtain a chest radiograph to assess the patient for a pneumomediastinum, pneumopericardium, or pneumothorax that may require decompression. Pulse oximetry and cardiac monitoring and capnography should also be continuously monitored.

The catheter and tubing must be secured to prevent accidental dislodgement.10 One person must continuously hold the hub of the catheter against the patient's skin during PTTJV while a second person secures it. There are three ways to secure the equipment. The first and preferred method is to suture it in place. Place a skin wheal of local anesthetic solution (1% lidocaine) next to the catheter hub. Using 3-0 nylon suture, place a stitch through the skin wheal and tie it securely. Do not cut the suture. Wrap the long end of the suture around the catheter hub two or three times and tie it securely to the tail of the suture. Wrap the long end of the suture around the oxygen tubing, just above the attachment to the catheter hub, two or three times and tie it securely to the tail of the suture. Alternatively, wrap a piece of umbilical or plain tape around the patient's neck, the catheter hub, and the oxygen tubing. A second alternative is to attach a commercially available endotracheal tube holder around the patient's neck and connect it to the oxygen tubing. The catheter will still have to be secured with suture or by being taped to the oxygen tubing and skin.

The patient should be reevaluated for possible endotracheal intubation. Studies have shown that subsequent attempts have been successful. It is possible that the positive pressure used in PTTJV increases the success rate.10

PTTJV is a relatively safe and effective means of establishing an emergent airway in a patient who cannot be intubated or ventilated by another mechanism. Complications are fewer than with a cricothyroidotomy, but they do occur and must be anticipated.

Subcutaneous emphysema occurs most commonly when the transtracheal catheter is misplaced, becomes dislodged into the soft tissues of the neck during ventilation, or is placed against the mucosa of the posterior tracheal wall.1,5,6 It may also occur if catheter placement is unsuccessful on the first attempt, creating a port for leakage of pressurized air into the subcutaneous tissues of the neck.5 Frequent examination of the catheter site for evidence of subcutaneous emphysema may provide the earliest clue to catheter malfunction.

Barotrauma may present as a pneumothorax, pneumomediastinum, or pneumopericardium. It may be a result of upper airway obstruction. The exhalation of air is passive and depends on a patent upper airway. It is therefore important to monitor chest rise and fall as evidence of continued air exchange.1 An oropharyngeal airway, nasopharyngeal airway, or jaw-thrust maneuver will often provide adequate upper airway patency.5 Assume, until proven otherwise, that any sudden change in the patient's heart rate or blood pressure during PTTJV is secondary to a tension pneumothorax. There has been a case report of laryngospasm with PTTJV use during an elective surgical procedure.16 It resulted in sudden desaturation and hypotension that were easily resolved with the administration of a paralytic agent.

Catheter obstruction is another potential complication. Most commonly, the catheter will kink as it traverses the soft tissues of the neck.1,5 This may occur if the catheter is dislodged or as a result of high-pressure ventilation. The use of a commercially available kink-resistant catheter greatly reduces this risk.

The catheter may be inappropriately placed. Misplacement of the catheter into the submucosa of the larynx can lead to a laryngeal pneumatocele. If this is suspected or identified, remove the catheter and reinsert a new one. The pneumatocele can be aspirated with a needle and syringe after placement of a new transtracheal catheter.5 Misplacement of the catheter posteriorly through the back of the trachea and perforation of the esophagus is a theoretical concern that has never been reported.1,5,6

Pulmonary aspiration is another potential complication of PTTJV. The epiglottis provides no airway protection, and the small transtracheal catheter does not prevent aspiration of secretions or gastric contents into the lungs. Animal studies have demonstrated that pulmonary aspiration in fact did not occur despite variable frequencies of ventilation, variable oxygen flow pressure, and cardiac compressions during cardiopulmonary resuscitation (CPR).17,18 Studies have shown that the pressurized flow of air through the catheter provides an adequate forceful gas outflow from the lungs which may prevent pulmonary aspiration. 17,18 Secretions and foreign bodies have been shown to stay above the jetting catheter while PTTJV is in progress. If PTTJV is to be discontinued, great care must be taken to assure complete suctioning and cleansing of the upper airway above the catheter.18

Less serious complications include local hematoma formation at the catheter insertion site, hemoptysis, and cough.1,5,6 The use of nonhumidified oxygen in the catheter has been reported to cause irritation and erosion to the tracheal mucosa.1

PTTJV is an effective and easy method for establishing an emergent airway in patients who cannot be ventilated with a bag-valve-mask device or intubated. The indications for PTTJV are the same as those for a cricothyroidotomy. Placement of a catheter through the cricothyroid membrane and attached to a high-pressure oxygen source will provide adequate oxygenation and ventilation until a more definitive airway can be established. This is an airway management technique that is rapidly performed and should be considered as a reliable backup rescue technique for the “can't intubate, can't ventilate” patient.