Needle cricothyrotomy or percutaneous transtracheal jet ventilation (PCJV) can truly be a life saving procedure. It is a fast, effective way of providing oxygen to a patient with an obstructed airway who does not respond to more conventional means of opening the airway. The “can’t intubate-can’t ventilate” scenario is a good example. PCJV is faster to perform than a surgical airway. It will buy you time to establish a more permanent airway such as an intubation or surgical airway if the patient is hypoxic.
However, PCJV carries some rare though potentially serious risks of worsening airway obstruction and cardiovascular collapse if the catheter is not correctly positioned within the trachea. Fear may prevent us from using it. In addition, most of us have never had to use PCJV in an emergency or even seen it used. Lack of familiarity with the equipment and simple lack of comfort may make us hesitate to try. We may not even think about it in the moment of crisis. So let’s look at some of the ways we can use PCJV safely.
Jet ventilation carries the potential risk of rare though significant complications, some of them potentially life-threatening. Because of this PCJV should only be used when you cannot ventilate using more conventional methods. Although this usually means using it in emergency situations it is occasionally used for airway surgery where intubation is not possible or would otherwise get in the way of the procedure. Some of these indications include plus:
- Can’t intubate, can’t ventilate
- Severe maxillo facial trauma
- Bleeding in the upper airway that obscures your ability to see anatomy
- Severe swelling/edema
- Chemical or thermal burns
- Surgical airway of choice for children younger than 12 years of age (due to the small airway and increased risk of laryngeal injury with cricothyrotomy)
- Diagnostic or surgical laryngoscopy requiring good exposure of the larynx, continuous control of airway patency, and immobility of the vocal cords where elective tracheostomy is not a good option. In this case usually high frequency jet ventilation is used rather than manual jet ventilation.(1)
Because of the risk of pneumothorax and subcutaneous or mediastinal emphysema, jet ventilation should not be used when you are able to secure the airway using more conventional and non-invasive means. In addition, it should not be used if there is:
- Damage to the trachea or tracheal rupture: pressurized air would escape into the soft tissues
- Severe obstruction of the airway above the cricothyroid membrane: patient would be unable to exhale and risk of pneumothorax would increase
- Bleeding diathesis
- Inability to identify cricothyroid landmarks: increased possibility of misplacing the catheter
If you have time, and if the patient is conscious, you can provide analgesia by injecting lidocaine at the insertion site. At the same time, you could easily inject a little lidocaine into the lumen of the trachea to blunt the cough reflex. However, if severe hypoxia is present don’t wait to numb the skin. Act quickly.
The patient should be supine. If there is no risk of cervical spine injury, extend the head to expose the neck. Prep the skin.
First identify the cricothyroid membrane by finding the cricoid ring. The membrane lies in the gap between the ring and the thyroid cartilage above it. The membrane is about 1 cm high and 2 cm wide in the average adult. The vocal cords lie about 1 cm above the membrane. The blood vessels tend to overlie the upper third of the cricothyroid membrane. Making your puncture in the lower third will minimize the risk of hitting them.
Use the largest IV catheter possible, such as a size 10 or 14 gauge in the adult. For a child choose a smaller catheter such as an 18 or 16 gauge. You can use any intravenous catheter-over-needle set to puncture the cricothyroid membrane, however, it should be a catheter that will attach to a syringe. Many of the common IV catheters in use today have built in shields to avoid accidental needle puncture and are not designed for syringe aspiration. This may mean that you need to keep a stock of appropriate large bore catheters for emergency use that are different than your standard IV catheters. Another option is stocking specific commercially available cricothyroidotomy catheters.
Attach a 10 ml syringe to the hub of the needle. The syringe should contain 3-5 ml of saline. Stand at the head of the bed and aim the needle slightly caudad at an angle of about 30-40 degrees. Aspirate as you advance. Your insertion should be slow and deliberate to avoid puncture of the posterior tracheal wall. The diameter of the adult trachea averages 18 mm. As soon as you enter the tracheal lumen you will see bubbles in the saline as you aspirate air, verifying intratracheal placement.
Once you have entered the trachea, slide the catheter off the needle into the trachea. The catheter should slide easily. Immediately attach your syringe to the hub of the catheter again and aspirate air. There should be no resistance. Do not skip verification of correct placement inside the tracheal lumen because you must be absolutely sure that the catheter is correctly placed inside the trachea. It’s essential that the catheter not be blocked by the tracheal wall or kinked. Jet ventilation against or into the tracheal wall can cause massive subcutaneous emphysema that can cause catastrophic airway distortion and obstruction.
Steady the catheter by the hub to ensure that it doesn’t move. Keep your fingers in contact with the neck while holding the hub to avoid accidentally pulling the catheter out of position.
Ventilating Using A Jet Ventilator
To ventilate the patient you now need to connect the catheter to a ventilation system. Because of the small diameter of the catheter, the best means of giving oxygen through this device is a jet ventilator. The typical jet ventilator consists of a device that allows precise manual triggering of oxygen flow when attached to a 50 psi oxygen source.
An attached regulator steps down the pressure and allows you control the pressure you are delivering to the patient and see the amount of pressure on a manometer. This device is connected to a long pressure hose that has a luer lock adaptor that allows connection to the catheter in the trachea.This is the jet ventilator from my OR as an example showing the parts common to all such devices.vYou should familiarize yourself with the jet ventilator available in your institution.
Jets can come with a variety of triggers. In this example the trigger is a squeeze lever. Other jets might have a button you can depress.
Note that you can set the highest amount of pressure to be delivered using the pressure regulator.
What Pressures Should I Use To Ventilate?
Connect jet ventilator to oxygen source (via quick connect) and luer lock on the catheter. With the device connected, watch the patient’s chest as you trigger the oxygen flow by pressing the button. As you keep the trigger pressed for several seconds — and only several seconds — the chest wall will rise as the lungs inflate.
If you have ever seen a balloon being filled from a helium tank then you know how quickly a large volume of gas enters a closed container. The lungs will inflate very quickly. Stop oxygen flow after the chest wall rises adequately. Monitor the pressure gauge. Typical pressures used are:
- 0 to <5 years old- < 20 mmHg (you can also consider use of Bag-Valve device to limit peak pressure: see below)
- 5 to 12 years old- < 30mm/Hg
- 12 years old – 50 mm/Hg
Use I:E ratio of 1:4 to 1:5, with a breath rate of 10 to 12/minute for most children. Change the ratio to 1:2 to 1:3 with a breath rate of 15 to 20/minute in the setting of increased intracranial pressure to improve CO2 elimination. With partial or complete upper airway obstruction, use the ratio of 1:8 to 1:10 with a breath rate of 5 to 6/minute to reduce the risk of pulmonary barotrauma. Adjust these ratios based on clinical monitoring, blood gas measurements, and chest radiography.
Allow The Patient To Exhale
The catheter is too small to permit the patient to exhale through it which is why it is essential that the airway above the cricothyroid membrane must be at least partially open to allow exhalation. You must let the lungs deflate before you trigger inhalation again. As you can see in the above suggested ventilatory ratios, paying attention to exhalation times critical.
You risk tension pneumothorax if the patient cannot exhale or isn’t given enough time to exhale. Never press the trigger unless you are watching the patient’s chest.
Securing the Catheter
Securing the catheter while in use is important. If the catheter migrates out of the trachea, then misplacement of the catheter can lead to subcutaneous emphysema. The person holding the catheter must ensure that the catheter does not kink or slip out of position.
For more prolonged use you can securely tape the hub into contact with the skin. Dedicated cricthyroidotomy catheters typically have a flange on the hub to allow securing the catheter.
Ventilating During Intubation Requires Good Teamwork
This ventilation technique can be used to ventilate while intubation attempts continue. The person ventilating with the jet must observe the chest and monitor vital signs while the intubator concentrates on a more permanent airway. Obviously this requires good communication and coordination of effort. Talk to each other.
One study has shown that there were two important benefits in the patients who underwent PTJV successfully during continued intubation attempts. First, PTJV provided effective oxygenation, while allowing adequate time for upper airway visualization and possible suctioning of oropharyngeal secretions. Second, tracheal intubation was subsequently easier, possibly because the high tracheal pressure from the gas insufflation opened the collapsed glottis (2).
When using the jet it’s imperative that the catheter be inside the trachea, and not in the soft tissue next to the trachea. A small amount of subcutaneous emphysema is common, especially if more than one puncture is required to place the catheter. However, applying high pressure gas flow into the soft tissue could cause catastrophic subcutaneous emphysema and even potential mediastinal emphysema. Mediastinal emphysema can impair venous return and drop cardiac output. Don;t hesitate to stop ventilating and reverify that the catheter is in the trachea before continuing.
It is also essential that the airway be at least partially open above the cricothyroid membrane to allow the patient to exhale. If the patient cannot exhale, or if you do not allow time for the patient to exhale, then the gas pressure will build and can potentially cause a pneumothorax, possibly a tension pneumothorax. Remember that airway obstruction can occur simply from failure to hold the airway open.
When A Jet Ventilator Is Not Available
You don’t need a jet ventilator to ventilate though a cricothyroid catheter. Thought not optimal, reports indicate that patients can maintain themselves for several minutes breathing spontaneously through a 10 g catheter. However, you can assist ventilation without a jet ventilator in you don’t have one available, or if you wish to limit the peak pressure in a baby or small child.
The connector from a number 3 endotracheal tube fits snugly into the hub of any intravenous catheter. However, this tiny assembly is often difficult to hold while squeezing the bag. I prefer to place the connector from a number 7.5 endotracheal tube into the barrel of a 3 ml syringe as shown in the illustration. The barrel of the syringe mates to the hub of your catheter and gives you something more substantial to hold.
You can also place an endotracheal tube within the barrel of a ten ml syringe and inflate the cuff to maintain the connection.
No matter which connector you use, you must ventilate vigorously to pass enough oxygen through the catheter.Gas will escape through the mouth.
You can attach the barrel from a tuberculin syringe to the catheter hub and connect this to oxygen tubing. If the oxygen tubing can then be connected to the fresh gas outflow from an anesthesia machine a “jet” can be jury-rigged. However, there is no way to measure how much pressure you are administering using this method .
Note: Hypercarbia Will Develop Without A Jet Ventilator
Although hypoxia is avoided with any of these non-jet ventilator techniques, hypercarbia will develop. This can cause significant respiratory acidosis if use of these techniques is prolonged. However, any oxygen supplied during emergency treatment of airway obstruction is useful.
Percutaneous jet ventilation is a life-saving technique that everyone who does advanced airways management should know. You should familiarize yourself with the equipment available for percutaneous transtracheal jet ventilation so that in an emergency, you not only remember that this is an option, you also feel comfortable performing the procedure. If you are assisting in a respiratory emergency, don’t be afraid to suggest it to the rest of your team as an option.
May The Force Be With You
Christine Whitten MD
- L. Bourgain, E. Desruennes, M. Fischler, P. Ravussin. Transtracheal high frequency jet ventilation for endoscopic airway surgery: a multicentre study. Br. J. Anaesth. (2001) 87 (6): 870-875
- Patel RG .Percutaneous transtracheal jet ventilation: a safe, quick, and temporary way to provide oxygenation and ventilation when conventional methods are unsuccessful. Chest. 1999 Dec;116(6):1689-94.