Cricothyroidotomy - Types, Procedure, Indications, Contraindications, and Complications

Introduction

Airway obstruction can happen due to many reasons leading to breathlessness. In order to increase the airflow in such patients, a surgical airway is created. Cricothyroidotomy is employed in potentially life-threatening situations with a failing airway by making a slit in the cricothyroid membrane and saving the patient's life. Cricothyroid is a membrane between the thyroid and cricoid cartilage, helping phonation. This membrane is pierced as an emergency procedure to establish a patent airway.

What Is Cricothyroidotomy?

Cricothyroidotomy is a surgical procedure by placing a tube through a cut on the cricothyroid membrane to secure the airway. This procedure is done in a "cannot intubate" or "cannot ventilate" situation. The procedure helps improve oxygenation and ventilation in a person with airway obstruction.

How to Assess for Obstruction in the Airway?

The easiest way to identify an airway obstruction is by using a scoring system. The higher the score, the highest the difficulty level in intubation. A procedure called 'intubation' is done to make them breathe effortlessly.

Intubation uses a tube (endotracheal tube) inserted into the patient's airway to create airflow in and out of the lungs. When intubating a patient becomes difficult, cricothyroidotomy comes to the rescue.

One of the scorings for difficulty in the airway is the 'Mallampati scoring system' by visualizing the hard palate (a hard portion of the throat), soft palate (a soft portion of the throat), and the uvula (soft hanging structure in the middle of the throat):

• Class I - The hard palate, soft palate, and uvula are visible when opening the mouth.

• Class II - The hard palate, soft palate, and the base of the uvula are visible.

• Class III - Only the hard palate and the soft palate are visible.

• Class IV - Only the hard palate is visible.

So, a Class IV patient has less space available, indicating difficult intubation.

In addition to the Mallampati scoring system, the Lemon law is also used to assess difficult airways.

1. L - Look at the external appearance for:

• Trauma in the head and neck region.

• Large front teeth

• Beard or mustache.

• Large tongue.

2. E - Evaluating the 3-3-2 rule:

• Three-finger distance between the upper and lower front teeth on mouth opening.

• Three-finger distance between the hyoid and the mental bone.

• Two-finger distance between the thyroid and the mouth.

3. M - Mallampati score of more than 3.

4. O - Presence of any obstruction like an abscess or due to trauma.

5. N - Neck mobility is limited.

Each of the signs mentioned above is given a score of 1 if present. Thus, a higher score indicated difficult intubation and switching to cricothyroidotomy.

How to Locate the Cricothyroid Membrane?

One of the most common mistakes is the misidentification of the membrane. It is recommended that the emergency procedure is performed only by professionals with good knowledge about the location of the cricothyroid membrane. The following flowchart shows the steps in locating the cricothyroid membrane.

• First, feel the front of the neck with the thumb and middle fingers.

• Now, locate the most prominent portion of the neck with the forefinger- the 'Adam's apple.'

• Move the finger slightly down from Adam's apple for approximately 2 centimeters.

• The point about 2 centimeters below Adam's apple is the cricothyroid membrane.

• Only a trained professional with regular practice knowing the anatomy of the neck can locate the membrane quickly and perform the procedure.

What Are the Types of Cricothyroidotomy Procedures?

There are various techniques to perform the procedure. They are surgical cricothyroidotomy, needle cricothyroidotomy, and percutaneous cricothyroidotomy. All are done under local anesthesia and total aseptic conditions. Each method is used in a specific clinical scenario.

Before starting the procedure, the neck is hyperextended to visualize the neck and locate the landmarks, except for patients with a cervical spine injury.

Open Cricothyroidotomy

• The following types of equipment are required: No.11 scalpel blade, endotracheal or tracheostomy tube, tape to secure the tube, hemostats, suction, and bag valve mask device for oxygenation.

• The cricothyroid membrane is first located, and a 3 to 5-centimeters vertical midline incision or slit is made on the skin and subcutaneous tissue, followed by a <1 centimeter horizontal incision on the membrane.

• The endotracheal tube is inserted correctly into position and secured.

• The bag-mask device is attached for ventilation.

Needle Cricothyroidotomy

• The equipment required is an angiocatheter, a 3 milliliter syringe x 2, and a bag valve mask for ventilation.

• It is a technique of choice in children when there is a lack of equipment available.

• The membrane is located and pierced with an angiocatheter at a 45-degree angle downwards, to which a 3 milliliter syringe containing saline is attached.

• Keep aspirating until a pop is felt on entering the membrane, and advance 1 centimeter more into the membrane.

• The catheter is advanced over the needle, after which the needle is removed.

• The bag valve mask or jet ventilator is then attached to the catheter for ventilation and secured.

Percutaneous Cricothyroidotomy

• The equipment required is a catheter attached with a 3 milliliter syringe filled with saline, a tracheal tube, a No.15 scalpel blade, a flexible guidewire in a plastic housing, and a bag valve mask.

• This procedure is not done in children under eight years of age.

• The same procedure mentioned above in the needle cricothyroidotomy is done.

• After removing the needle, the guide wire is attached through the catheter into the trachea.

• This is followed by attaching the bag valve mask for proper ventilation.

Who Should Undergo Cricothyroidotomy?

This emergency procedure is indicated in a "cannot intubate, cannot ventilate" situation. Some of these situations include:

• When there is an inability to intubate and ventilate.

• Failure to maintain blood oxygen levels above 90.

• Trauma in the head and neck region.

• Severe bleeding from the throat behind the mouth.

• Airway edema.

• Airway trauma.

• Severe vomiting.

• Cervical spine trauma.

Who Should Not Undergo Cricothyroidotomy?

• Children younger than five to 12 years of age.

• Patients with any laryngeal disease.

• Patients with a fractured larynx.

• Those who are undergoing tracheal surgery.

• Patients with any abnormalities in the neck region like goiter.

• In case of laryngotracheal disruption.

What Are the Complications Associated With Cricothyroidotomy?

Apart from being an emergency procedure, many complications are involved.

The complication rates range from zero to 54 percent. There are short-term and long-term complications.

Short-Term Complications

• Bleeding is the most commonly encountered complication due to incorrect incision or damaging the adjacent blood vessel.

• Displacement of the endotracheal tube.

• Obstruction in the endotracheal tube.

• Bronchial intubation.

• Laryngotracheal injury.

• Tension pneumothorax.

Long-Term Complications

• Infections.

• Change in voice.

• Difficulty in swallowing and breathing.

• Persistence of the opening made.

• Narrowing of the airway.

Conclusion

In patients with difficult airways, intubation is first tried, and if failed even after three attempts, one of the last resorts to revive them is cricothyroidotomy. This procedure is to be done by a trained doctor and involves an interprofessional team of physicians, respiratory therapists, and nurses. The failed airway is no longer feared after the invention of cricothyroidotomy as a successful life-saving procedure.