Clinical Exercise: Cricothyrotomy
Scenario:
You are at the site of a severe motor vehicle crash and the fire fighters have just extracted a patient from a damaged vehicle. The patient has major mid-face craniofacial injury including broken nasal passages, maxilla and mandible fractures combined with soft tissue damage around the mouth and nose.
The patient is unconscious and clearly struggling to get air past the facial trauma. Skin coloration is turning blue and respiration rate is very high, with minimal indications that air is passing the oral or nasal regions of mid-face trauma.
Diagnosis:
You recognize that the patient is in acute respiratory distress due to tissue trauma and that edema is restricting the upper airways. The degree of mid-face trauma makes ventilation or intubation unlikely to be successful. You conclude that forming a temporary airway by performing a cricothyrotomy is the only possible management to stabilize the patient's airway for transport to the Shock Trauma Center.
Mechanism:
In cases where the upper airways are blocked due to trauma, chemical inhalation injuries, or anaphylaxis it is necessary to make a temporary alternate airway for patient breathing.
Unlike television, where the procedure is performed often using an exact-o-knife and ball-point pen in nearly every episode of the show, a cricothyrotomy is an extreme procedure of last resort in airway management requiring the correct instruments and training to have any chance of success.
The goal is to make an opening into the front of the airway through the membrane between the cricoid and thyroid cartilage. Through this opening a tube is inserted and secured, forming a pathway for air bypassing the upper airways.
The cricothyrotomy is a procedure for temporary access to the airway compared to a tracheostomy procedure (where the opening is made more inferiorly between trachea rings). In the field it has been demonstrated that the cricothyrotomy is easier and quicker to perform. A cricothyrotomy should be converted to a more durable tracheostomy when the patient is stable.
Treatment (perform these steps on the donor in a mock-procedure):
PREPARATION: Send a member of your team to the instrument supply tables to fetch one of the tracheostomy kits, a tracheal hook, and a 10ml syringe. You only need one kit and one 10ml syringe per table, leave the remaining kits/syringes for other groups. Exercise care with the tracheal hook as it has a sharp point.
Clinically, tracheostomy tubes come in a variety of sizes from large to small to best match patient stature. In the lab we are using one of the smaller size tubes (6mm) so that it will be suitable across most of the statures of our donors.
Open the package and remove the tracheostomy tube, obturator and liner (do not dispose of kit packaging as we will re-use the kit for other training groups).
Take the syringe and draw air into the syringe, then attach the syringe to the end of the tracheostomy inflation mechanism.
Test the function by gently depressing the syringe and observing that the cuff around the distal end of the tube expands (the function of this cuff is to prevent air leaking out the nose/mouth or fluids leaking into the lungs after it is placed in the patient). The blue bellows near the syringe will expand when the cuff is fully inflated as a visual indicator of maximal expansion (do not over-expand as the cuff or connections can rupture). Draw the air back into the syringe such that the cuff and bellows are fully deflated.
Place the obturator into the tracheostomy tube. The obturator provides a 'handle' for controlling the tube as well as a plug preventing blood or tissue from entering the tube during insertion.
1) Given that the patient is in acute respiratory distress, there is no time for administration of local anesthesia.
Most times the patient is already unconscious from respiratory distress.
2) Using your fingers feel along the anterior side of the neck for the laryngeal prominence of the thyroid cartilage (the Adam's apple).
3) Slide your finger inferiorly along the front edge of the thyroid cartilage to the point here you feel the space between the thyroid and cricoid cartilages.
In a larger individual it may be difficult to feel the exact point, however, you know that it will be between 2-4cm inferior to the laryngeal prominence (the Adam's apple).
4) With a scalpel make a vertical incision at the midline approximately 3-5 cm long in the skin spanning the thyroid and cricoid cartilages.
It is important that this incision be at the midline as there are large vascular structures located immediately lateral in the neck.
In the living it is never a mistake to make the incision larger. Making an overly small incision and being unable to access the airway quickly is a problem. Once patient color is going blue from lack of oxygen then there is little time (seconds to minutes) to establish oxygenation and ventilation before the patient suffers anoxic brain injury or death.
5) Using your finger widen the skin gap and feel for the softer 'bouncy' cricothyroid membrane between the thyroid and cricoid cartilage.
6) Using that as a guide, press the scalpel into the membrane to make a horizontal incision through the membrane of sufficient size that there is room for your tracheostomy tube.
You will feel a 'pop' as the scalpel pieces the membrane and enters the trachea. Do not go too deep as cutting all the way through to the other side would cause damage to the trachea resulting in significant complications (potentially puncturing all the way through into the esophagus located directly posterior to the trachea).
7) Remove the scalpel and insert a tracheal hook to hold the cricoid cartilage (inferior end of the incision) to keep control of the trachea.
If you are lacking a tracheal hook, any blunt instrument or probe including a finger can be pressed into service in the field, although a tracheal hook is far easier to use.
8) Insert your tracheostomy tube (with obturator in place) positioned with the angled side pointing inferiorly into the trachea.
If your opening in the cricothyroid membrane was insufficient you may have to widen the incision, which in the clinical setting costs valuable time for the patient in respiratory distress.
9) Push the tube all the way in such that the flanges at the base of the tube become flush or nearly flush with the skin.
10) Immediately remove the obturator (since the obturator prevents a patient from breathing it must be removed promptly) and then remove the tracheal hook.
11) Depress the syringe plunger until the blue bellows inflates fully.
Since the cuff cannot be observed directly the bellows serves as a visual indicator of maximal inflation of the cuff within the patient's airway. The cuff presses gently against the internal surface of the trachea serving to make an air-tight seal and prevent any blood/mucus flowing inferiorly into the lungs
It is a common misconception that the cuff serves to stabilize the tube, but that is incorrect. To stabilize the cuff the tracheostomy tube has lateral flanges to which a necklace can be attached.
12) Next insert the tube liner.
The tube liner serves as a removable/washable part allowing ready cleaning as mucus otherwise will build up inside the tube.
13) The tracheostomy tube remains in place during transport and until a more permanent airway solution is implemented at the hospital.
To further prevent dislodgement during movement of the patient, tracheostomy tubes are typically secured with tape or a neck-tie apparatus looped through the slots in the flanges. In this exercise we will not be securing the tube.
14) Draw the air back into the syringe such that the bellows deflates and to the point where you feel resistance to the draw (meaning the cuff is fully deflated). Remove the tube so that other members of the team can practice inserting/inflating the apparatus.
15) When finished this exercise remove the tube to allow other members of your team to insert the tracheostomy tube (with obturator followed by switching out for liner)
16) When everyone has utilized the tubing, clean the components of the kit and the tracheal hook. Then repack the kit neatly and return the kit along with the tracheal hook to the supply tables for future use.
Outcome:
Immediately upon completing the procedure, airflow is felt and heard through the tube, indicating that the patient is receiving air. The patient's color returns and respiration rates recover to more normal levels, thus stabilizing the patient for transport to the Shock Trauma Center.