Thursday, April 18, 2013

The Trauma Cupid's Arrow: Intracardiac Epinephrine

A patient is wheeled into your trauma bay after a nasty head-on collision on a major highway. According to the paramedics, the downtime and length of anoxia in the patient is unknown, and because of this, the patient is intubated. Vital signs are unobtainable, and pulses are lost on the scene. The patient is now in pulseless electrical activity (PEA), and cardiopulmonary resuscitation is initiated. The decision is made to perform an emergent thoracotomy.

The process is underway and it is time for the next epinephrine dose. The trauma surgeon calls out, "Alright, let's use intracardiac epinephrine."

Wait...what? Perhaps this movie scene pops into your head as you hear the order:

Very few case reports and small anecdotal studies describe the use of intracardiac epinephrine in the setting of emergent thoracotomy in traumatic cardiac arrest.

Here are some pointers to remember regarding this technique for administration:
  • The dose is the same dose that is used in the guidelines for advanced cardiovascular life support (ACLS): 1 mg.
  • Use whatever epinephrine product you have available, whether it be the 1:10,000 (1 mg/10 mL) or 1:1,000 (1 mg/mL) concentration; both concentrations have been studied and are acceptable for use.
  • In terms of needle size and length:
    • The best bet to use is an 18-gauge or 22-gauge needle; anything smaller than this is generally not recommended due to the potential for vascular injury to the cardiac tissue.
    • A 1.5-inch needle should be sufficient. Interestingly enough, a number of pharmaceutical companies have manufactured epinephrine specifically for intracardiac injection, which is available in a pre-filled syringe with a 3.5-inch needle attached (fancy, but can create "trauma drama" and probably not truly necessary).
  • Cardiac compressions should be discontinued temporarily while intracardiac administration occurs to prevent injury to the person performing chest compressions.
  • The epinephrine should be administered as rapid push and directly injected into the chamber of the left ventricle while cardiac massage is ongoing. This can be achieved by lifting the heart outwards to allow for easier visualization of the left ventricle.
  • Chest compressions can be resumed once the dose has been administered.
  • The dose of intracardiac epinephrine of 1 mg can be repeated every 3 to 5 minutes, as per the ACLS algorithm.
Some complications that patients may experience include ventricular and coronary artery laceration, pneumothorax, and cardiac tamponade. Because of this, an organized method is necessary for this technique in order to ensure appropriate administration.

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