What is Pulseless Electrical Activity (PEA)?
Pulseless electrical activity, or PEA, is a common occurrence during arrest situations. In PEA, the monitor will show electrical activity in the heart, but the patient will have no palpable pulse. This is a very dangerous situation for the patient, and it takes a skilled ACLS practitioner to learn how to manage this condition. In other pulseless rhythms, such as ventricular fibrillation and pulseless ventricular tachycardia, shocks are advised, but defibrillation will do nothing to help the patient in PEA. The primary treatment is to find the underlying cause of the arrest.
If you encounter a patient in PEA, you will need to know the Hs and Ts to help you find the cause of the problem. When you find the cause, it is sometimes (but not always) possible to reverse PEA and achieve ROSC. While you are considering the cause your team should continue to focus on high quality CPR, including optimization of ventilations. It may take some time to find the cause of the arrest, but a good team environment and feedback from other team members can often help the practitioner find the cause more quickly. Don’t forget to use your fellow team members when considering the Hs and Ts.
PEA may be caused by many conditions, but its most frequent causes are hypovolemia and hypoxemia. If your patient has lost a great deal of blood, hypovolemia should be considered as a cause of PEA. You should also be on the lookout for fluid shifts that may deprive the vasculature of blood volume; for instance, shifts caused by electrolyte imbalances can cause the overall fluid available to drop considerably. Also consider this problem in patients who have kidney disease who may just have had dialysis- It could be that too much fluid has been taken off.
Another problem to consider with PEA is internal bleeding. This is another “hidden” way in which hypovolemia can rear its ugly head. Hypoxemia can be easily corrected with proper ventilation of the patient’s lungs. The other Hs and Ts are important as well. For instance, trauma is very closely related to hypovolemia and can cause PEA, especially if the patient is experiencing third spacing, or a shift in fluid volume. In essence, any of the Hs and Ts can cause PEA.
A patient in PEA will be completely unconscious. When the monitor is attached, you will see a rhythm on the monitor. Normal sinus rhythm, bradycardia, and ventricular tachycardia are possible rhythms that you might see. Despite having a rhythm on the monitor, the patient will not have a palpable pulse or blood pressure. If left untreated, the electrical activity will eventually stop, and the patient will then be in asystole. The most important part of managing PEA is assessment of the patient.
To assess for a pulse, you can palpate the carotid artery in the neck. Usually, this is enough to confirm the presence (or absence) of a pulse. You can also listen over the apex of the heart with a stethoscope if there is still doubt as to whether a pulse is present.
Skin color in patients in PEA is often blue-tinged or grey because they aren’t being well-oxygenated. Color should improve with CPR, so you may see a change in color even in patients in PEA. However, the most important symptom of this condition is the disparity between what you see on the monitor and your assessment of the patient.
PEA is treated much like asystole. It is not a shockable rhythm because the electrical system in the heart is actually working properly. Shocking the patient is done to ‘reset’ the heart’s rhythm, but the problem in PEA isn’t in the conduction of electrical stimuli in the heart. You should have your team continue CPR for at least two minutes, and then you need to perform both a rhythm and pulse check. If the rhythm is shockable, you would proceed with defibrillation. If the patient is still in PEA, you would continue with CPR, administer epinephrine and begin to consider possible causes. Epinephrine can be given every 3 to 5 minutes.
During this time, you should consider securing an advanced airway, but you should not neglect your Hs and Ts. If hypovolemia is a problem due to gross bleeding or as evidenced by laboratory test results, then you need to replace the fluids lost with blood products or normal saline. Search for and treat problems such as tension pneumothorax, MI, cardiac tamponade, drug overdose or any other problem that could cause PEA. CPR, epinephrine, and causation should all be pursued simultaneously to overcome the effects of PEA.