What is pulseless electrical activity?
In dramas or movies, we probably had watched scenes in the hospital where the protagonist or the antagonist died in the hospital. Then the scene shows a heart monitor or best called the electrocardiography (ECG) monitor shows a straight line or flat line. Then, a scene of a doctor checking for pulses before pronounced the person has died. Do you know that in real life, the ECG might actually show some wavy spikes reading but the patient’s pulses are not detected? It sounds weird but this can be a condition called pulseless electrical activity (PEA) and this DoctorOnCall article will further explain this.
ECG tests in general record the electrical signals in the heart. The way the heart pumps the blood in the body is through the electrical conduction system that is generated by the cardiac (heart) cells itself. A regulated electrical system of the heart is important for the various chambers of the heart to work in sync. Any problem with electrical activity such as in PEA can cause great disturbance to the heart system. PEA is formerly known as electromechanical dissociation. PEA is characterised by the presence of cardiac electrical activity which may be organised or disorganised in absence of the ventricular tachycardia/ fibrillation (an irregular electrical impulse from the lower chambers of the heart, the ventricle) and no measurable cardiac output marked by the absence of the pulse or blood pressure.
PEA accounts for almost 30 % cardiac arrest happening outside the hospital while 40% PEA cases happen inside a hospital setting. The survival rate for a patient after a PEA is very low, just around 2-5 %. Those above 70 years old are very at risk of getting PEA. PEA can be caused either by the heart problem itself such as a cardiac arrest or other problems not directly related to the heart. The other problems causing a PEA is included in the famous “5Hs and 5Ts”:
1- Hypovolemia: a body condition loses fluid such as water or blood
2- Hypoxia: a body condition depleting in oxygen
3- Hydrogen ion: when a body condition in acidosis state
4- Hypo/hyperkalemia: low or high level of potassium in the body
5- Hypothermia: very low temperature of the body
1- Tension pneumothorax: a severe condition of air trapped in the space covering the lung
2- Trauma: any injury to the chest
3- Tamponade: fluid or blood filled the space around the heart
4- Thrombosis-pulmonary: blood clots blocking the lung’s blood vessel
5- Thrombosis-coronary: blood clots blocking the heart’s blood vessel
PEA is considered an emergency as it is life-threatening. Hence, healthcare providers will activate protocol such as the advanced cardiac life support (ACLS) to resuscitate patient which includes chest compression, intubation or ventilation support, usage of medication like adrenaline or epinephrine and at the same time finding the cause for the PEA based on the “5Hs and 5Ts”. Once it is known or suspected what can cause the PEA, further intervention specifically to the cause is done. Time is crucial for patients with PEA and only the precise treatment by an excellent healthcare provider can help revive the patient and reduce further sequelae or disability in the surviving patients.
Treatments example based on PEA causes:
1- Hypovolemia- fluid resuscitation, stopping the bleeding
2- Hypoxia- intubation and ventilation
3- Hydrogen ion- bicarbonate usage
4- Hypo/hyperkalemia- potassium replacement/calcium gluconate usage
5- Hypothermia- provide warmth environment
6- Tension pneumothorax- needle decompression
7- Trauma- appropriate medical and surgical approach based on trauma severity
8- Tamponade- pericardiocentesis or open chest surgery
9- Thrombosis- thrombolysis procedure