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Show full transcript for What is Asystole? video

Asystole, sometimes referred to as a flat line on the monitor, represents an absence of both electrical and mechanical activity in the heart. In this lesson, we'll dig a little deeper into what it is and how it can be treated. And at the end of the lesson, you'll find a Word about the duration of resuscitative efforts.

Pro Tip #1: It's important to understand that if a patient has no pulse and this is confirmed in one lead, there are a few things you can double-check to confirm this, such as:

  • Are all the leads on correctly?
  • Are all the leads attached to the patient with good contact?
  • Does the ECG have a sufficient power supply?
  • Is the amplitude set correctly to determine asystole vs. fine VFib?

Like pulseless electrical activity (PEA), it's also important to determine what may have caused the patient's asystole, or in other words, examine the H's and T's. If you can figure out why the patient went into cardiac arrest, looking at the H's and T's will help you determine the possibility of treating any reversible causes of the asystole.

Those H's and T's are:

  • Hypovolemia
  • Hypoxia
  • Hydrogen ion (acidosis)
  • Hypokalemia
  • Hyperkalemia
  • Tension pneumothorax
  • Cardiac tamponade
  • Toxins
  • Cardiac thrombosis
  • Coronary thrombosis

Pro Tip #2: Asystole is not a shockable rhythm. So, treatment will involve high-quality CPR, airway management, IV or IO therapy, and medication therapy – specifically 1mg of epinephrine 1:10,000 concentration every 3 to 5 minutes via rapid IV or IO push.

Having said that, it's rare for asystole to be reversed, especially if the patient has been in asystole for a long duration of time.

Stopping resuscitation efforts is never an easy choice to make, and this is a gross understatement. However, if the patient is not responding to all of your basic and advanced cardiac life support treatment attempts, the decision to terminate resuscitation will need to be made.

If you have a high degree of certainty that the patient will not respond to further ACLS interventions, then it would be appropriate to stop.

When to Terminate Resuscitative Efforts

As stated above, this will never be an easy decision. And the decision to do so must be based on your specific protocols and consideration of the following criteria:

  • The time from the patient's collapse to CPR
  • The time from the patient's collapse to your first defibrillation attempt
  • The underlying causes if you've found any
  • The patient's response to your resuscitation measures
  • When the patient's EtCO2 is less than 10 after 20 minutes of CPR

All of the above should be considered before deciding to terminate your resuscitation attempts in all patients in asystole.

A Word About the Duration of Resuscitative Efforts

While we already provided you with a list of criteria above that you can use to make this very difficult decision, let's dig a little deeper into the duration of resuscitative efforts.

Deciding to terminate resuscitative efforts can never be as simple as an isolated time interval. If the return of spontaneous circulation of any duration occurs, it may be appropriate to consider extending your resuscitative efforts.

Experts have developed clinical rules to assist in decisions to terminate resuscitative efforts for in-hospital and out-of-hospital arrests. However, you should also familiarize yourself with the established policy or protocols for your hospital or EMS system.

For Out-of-Hospital Arrest

You should consider the continuation of out-of-hospital resuscitative efforts until one of the following occurs:

  • Restoration of effective, spontaneous circulation and ventilation
  • Transfer of care to a senior emergency medical professional
  • The presence of reliable criteria indicating irreversible death
  • You, the rescuer, are unable to continue because of exhaustion or dangerous environmental hazards or because continued resuscitation will place the lives of others in jeopardy
  • A valid DNAR order is presented
  • Online authorization from the medical control physician or by prior medical protocol for the termination of resuscitation

It might also be appropriate to consider other issues, such as drug overdose and severe prearrest hypothermia, due to submersion in icy water, for instance, when deciding whether to extend resuscitative efforts.

Special resuscitation interventions and prolonged resuscitative efforts might be indicated for patients with hypothermia, drug overdose, or other potentially reversible causes of the arrest.