The findings of cardiac arrest are straightforward. A patient who is in cardiac arrest is unresponsive to all stimuli and is without spontaneous breathing or a palpable pulse. The American Heart Association (AHA) has simplified their basic life support (BLS) cardiac arrest algorithm to encourage minimal compression interruption. The current algorithm has eliminated the “look, listen, and feel” step to check for breathing in an unresponsive patient. Instead, the rescuer should observe to see whether the patient is breathing normally. Emphasis is placed on “gasping” or agonal breathing being abnormal. If the patient is not breathing or only has agonal respirations, the rescuer should check for a carotid pulse for the unresponsive adult or the brachial pulse in the unresponsive infant for no more than 10 seconds. If a pulse is not felt or the rescuer is unsure if a pulse was felt, CPR should be initiated immediately.

Asystole is identified on cardiac monitoring. In asystole, there is no waveform present on the cardiac monitor, only an isoelectric “flat” line. This includes a lack of P-waves, QRS complexes, and T-waves.

An arterial blood gas and potassium levels should be obtained stat. If available, an echo can be done to document the absence or presence of heart wall motion.

Asystole should be treated following the current American Heart Association BLS and ACLS guidelines. High-quality CPR is the mainstay of treatment and the most important predictor of a favorable outcome. Asystole is a non-shockable rhythm. Therefore, if asystole is noted on the cardiac monitor, no attempt at defibrillation should be made. High-quality CPR should be continued with minimal (less than five seconds) interruption. CPR should not be stopped to allow for endotracheal intubation. Epinephrine (1 mg via intravenous or intraosseous line) should be delivered every three to five minutes and treatment of reversible causes addressed.

Vasopressin can be administered before or after epinephrine but the benefits remain questionable.

Even though transcutaneous pacing is widely done, there is no evidence that it improves survival.

Asystole is considered a terminal rhythm of cardiac arrest. Therefore, discussion of termination of resuscitation should be considered during an in-hospital cardiac arrest in the appropriate clinical picture. Out-of-hospital cardiac arrest patients in asystole should also be considered for the cessation of efforts according to local protocol.[4]

Patients who are resuscitated need to be monitored in the ICU. Some experts recommend inducing hypothermia on all patients who survive cardiac arrest.

• Acidosis

• Hyperkalemia

• Hypokalemia

• Hypothermia

• Hypovolemia

• Hypoxemia

• Syncope

• Ventricular fibrillation

The prognosis in asystole depends on the cause of the rhythm, time of intervention and success of ACLS. Resuscitation is generally successful in cases of cardiac arrest due to choking on food or due to pacemaker failure. Overall the prognosis is poor and the survival is even poorer if there is asystole after resuscitation. Data indicate that less than 2% of people with asystole survive. Recent studies do document improved outcomes but many continue to have residual neurological deficits.

• Pneumothorax
• Air embolism
• Spleen, stomach or colon rupture
• Hemothorax
• Liver laceration
• Fractured ribs

Pitfalls

Providers should ensure that, if a patient appears to be in asystole on the cardiac monitor, that the patient is, in fact, in cardiac arrest. Disconnected cardiac monitoring leads can appear as asystole. Additionally, providers should differentiate between asystole and fine ventricular fibrillation, which may respond to defibrillation.

When considering terminating care of a patient in asystole, the rhythm should be confirmed in two separate leads.

Disclaimer: The views expressed in this article are those of the authors and do not necessarily reflect the official policy or position of the Department of the Navy, Department of Defense, or the United States Government.

I am a military service member. This work was prepared as part of my official duties. Title 17 U.S.C. 105 provides that “Copyright protection under this title is not available for any work of the United States Government.” Title 17 U.S.C. 101 defines a United States Government work as a work prepared by a military service member or employee of the United States Government as part of that person’s official duties.

All healthcare workers including the nurse practitioner should be familiar with asystole and its management. In the hospital, it is usually the nurse who first identifies a patient in asystole and sounds the alarm to the interprofessional team, usually a clinician and respiratory therapist. The team should work together to treat the acute condition while an additional nurse informs the family of the event.

Asystole should be treated according to current American Heart Association BLS and ACLS guidelines. One person should take charge and control the resuscitation. In all hospitals, there are specially assigned teams consisting of different professionals who attend cardiac arrests. The role of the nurse is to document and provide the necessary supplies as well as assist with CPR. High-quality CPR is the mainstay of treatment and the most important predictor of a favorable outcome. Asystole is a non-shockable rhythm. Therefore, if asystole is noted on the cardiac monitor, no attempt at defibrillation should be made. In many hospitals, it is mandatory for all healthcare workers who look after patients to be certified in BLS and ACLS. Often the patient is intubated. This requires coordination of the clinician, respiratory therapist, and nurse providing both equipment and drugs necessary to quickly and successfully intubate the patient.

After every resuscitation, the ACLS cart should be refurbished with supplies. One member of the nursing staff should always make sure that the supplies and equipment to run a cardiac arrest are in working order and available.

The best outcomes are achieved with a coordinated interprofessional team approach. [Level V]