Emergent Management of Asystole Treatment & Management

Mainstays of treatment in the emergency department are providing oxygenation and ventilation via endotracheal intubation and circulation via cardiopulmonary resuscitation (CPR), attempts at transcutaneous or transvenous pacing (that have some small potential to be fruitful in primary asystole that has just occurred), and administration of pharmacologic agents.

There has been a case report of a long but successful resuscitation from asystole of a patient who was hyperkalemic secondary to renal failure. The treatment included calcium chloride to reverse the physiologic effects of hyperkalemia and insulin and glucose to lower serum potassium levels. However, this therapy cannot be recommended routinely for all cases of asystolic arrest.

Electrical defibrillation

Electrical defibrillation should not be applied indiscriminately to the patient in asystole. This is not only fruitless, but also detrimental, eliminating any possibility of recovering a rhythm. Asystole following electrical defibrillation has an even worse outcome than that in a patient whose first documented rhythm was asystole. One caution is that, following defibrillation, a brief spurious asystole can occur using manual monitoring through the defibrillator paddles. This does not occur with the rhythm monitoring leads or hands-off monitor pads. If not taken into consideration, it could lead to a delay in defibrillation, when indeed VF is present.

The intensive care unit is the appropriate disposition for the occasional patient who survives bradyasystolic cardiopulmonary arrest and requires further treatment and diagnostic evaluation. In the past decade, survivors who achieved electrical and hemodynamic stability but remained comatose and were modestly cooled to 32-34°C for the first 24 hours showed improvement in overall neurologic outcome.^[19] The studies were conducted on prehospital arrests with ventricular fibrillation as the presenting rhythm, but results could be generalized to bradyasystolic survivors.^[19]

Primary asystole may be prevented by the appropriate use of a permanent pacemaker in those patients who have high-grade heart block or sinus arrest. Prevention of secondary asystole requires early recognition and treatment of the preceding event.

Continuous cardiac monitoring is useful during attempts at resuscitation to determine rhythm and effects of intervention. Endotracheal intubation is indicated with attempts at resuscitation, and central venous access or intraosseous access may be needed for vascular access.

The only 2 drugs recommended or acceptable by the American Heart Association (AHA) for adults in asystole are epinephrine and vasopressin. Atropine is no longer recommended for young children and infants since 2005 and for adults since 2010 for pulseless electrical activity (PEA) and asystole. In spite of full vagolytic doses of atropine (0.03 mg/kg) and high-dose epinephrine (0.20 mg/kg), or the use of vasopressin 40 units (U), few patients survive to leave the hospital neurologically intact.

Atropine is no longer recommended in young children and infants in asystole but can be considered in adults with slow pulseless electrical activity (PEA) rhythms.

Vasopressin therapy

If spontaneous circulation has not been restored, administering intravenous (IV) vasopressin 40 U for the first 2 doses or followed by epinephrine given at the physician's discretion has showed some promising if mixed results.

Wenzel et al reported that more patients who were administered vasopressin survived to hospital discharge than those on epinephrine, although the neurologic status of the patients at discharge was not clearly stated.^[16] Further analysis suggested a tendency for a worse neurologic outcome in those who received both vasopressin and epinephrine, many of whom ended up in a vegetative state.

Of the 528 patients with asystole in the study, 12 patients in the vasopressin group survived to discharge compared with 4 in the standard therapy group.^[16] In this study, the odds ratio stated may not be statistically significant, and there was also a nonstatistically significant trend toward worse results for ventricular fibrillation (VF) and PEA.^[16]

In a larger comparison study between epinephrine alone and epinephrine with vasopressin 40 U, Gueugnaiud and colleagues found that there were no significant differences between groups in terms of return of spontaneous circulation, survival to hospital discharge, 1-year survival, or good neurologic recovery among survivors at hospital discharge.^[17]

The advanced cardiac life support (ACLS) 2005 guidelines allow vasopressin 40 IU IV as a 1-time dose treatment option in VF and asystole. This treatment can be given either before epinephrine or after the first dose of epinephrine.

Transcutaneous pacing

Transcutaneous pacing (TCP), even when used immediately, has not altered meaningful survival (ie, functional lifestyle) significantly.^{[12, 18]} However, when no metabolic deficit exists, such as in a cardiac arrest preceded by a conduction or impulse generation disorder (ie, primary asystole), immediate use of TCP may be lifesaving.