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Difficulty: MediumCardiovascular System

A 58-year-old man suddenly collapses while walking in the hospital hallway. He is unresponsive, apneic, and has no palpable carotid pulse. The emergency response team arrives immediately with a resuscitation cart. The cardiac monitor displays coarse ventricular fibrillation. According to the Advanced Cardiovascular Life Support (ACLS) guidelines, arrange the following management steps in the correct chronological order for this patient.

  1. 1Initiate high-quality chest compressions and bag-mask ventilation
  2. 2Deliver the first unsynchronized biphasic shock
  3. 3Immediately resume chest compressions for 2 minutes and obtain intravenous access
  4. 4Deliver a second unsynchronized shock and administer epinephrine
  5. 5Deliver a third unsynchronized shock and administer amiodarone

Answer

The correct sequence is: 1) Initiate high-quality chest compressions, 2) Deliver the first unsynchronized shock, 3) Immediately resume chest compressions and obtain IV access, 4) Deliver a second shock and administer epinephrine, and 5) Deliver a third shock and administer amiodarone.
The Advanced Cardiovascular Life Support (ACLS) algorithm for shockable rhythms (ventricular fibrillation or pulseless ventricular tachycardia) dictates starting with high-quality CPR. As soon as the defibrillator is ready, the first unsynchronized shock is delivered. CPR is then immediately resumed for 2 minutes while intravenous or intraosseous access is obtained; no rhythm check should occur immediately after the shock. If the rhythm remains shockable at the next check, a second shock is delivered, CPR is resumed, and epinephrine (1 mg) is administered. If the rhythm is still shockable after another 2 minutes of CPR, a third shock is delivered, CPR is resumed, and an antiarrhythmic like amiodarone (300 mg) is administered.

Step-by-Step Solution

1
Identify cardiac arrest and begin basic life support.
Chest compressions provide temporary circulation.
Immediate CPR is critical for survival and neurological outcome by maintaining minimal organ perfusion.
2
Analyze the rhythm and deliver the first shock for ventricular fibrillation.
Attempts to depolarize the myocardium to allow the sinus node to reset.
Early defibrillation is the definitive treatment for pulseless ventricular tachycardia and ventricular fibrillation.
3
Immediately resume CPR and establish vascular access.
Maintains perfusion without delaying compressions.
Prolonged pauses in chest compressions (such as checking for a rhythm immediately after a shock) decrease the chance of successful defibrillation and survival.
4
Deliver a second shock if VF persists, resume CPR, and give epinephrine.
Epinephrine provides vasopressor support during continued arrest.
Alpha-adrenergic effects of epinephrine cause peripheral vasoconstriction, increasing aortic diastolic pressure and improving coronary perfusion pressure.
5
Deliver a third shock if VF persists, resume CPR, and give amiodarone.
Antiarrhythmic therapy for shock-refractory VF.
Amiodarone affects sodium, potassium, and calcium channels and has been shown to improve the rates of return of spontaneous circulation (ROSC) in shock-refractory VF.

Key Concept

Advanced Cardiovascular Life Support (ACLS) Pulseless Arrest Algorithm for Shockable Rhythms
Estimated Time:1m 30s
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Topics

Cardiovascular System

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