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Difficulty: MediumCardiovascular System

A 58-year-old man suddenly collapses while walking in the hospital lobby. He is unresponsive, lacks a palpable pulse, and is not breathing. The emergency response team arrives and attaches a cardiac monitor, which reveals ventricular fibrillation. According to the Advanced Cardiac Life Support (ACLS) algorithm for adult cardiac arrest, arrange the following subsequent management steps in the correct chronological sequence.

  1. 1Deliver the first unsynchronized defibrillation shock.
  2. 2Resume high-quality cardiopulmonary resuscitation for 2 minutes and establish intravenous access.
  3. 3Deliver the second unsynchronized defibrillation shock.
  4. 4Administer 1 mg of intravenous epinephrine while continuing cardiopulmonary resuscitation.
  5. 5Deliver the third unsynchronized defibrillation shock and administer intravenous amiodarone.

Answer

The correct sequence for managing ventricular fibrillation is: deliver the first defibrillation shock, resume CPR and establish IV access, deliver a second shock, administer epinephrine during the next CPR cycle, and finally deliver a third shock followed by amiodarone.
The Advanced Cardiac Life Support (ACLS) algorithm for shockable rhythms dictates an alternating sequence of shocks and medications interposed with continuous 2-minute cycles of high-quality CPR. The sequence strictly follows: Shock 1 → CPR (establish IV) → Shock 2 → CPR (administer Epinephrine) → Shock 3 → CPR (administer Amiodarone). This maximizes coronary perfusion pressure while utilizing electrical and pharmacological therapies to terminate the arrhythmia.

Step-by-Step Solution

1
Recognize ventricular fibrillation and immediately deliver the first unsynchronized shock.
Depolarizes the myocardium in an attempt to allow the sinus node to reset.
Early defibrillation is the single most important intervention for survival in shockable cardiac arrest rhythms.
2
Resume CPR immediately for 2 minutes and obtain IV/IO access.
Maintains coronary and cerebral perfusion.
Pulse checks immediately after shocks cause detrimental delays in perfusion; CPR must be initiated instantly.
3
Perform a rhythm check and deliver a second shock if ventricular fibrillation persists.
Attempts electrical cardioversion a second time for refractory arrhythmias.
Repeated electrical therapy is required when the initial shock does not terminate the fibrillation.
4
Administer epinephrine 1 mg during the subsequent 2 minutes of CPR.
Increases aortic diastolic pressure.
Epinephrine is given after the second shock to enhance coronary and cerebral blood flow during CPR, increasing the likelihood of successful subsequent defibrillation.
5
Deliver a third shock and administer an antiarrhythmic like amiodarone.
Suppresses ventricular irritability.
Antiarrhythmics are indicated for ventricular fibrillation that is refractory to CPR, shocks, and vasopressors.

Key Concept

Advanced Cardiac Life Support (ACLS) Pulseless Arrest Algorithm for Shockable Rhythms
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Topics

Cardiovascular System

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