The Different Phases of Cardiac Arrest: Two Scenarios, Two Realities

Scenario 1: Time Against You
Imagine: It’s 3 AM. You’re dispatched to a cardiac arrest. The patient was last seen around midnight, complaining of feeling unwell. Upon your arrival, they are unresponsive and not breathing. You already know: the delay is long, and the chances of success are minimal. Every passing minute works against you.

Scenario 2: When Every Second Counts
Now, imagine another situation. You are covering a sporting event. Over the radio, you hear that someone has collapsed nearby, just 100 meters away. You run. In less than a minute, you’re on scene, and a bystander has started chest compressions. Everything changes: rapid intervention increases the chances of survival.

So what distinguishes these two situations? Time and managing the key phases of resuscitation.

The 4 Key Phases of Resuscitation: Why They Matter

1. Heart (4 to 6 minutes)
The top priority: rapid defibrillation and effective chest compressions. This is the first step because every second without blood circulation increases mortality.

  • Scenario 1: You arrive late; defibrillation may have little effect or may not even be indicated.
  • Scenario 2: Within a minute, the victim benefits from chest compressions and rapid defibrillation.

2. Oxygen (6 to 10 minutes)
Once compressions have started and defibrillation is underway, the focus shifts to oxygenation. Ventilations, airway management… The goal is to balance oxygen delivery to the heart and brain.

  • Key Point: Professionals know oxygen alone is useless without compressions. Compression rhythm remains the top priority.

3. Evacuate (Less than 10 minutes)
Evacuation is not immediate. After three defibrillation attempts, it’s time to prepare for evacuation. This phase differs depending on the scenario:

  • Scenario 1: The delay is already significant. Transport is an option for advanced care, though in some contexts, professionals may declare death on scene.
  • Scenario 2: Resuscitation continues while preparing for evacuation with better-equipped support teams.

4. Identify the Cause (More than 10 minutes)
When defibrillation fails, focus shifts to reversible causes: hypoxia, hypothermia, hemorrhage, etc. At this stage, advanced care becomes critical when available.

Questions to Ask: Could the situation have been avoided? Are other treatments indicated? Why did this patient’s heart stop?

The Perfect Sequence: Scenario 2

  1. Instruct the bystander to continue chest compressions while you install the defibrillator, confirm cardiac arrest via radio, and call for backup.
  2. After the first shock, if the bystander feels comfortable, they continue uninterrupted compressions while you install an oropharyngeal airway and a high-concentration oxygen mask. Set up the suction unit and organize your space: suction and airway equipment at the patient’s right shoulder, defibrillator at the left shoulder.
  3. Ask those nearby if anyone knows the patient or witnessed what happened.
  4. Prepare a person to take over compressions at the next analysis.
  5. Note the time of the analysis and/or shock (via radio or written down).
  6. Prepare the bag-valve mask (BVM) or intubation equipment, depending on your level of care.
  7. When backup arrives, transfer the key information: witnessed or unwitnessed arrest, number of shocks/analyses, and the context of the collapse.
  8. After the third analysis, if the patient is not intubated, transition to a 30:2 compression-to-ventilation ratio using the BVM.
  9. Prepare for evacuation: set up the backboard and identify the evacuation route.
  10. Rotate the person performing compressions after every analysis to maintain quality.
  11. Evacuate to your medical clinic where advanced providers can continue treatment and address reversible causes.

Key Takeaway: Time Is Vital

In Scenario 1, you are fighting against an irreversible delay. In Scenario 2, every second gained improves the chance of survival.

Consider this: Nearly 70% of cardiac arrests occur outside of hospitals. Will you be ready to act effectively through these 4 key phases?

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