ED ACLS Cardiac Arrest Megacode Scenario 2: The Most Effective Strategies

ACLS or Advanced Cardiac Life Support is a set of clinical guidelines that are used to treat cardiac arrest and other life-threatening medical emergencies.

One of the most complex ACLS algorithms providers will encounter is cardiac arrest. We will cover both shockable and unshockable rhythms.

In this blog post, we will discuss the most effective strategies for managing cardiac arrest using the ACLS megacode.

Table of Contents

Adult Emergency Department Cardiac Arrest Megacode Scenario

The following is a scenario in which you would use the emergency department adult cardiac arrest megacode:

EMS arrives at the emergency department with an unresponsive patient. EMS is states bystanders called after witnessing the female patient collapse during a 5k run. The patient is actively being ventilated by EMS.

Demonstrate what you would do next upon arrival

Initial Impression

The patient is an unknown-age female lying down on the stretcher. She is agonal breathing and not responsive.

Primary Assessment Survey (A, B, C, D, E)

Airway: The airway is patent but agonal breathing 4 breaths per minute are noted upon assessment. The flow through the trachea is not impaired.

Breathing: Oxygenation is showing 60% via a bag valve mask. A nasopharyngeal airway is placed.

Circulation: Blood pressure is 90/60, heart rate is 110 bpm, the rhythm check is showing sinus tachycardia, and the pulse is present but very weak.

Disability: The patient is unresponsive.

Exposure: No obvious signs of trauma, bleeding, burns, markings, or medical alert bracelet.

What are your next actions?

  1. Check responsiveness: Tap the shoulders and shout, “Are you okay?” The female does not respond to any form of stimulation.
  2. Activate the emergency response system. Shout for backup and announce what room you are in.
  3. Check for breathing: Look for visible chest rising and falling. Breathing is still agonal with help from the NPA. Oxygenation is rising.
  4. Check for a pulse: Place your fingers on the inside of the patient’s neck, just below the angle of the jaw. You will palpate the carotid pulse for no more than 10 seconds. Pulse is present but very weak.

What are your next actions?

Pulse and breathing are present so we will not begin CPR starting with compressions at this time.

H's and T's

It is important to consider your H’s and T’s for these rhythms and treat accordingly.

H’s and T’s are mnemonics for the major causes of arrest:

  • Hypovolemia – could potentially be a cause
  • Hypoxia
  • Hydrogen ions (acidosis) – could also be potentially a cause
  • Hyperkalemia or hypokalemia
  • Hypothermia
  • Tamponade (cardiac, tension)
  • Toxins
  • Tension pneumothorax
  • Thrombosis (coronary, pulmonary)


What interventions could you perform next?

  • Additional IV access
  • Connect to the monitor and equipment
  • Provide fluid resuscitation
  • Consider intubation if the patient continues to decline

Change in Patient Condition

Upon reassessment, the patient loses her respiratory drive and pulse. The monitor is now showing Ventricular Tachycardia.

What are your next actions?

Pulse and breathing are no longer present so we will begin CPR starting with compressions at this time.

Cardiac Arrest Algorithm

Adult Compressions

Perform High-Quality Compressions

  • Hands should be placed on the lower half of the sternum
  • 30 compressions at a rate of 100 to 120 compressions per minute
  • Compresses at least 2 inches (5 cm)
  • Complete chest recoil after each compression

Adult Rescue Breaths

Give 2 breaths with a barrier device

  • Each breath should be given over 1 second
  • Visible chest rise and fall with each breath
  • resume compressions in less than 10 seconds

You will need to perform one to two rounds of high-quality CPR.


Defibrillation is the use of electrical shocks to reset the heart’s electrical impulses and rhythm without syncing to the patient’s intrinsic rhythm.

The recommended dose of electricity is 120-200 J for biphasic machines and up to 360 J for monophasic.

Defibrillation Procedure

  1. Turn on the defibrillator and set the joules based on the machine used
  2. Place adhesive pads on the patient: one on the right anterior chest wall and one on the left axillary position
  3. Announce to the team “Charging defibrillator” and press the charge button
  4. When the defibrillator is fully charged, verify all team members are clear by announcing the shock. Once the team announces all clear and you have verified the team is not touching the patient or bed, call “All Clear!”
  5. Press the shock button on the defibrillator
  6. Immediately after shock is delivered, resume CPR for 5 cycles (2 minutes) then reassess rhythm

The defibrillator does show a shockable rhythm. This means the patient is either in Pulseless Ventricular Tachycardia or Ventricular Fibrillation.

What are your next steps after defibrillation?

Resume CPR immediately!


What interventions could you perform next?

  • IV/IO Access
  • Epinephrine 1 mg every 3 to 5 minutes.
  • Amiodarone 300 mg IV push – Second dose 150 mg IV push
  • Lidocaine 1 to 1.5 mg/kg IV
  • Placement of advanced airway


Two attempts at delivering a shock were advised without success. The patient received 3 doses of epinephrine. Upon the third attempt, another deliverable shock was advised.

The team continued high-quality chest compressions and ROSC was achieved.

Next steps for this patient:

  • Airway Management
  • Hemodynamic monitoring
  • Targeted Temperature Management
  • Brain CT
  • EEG monitoring
  • Labs – electrolytes and cardiac biomarkers
  • Fluids
  • Chest x-ray
  • Critical Care Consultation
  • Transfer to a higher level of care

You will begin the transfer to a higher level of care. Your scenario has concluded.