CPR vs. AED — When to Drop the Paddles

CPR vs. AED — When to Drop the Paddles

Steven Cumper

Steven Cumper

Published in MedShop Blog

0 min read

September 13, 2023


This information is not intended to be a substitute for professional medical advice.To understand the latest medical guidance on using CPR or an AED please consult  Australian Resuscitation Council or the American Heart Association

In a medical emergency, every second counts. Whether it's a sudden cardiac arrest or a critical respiratory event, having the knowledge and skills to respond effectively can meanthe difference between life and death. Two crucial tools in such situations are Cardio-Pulmonary Resuscitation (CPR) and the use of an Automated External Defibrillator (AED).

Understanding when to administer CPR versus employing an AED is important knowledge that can save lives—whatever your background. Both techniques are designed to support a failing heart, but they serve distinct roles when caring for a patient. This article explains the critical differences between CPR and AED, delving into when to employ each technique and how they can work together to save lives. Read on to learn more. 


The Importance of Immediate Response in Cardiac Emergencies

Cardiac emergencies, such as heart attacks and sudden cardiac arrest, are critical and time-sensitive situations that require immediate and effective response. The importance of immediate action cannot be overstated, as it can significantly impact the outcome and increase the chances of saving a person's life.

When the heart's blood supply is compromised, either due to a blockage in the arteries (heart attack) or a sudden malfunction of the heart's electrical system (cardiac arrest), every passing moment can lead to irreversible damage to the heart muscle and vital organs. Immediate response can help minimise the extent of damage and increase a person's chances of survival.


What Is CPR And How Does It Work

What Is CPR

Cardiopulmonary resuscitation (CPR) is a life-saving technique performed by first responders in emergencies when a person's heartbeat or breathing has stopped. CPR aims to manually circulate blood and oxygen throughout the body to maintain essential organ function until professional medical help arrives. CPR is a critical intervention during cardiac arrests, drowning incidents, suffocation, and other situations where the normal circulation of blood is disrupted.

The basic steps of CPR include:

  1. Check Responsiveness: Gently shake the person and shout to check if they are responsive. If there is no response, it indicates an emergency.
  1. Call for Help: Dial emergency services or ask someone nearby to do so.
  1. Open the Airway: Tilt the person's head back slightly and lift the chin to open the airway. 
  1. Check for Breathing: Look, listen, and feel for normal breathing. If the person is not breathing or is breathing abnormally, CPR should be initiated.
  1. Chest Compressions: Place the heel of one hand on the centre of the person's chest, just below the nipple line. Place the other hand on top and interlock the fingers. Deliver chest compressions by pushing hard and fast at a rate of about 100-120 compressions per minute. Allow the chest to fully recoil between compressions.
  1. Rescue Breaths: After 30 compressions, give two rescue breaths. Pinch the person's nose shut, cover their mouth with yours, and give breaths until the chest rises.
  1. Continue Compressions and Breaths: Alternate between 30 compressions and 2 rescue breaths until the person starts breathing on their own, emergency personnel arrive, or you are too exhausted to continue.

CPR helps maintain blood circulation, delivering oxygen to the brain and other vital organs. It can buy valuable time until more advanced medical interventions, such as defibrillation, can be administered. Automated external defibrillators (AEDs) are often used in conjunction with CPR to restore the heart's normal rhythm.


When to Use CPR — Situations and Indications  

Cardiopulmonary resuscitation (CPR) is a critical technique used to revive a person whose heart has stopped beating or is beating irregularly, and who is not breathing or not breathing normally. Knowing when to use CPR is essential for providing timely and effective assistance in life-threatening situations. Here are some key situations and indications for performing CPR:

  • Cardiac Arrest — CPR is most commonly used during cardiac arrest. Cardiac arrest occurs when the heart suddenly stops pumping blood effectively. This can result from various causes, such as a heart attack, arrhythmias, drowning, electrocution, or severe trauma. If a person is unresponsive, not breathing, and has no pulse, CPR should be initiated immediately.
  • Unresponsiveness — If an individual is unresponsive and not breathing normally, CPR should be started. Gently tap the person and shout loudly to check for responsiveness. If there is no response, begin CPR.
  • No Normal Breathing — If a person is not breathing or is only gasping, CPR should be initiated. Gasping is not considered normal breathing and requires immediate action.
  • Choking — If a person becomes unresponsive due to choking and is not breathing, CPR should be started after attempting to clear the airway with back blows and abdominal thrusts (Heimlich manoeuvre). If the person regains responsiveness, CPR is not needed. 
  • Drowning — Individuals who have experienced near-drowning incidents and are unresponsive with no normal breathing require CPR to restore breathing and circulation.
  • Drug Overdose or Poisoning — In cases of severe drug overdose or poisoning leading to unconsciousness and no normal breathing, CPR is necessary to maintain blood flow and oxygen delivery.
  • Sudden Collapse — If a person collapses suddenly and is unresponsive, CPR should be started to provide immediate life support while awaiting medical help.
  • Unknown Cause of Unresponsiveness — If the cause of unresponsiveness is unknown and the person is not breathing or not breathing normally, CPR should be initiated to address potential cardiac arrest.

It's important to note that CPR is not typically performed in situations where the person has a pulse and is breathing normally, even if they are unconscious. In such cases, placing the person in the recovery position and monitoring them until medical help arrives may be appropriate.

Remember, early initiation of CPR significantly improves survival rates and reduces the risk of brain damage. If you are unsure whether CPR is needed, it's safer to begin chest compressions until professional medical assistance arrives. Proper CPR technique and training are crucial to ensure the best possible outcomes in these critical situations.

How does CPR compare to Basic Life Support (BLS)?

CPR compare to Basic Life Support

In short, CPR and BLS are similar as they share the same goal—to keep the airway open, the heart beating, and the circulation of oxygen to the body going without the use of advanced life support. However, understanding the difference between the two will allow you to know when to use CPR and when to use BLS.

A BLS certification is a little more advanced, not so much as an Advanced Life Support (ALS) certification, but more than a standard CPR certification. That said, in practice, there is little daylight between these two.

Some BLS certifications teach advanced methods like the administration of oxygen, team approaches, and in-hospital procedures, but the two certifications are close neighbours. In the case of someone seeking a certification for employment, it’s best to check with the employer if they consider the certifications as equivalent qualifiers. 

To someone suffering a catastrophic cardiovascular event, it will make little difference whether their attendant is CPR or BLS certified. Both are better than doing nothing when an AED is not available.


What is an AED and How Does it Work?

What is an AED

The acronym AED stands for Automated External Defibrillator, and they are placed in public places, often as part of a broader first aid kit, to provide emergency care in the event of cardiac arrest.

Defibrillator AEDs, like the ones produced by Laerdal, Zoll, and HeartSine allow untrained people to administer ventricular fibrillation (VF) to a human body that has suffered a cardiovascular event such as a heart attack.

The AED has changed the fate of cardiac arrest victims forever. Before their introduction, without medical attention, standard CPR was the only chance someone had of surviving a cardiac event.

Today, in cities where CPR is widely practised and AEDs are readily available, success rates range from 25 to better than 60 percent. The high end of the data comes from cases where the AED came into play. In the absence of CPR training and AEDs, success rates drop closer to 10 percent. It’s the AED units that improve these data the most.

Unlike the hospital defibrillation machines, which predated AEDs and required specific training, these new consumer-friendly defibrillators are accessible to even the untrained.

As stated by Defib First Australia, “Modern AEDs cannot be used inappropriately and it is not possible to do any further harm to a cardiac arrest victim who is, in effect, dead and will remain so unless defibrillated.”

As far as the value of the AED on cardiac patients, the same site said it best:

“An AED is the most vital piece of emergency first aid equipment and the only effective first aid treatment for cardiac arrest.”

You can learn more about how to use an AED defibrillator here.


Check HeartStart AED with FREE carry case*


When should you deliver shock from AED?

In short, whenever someone’s heart has stopped beating, that’s the best time to use the AED pads. When a heart stops beating, time is of the essence, because after six minutes of oxygen depletion, the brain begins to die. 

Damage can and will likely occur long before that point. That means you have minutes to get the oxygen moving through the body again. In the heat of such a moment, even though time seems to slow down, minutes slip away quickly.

The good news about today’s AEDs is that they will not deliver a shock to a body with a beating heart. As such, there is no bad time to grab the AED if someone has fallen down. For this reason, most response training advises you to delegate retrieval of the nearest AED in the first moments of the incident.


Key Differences Between CPR And AED 

Cardiopulmonary Resuscitation (CPR) and Automated External Defibrillator (AED) are both crucial components of cardiac arrest response, but they serve different roles in the effort to save a person's life. Here are the key differences between CPR and AED:

CPR (Cardiopulmonary Resuscitation)

  • Manual chest compressions and rescue breaths.
  • Maintains minimal blood flow until normal heart activity is restored.
  • Trained individuals perform CPR.
  • Requires training for proper technique.
  • No specialised equipment needed.

AED (Automated External Defibrillator)

  • Delivers electric shock to restore normal heart rhythm.
  • Resets the heart's electrical activity during specific arrhythmias.
  • Designed for use by laypeople.
  • Minimal to no AED training required due to voice prompts.
  • Specialised device that analyses and corrects heart rhythm.

Combined Use

  • CPR and AED are used together to maximise survival chances.
  • CPR starts blood circulation, AED assesses and corrects heart rhythm.


The Role of CPR and AED In Cardiac Arrest Response

When responding to a cardiac arrest, CPR and AED work together to improve the chances of survival:

  • CPR — Provides manual chest compressions and rescue breaths to circulate oxygenated blood to vital organs, buying time until professional medical help arrives.
  • AED — Analyses the heart's rhythm and delivers an electric shock if needed, aiming to restore a normal heart rhythm. AED use is often combined with CPR.


Common Misconceptions and Myths About CPR And AED

Myths About CPR And AED

There are several misconceptions and myths surrounding CPR and AED:

  • Myth — Only medical professionals can perform CPR.
  • FactBystanders and laypeople can effectively perform CPR and should do so in emergencies.
  • Myth — AEDs can cause harm.
  • Fact — AEDs are designed to be safe and will only deliver a shock if a shockable rhythm is detected.
  • Myth — AEDs can restart a stopped heart.
  • Fact —  AEDs aim to restore a normal rhythm in a heart that is still beating abnormally; they don't "restart" a stopped heart.
  • Myth —  CPR can restart the heart.
  • Fact — CPR can help maintain blood flow and oxygenation but may not restart the heart. AED use is often necessary for rhythm correction.
  • Myth — Only older adults need CPR and AED.
  • Fact — Cardiac arrest can happen to people of all ages, including children and young adults.
  • Myth — You need to be certified to use an AED.
  • Fact — While training is helpful, AEDs are designed for use by anyone, even without formal certification.
  • Myth — You should stop CPR when using an AED.
  • Fact — Continue CPR until the AED is ready to analyse or deliver a shock. The AED will prompt you when to pause.


FAQs — Clearing Doubts About CPR And AED 

Do you use an AED on someone with a pacemaker?

The simple answer is yes, but there are a few caveats to AEDs used with pacemakers. Know that pacemakers of any sort should withstand external defibrillation without a problem.

The problem with the pacemaker placement is that it usually coincides with the placement of one defibrillator pad. As such, you’ll have to get as close as possible to the correct location.

Some AED units may assist with placement. Others may reject the placement. You may need to place the pad directly on the pacemaker, but try to avoid this.

In any case, remember that any effort you make is better than none. This person only stands to improve their situation as they are essentially terminal without a heartbeat.

Once the pads are in place, run the AED as normal and keep your hands off. After a successful resuscitation, their pacemaker may require attention from a professional, but that’s not a reason to avoid AED administration.

Can you use an AED on an infant?

If you find yourself in this spot, know that there are special pads and accompanying instructions with most AED units for delivering a shock to a child. The cutoff age is eight. Any human under eight years old will need specially sized defibrillation pads.

You should NEVER use the adult pads on a child under the age of eight, even if you have no other options. The risk is not only to the child but to those in the near vicinity.

Again, check with your accredited CPR/AED organisation for more details on that.

When not to use an AED?

Automated External Defibrillators (AEDs) are life-saving devices, but there are specific situations when their use should be avoided. Firstly, AEDs should not be used when the victim is breathing normally or has a detectable pulse. These devices are designed for cases of sudden cardiac arrest where the victim is unresponsive, not breathing, and lacks a pulse.

Additionally, AEDs should not be used in environments with moisture or water present, as this can compromise their effectiveness. Moving the victim to a dry area or ensuring their chest is dry before attaching the AED pads is crucial.

If the victim's chest is obstructed by medicinal patches or excessive hair, it's essential to clear the area quickly by wiping or shaving before applying the AED pads.

Using an AED in areas with explosive or flammable materials is highly dangerous, as the electrical shock delivered by the device could potentially ignite a fire or cause an explosion.

In cases of severe hypothermia where the victim's body temperature is extremely low, it's important to prioritize warming the victim before attempting defibrillation, as their heart's response to the shock can be significantly affected.

Lastly, if there is a valid, visible Do Not Resuscitate (DNR) order for the victim, it indicates their explicit wish not to be resuscitated. In such cases, using an AED would be inappropriate. In summary, while AEDs are valuable tools for cardiac arrest situations, careful assessment of the circumstances and the victim's condition is essential to their appropriate use. 

Why is defibrillation important in CPR?

Defibrillation is crucial in emergencies involving cardiac arrest for several reasons. Firstly, it delivers an electrical shock to the heart, momentarily stopping all electrical activity. This pause allows the heart's natural pacemaker to reset, potentially restoring a normal rhythm

In addition, defibrillation complements CPR efforts. While CPR maintains minimal blood flow to vital organs, it cannot correct an irregular heart rhythm. Defibrillation steps in to potentially restore a normal rhythm, maximally boosting the odds of successful resuscitation.

Certain abnormal heart rhythms, specifically ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT), respond well to defibrillation. These are categorised as "shockable" rhythms, and without swift intervention, they often lead to fatal outcomes.

Finally, Automated External Defibrillators (AEDs) are designed to be portable and user-friendly. They offer clear voice and visual prompts, making them accessible in various settings, from homes to public spaces. They can be operated by individuals with minimal training, extending their potential life-saving reach.



Author: Steven John Cumper, B.App.SC. (Osteo.), M.Ost., is a businessman with a strong foundation in biomedical science and osteopathic medicine, who founded and led Medshop to international success, culminating in its acquisition by the Bunzl Group in September 2021, where he continues to serve as Managing Director (Medshop Group).

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