Difference Between Fully Automatic and Semi-Automatic AEDs


Would you know what to do if you were faced with an emergency and the only way to save the victim was to use an automated external defibrillator (AED)? Too many bystanders willing to help during an emergency don’t due to the fear of not being educated enough to save a person’s life.



Luckily, AED machines are made for the lay rescuer with easy-to-use technology. However, some AEDs, known as semi-automatic AEDs, require a bit more knowledge than their fully-automatic counterparts. Read on to learn the differences and similarities between a fully automatic AED and a semi-automatic.


Key Differences Between Fully Automatic & Semi-Automatic AEDs

While both the fully automatic AED and semi-automatic AED can be beneficial to use during a cardiac emergency, it’s important to remember the key differences between them. Use the chart below to compare the different features of each.


Fully Automatic AED Semi-Automatic AED
Automatically Shocks Click the Shock Button Required for Shock
Well-suited for users with limited training or high-stress situations More control and involvement in rescue
Higher in cost Lower in cost
Less interaction required Allows users time to assess the patient and confirm shock is needed
May be preferred in an environment where a broad range of users may be responding to emergencies Commonly used in healthcare settings and by trained responders


Key Similarities Between Fully Automatic & Semi-Automatic AEDs

Even though they have their differences, the fully automatic & semi-automatic AEDs function primarily in the same way. Use the table below to read some of the features both AEDs offer.


AED Feature Fully Automatic AED Semi-Automatic AED
AED requires electrode pads attached to the patient to deliver a shock. x x
AED does not allow anyone to touch the victim when a shock is delivered. x x
AED will NOT shock the patient unless the device detects a shockable rhythm. x x
Dependent on Model: AED will provide voice and/or visual rescue instructions x x
AED provides a shock to treat sudden cardiac arrest x x


Fully Automatic AEDs

Fully automatic AEDs require little user intervention. After electrode pads are connected to a patient’s chest, fully automatic AEDs detect an irregular heart rhythm, automatically analyze the condition, and administer the shock to the patients without the rescuer’s help.

Defibtech Lifeline [Fully automatic]

Most of the time, the fully automatic AED will be slightly more expensive. This may be something you as a buyer consider when investing in an AED – is it really a significant enough difference to own a fully automatic compared to a semi-automatic to warrant the slight price increase? Be sure to consider all the other choices you have to make when considering purchasing an AED as well.


How to Use a Fully Automatic AED

Using a fully automatic AED has similar steps to any other AED.

  • After electrode pads are attached to the victim’s chest, stand clear and allow the AED to analyze the victim’s heart rhythm.
  • Ensure no one touches the victim during this analysis to avoid interference.
  • If a shock is advised, meaning the AED detects an abnormal rhythm such as ventricular fibrillation or ventricular tachycardia, the AED will issue a prompt to stand clear and will automatically deliver the shock without further user intervention.

For full step-by-step guidelines on How to Use an AED, click here.


Benefits of Fully Automatic AEDs

The fully automatic AED can be a lifesaver in high-stress situations for individuals who have never been trained or handled an AED device in the past. Fully automatic AEDs are one step simpler than semi-automatic by minimizing the need for users to make critical decisions like pressing a shock button. Skipping this step eliminates the risk of hesitation during an emergency when a chaotic scenario may delay a rescuer’s quick and accurate action.


Fully automatic AEDs would be ideal for the following:

  • Busy public places: public transportation, shopping malls, sports stadiums, or theaters
  • In a facility with untrained potential rescuers
  • In remote areas where immediate defibrillation is essential like camping sites, hiking trails, recreational parks
  • For places that may have elderly rescuers such as senior living, elderly community HOAs, or lodges/clubs for seniors


Potential Drawbacks of Fully Automatic AEDs

When using a fully automatic AED, users have limited control over the timing of the shock, potentially posing a safety concern in specific scenarios. If your AED is automatically shocking a victim, it is crucial to listen to the AED prompts and be sure the rescuer and others around are not touching the victim.


Semi-Automatic AEDs

Semi-automatic AEDs, on the other hand, require some user intervention. After analyzing the patient’s heart rhythm, a semi-automatic AED prompts the rescuer to initiate the shock if one is needed. This extra step of clicking the shock button ultimately leaves it up to the user to decide.

Defibtech Lifeline [Semi-automatic]

How to Use a Semi-Automatic AED

Like the fully automatic AED, semi-automatic follows similar step-by-step guidelines. Once AED pads are attached, remember to stand clear and be sure no one is touching the victim while the AED analyzes the heart’s rhythm.


Unlike the fully automatic, if a shock is advised on a semi-automatic, the AED will prompt the rescuer to click the shock button, typically located on the front of an AED device. This signals the rescuer to click the shock and wait for the AED to instruct the user on the next steps. For full step-by-step guidelines on How to Use an AED, click here.


Benefits of Semi-Automatic AEDs

Semi-automatic AEDs may benefit trained rescuers or healthcare professionals. While anyone can use a semi-automatic device, the stress of any emergency can fluster many, making the semi-automatic better for those who have had training or experience with defibrillators.


Having the ability to be in control of the shock that is delivered can help rescuers assess the situation before clicking shock to be sure everyone is clear from touching the victim, and the victim is in a safe environment free from water, obstacles, or potential hazards.


Semi-automatic AEDs would be ideal for the following:

  • Healthcare settings: hospitals, facilities with medical professionals who may prefer control over the timing of shock
  • In EMS vehicles or any emergency vehicles
  • In buildings for childcare such as schools, daycares, nursery facilities, due to some AEDs having a “push for pediatric shock” button that adjusts shock levels
  • In a facility with AED/CPR trained professionals


Potential Drawbacks of Semi-Automatic AEDs

For individuals not trained in the difference between semi-automatic and fully automatic, a semi-automatic can cause hesitation. During a cardiac emergency, every minute matters, leaving little time for the user to dwell on making critical decisions like delivering a shock. The important thing to keep in mind is that even if the shock button is pressed, the device will not deliver the shock unless it is analyzed that it is necessary. Taking CPR/AED training courses helps and gives users more confidence in using an AED device.


Choosing the Right AED for Your Needs

When choosing between a semi-automatic or a fully automatic, consider who may be using the AED:



  • Will this individual be likely to remain cool and calm?

Are the individuals using the AED likely to stay composed and focused during high-stress, life-or-death situations? Some individuals naturally can remain calm under pressure, while others may find it more challenging.


  • Will they be inclined to tense up during a crisis?

Consider whether the anticipated rescuers are prone to anxiety or panic during crises. The intense pressure of responding to sudden cardiac arrest can cause even the most well-intentioned individuals to feel overwhelmed.


  • Have they had any training in AED use?

Assess the level of training and familiarity with AED operation among potential users. Have they received proper training instruction on how to use the device effectively, or are they relatively inexperienced?


  • Is the AED going in a public place so anyone (trained or untrained) could use it?

Determine the public accessibility of the AED. Will it be placed in a public area where both trained and untrained individuals may encounter it? Public accessibility can influence the choice between semi-automatic and fully automatic AEDs significantly.


It’s important to remember that someone in sudden cardiac arrest is already in a life-threatening state, and any rescue efforts can only improve their odds of survival.


Types of AEDs Available

AEDSuperstore offers multiple AEDs that are available as both fully automatic or semi-automatic. Check out the following:



AEDs only available in semi-automatic versions include:


Choosing the right AED for your needs means understanding the value each AED brings to the table. Use our AEDSuperstore Buyer’s Guide, or review our article on the best AEDs for sale to learn more about the many benefits and features each AED defibrillator offers as you work through choosing an AED.


At the end of the day, acting quickly during an emergency is lifesaving. By familiarizing yourself with the various types of AEDs, including the distinctions between fully and semi-automatic models, you’re equipping yourself to respond faster and, ultimately, become a lifesaver.


Still have questions or need expert guidance? Don’t hesitate to reach out to AEDSuperstore at 800-497-3987 or complete our Contact Us form today.


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