Automated External Defibrillator (AED) Buyer's Guide - REAL First Aid

Automated External Defibrillator (AED) Buyer's Guide

8th October , updated 24th June

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Timely defibrillation is considered the single most important factor in the treatment of Cardiac Arrest in a Pre-Hospital environment.  With the increased public awareness of AED's together with their improved technological advances, ease of use and decreasing prices, the provision of an AED is now considered a reasonable consideration in a First Aid Needs Assessment.

If you feel an AED is appropriate to your needs, there are a range of machines available, with each manufacturer claiming to offer the best machine.   We don't sell AEDs and we have no commercial interest in any manufacturer so the information provided within this article is completely objective.  what is important is you choose the right AED for your particular needs. 

Here are a few considerations to make before purchasing an AED.

Decision Factors

Manufacturer
With a larger, more established manufacturer one should have a greater availability of parts and more accessible customer services.  This is not always true in the commercial world but all manufacturers here are of generally equal quality and reputation.

Price
Price is a consideration that every individual or business should make.   Price does not always relate to quality or functionality but most machines currently start at around £1,000 and generally go no higher than £3,000 for pubic access or lay-responder devices.  Every AED analyses rhythm and then, if required, delivers a shock.   There is no need to pay more than £1,500 for basic functionality but the increasing price tends to equate to a longer warranty, longer battery and pad life, greater durability and build quality and so on.

Semi or Fully Automatic?
One of the big questions is do you purchase a Fully Automatic or Semi Automatic device?  

A Fully Automatic device is best suited to those with little or no training and those operating in relatively quiet environments.  After the device has been turned on and the pads applied it will analyse the heart rhythm and, if required, it will announce "Stand clear - delivering shock!" (or words to that effect) before automatically delivering a shock.   

A Semi Automatic device will prompt the user to deliver the shock, if required, by pressing a button with a command similar to "Shock required - Press the flashing button now!" 

The benefit of a fully automatic device is the speed to defibrillation as it does not require the user to deliver the shock.  

Semi-automatic devices are a safer option in our opinion as there is the chance of the user or a bystander being in contact with the casualty while the shock is automatically delivered if they are not able to hear the audible warning.   The semi automatic device requires the user to make certain that no one is in contact with the casualty before delivering the shock.   With practice and familiarity with the AED there is no reason why a Semi Automatic device should be any slower in delivering the shock when operated by a competent person.

Energy Delivery
AEDs deliver a fixed current (usually or 150J) for every 'shock' or an escalating current from the first and subsequent shocks e.g 200J followed by 300J and 360J.

There is little or no difference in the survival rates of those who are successfully defibrillated on the first shock (150J versus 200J) but there is a slightly increased chance of recovery for those who receive escalating defibrillation from subsequent shocks.(1)

IP Rating
This two-digit value represents the machine's tolerance to dust and moisture.  A rating of 55 would be more resilient to dirty environments.  A device with a rating of 21 would be better suited to a more traditional office environment.

CPR Coaching
Some devices have a 'CPR Coaching' facility.   This may be a basic metronome to help regulate the speed of your compressions or it may give verbal feedback on the quality of your compressions including, depth, location and rate.  For the lay rescuer with no First Aid training this would be valuable.  For the experienced responder this is less of a priority.  

ECG
ECG monitoring allows the AED to collect information about the casualty's heart rhythm which may be of use for healthcare professionals once the care of the casualty has been handed over post treatment.  This is an additional feature which does not immediately benefit the casualty but may support better care when the casualty is handed over to the next echelon of care.

Memory
The collection of data is a requirement of AEDs and can be used to examine the treatment the casualty received.  The amount of memory required should be based on how long one can expect to deal with the casualty before being able to hand over to a healthcare professional.

Data Download
Data collected can be downloaded in a variety of ways, typically via a Data Card, USB cable or sometimes via Infra red connection or Wi-Fi.  

Battery Standby Life
Some batteries can cost up to £400.00   For this price you would expect significant life from them.  Others are significantly cheaper but don't last as long.   For the regular user, the battery will be depleted much sooner.  For the occasional user there is mileage in having a long-life battery as it reduces the regularity of battery replacement.  For regular uses, some models are available with rechargable batteries as an optional extra.   This increases your initial expense but should save money over the longer term.

Electrode Shelf Life
Similarly the electrodes or 'pads' have a shelf life whether they are used  or not.   Short life pads are not necessarily cheaper.   Some pads feature a compression analysis pad on the sternum which provides guidance on the quality of your chest compression - this is an additional cost which is thrown away once the pads expire.   One brand features the battery built into the pad unit; if the device is rarely used this reduces the long term running costs.  If the device is used frequently this can significantly increase costs as the batteries are thrown away after each use.

Annual Costs
In the table below we have calculated the annual costs of ownership (replacing the batteries and pads) by simply dividing the cost of the replacement battery and pads by their respective shelf lives and adding the two values together.  This can give an indication of how expense the device is to own.  These costs are based on replacing the batteries and pads at the time of shelf life expiration.   If the device is used more often the annual costs will increase.

Number Crunching

In this table we have compiled a list of the most commonly available AEDs in the UK for comparison.

To view the table in full screen, click here.

Which is best?

Lets apply an iterative process here; firstly let's get rid of the Fully Automatic defibrillators.   That still leaves an awful lot.   So now lets get rid of the Fixed energy delivering AEDs.   That gets rid of every device from CU Medical Systems, Defibtech, Philips and Schiller.

Now we are getting closer.   Lets get rid of everything which has a warranty of less than 5 years and a battery life of 5 years and a pad life of less than 3 years.  You want something which is going to last.

Now we've got a smaller range and all seem to be in the similar budget so let's get rid of everything which has an annual running cost of over £46.00 per year.

We've still got a selection.

Link to Jousing Medical

So now lets get rid of everything which weighs over 2kg.  You don't need extra weight.

That leaves us with the Heartsine Samaritan PAD 350 and 500.  The difference between the two is the 500 features CPR coaching where the 350 does not...but it costs £465.00 more.  The decision of whether you chose a 350 for lower cost or 500 for the CPR coaching is entirely up to you.

The terms Monophasic and Biphasic refer to two different shock techniques that can help save a person’s life during Sudden Cardiac Arrest (SCA). You may have heard these words in the context of Monophasic Defibrillators vs. Biphasic Defibrillators, and in this article, we’re breaking down the differences below.

Defibrillation with an AED, or Automated External Defibrillator, is a crucial step to restoring the heart to normal rhythm and reviving someone who has suffered SCA. Anyone can use an AED, including children, and AEDs safely analyze a patient’s heart rhythm before determining if an electrical shock can help.

An important part of defibrillation is the waveform of the electric shock that it delivers to the heart. There are two main types: monophasic and biphasic.  

Before diving into preferences, it should be acknowledged upfront that both types of waveforms have roughly the same efficacy in saving someone’s life; however, there are many perks of using a biphasic defibrillator, which is why biphasic has become the more common, preferred type of device.

What are Waveforms? 

Electricity is made up of charged atoms. These charged atoms move through space in the shape of a wave, forming what is called a current. Waveforms are the direction a current takes. 

Reminder: Luckily, you do not need to be an expert on waveforms (or even know what they are) to successfully operate an AED and save someone’s life from SCA. AEDs are safe, easy to use, and designed to be successfully used by ANYONE, including children. 

What is Monophasic Defibrillation?

Monophasic defibrillation sends an electric current in one direction. In the context of a monophasic AED, the current travels straight to the heart.  

What is Biphasic Defibrillation?

In contrast to the single current of monophasic defibrillation, biphasic defibrillation sends a  current in two directions, consisting of two stages. In the first phase, electricity goes out from one electrode toward the other, just as it does in monophasic defibrillation. In the second phase, the electrical current returns back to the originating electrode. In the context of AED shocks, this means biphasic shocks travel to the heart and back through it a second time as they return to their source, the AED pads.  

All AEDs on the market today use biphasic defibrillation techniques, including the Avive Connect AED™.

While neither waveform has proven to be superior in improving the rate of ROSC or survival from SCA, biphasic waveform defibrillators expose patients to a much lower peak electric current (with equal or greater efficacy than monophasic defibrillators do), which makes them the safer, preferred type of defibrillators.

Today, biphasic defibrillation has largely replaced monophasic as the superior method, so much so that monophasic devices are no longer manufactured. The newest AED to hit the market, the Avive Connect AED™, uses biphasic waveform. While both waveforms have been proven effective in restoring a normal heart rhythm, they differ in several important ways. 

Monophasic vs. Biphasic: Read the Differences 

Popularity, Effectiveness & Safety

Research shows similar survival outcomes for patients who have received AED shocks from a monophasic defibrillator and those who have had shocks from an AED with biphasic defibrillation. However, despite the dual current, biphasic defibrillation actually requires less energy to administer a lifesaving shock compared to its monophasic counterpart. Since biphasic defibrillators require significantly lower levels of energy, they can cause less damage to the surrounding organs and tissue, making them the safer, preferred method. 

Because biphasic defibrillators use less energy, they are also generally smaller and lighter than monophasic ones. As a result, biphasic AEDs are more portable, making them more often used in public spaces.

In plain terms, Avive’s electrical engineer, Andrea Martin, explains, “Using a biphasic shock for the Avive Connect AED allowed us to create a high efficacy product that is also very small and energy efficient. The biphasic waveform gives you the same, or better result, for a lot less energy, so there’s less risk there.”

Strength of the Current

The strength of the current is another important, differentiating factor between monophasic and biphasic defibrillators. Research has shown that biphasic defibrillation achieves similar success rates in helping SCA patients survive while delivering less energy. Monophasic defibrillation delivers a high-energy electric pulse, anywhere from 200-360 joules per shock, whereas biphasic defibrillation delivers an initial shock in the 120-200 joules range. 

Battery Life

Biphasic defibrillators typically have a longer battery life than monophasic defibrillators. Because biphasic defibrillators use a lower-energy electric pulse, it takes less power for them to deliver a shock, which allows the battery to last longer. Meanwhile, monophasic defibrillators use a higher-energy electrical pulse that requires more power to deliver, which can drain the AED battery more quickly. 

If you’re considering purchasing an AED and battery life is important to you, the Avive Connect AED has the only FDA-approved embedded rechargeable AED battery that will last throughout the life of the device.

The Preferred Method?

When it comes to purchasing a public access defibrillator, biphasic AEDs are commonly accepted as the better option for many reasons. Biphasic AEDs are smaller, lighter, and have a longer battery life than monophasic AEDs. They are often more widely available than monophasic defibrillators, and can be less intimidating for the user to approach. 

Ultimately, though, when it comes to cardiac arrest, the “best” AED is the closest AED, and it would be far better to use a monophasic AED when responding to a cardiac arrest emergency than no AED at all. Although, if you are purchasing an AED for the first time, we recommend a biphasic defibrillator.

FAQ

Are Avive’s AEDs biphasic or monophasic?

The Avive Connect AED delivers biphasic shocks to patients suffering from SCA.

Is cardioversion monophasic or biphasic?

Cardioversion is the name for returning a heart from an irregular heart rate to a normal one. For decades, researchers recommended biphasic shocks during cardioversion. However, monophasic shocks can also help with cardioversion. And recent recommendations from the American Heart Association (AHA) say that it is hard to compare how effective the two different waveforms are at cardioversion because the defibrillators available today use different electric patterns to send out shocks.

How many joules is monophasic vs biphasic?

The joules of monophasic shocks are higher than those of biphasic. A monophasic shock typically has a sequence of 200- 360J, and a biphasic shock is much lower, between 120-200J.

How many joules should I set my AED to deliver in each shock?

Biphasic and monophasic AEDs deliver different amounts of energy, even when set to the same level. As a result, recommended energy levels vary from device to device. So, the AHA says to always follow the manufacturer's instructions for what energy levels to use for that defibrillator's specific pattern.

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