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What is the purpose of an AED?

What is the purpose of defibrillation?

Defibrillators are medical devices that send an electric pulse to the heart to restore a normal heartbeat in the event of an emergency. These devices are used to stop uneven heartbeats or to correct an arrhythmia

Most hospitals and medical clinics employ the use of defibrillators on a routine basis because they strengthen an individual’s chance of survival. Studies show that when a person suffers a debilitating sudden cardiac arrest, their chances of survival decrease by as much as 10% for each minute that passes without a defibrillator or cardiopulmonary resuscitation (CPR).

An Overview of Defibrillation

What is a defibrillator used for? Defibrillation is executed to correct serious heart arrhythmias including ventricular fibrillation or pulseless ventricular tachycardia. During an emergency, the device should be used as soon as the patient collapses, loses consciousness and stops breathing. 

A defibrillator delivers a dose of electricity, called a counter-shock, to the heart. A large part of the heart muscle is depolarized, ending in dysrhythmia. At this point, the body’s natural heart rhythm is able to re-establish itself. 

Early defibrillators were large and cumbersome and were used almost exclusively in ambulances and emergency rooms. However, the invention of the automated external defibrillator (AED)  made it possible for the public to access and utilize these devices. 

State laws vary quite a bit, but some require that AEDs be available in airplanes, police cars and at public places with large gatherings. While portable defibrillators are already available in many public spaces, accessibility is expanding every year.

What Are the Different Types of Defibrillators?

There are five main types of defibrillators. While all units have the same basic purpose, they function a bit differently. Below is more information on the main types of defibrillators used today:

Automated External Defibrillators: 

  • Invented in 1965 by renowned cardiologist Frank Pantridge, AEDs are portable devices that are designed to be used by trained or untrained bystanders. 
  • The device is strong enough to diagnose and treat life-threatening arrhythmias. 
  • While sophisticated, AEDs are designed to be easy to use. First, you turn on the device and attach the device’s pads to the affected person’s bare chest. After you press the “analyze” button on the machine, the device tells you if a shock is needed. If a shock is needed, you do so by pressing the “shock” button. You should perform CPR until an ambulance arrives.

Implantable Cardioverter Defibrillators:  

  • Unlike AEDs, ICDs are surgically implanted inside the body, right below the collar bone.
  • These devices are designed to diagnose and fix cardiac issues such as abnormal heart rhythms. 
  • These machines are composed of three different parts: a pacemaker, a pulse generator, and electrode-tipped wires, which are connected to veins to the heart. ICDs are only implanted in individuals who have a known cardiac condition. 
  • According to recent studies, ICDs are effective and can reduce the risk of death by as much as 60%.

Advanced Life Support Units:

  • Used primarily in hospitals and ambulances, these units allow medical professionals to monitor a patient’s heart rhythm. 
  • It can also provide an electrical shock if needed. The device is designed to inform the medical practitioner if a shock is needed based on the patient’s condition. 
  • Many devices also come with the functionality to monitor temperature, carbon dioxide levels, blood pressure and oxygen levels.

Wearable Cardioverter Defibrillators: 

  • Similar to AEDs, wearable cardioverter defibrillators are portable units worn by those who have been diagnosed with a serious heart condition. 
  • WCDs are primarily prescribed for people who have recently undergone heart surgery. 
  • The unit is composed of a vest and a monitor. The individual wears the monitor around the waist while the vest is typically worn under clothing. 
  • While WCDs must be worn daily to be effective, they are proven to deliver shocks that are highly efficient at reducing the risk of death.

Manual External Defibrillators:

  • Of all the units mentioned, MEDs are by far the most advanced.
  •  The units are primarily used in a clinical setting by physicians and paramedics. 
  • MEDs are also unique because they are typically used in tandem with electrocardiograms. 
  • These devices test the health of the heart and are useful in diagnosing certain cardiac conditions. 
  • Once a healthcare practitioner determines the heart rhythm, he or she will manually input the voltage necessary for an effective shock.

While there are other types of defibrillators on the market, the ones mentioned above are the most commonly used in the U.S. health system.

How Do Defibrillators Work? 

When you have an irregular heartbeat, a defibrillator may be needed to regulate your heart’s rhythm and prevent a serious cardiac event. Depending on the problem, a low or high energy shock may be needed. 

For example, implantable cardioverter defibrillators can be programmed to deliver a low-energy pacing sensation or a higher-energy shock. If the device detects a minor problem, the ICD will attempt to regulate the issue using a painless low-energy pacing mechanism. You will most likely feel nothing. 

For more serious rhythm issues, the ICD will use a high-energy shock. These shocks can be uncomfortable, but they only last for a few seconds.

Typically, one shock is all that is needed to regulate a heart rhythm problem. If the device detects a more severe problem, multiple shocks may be needed. Receiving multiple shocks in 24 hours is usually referred as to an electrical storm. 

After you experience a multiple shock event, it is best to consult your doctor right away to perform more extensive tests on the health of your heart. Your doctor can also adjust your device’s settings to reduce the frequency or intensity of shocks if necessary.

You should also ensure your device is still working properly because some only work through one actual event. 

What Precautions Need to Be Taken? 

A number of proper precautions, like the following, need to be taken when utilizing an automated external defibrillator:

  1. Don’t touch the patient during the defibrillation process. You could unintentionally shock yourself or another individual.
  2. Because alcohol is flammable, do not use alcohol wipes during the defibrillation process.
  3. Do not perform the procedure in a moving automobile. The movement can affect the effectiveness of the defibrillator.
  4. Never perform the procedure on an individual if they are in contact with water. Move the patient away from water before beginning the defibrillation process.
  5. Never use an automated external defibrillator on a patient under the age of 8 or someone who weighs less than 90 pounds. AEDs cannot be adjusted to emit energy suitable for small individuals.
  6. Ensure the patient does not have nitroglycerine or another similar patch before using a
  7. The device’s paddles should never be placed directly over an internal pacemaker.
  8. Do not touch or move the patient while the unit is performing its analysis. Movement can affect the outcome of the analysis.
  9. Do not perform the procedure around flammable materials including alcohol and gasoline.
  10. Do not use a cellular phone within six feet of the patient while the machine is performing its analysis.
  11. Do not use the device if the patient is lying on a conductive surface such as a metal bleacher. These surfaces may transfer shock from the patient to other individuals.

Additionally, defibrillation should never be done on an individual who has a pulse or is exhibiting signs of alertness. If performed on an alert individual, the victim is not experiencing SCA and the defibrillation process can cause more harm than good. Today’s AEDs will  not deliver a shock if the situation doesn’t warrant one. This is an important safety measure.

How Can I Prepare an Individual for Defibrillation?

If you suspect your loved one is having a serious cardiac episode, check to see if he or she has a pulse. If the patient is not responding, call an ambulance and immediately begin cardiopulmonary resuscitation. Continue to provide CPR somebody attempts to locate an AED. Continue CPR and execute the AED until the medical response team arrives.

To prepare the patient for defibrillation, the paramedics will attach an electrocardiogram to the center of the chest. Gel or paste is then placed on the defibrillator paddles. Gel pads are sometimes placed on the chest as an alternative to placing gel on the paddles. The medical response team will then affirm the patient has no pulse before delivering the first shock.

Ideally, defibrillation should be performed within five minutes of the cardiac episode. A quick shock is effective at preventing further injuries or death because it allows the heart to produce a rhythm strong enough to create a pulse.

What Happens After Defibrillation? 

After the process is complete, the patient should be transferred to a hospital critical care unit for more tests. 

While at the hospital, the patient’s vital signs, heart health and breathing levels are closely monitored. A doctor may perform more tests, such as a chest x-ray, to determine the damage to the heart. 

Also, treatment for electrical burns may be necessary if the patient experienced any trauma during the defibrillation process. 

If the cardiac episode caused respiratory problems, the patient may also need to be intubated until normal breathing resumes. Treatment options for the cardiac problem will be decided after all tests are completed. 

There are many medications available to improve the function of the heart and regulate irregular heartbeats. A medical professional can help you decide the best medications to take in the future.

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