Using an AED to save lives

Participants in a training class practising cardiopulmonary resuscitation, to be used alongside the automated external defibrillators.
Participants in a training class practising cardiopulmonary resuscitation, to be used alongside the automated external defibrillators.PHOTO: SINGAPORE HEART FOUNDATION

The device is most effective when used alongside CPR and by trained persons

These days, you can find portable devices used to treat sudden cardiac arrest in many places, such as the airport, MRT stations, shopping malls and schools.

These automated external defibrillators (AEDs) work by sending an electric shock to the heart in order to revive it.

Since March, you can even rent one for free from the Singapore Heart Foundation (SHF), if you are holding an event for over 50 participants. But two people will need to undergo a 15-minute introductory AED training session beforehand.

And the organisation requesting the life-saving devices for the event should also have someone certified in cardiopulmonary resuscitation (CPR), said the foundation.

This is because an AED, when used with CPR, offers the best chance of survival for a person who suffers a sudden cardiac arrest. "The mouth-to-mouth ventilation done during CPR provides just a sufficient amount of oxygen to the casualty," said Dr Chee Tek Siong, an SHF board member and a consultant cardiologist in private practice.

  • Sudden cardiac arrest v heart attack

  • A heart attack happens when blood flow to the heart is blocked, while sudden cardiac arrest is when the heart malfunctions and stops beating suddenly. A person who has a heart attack remains conscious, while a person experiencing cardiac arrest will suddenly lose consciousness. A sudden cardiac arrest is usually caused by ventricular fibrillation, which is when the heart goes instantly from a normal rhythm to a chaotic one. Only an electric shock across the chest and through the heart can turn the fatal rhythm of ventricular fibrillation back to a normal heart rhythm, if it is delivered in time.

And the chest compression "squeezes the heart between the breastbone and the spine to help circulate the blood and deliver oxygen to the vital organs", he added.

If CPR is performed promptly and correctly, it can maintain a minimal but adequate blood flow to the vital organs during a cardiac arrest.

"It buys time for further resuscitative efforts, such as the arrival of paramedics and an AED," said Dr Chee.

AEDs are user-friendly devices that do not need to be administered by medically-trained professionals, though training is advised.

Here is how it is used: If you see someone pass out, first check that he is unconscious and not breathing. When you have confirmed he is unresponsive, ask someone to call an ambulance and get an AED.

Then, start CPR until the AED arrives. Once the device is switched on, it will give you voice prompts on what to do. Wipe away any sweat from the unconscious person's chest before attaching the electrode pads to the bare chest.

The first pad should be placed on the victim's upper right side, just below the collarbone, while the second pad is placed just below and to the left of the left nipple. The device will tell you if shock is advised.

If shock is advised, make sure that no one is touching the person before pressing the button. Continue to follow the voice prompts until the ambulance arrives.

A version of this article appeared in the print edition of The Straits Times on August 25, 2015, with the headline 'Using an AED to save lives'. Print Edition | Subscribe