The chance of an SCA victim's survival decreases by 10 percent for every minute that passes, so in order to be effective, defibrillation treatment must be administered within the first few minutes of SCA.

RISK OF SUDDEN CARDIAC ARREST

Sudden cardiac arrest is one of the leading (hidden) causes of death in Australia.  In fact, sudden cardiac arrest is truly a public health crisis.  Unlike other health problems of this magnitude, however, sudden cardiac arrest is treatable.  The cure for most cases of sudden cardiac arrest is immediate treatment with a defibrillator, a device that shocks the heart out of a fatal rhythm, allowing a normal, healthy rhythm to resume.

Unfortunately, although science and industry have developed a safe and effective remedy that works, few victims of sudden cardiac arrest have quick access to this treatment.  That situation occurs because many organisations have not yet developed strategies to ensure that a defibrillator reaches every victim of sudden cardiac arrest within five minutes of collapse.

As a result, in most organisations, fewer than five percent of victims survive.  In contrast, some organisations with strong response systems have achieved survival rates of 30 to 50 percent and more.

It really doesn't matter who brings the defibrillator to the victim's side.  The important thing is to make sure a working defibrillator is readily available and there is an action plan to ensure the device and trained rescuers reach the victim in time.

Although victims of sudden cardiac arrest tend to fit in certain categories, sudden cardiac arrest, by its nature, is completely unpredictable.  It can strike anyone, anywhere, any time.  Chances are that almost anyone knows someone who has experienced a sudden cardiac arrest of a friend, a relative or a co-worker.

Sudden cardiac arrest does not have to be fatal

Sudden cardiac arrest does not have to result in "sudden death." When sudden cardiac arrest occurs, most victims have an abnormal heart rhythm called ventricular fibrillation (VF).  When the heart is in this state, it cannot beat in a coordinated fashion and blood does not circulate to the heart and the brain.  First, the pulse stops.  Then, breathing stops.  The victim loses consciousness, collapses and appears lifeless.

But the victim doesn't have to stay that way.  Ventricular fibrillation is a treatable irregular rhythm.  In this state, electrical energy is present in the heart, but it is chaotic.  If the heart can be shocked quickly with a defibrillator, a normal heart rhythm may be restored.  This process is known as defibrillation.  If this shock is delivered within minutes after collapse, many victims can and do survive.

The key is to be quick

Studies conducted at cardiac rehabilitation centres have shown that when sudden cardiac arrest victims in ventricular fibrillation receive defibrillation therapy within the first minute or two after collapse, more than 90 percent survive to be discharged from hospital.

In more typical workplace settings, victims of sudden cardiac arrest rarely survive because most victims do not have immediate access to prompt, definitive treatment.  Too much time elapses before the defibrillator arrives-if it arrives at all. 

Ambulance response times

A common misconception is that an ambulance will arrive in time to resuscitate the victim. 

According to the NSW Auditor-General’s Report Performance Audit Readiness to Respond Ambulance Service of New South Wales, June 2007 response times for most ambulances in Australia are well outside the critical few minutes in which the victim’s life can be saved.  The comparative response times in 2005-2006 for NSW and other Australian ambulance services are shown below in Table 1 for potentially life threatening cases (Priority 1), the Council of Ambulance Authorities standard.

Table 1 – Ambulance Response Times Source: Ambulance Service of NSW February 2007

‘Response time’ is the time from first recording of an emergency call to arrival of a trained ambulance team at the scene, ready to provide the patient with initial clinical care. 

In all known reports of survival, the shorter the time from collapse to defibrillation, the better the chances of survival.  If defibrillation is delayed for more than 10 minutes, survival rates drop to less than 5 percent.

All workplaces can aim to reduce the critical interval from collapse to defibrillation.  Since the exact time of collapse often is difficult to identify and measure, workplaces can focus on minimizing the interval from the 000 call to the first defibrillatory shock.  Workplaces that reduce this "call-to-shock" time to five minutes or less can expect as many as one-third to one-half of sudden cardiac arrest victims found in ventricular fibrillation to be resuscitated.  Reducing "call-to-shock" time by even one minute can mean the difference between life and death.

Summary

Sudden cardiac arrest remains one of the leading causes of death in Australia.  The key to survival is prompt defibrillation.  The challenge for workplaces is to respond, defibrillator in hand, to every victim of sudden cardiac arrest within minutes.  If the time from 000 call to defibrillation is seven minutes or less, as many as one-third to one-half of sudden cardiac arrest victims found in ventricular fibrillation can be resuscitated.