Defibrillators: strengthening the chain of survival
Phone boxes used to be a fixture of the British urban landscape, but as more people reach for their smartphone rather than a handful of loose change, increasing numbers of villages have been turning these iconic landmarks into defibrillation points.
And with good reason. Unexpected, sudden death at a young age is a particularly devastating event. Together with road accidents, suicides and violence, sudden deaths are among the most common reasons to die at young age. Approximately ten persons below the age of 35 years die suddenly every week in England and Wales, most often due to a heart attack, which is more common in elderly persons, or inherited cardiac diseases, which are more common in younger people and schoolchildren.
Sudden death usually occurs when the coordinated electrical activity that triggers every heart beat is massively disturbed, leading to ventricular fibrillation. When the heart is in ventricular fibrillation, it stops pumping blood, leading to loss of consciousness and, unless the circulation of blood is restored, to death after a short while.
Cardiologists and biomedical researchers around the globe work together to develop safe and effective ways to identify young persons at risk for sudden death before it happens. Unfortunately, this ’search for the golden needle in the haystack‘ is not always successful. When ventricular fibrillation happens, life support in the first minutes is critical for survival and for protection of the brain and other vital organs. Without a witness, this is almost impossible.
Early chest compression by bystanders restores a minimal blood circulation, improves survival and neurological outcome. Electrical defibrillation has the potential to restore normal cardiac activity and thereby normalise circulation of blood. Defibrillation means that a short, strong electrical shock resets the heart and brings it back to its normal rhythm.
Hospitals have trained personnel and defibrillators at every location, leading to relatively high survival of sudden death events that occur in hospitals. Public access defibrillators allow laypersons without specific training to deliver defibrillation shocks to sudden death victims, guided by an algorithm built into the machine.
Public access defibrillators have been successfully used in highly frequented locations and are noadays widely accessible in places such as airports, train stations or sports stadiums. Both chest compression and the use of public access defibrillators improve survival in cardiac arrest victims.
While public access defibrillators are useful, only one in a thousand devices that are currently provided in Japan have been used to save a life. Initial data suggest that alerting trained laypersons who are in the vicinity of a sudden death victim via mobile phone systems results in earlier CPR.
There is a clear need to strengthen the chain of survival for out-of-hospital cardiac arrest victims. A concerted action seems warranted, making use of:
- Better methods to detect and treat inherited cardiac conditions associated with ventricular fibrillation
- Wide-spread training of the public in chest compression and bystander life support
- Research into novel ways to alert trained bystanders to a cardiac arrest, and
- Increased availability of public access defibrillators
Joined up, these measures will have the potential to strengthen the chain of survival that currently often breaks up, thereby improving the fate of victims of out-of-hospital cardiac arrest and breathing a new lease of life into former phone boxes across the country.
Deputy Director of the Institute of Cardiovascular Sciences, University of Birmingham