What is cardiac arrest?
Cardiac arrest is nothing but sudden stoppage of the functioning of the heart. It is different from heart attack which is abrupt loss of blood supply to a region of the heart muscle. Heart attack can lead to cardiac arrest in some of the victims. Though both are medical emergencies, cardiac arrest is equivalent to death unless immediate measures are taken to swing heart back into action. This is usually done by chest compressions and artificial breathing (cardiopulmonary resuscitation or CPR – Basic life support or BLS), to be soon followed by electrical countershock (defibrillation) delivered by a device known as defibrillator, to correct the abnormal rhythm of the heart which caused the cardiac arrest.
How soon should CPR be started?
CPR should be started as soon as possible. The time window for successful CPR is very narrow. Irreversible brain damage can occur if blood circulation stops more than 4 minutes as the brain is very much dependent on oxygen supplied by the blood. Even with CPR, it is difficult to maintain good blood circulation to the brain to sustain it for a long period. Usually CPR provides only about one fourth of the normal blood supply. Hence the time window available to us is about 12 minutes with CPR, unless advanced cardiac life support (ACLS) is available.
What is AED?
AED is short for automatic external defibrillator. AED is an electronic device being deployed more and more in public places to treat victims of cardiac arrest. It is also known as public access defibrillation. AED has two electrode patches which can be applied to the chest. It will sense the cardiac rhythm and interpret it using a built in computer algorithm. If a rhythm which can be shocked back to normal (ventricular fibrillation or tachycardia – fast rhythms of the heart) are detected, the devices prompts a shock delivery. Everyone should clear off the victim when the shock is being delivered. If it is not a shockable rhythm, the device gives audio prompts to continue CPR.
What is ROSC?
ROSC is the acronym for return of spontaneous circulation. Once ROSC is achieved, further care is known as post resuscitation care or post cardiac arrest care. This is aimed at minimizing the brain injury caused by the period of lack of oxygen supply to the brain during cardiac arrest.