Chain of Survival in VF Sudden Cardiac Arrest

Chain of survival in VF sudden cardiac arrest

Chain of survival is used to illustrate the importance of timely actions for the survival of victims of sudden cardiac arrest due to ventricular fibrillation. The components of adult chain of survival as portrayed by the American Heart Association are:

1. Early recognition of the emergency and activation of the emergency medical services or the local emergency medical response system.
2. Early (immediate) cardiopulmonary resuscitation, by the bystander, which can double or triple the victim’s chance of survival in case of sudden cardiac arrest due to ventricular fibrillation.
3. Early defibrillation with a shock delivered by a defibrillator – CPR with defibrillation within three to five minutes of collapse can lead to survival rates upto 75%.
4. Early advanced life support and
5. Post resuscitation care by healthcare providers
6. Physical and emotional recovery was added by AHA in 2020.

It may be noted that a chain is as strong as its weakest link, thereby emphasizing the importance of each of the links!

With the availability of automated external defibrillators (AED) in public places, bystanders can perform three of the initial links in the chain of survival. Since the arrival of emergency medical service is likely to delayed beyond the time window for useful CPR, bystander initiated CPR is the factor likely to determine survival. CPR provides a small but critical amount of circulation to the vital organs: heart and brain. The chance of VF being present at the time of availability of defibrillation from the emergency medical services is increased by CPR. Please note that the heart should be viable for spontaneous rhythm to get initiated by the natural pacemakers of the heart after defibrillation. Even if the rhythm is re-established, effective perfusion may not occur in the initial few minutes, mandating ongoing CPR. Only 25 to 40% may have an organized rhythm in the immediate post defibrillation period, again highlighting the need for ongoing CPR after defibrillation, even prior to a rhythm check, which obviously needs a suspension of CPR.