Until recently the focus for cardiac arrest patients in ventricular fibrillation has all been around getting the AED to the scene and to give a shock as quickly as possible.

However, recent evidence indicates that this approach can be sub-optimal for patients where the response interval before arrival of the AED is more than 4-5 minutes. Because bystanders are to a large extent either not willing or able to do CPR, most patients will not have been given effective CPR from the time of collapse until the AED arrives. This patient group, untreated effectively for minutes, is likely to benefit from 2-3 minutes of CPR by the professional responder before receiving a shock.

In such cases, therefore, the professional responder should start to provide CPR rather than give a shock to maximise the chances of survival. But how does the professional responder know if CPR has been done effectively before his arrival. Some response systems have decided to “play safe” and now give CPR before defibrillation in all cases of delayed response i.e. where the arrest is not witnessed by the professional responder. But this may result in unnecessary delays in giving a shock for some patients where the response time has been short or good bystander CPR has been given. So what is the answer?

For the first time an AED is now capable of making the decision on whether the appropriate treatment should be CPR first or shock first. The SMART CPR feature introduced in Heartstart FR2 evaluates the patient heart condition from a detailed mathematical analysis of the presenting heart rhythm and makes this decision for the responder.

The FR2 can now be configured either to give a shock first – for systems that always respond in under 4 minutes, CPR first – for systems that always have very long response intervals, or the AUTO function where the AED decides on the appropriate therapy for each individual patient regardless of response interval or whether good bystander CPR has been done.