Tuesday, May 17, 2016

Pre-Charge the Defibrillator

ALiEM - By Sam Ghali - May 16th, 2016
"In cardiac arrest care it is well accepted that time to defibrillation is closely correlated with survival and outcome. There has also been a lot of focus over the years on limiting interruptions in chest compressions during CPR. In fact, this concept has become a major focus of the current AHA Guidelines. Why? Because we know interruptions are bad. One particular aspect of CPR that has gotten a lot of attention in this regard is the peri-shock period. It has been well established that longer pre- and peri-shock pauses are independently associated with decreased chance of survival. Can we do better to shock sooner and minimize these pauses?
Pre-Charge the Defibrillator figure 1
Figure 1: Perfusion pressure changes during CPR without pre-charging the defibrillator. Once a shockable rhythm is identified, there is a delay in shock delivery while awaiting defibrillator charging. There is not just 1 but 2 interruptions in chest compressions. The exact decrease in perfusion pressure during these pauses is variable. Modified from [2].
Pre-Charge the Defibrillator CPR Perfusion Pressure 2
Figure 2: Perfusion pressure changes during CPR with pre-charging the defibrillator. Not only is the shock delivered earlier but the second interruption seen in Figure 1 is avoided completely. Modified from [2].

Pre-charging the defibrillator during chest compressions in anticipation of a shockable rhythm at the rhythm check shortens time to defibrillation and minimizes the number of pauses in chest compressions during CPR.