Question: Why did CPR change from A-B-C to C-A-B?
The 2010 CPR Guidelines rearranged the order of CPR steps. Now, instead of A-B-C, which stands for airway and breathing first followed by chest compressions, the American Heart Association wants rescuers to practice C-A-B: chest compressions first, then airway and breathing. Some have asked, why did CPR change?
Answer: Just like you can hold your breath for a minute or two without having brain damage, victims of cardiac arrest can go a minute or two (actually a lot longer than that) without taking a breath. What cardiac arrest victims really need is for that blood to get flowing again.
When rescuers are worried about opening the airway and making an adequate seal, plus the "ick" factor and possibly digging a CPR mask out of a purse or briefcase, the delay can be significant. All that extra time is getting in the way of real help: Chest compressions.
In its summary of the changes, the American Heart Association explained it this way:
In the A-B-C sequence chest compressions are often delayed while the responder opens the airway to give mouth-to-mouth breaths or retrieves a barrier device or other ventilation equipment. By changing the sequence to C-A-B, chest compressions will be initiated sooner and ventilation only minimally delayed until completion of the first cycle of chest compressions (30 compressions should be accomplished in approximately 18 seconds).
So as you can see, by starting chest compressions first, the victim only has to hold his breath an extra 18 seconds while blood gets flowing again. In my opinion, that's a good trade.
Field JM, Hazinski MF, Sayre MR, Chameides L, Schexnayder SM, Hemphill R, Samson RA, Kattwinkel J, Berg RA, Bhanji F, Cave DM, Jauch EC, Kudenchuk PJ, Neumar RW, Peberdy MA, Perlman JM, Sinz E, Travers AH, Berg MD, Billi JE, Eigel B, Hickey RW, Kleinman ME, Link MS, Morrison LJ, O’Connor RE, Shuster M, Callaway CW, Cucchiara B, Ferguson JD, Rea TD, Vanden Hoek TL. "Part 1: executive summary: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care." Circulation. 2010;122(suppl 3):S640–S656.