Does the thought of putting your mouth on the mouth of a total stranger give you the heebie-jeebies? Even if you’re aware of CPR’s role in saving lives, you may think twice about performing mouth-to-mouth resuscitation because of the fear of getting an infection.

The good news is that in 2010, the American Heart Association (AHA) changed CPR’s longstanding A-B-C (Airway, Breathing, Compressions) sequence to C-A-B (Compressions, Airway, Breathing). The old A-B-C sequence for CPR consisted of the following steps:

  1. Airways – Tilt the victim’s head and lift his chin to open the airway
  2. Breathing – Pinch the victim’s nose and breathe into the mouth
  3. Compressions – Apply pressure to the victim’s chest

The new C-A-B (Compressions, Airway, Breathing) sequence teaches rescuers to perform chest presses before anything else. But after four decades, why did the AHA implement such a drastic change? There is a lot of buzz surrounding the A-B-C to C-A-B update because it requires anyone who learned CPR previously to get re-educated, but the AHA thinks the pros outweigh the cons.

The Science behind the Decision

In an adult who has been breathing normally, there is enough oxygen in the blood to supply the heart and the brain for several minutes following cardiac arrest. Chest compressions are needed, however, to circulate the oxygen and ensure that it is distributed quickly.

Rescue breaths are thought to be harmful because they require the rescuer to stop doing chest compressions for several seconds. Additionally, rescue breaths lower air pressure in the chest cavity, which in turn slows down circulation, a key factor in resuscitation. If the rescuer does chest compressions first, the victim gains approximately 30 seconds of time in his favor.

When people follow the A-B-C sequence to perform CPR, there is often a significant delay because they spend so much time trying to open the airway, make an air-tight seal around the mouth, or get over their reluctance to do mouth-to-mouth resuscitation. With the new C-A-B sequence, people initiate chest compressions sooner and ventilation is only slightly delayed. The AHA also predicted that the number of people who receive CPR will increase because of this change, since bystanders often balk at the idea of performing mouth-to-mouth resuscitation on a total stranger.

However, the change from A-B-C to C-A-B only applies to adult victims of sudden cardiac arrest. For children and in cases of asphyxial arrest, drug overdose, or near-drowning among adults, rescuers are still recommended to follow the A-B-C sequence.

What Else Is New?

In 2010, AHA’s new guidelines also called for faster and more forceful compressions. They recommended that rescuers compress the chest by at least two inches on each push and perform a minimum rate of 100 compressions per minute.

But in 2015, they changed the protocol for compressions to be between 100-120 compressions per minute. This update was a result of a study which showed the faster rate lead to more cardiac arrest survival to hospital discharge and increased ROSC (Return to Spontaneous Circulation).

In addition, the new guidelines strongly advise 911 dispatchers to guide callers in “compression-only” CPR. Their recommendation that untrained bystanders perform compression-only CPR still stands, which has been increasingly utilized over the past decade.

Since the AHA updates their guidelines every five years, we will keep you abreast of further changes to CPR.

About EMC CPR & Safety Training, LLC
Founded by New York CPR expert Stephanie Duehring, EMC CPR & Safety Training, LLC offers American Heart Association, ASHI, ECSI, and Red Cross CPR/AED/First Aid classes. We utilize a hands-on learning approach that leads to high comprehension and retention levels among students. The company offers on-site training for businesses nationwide, including New York City, Los Angeles, Chicago, and Houston.

Updated 7/23/2020



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