Compression only CPR: Be the Beat

When someone is having a heart attack, bystanders (outside of a hospital) are encouraged to administer life-saving cardio-pulmonary resuscitation (CPR). The traditional form of CPR involves a ratio of 30 chest compressions per minute alternating with two mouth-to-mouth rescue breaths. When I learned CPR, students were provided with a sealed, sterile cloth for covering the victim’s mouth. This was to remain in your wallet in anticipation of an emergency.

When the American Heart Association (AHA) studied the effectiveness of bystander CPR (as opposed to CPR from medical professionals), they learned a number of things. It turns out only 15% of bystanders are willing to perform the mouth-to-mouth part — the rescue breath. That may explain why only 25% of heart attack victims receive bystander CPR before emergency services arrive.

Forced rescue breathing has some disadvantages

Another statistic that turned up was that certified CPR practitioners took an average of 16 seconds to deliver those two breaths. That’s a long time when the brain and the heart are desperately in need of more oxygen.

Chest compressions, which manually force the heart to pump, can save lives because most people typically have eight to 10 minutes worth of oxygen in their bloodstream. The idea is to keep that oxygenated blood circulating fast enough so the brain stays alive and isn’t damaged.

Not only is 16 seconds a long time, but the forced breathing of traditional CPR can itself be counterproductive. When the heart has stopped beating, forcing air into the chest increases pressure in the chest. This makes it harder for blood from the veins to return to the chest. Consequently, there’s less blood flow to the brain and heart. Here’s a technical description of that sequence from the AHA:

Further concern about the utility of mouth-to-mouth ventilations came from reports of Aufderheide and associates, who found that during CPR for cardiac arrest, positive pressure ventilation increases intrathoracic pressure, decreases venous return to the chest, and decreases blood flow to the heart and brain. Therefore, so-called rescue breathing not only results in excessive interruption of marginal blood flow produced by chest compressions but also further decreases blood flow to the heart and brain by increasing intrathoracic pressures and thereby decreasing venous return to the chest.

Chest compressions

In 2005, the AHA issued new guidelines for assisting heart attack victims, recommending chest compressions only, without the forced breathing. This is known as CCC-CPR or Continuous Chest Compression CPR.

The compressions are done rapidly – 100 times a minute – compared to the 30 per minute of traditional CPR. Chest compressions are most effective when they are forceful, allow the chest to return to its full expanse after each compression, maintain a rate of 100 compressions per minute, and when there’s a minimum of interruptions. Traditional CPR used to include frequent pauses to check the airways and feel for a pulse.

Compressions are also interrupted to apply a shock from a defibrillator. Studies found that 200 compressions was good preparation for an electrical jolt to the heart.

It may appear that defibrillators restart the heart, but that’s not exactly what happens. They work when the heart is in a state called ventricular fibrillation (VF), which leaves the heart quivering and unable to pump blood effectively. A defibrillator stuns the heart, stopping the VF and any other electrical cardiac signals. If the heart is capable of beating on its own, its normal pacemakers will start to fire. If they don’t, continued compressions keep the blood circulating. Chest compressions prolong the time that VF is present, which increases the chances that defibrillation will be successful.

Not for children

Chest compression, as opposed to traditional CPR, is recommended by the AHA only for adults 18 and over, and is not recommended in cases of near drowning or drug overdoses. The cardiac arrest associated with drowning and drugs is caused by too little oxygen and too much carbon dioxide in the blood, otherwise known as asphyxia. Cardiac arrest in children can also be due to asphyxia. In all these cases, the traditional CPR rescue breaths are essential.

How do you know if an adult is suffering from a heart attack as opposed to asphyxiation? With a heart attack, there is a sudden collapse. According to Dr. Gordon A Ewy, an advocate of compression only CPR: “the public could be taught very easily that witnessed, unexpected collapse in a nonresponsive person, with abnormal breathing, is cardiac arrest.”

Professionals such as doctors, nurses, and others in healthcare, as well as emergency-response workers of all kinds, should continue to learn conventional CPR, he said, because they are more likely to encounter victims with respiratory arrest. But that isn’t so with the public, according to Ewy. Overwhelmingly, he observed, most of the public who learns standard CPR will never have an opportunity to use it on victims who might benefit from assisted ventilation, who account for a fraction of witnessed arrests, “whereas chest-compression-only [CPR] can be taught very easily, and people are more likely to do it.”

Making it memorable

Emergency medical providers, such as firemen, report that it’s easier to train people in continuous compression CPR than traditional CPR. You can also gain confidence in CCC-CPR even without formal training. That’s the idea behind this video from the AHA’s Be the Beat campaign. It uses rap to fix the idea in your memory.

Thanks to KevinMD for the video link.

Update 6/22/10:

An instructional video from Super Sexy CPR on Vimeo. It’s the two-breaths version, however, not compression only. But check out the Super Sexy Abdominal Thrust video below. It’s well done, memorable, and has a sense of humor.