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Originally published in the February 2006 Harvard Heart Letter

Streamlined CPR guidelines a life-saving move

Updated recommendations make cardiopulmonary resuscitation easier to learn and to do: Press hard. Press fast. Don’t stop.

Without warning, a family member or friend collapses, twitches and gasps a few times, then lies deathly still. What do you do?

After calling 911 — exactly the right first move — most people do nothing during the agonizing wait for an ambulance to arrive. Starting cardiopulmonary resuscitation, even if you have never taken a CPR class, can make the difference between life and death.

Here’s all you need to know: Put your hands on the middle of the person’s chest, push hard, and relax. Repeat the push-relax cycle twice a second. Don’t stop.

And don’t worry about doing it wrong — poor CPR is better than no CPR.

“A bystander who witnesses someone collapse and who is ready, willing, and able to act doubles or triples that person’s chances of surviving,” says Mary Fran Hazinski, RN, the lead author of streamlined CPR guidelines from the American Heart Association (AHA), published in 2006. (You can read a later iteration of the AHA's 2008 guidelines for "hands-only" CPR in case of a witnessed cardiac arrest.)

The guidelines represent a back-to-basics approach aimed at making CPR less intimidating and more effective.

Previous guidelines were so detailed that performing CPR not only seemed like a daunting task but was tough to do properly. A rescuer was supposed to check the airway, give two breaths for every 15 chest pushes, and look for a pulse or heartbeat every so often, all while pressing on the chest 100 times a minute. Influential studies have shown that even trained professionals were spending too little time doing what mattered — compressing the chest to move blood around the body.

The updated guidelines underscore the importance of maintaining a steady flow of blood through the heart, brain, and other vital organs by emphasizing chest compressions over everything else. They call for two breaths every 30 compressions and, in some cases, no breaths at all.

Keep in mind that the AHA’s 2006 guidelines are meant to cover virtually all emergency situations, from drowning and drug overdose to cardiac arrest, for children and adults. One goal was to come up with a single set of recommendations for CPR so that professional and lay rescuers wouldn’t need to learn different strategies for different situations.

In reality, though, what’s needed for someone whose heart suddenly stops beating (a cardiac arrest) is different from what’s needed for someone whose heart isn’t beating due to drowning. We’ll focus on what’s needed to help someone having a cardiac arrest.

A skill you need

Every day, a thousand or so Americans have a sudden cardiac arrest. Their hearts start beating so wildly that they can no longer pump blood. Most such events happen at home.

Only about 5% of people now survive a cardiac arrest. Wider use of CPR and faster access to heart-shocking defibrillators could increase survival rates to 50% or more.

Sudden cardiac arrest sometimes strikes people with seemingly healthy hearts. Other times it is triggered by the painful, slower-developing kind of heart attack caused by a blocked coronary artery. Either way, it occurs when the heart’s powerful lower chambers, the ventricles, veer away from a normal, steady rhythm and start beating very fast (ventricular tachycardia) or fast and chaotically (ventricular fibrillation). Contractions are so close together that the heart can’t relax enough to fill with blood. Circulation stops.

Five seconds without blood flow to the brain is enough to make a person pass out. After another few seconds, the lack of oxygen in the brain causes nerves to start firing, making the muscles twitch and the eyes roll back. Even that activity stops in less than a minute.

The only way to stop ventricular tachycardia or fibrillation is with a well-placed shock from a defibrillator. That’s why people who have survived one of these arrhythmias or who are at high risk for one often have a small defibrillator implanted in the chest. Because external defibrillators are rarely at hand, CPR is needed to buy precious time until one arrives.

Pressing trumps breathing

There’s no question that the body needs a constant supply of oxygen. That’s why earlier CPR guidelines called for two breaths for every 15 chest compressions. It turns out, though, that this can be counterproductive, especially for people with sudden cardiac arrest.

Most victims of a sudden cardiac arrest already have a fair amount of oxygen in their lungs and bloodstreams. The people aren’t moving, so they aren’t using much oxygen. That means it takes a few minutes for their bodies to use up that stored oxygen. Meanwhile, a little bit of air is passively pushed out and pulled in with every chest compression a rescuer performs.

If you are doing CPR alone, stopping chest compressions to give breaths takes precious time away from compressions. In studies of doctors and paramedics, following the old guidelines resulted in about 40 compressions per minute, way under the 100-per-minute target. Too many breaths also increase the pressure inside the chest. This makes it harder for chest compressions to circulate blood through the arteries that feed the heart muscle.

A revolutionary approach called compression-only CPR seems to work as well as standard CPR for people with sudden cardiac arrest. In fact, this is what emergency dispatchers have been coaching people to do by telephone, an approach sanctioned by the new AHA guidelines.

Be a link in the chain

Surviving a cardiac arrest depends on what’s been called the chain of survival. You can forge most of the chain with quick action (see “CPR for a sudden cardiac arrest” above).

Call 911. This essential first step summons experienced health care professionals and their equipment. The dispatcher on the other end of the line can help you do what needs to be done until they arrive.

Start CPR. For a sudden cardiac arrest, the most important part of CPR is pressing on the chest; breathing is secondary. If you start immediately after someone collapses, you can give up to 50 or 100 compressions between breaths. Each time you stop to deliver a breath, get back to doing compressions as fast as you can. If there are two of you doing CPR, have the larger or stronger one do the chest compressions and the other do the breathing. Switch when the person doing the compressions starts to tire out.

Restart the heart. CPR by itself won’t transform a lethal heart rhythm into the regular tick, tick, tick of a healthy heart. That takes a shock from a defibrillator. The ones made for the home or public places have simple instructions printed on the case. The new guidelines say to give just one shock.

Advanced life support. The fourth link involves medications and other techniques such as cooling the body and brain that can improve survival from a sudden cardiac arrest.

Learn CPR before you need it

Although you can be taught how to do CPR on the spot, why wait until you are in a life-or-death situation? Learning how to do it correctly from a trained instructor could pay off when you really need it. Classes are offered in almost every city and town, at YMCAs, civic centers, schools, doctors’ offices, and elsewhere (see “For more information”).

You can even learn at home. The American Heart Association has developed a kit that comes with a videodisc, an instruction manual, and an inflatable mannequin so you can get the feel of doing CPR and practice at home.

A cardiac arrest is a chaotic, confusing event. It’s even worse if you know the person who seems to be slipping toward death. If you can keep your wits about you, call 911, and start CPR, then his or her life is literally in good hands.

CPR for a sudden cardiac arrest

These instructions are for a witnessed cardiac arrest — you are with a person when he or she suddenly collapses.

  1. Call 911. Doing this summons health care professionals and a life-saving defibrillator, and the emergency dispatcher may be able to coach you through CPR until experienced help arrives. (If there are other people to help, ask someone to see if an automated external defibrillator is near by.)
  2. Start CPR. Put one hand on the breastbone in the middle of the chest. Cover it with your other hand. Press down hard enough to make the chest move 1½–2 inches. Relax to let the chest rebound. Repeat this press-and-relax quickly, almost twice a second if you can. If you get tired, ask someone else to take over for a spell.
  3. Restart the heart. If a defibrillator arrives, ask the person who brought it to attach the pads to the victim’s chest so you can keep doing CPR. When everything is ready, stop CPR and follow the directions on the defibrillator.
  4. Go back to CPR. Immediately after the shock, start pushing on the chest again. This helps the heart get back into a normal rhythm. After two minutes, if there doesn’t seem to be any recovery, go through the defibrillation process again and get right back to CPR.