Without warning, a family member or their friend collapses..........can improve survival from a sudden cardiac arrest.

Press hard. Press fast. Don't stop

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

After calling for help -- exactly the right first move -- most people do nothing during the agonizing wait for an ambulance to arrive. Starting cardiopulmonary resuscitation, even if you've 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.

"A bystander who witness someone collapse and who is ready, willing and able to act doubles or triples that person's chances of surviving," says Mary Fran Hazinski, lead author of streamlined CPR guidelines from the American Heart Association.

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 he airway, give two breaths for every 15 chest pushes and look for a pulse or heart beat every so often, all while pressing on the chest 100 times a minutes. 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 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 set up of recommendations for CPR so that professional and lay rescuers wouldn't need to learn different strategies for different situations.

In reality, though, what is 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.

Every day, thousands of people 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 or fast and chaotically.

Surviving a cardiac arrest depends on what has been called the chain of survival. Quick action is vital.

Call the ambulance. 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.

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 wont' transform a lethal heart rhythm into a regular tick, tick, tick of a healthy heart. That takes a shock from a defibrillator.

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.

Summary: When someone collapses, starting CPR can save the person's life. Put your hands on the person's chest and push hard. Relax. Repeat the push-relax cycle twice a second without stopping. Previous guidelines were tough and daunting. Undated guidelines make CPR more effective by emphasizing the importance of maintaining a steady flow of blood in the vital organs through chest compressions. The guidelines apply to all emergency situations for children and adults. Wider use of CPR and faster access to heart-chocking defibrillators could dramatically raise cardiac arrest survival rates. Quick action is vital in surviving a cardiac arrest. call the ambulance for help. Next, start CPR by pressing on the chest first and then allow breathing. Restart the heart using a defibrillator. The last step is advanced life support involving medications.