CPR: What You Need to Know

Contrary to popular belief, sudden cardiac arrest (SCA) is not the same thing as a heart attack. SCA occurs when abnormal rhythms disrupt the electrical impulses of the heart, which cause it to abruptly stop pumping. On the other hand, a heart attack (myocardial infarction) is the final stage of heart disease, a condition that slows blood flow over time. Both medical events require immediate attention; however, the prognosis for SCA is much more grim. Only about 5 percent of people who experience sudden cardiac arrest survive, while many heart attack sufferers can expect to recover [sources: Red Cross; American Heart Association].

Despite the varying prognoses of these heart conditions, CPR does help play a role in survival by extending the window of time a person can be kept alive before they receive additional medical attention, such as defibrillation and emergency surgery. In addition, other sudden medical events -- such as near drowning, carbon monoxide poisoning or an electrical shock -- can lead to loss of heart or lung functioning that requires CPR.

If you witness someone collapse suddenly, or if you come across a person who appears lifeless, tap him or her on the shoulder and ask if they are OK. If they don't respond, you should immediately call for emergency responders and then try to resuscitate the unconscious per using CPR. If it's a baby that appears to be in distress, stroke the infant to see if he or she responds to touch; but never shake a baby to try to get a response.

On the next page, we'll look at the different levels of CPR.

CPR is a first-aid technique used to keep victims of sudden cardiac arrest and other emergencies alive and to prevent brain damage until more advanced medical professionals can arrive. Traditional CPR has two goals: to keep oxygen flowing in and out of the lungs and to keep oxygenated blood flowing throughout the body.

While the modern emergency room has high-tech equipment and an arsenal of drugs to help treat people who are experiencing heart and breathing emergencies, CPR is a simple technique most anyone can do with little or no equipment.

There are different types of CPR, and the one you perform on a person depends on your level of training and your access to additional lifesaving aids. The following are varying levels of CPR broken down by the Mayo Clinic:

When it comes to CPR, comprehensive training is ideal, but even some knowledge is better than no knowledge at all. In fact, hands-only CPR is just as effective as traditional CPR in the first few minutes following an attack [source: Mayo Clinic]. In the next section, we'll go over the step-by-step basics of CPR so you can be better prepared to help others in case of emergency.

What should you do to help a seemingly unconscious victim? As we mentioned previously, the first thing you do is determine whether or not the victim is really unconscious. Call out to them, tap them and gently shake them to try and provoke a response. However, you should never shake an infant, even if you suspect he or she is unconscious.

You also should check for signs of breathing. If a person looks slightly blue in the face or if their chest is not rising and falling, there's a good chance they've stopped breathing and will need CPR. If you perform CPR on someone who does not need it, you could actually do damage, so be certain before you begin.

If you suspect someone is unconscious and you can't rouse them, the very next thing to do is have someone call 911 so paramedics will be on their way while you are performing CPR. This is very important because, with the exception of choking, CPR doesn't address the underlying causes of cardiac arrest and other breathing emergencies. It is only meant to buy time until the victim can get intensive medical care.

After you've called for medical assistance, you should begin CPR. In order for CPR to work, the person must be lying on his or her back on a hard, flat surface. If he or she is face down, gently roll him or her toward you while, supporting the neck. Once the person is on their back, you can then use the C-A-B method, which stands for:

Step one ("circulation") is the only one you should perform if you have no training in CPR -- it's called the hands-only method and we discuss it in detail next.

You probably know that mouth-to-mouth resuscitation has always been a prominent component of CPR. However, in recent years, experts have changed the process to emphasize the highest-priority method -- chest compressions -- and to make layperson-conducted CPR more effective.

The steps for performing CPR used to follow the acronym "A-B-C" -- airway, breathing and circulation. But as we discussed earlier, CPR should now be performed C-A-B -- circulation, airway and breathing. The American Heart Association introduced this new approach in 2010 as a way to make chest compressions the priority of CPR.

If you take classes to learn advanced CPR methods, you'll be trained to provide airway and breathing support to a victim. If you are untrained, however, you should focus only on the circulation step.

For this method, known as hands-only CPR, you essentially become a surrogate heart to pump oxygenated blood to the rest of the victim's body. How can you have any effect on blood flow from outside of the body? All it takes is your hands and some strength. The steps are simple and include the following:

In reality, all you are doing is squeezing the heart between the breastbone and the backbone to force blood out. Compressing the chest creates positive pressure inside the chest that pushes oxygenated blood out of the heart through the aorta. From here, it travels to the brain and then on to other parts of the body, delivering oxygen for cellular respiration.

It may sound easy enough in theory, but when someone collapses in front of you, your first reactions can be confusion and terror. But while you're panicked and unable to act, valuable minutes are slipping away. To counter this, many organizations, such as the American Red Cross, offer classes that give you hands-on practice to hone your CPR skills. There are even online sites, like HandsOnlyCPR.org, that simulate the compression-only method online and help you learn the speed and rhythm at which you need to perform it.

Keep reading to learn more about the difference between CPR and defibrillation.

CPR extends the window of opportunity for professionals to perform more elaborate first aid procedures, but by itself it cannot save the majority of victims of sudden cardiac arrest. Most of the people who experience SCA have ventricular fibrillation (VF), which causes the heart muscle to quiver rapidly and beat improperly. CPR cannot correct VF. An electrical shock, known as defibrillation, is what's required to successfully restore a normal heartbeat in someone with the condition.

The shock itself doesn't switch the heart back on -- it's not like flipping a tripped circuit breaker. Instead, defibrillation actually stops the heart briefly. This gives the pacemaking cells a chance to re-establish a normal heartbeat.

So why do CPR at all if it can't address the root causes of sudden cardiac arrest? The bottom line is that CPR is an important part of a comprehensive response to a cardiac emergency. Defibrillation requires special equipment -- an automatic external defibrillator (AED) -- that has to be brought to the patient, and CPR can keep a patient alive until it arrives. In fact, defibrillation is less successful when CPR hasn't been performed [source: American College of Emergency Physicians].

CPR is helpful for those suffering from SCA, but does it pose any hazards to the person performing it? Check out the next section to learn more.

It's clear that CPR is an effective part of the emergency response to cardiac arrest and other emergencies -- one that could potentially save thousands of lives a year. Yet, in most cases, victims aren't getting this lifesaving treatment, even when bystanders are familiar with CPR.

Why won't people perform CPR on strangers? It turns out that most people are afraid of doing it incorrectly or inadvertently harming the victim further [source: Sayre, et. al]. Some people, however, may even fear they'll contract an infectious disease, if they perform CPR on a stranger. Even though there have been no documented cases of anyone catching a serious disease from performing CPR, the new recommendation of hands-only resuscitation offers an alternative that should help assuage any fears a person may have about the practice.

As we discussed, hands-only CPR focuses only on chest compressions. The mouth-to-mouth and mouth-to-nose components are left out. If you still have concerns about coming into contact with a bodily fluid like blood when performing CPR, you should keep a pair of latex gloves in your first aid kit.

Continue reading for more links to information on CPR and first aid.