How Does CPR Actually Work?

How Does CPR Actually Work? - A lifeguard pulls a drowning child from the ocean. An old man collapses in the street. A woman faints, not breathing. These are all situations that might call for CPR. CPR stands for Cardio Pulmonary Resuscitation, and the American Heart Association describes CPR as “an emergency lifesaving procedure performed when the heart stops beating”, which is a condition known as cardiac arrest.

CPR is typically done until an automated external defibrillator  can be applied and or trained medical professionals can provide assistance. There are some things you should do before you perform CPR. One of them is to make sure you and the person who might need CPR are in a safe area. You should also check to see if the person really needs help.

If the person is an adult, try asking if he or she is okay in a loud voice. You can also tap or shake the person. If the person does not respond, call 911. There are two common versions of CPR, the simplest one being called hands-only CPR and involves performing chest compressions after calling 911. You don’t need special training to do hands-only CPR, and the American Red Cross describes how to perform this type of CPR:

How Does CPR Actually Work

1. Kneel beside the person who needs help.
2. Place the heel of one hand on the center of the chest.
3. Place the heel of the other hand on top of the first hand, then lace your fingers together.
4. Position your body so that your shoulders are directly over your hands, and keep your arms straight.
5. Push hard, push fast. Use your body weight to help you administer compressions that are at least 2 inches deep and delivered at a rate of at least 100 compressions per minute. (Just be sure to let the chest rise completely between compressions).
6. Keep pushing. Continue hands-only CPR until you see obvious signs of life like breathing, another trained responder or EMS professional can take over, you're too exhausted to continue, an AED becomes available, or the scene becomes unsafe.

How do chest compressions help keep a person alive? When the heart stops beating, blood flow also stops, and this can be fatal because blood is how oxygen gets transported to the brain and other parts of the body. The Mayo Clinic explains it this way: “When the heart stops, the lack of oxygenated bloodcan cause brain damage in only a few minutes. A person may die within eight to 10 minutes”.

According to the Very well Health website, "compressing the chest moves blood through the brain, keeping it alive until the heart can get started again”. The second common version of CPR is called traditional CPR. It also involves performing chest compressions but adds two other actions that require some training: opening the airway and rescue breathing.

According to one of its fact sheets, the AHA “recommends CPR with compressions and breaths for infants and children and victims of drowning, drug overdose, or people who collapse due to breathing problems”. The purpose of opening the airway and giving rescue breaths is to provide air to someone who is not breathing or is having difficulty breathing.

It is a form of artificial respiration that helps to keep the body and brain from dying due to lack of oxygen. While many health professionals agree about the importance of chest compressions, they disagree about the value of rescue breaths. Very well Health describes rescue breathing as “one of the most controversial steps in CPR. ”

It adds that the “ debate is ongoing about how much is enough  and whether it's even necessary”. The American Red Cross provides some instructions about what to do before performing traditional CPR on an adult. It advises to “check the scene and the person”. Next, you should open the airway. To do this, the American Red Cross instructs you to “tilt the head back slightly to lift the chin” of the person while he or she is “lying on his or her back”.

After opening the airway, listen for breathing “for about 10 seconds”, and begin CPR if you don’t hear any breathing. In addition, the American Red Cross lists the following steps to perform traditional CPR on adults:

1. Push hard, push fast. 
Place your hands, one on top of the other, in the middle of the chest. Use your body weight to help you administer compressions that are at least 2 inches deep and delivered at a rate of at least 100 compressions per minute.

2. Deliver rescue breaths. 
With the person's head tilted back slightly and the chin lifted, pinch the nose shut andplace your mouth over the person's mouth to make a complete seal. Blow into the person's mouth to make the chest rise. Deliver two rescue breaths, then continue compressions. Note: If the chest does not rise with the initial rescue breath, re-tilt the head beforedelivering the second breath. If the chest doesn't rise with the second breath, the person may be choking. After each subsequent set of 30 chest compressions, and before attempting breaths, look for anobject and, if seen, remove it.

3. Continue CPR steps. 
Keep performing cycles of chest compressions and breathing until the person exhibits signs of life, such as breathing, an AED becomes available, or EMS or a trained medical responder arrives on scene. Note: The Mayo Clinic states that “thirty chest compressions followed by two rescue breaths is considered one cycle”.

Other sources such as the AHA also recommend “using chest compressions and mouth-to-mouth breathing at a ratio of 30:2 compressions-to-breaths” in traditional CPR. There are some differences in the steps you take to perform CPR on a child or an infant. For example, the procedure for checking if the child or infant really needs help is not the same as the one used for an adult. Tap or shake a child more gently than you would an adult.

However, do not shake an infant. The National CPR Association warns that you should “never shake an infant as this may cause brain damage”. Instead, the American Red Cross advises you to “flick the bottom of the foot to elicit a response”. The American Red Cross also offers different advice about when to call 911. You can “ask a bystander to call 911, then administer approximately 2 minutes of care”. However, “if you're alone with the child or infant, administer 2 minutes of care, then call 911”. The “care” involves the following steps:

1. Open the airway. With the child lying on his or her back, tilt the head back slightly and lift the chin.
2. Check for breathing. Listen carefully, for no more than 10 seconds, for sounds of breathing.
3. Deliver 2 rescue breaths if the child or infant isn't breathing. With the head tilted back slightly and the chin lifted, pinch the child's nose shut,make a complete seal by placing your mouth over the child's mouth and breathe into the child's mouth twice. For infants, use your mouth to make a complete seal over the infant's mouth and nose, then blow in for one second to make the chest clearly rise. Now, deliver two rescue breaths.
4. If the child or infant is responsive, you should still call 911 in order to “report any life-threatening conditions and obtain consent to give care”.
5. If the child or baby is unresponsive to the rescue breaths, begin CPR.

Here are the steps to perform child and infant CPR provided by the American Red Cross:

1. Kneel beside the child or baby.
2. Push hard, push fast. For children, place the heel of one hand on the center of the chest, then place the heel of the other hand on top of the first hand, and lace your fingers together. Deliver 30 quick compressions that are each about 2 inches deep. For infants, use 2 fingers to deliver 30 quick compressions that are each about 1.5 inches deep.
3. Give 2 rescue breaths.
4. Keep going. Continue these baby or child CPR steps until you see obvious signs of life, like breathing, or until an AED is ready to use, another trained responder or EMS professional is available to take over, you're too exhausted to continue, or the scene becomes unsafe.

Modern CPR was created in 1960 as the joint effort of several doctors and researchers. According to Baylor College of Medicine Professor William L. Winters, two anesthesiologists at Johns Hopkins Hospital, Peter Safar and James Elam, came up with an “emergency ventilation technique that involved tipping the victim’s head back and pulling the jaw forward in order to clear the air passage and then blowing air into the victim’s lungs through a mouth-to-mouth connection”.

The AHA states that Dr. Elam and Dr. Safar were able to “prove that mouth-to-mouth resuscitation is an effective lifesaving method” in 1956, and they and another doctor named Archer Gordon promoted its use. In a JAMA article published in 1960, an electrical engineer named William B. Kouwenhoven and his colleagues James Jude and Guy Knickerbocker presented the concept of “closed-chest cardiac massage” which was a “method of restoring circulation in a heart-attack victim by pushing down rhythmically on the sternum”.

Winters states that the “combination of Kouwenhoven’s technique with Safar’s ventilation technique evolved into the basic method of CPR. ”In 1960, the AHA began a program that became the “forerunner of CPR training for the general public”. Hands-only CPR is a more recent development. Winters states it emerged from research conducted at the University of Arizona Sarver Heart Center in the mid-1990s.

This research led to the discovery that “continual chest presses kept blood circulating in adult victims of cardiac arrest better than conventional CPR techniques”. Hands-only CPR for adults was adopted by the AHA in 2008. Would you perform CPR on someone who needs it? Why or why not? Let us know in the comments.