Basic Facts

• In a cardiac arrest, the heart stops beating and a person will die if circulation is not restored within minutes.

• If you witness someone collapse with a cardiac arrest, you should call 911 and start CPR. Cardiopulmonary resuscitation, or CPR, will establish blood flow to the brain and other vital organs.

• In CPR the chest is compressed repetitively. Breathing into a person’s mouth is not needed.

• Cardiac arrest victims may gasp or have other breathing patterns. If the victim is unresponsive you must perform CPR.

• An automated external defibrillator (AED) is a device with patches placed on the skin that can detect the heart rhythm and deliver a shock if needed.

  It is critical to call 911 and to perform CPR until the arrival of emergency personnel.  The sooner CPR is commenced, the higher the chance that the person will survive.

A More Detailed Explanation

Cardiopulmonary resuscitation, or CPR, is an emergency procedure to keep a person alive who is suffering from a cardiac arrest, or “sudden cardiac death”. Cardiac arrest may be caused by ventricular fibrillation, a state where the heart’s electrical impulses are completely disorganized, and preventing the heart from performing any mechanical contraction. Emergency CPR can keep a patient alive until a defibrillator (AED) can be used to deliver an electrical shock to restore rhythm.

This ECG shows the onset of ventricular fibrillation.

The most important component of performing CPR is the use of   chest compressions. Mouth to mouth breathing is not needed if the cardiac arrest has been witnessed. You do not need to be trained to perform chest compressions  (see video – link when available for hands only-CPR). However, trained rescuers are also taught how to use an automated external defibrillator, or AED (see AED video – link when available) to shock the heart. You can attend a class (usually just a couple of hours) and learn how to use the AED device as well. Rescue breathing (also called mouth to mouth breathing) is not needed if the cardiac arrest is witnessed, but still recommended for unwitnessed cardiac arrest as well as for situations that involve suffocation, such as drowning.  Many organizations offer CPR classes, including the American Heart Association (AHA) and the American Red Cross. To find a local CPR class taught by the Red Cross, click here. With bystander CPR there is an approximate 50% likelihood that the victim will survive. Without bystander CPR, the likelihood of survival drops to about 5%. If you witness someone collapse in a cardiac arrest they may or may not complain of symptoms just beforehand, such as chest pain, shortness of breath or severe lightheadedness.

An automated external defibrillator (AED) is device that includes a computer and adhesive patches that can deliver an electrical shock.  When the patches are placed on the chest and the AED is turned on, the device will analyze the rhythm and determine if ventricular fibrillation is present, in which case the device will advise that the shock button be pressed.  (insert link for AED video when available). You will see AEDs in public places such as airports and sporting facilities.

ARE THERE PEOPLE WHO SHOULD NOT RECEIVE CPR?

Some patients who are at risk for cardiac arrest have decided in advance that they do not want CPR. Such people can have a written document from a physician that indicates that they do not want to have CPR (“Do Not Resuscitate”). Such patients will typically be elderly or severely ill.

To Administer CPR

Untrained rescuers:

Assess the Victim for Responsiveness

If the victim appears unconscious, firmly rub the chest and ask the person if he or she is all right in a loud voice to confirm unresponsiveness. It is very important to recognize that cardiac arrest victims may gasp or have other breathing patterns – you must still initiate CPR once you have determined that the victim is not responsive to either your voice or your rubbing the chest.

Call 911

 If the person is unresponsive, 911 should be called immediately. You should inform the 911 operator of the patient's location and provide a telephone number, if possible. You should request emergency medical assistance and state what is being done for the victim.

Start Hands-Only CPR

Kneeling beside the victim’s chest, place your hands, one on top of the other over the middle of the breastbone and compress the chest at a rate of 100 times a minute. Continue compressions until an AED becomes available or paramedics have arrived.

TRAINED RESCUERS:

The American Heart Association, AHA, sets the standards for CPR training, which includes the basic concepts of Airway, Breathing and Circulation. These steps are taught in CPR classes and include additional techniques including rescue breathing. Rescue breathing is not needed if the collapse of the victim is observed, but is acceptable if the rescuer is confident that they can perform rescue breathing in accordance to their training. Rescue breathing is still recommended, however, for  unwitnessed cardiac arrest victims, who are likely to have been in a cardiac arrest for a long time or for victims of suffocation such as drowning. A summary of each step follows, for trained rescuers.

Airway (trained rescuers)

The trained rescuer lifts the patient's chin or tilts back the head.  The trained rescuer then examines the chest to see if it is rising and falling to indicate breathing, listens for sounds of breathing and feels for exhaled breath on their own cheek.

As stated earlier in this document, do not mistake gasping as true breathing. Patients in a cardiac arrest may exhibit gasping and other abnormal breathing patterns, and must be given CPR.

Breathing (for trained rescuers)

If the victim is not breathing normally, the rescuer pinches the nose and breaths into the mouth of the victim two times.

Circulation (for all rescuers, trained and untrained)

To perform CPR, the rescuer pushes on the patient's sternum (middle of the breastbone about 100 times per minute. How fast is 100 times a minutes? Try singing to yourself the song “Staying Alive” by the BeeGees and you will have the rhythm down just right! Push hard and push fast.  Trained rescuers who are comfortable in giving rescue breathing can deliver two breaths for every 30 chest compressions. If you do not feel comfortable in delivering breaths or do not know how to do rescue breathing, it is only necessary to keep pressing on the chest at a 100 times a minute until the paramedics arrive.

Figure (click to enlarge). Call 9-1-1. Find the center of the chest and do forceful, fast compressions. Lift hands slightly off chest after each compression. Figure courtesy of Margaret Hartshorn, Biomedical Communications, The University of Arizona, Tucson.

With every chest compression blood will be delivered to the brain and organs.   Valves in the heart keep the blood moving forward and not backwards.

Automated External Defibrillator (AED)

In most public places, AEDs will be visible on the walls. If you see a victim of a cardiac arrest, get the AED and turn it on. The AED will then give voice directions that will include directing you to place the electrode patches on the chest and to press a button to allow the AED to analyze the rhythm. If a shock is indicated, the device will direct the rescuer to make sure no one is touching the victim and to press the shock button. After a shock you should resume CPR by delivering chest compressions, and checking for a pulse or return of responsiveness about every 2 minutes or until paramedics arrive. AEDs will also have electrodes for children under the age of 8; do not use pediatric patches on adults as they will be ineffective.

RECOVERY AFTER A CARDIAC ARREST

People who are resuscitated quickly from a cardiac arrest within one to two minutes may immediately regain consciousness. Others however who are successfully resuscitated from a longer cardiac arrest will need more intensive therapy, which may include the need for a breathing tube (ventilator) and medications to support the blood pressure. Other victims may suffer serious neurological injury from the lack of blood flow that the brain experienced during the arrest. For this reason it is especially important to emphasize the need for bystander CPR, even if the rescuer has not been trained.  In the hospital, cardiac arrest victims who are comatose may be cooled, a process called “hypothermia” for a period of time to minimize permanent injury to the brain. Victims brought to the hospital will also be assessed for the possibility that a heart attack from a clogged artery was the cause for the cardiac arrest. Cardiac arrest victims may also exhibit other problems during their recovery, including seizures, heart failure, low blood pressure, heart arrhythmias and problems with other organs such as kidney failure. CPR often can break ribs – but this is common when CPR is done correctly. CPR can also damage abdominal organs, particularly if pressure is applied too low on the sternum. A victim may also vomit during CPR or inhale stomach contents leading to pneumonia.

Sources

American Heart Association. Hands-Only (Compression-Only) Cardiopulmonary Resuscitation: A Call to Action for Bystander Response to Adults Who Experience Out-of-Hospital Sudden Cardiac Arrest: A Science Advisory for the Public from the American Heart Association Emergency Cardiovascular Care Committee. Accessed on July 16, 2008 at: http://circ.ahajournals.org/cgi/reprint/CIRCULATIONAHA.107.188486

American College of Emergency Physicians. Automatic External Defibrillators. Accessed on November 12, 2007 at http://www.acep.org/.

American Heart Association. 2005. American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular Care. Circulation112[Suppl]. Accessed on November 12, 2007 at http://circ.ahajournals.org/content/vol112/24_suppl/#INDEX.

American Heart Association. CPR Facts and Statistics. Accessed on November 12, 2007 at http://americanheart.org/presenter.jhtml?identifier= 3034352.

Bocka J. 2006. Automatic External Defibrillation. eMedicine. Accessed on November 12, 2007 at http://www.emedicine.com/emerg/topic698.htm.

Gersh BJ, ed. in chief. 2000. The Mayo Clinic Heart Book. New York: William Morrow and Company, Inc.