Cardiopulmonary resuscitation (CPR) refers to a group of procedures that may include artificial respiration and intubation to support or restore breathing, chest compressions or the use of electrical stimulation, or medication to support or restore heart function. CPR can either replace the normal functioning of the heart and lungs or stimulate them to begin working again. The public as well as health care professionals vastly overrate CPR's overall effectiveness.

• CPR is given when a person stops breathing (respiratory arrest) or the heart stops beating (cardiac arrest).
• CPR's success rate depends heavily upon how quickly it is started after the arrest andthe person's underlying medical condition. CPR was developed to treat people who have an unexpected arrest due to a heart attack, an adverse reaction to anesthesia, a drug overdose, or an accident like drowning or electrocution. It was never intended for seriously ill people.
• CPR has a small chance of working for people who are seriously ill or dying. One study shows that individuals with overwhelming infection have less than a 3 percent chance of being discharged from a hospital after CPR; those with advanced cancer that has spread to other parts of the body have virtually no chance.
• According to the medical literature, the chance of surviving CPR is, at best, 18 percent.
• This reality is not at all what is portrayed on television. A 1996 study of 97 episodes of “ER,” “Chicago Hope,” and “Rescue 911” in which CPR was depicted showed 75 percent surviving in the short term and 67 percent surviving in the long term.
• The public seriously overestimates CPR's effectiveness. A survey that included health care workers found that those who were over 65 years old predicted a 59 percent survival rate for a person treated with CPR. People under 30 were even more optimistic, predicting a 75 percent survival rate.
• Even more troubling, the surveyors found, was that those who had medical training estimated CPR's effectiveness at 75 percent! In an effort to understand why this would be so, the authors examined a standard text used to train health care workers and found only a brief acknowledgement that CPR was unlikely to be effective. The handbook that the Red Cross uses to teach its CPR classes to the public did not confront the issue of low CPR success at all.
• If people understood how poor the chances of surviving CPR really are, many patients or their proxies might choose not to have it. One study, of people over the age of 60, found that 41 percent wanted CPR if they had cardiac arrest during an acute illness. When the real likelihood of success was explained to them, only 10 percent wanted it.
• CPR must be started as quickly as possible to have any chance of success. Otherwise the brain's blood supply is cut off and serious brain damage occurs, even if the patient survives.
• Despite the poor real-life odds, CPR normally is provided to every patient who has a cardiac or respiratory arrest unless there is a “do not resuscitate” (DNR) order in place or unless the patient has clearly been dead for some time.
• A DNR order is a physician's written order that instructs other healthcare workers not to attempt resuscitation. If this order is not written, it is assumed that CPR is wanted, no matter what the condition of the patient.
• A patient, family member or health care agent can ask that a DNR be written, but they cannot write it themselves. A person can say in a living will that CPR is not wanted, but this will not stop CPR until the doctor has written the order.
• Emergency medical personnel must start CPR if they are called when someone has had or is having cardiac or respiratory arrest. Unwanted CPR can be avoided if the patient has a “non-hospital DNR” order at home. Emergency personnel cannot honor an advance directive (living will or medical power of attorney).
• A non-hospital DNR order is a physician's order not to attempt CPR. This order can protect seriously ill or dying individuals who are being cared for at home from unwanted resuscitation. While not every state has provided for such orders, many have created statutes or regulations permitting them. These laws and regulations vary from state to state.
• A DNR order is not a “do-not-treat” order. A patient should continue to receive any other treatments that are desired.

Editor's Note: This article was originally published on www.lastacts.org, the Web site for Last Acts, formerly a national program of the Robert Wood Johnson Foundation. Be advised that the content of this article might be dated or inaccurate. The Foundation is reprinting the article here as a matter of general and historical interest.