Cardiopulmonary resuscitation (CPR) is carried out when a patient's heart stops or fails to supply enough oxygen and blood flow to the tissues of the body. Such patients have either just died or are very close to death. The goal of CPR is to attempt to bring the patient back to life. There are two types of CPR. The first, termed Basic Life Support (BLS), has two parts:
- Pressing on the patient's chest to help the heart pump blood to all the parts of the body. This is called chest compressions.
- Getting air into the lungs is done by someone giving mouth-to-mouth breathing or squeezing air into the lungs with a bag attached to a mask placed over the patient's face.
Basic Life Support is important in a patient whose heart stops inside or outside the hospital. When someone stops breathing or has no heart beat outside the hospital, by-standers can help save a patient's life if they begin Basic Life Support until paramedics arrive.
The second topic of CPR, Advanced Cardiac Life Support (ACLS), includes the steps in Basic Life Support and additional ways of restarting the heart. These include:
- The use of electrical shocks and/or medications to make the heart work again. Until the heart starts to work again, someone presses on the chest to pump blood to other parts of the body.
- Putting a tube into the patient's windpipe and then connecting the tube to a bag that has oxygen. The bag is squeezed to push oxygen into the lungs and from there the heart pumps the oxygen to other parts of the body. The tube in the windpipe is later attached to a mechanical ventilator if the patient's heart beat and blood pressure return (see Information Sheet on Mechanical Ventilation).
ACLS is carried out by health care professionals including emergency medical staff. A panel of national experts has decided the best way to do CPR and clinicians are trained in these approaches.
If CPR is started within a few minutes of the heart stopping, the patient can sometimes be returned to normal without serious damage to the brain and other organs of the body.
Patients who need CPR because their heart has stopped have low rates of survival, often around 10-20%. Usually patients and families have the mistaken idea that CPR is more successful than is actually true. Success in CPR is related to factors such as the patient's age (success is greater in young people), the number of medical problems the patient has, whether the patient is in or out of the hospital, and how quickly CPR is begun. Even when the heart beat is brought back, damage to some organs, such as the brain, may have already occurred depending on how long the heart had stopped. When a patient's heart stops outside the hospital, CPR has an even lower likelihood of success. When CPR brings back a normal heartbeat, if enough damage has been done to organs of the body the overall result is to prolong dying.
Another risk of CPR results from the emergency placement of the breathing tube. The tube sometimes damages the windpipe or the tube may be placed accidentally into the gullet or esophagus (the tube leading to the stomach).
When coming into the hospital, sick patients should be asked whether they want CPR in case their heart stops. If patients have not considered this issue, they can be given information to consider at the time of admission. This decision needs to take into account the risks and benefits described above. It is best if patients think about this choice before they get sick, and tell their wishes to loved ones and also produce a document which states these wishes (see Making Decisions About the End of Life). In this document, patients should say clearly whether they do not want CPR under any circumstances or they do not want CPR if the doctors believe that they have a condition that will lead to death in the near future. Limiting CPR does not mean that all other treatments will be withheld.
Doctors need time getting to know a patient's condition before being able to tell if a disease is "terminal", meaning that it will lead to death in the near future. What is thought to be terminal by some doctors may not be thought terminal by others, and so it is best to discuss these issues with doctors when you are well. Patients can change their mind at any time and have the right to do so. They should make any change or new wishes known to family and hospital staff. If a patient has left careful instructions in writing and made them known to family members, the family won't be faced with making difficult decisions on the patient's behalf at a later time.