CPR Facts vs. Fiction
According to fact sheets issued by the American Heart Association, cardiopulmonary resuscitation (CPR) performed by bystanders before the arrival of emergency personnel can double a cardiac arrest victim's chance of survival. This statistic is indeed true. However, these fact sheets rarely mention that the doubling is from a 2% chance of survival to a 4% chance of survival.
While CPR is unarguably a lifesaver for a few lucky individuals, surveys show that the general public grossly overestimates the effectiveness of the procedure. This misperception can lead to unrealistic expectations when a CPR-trained individual has to actually use the technique on a loved one, colleague, or stranger. This could be quite traumatic for the responder in the statistically likely event that the patient does not survive.
How Fast is 100 Beats Per Minute?
What Is CPR?
Cardiopulmonary resuscitation (CPR) is an emergency medical procedure used to provide circulation to the brain and vital organs in the event of cardiac arrest. The technique has been designed so it can be used by laypersons without a professional medical degree, and can be learned in a brief first aid training course.
The technique consists of a regimen of chest compressions at a rate of 100 beats per minute, punctuated by artificial mouth-to-mouth respiration. The purpose of the technique is not to revive an unresponsive patient or re-start the heart, but to keep oxygenated blood flowing to the brain and organs long enough for professional medical assistance to arrive.
While current guidelines still recommend artificial respiration, recent studies have shown that in most cases it does not significantly improve the patient's prognosis. This fact itself may be of some comfort to trained individuals who find themselves a bit squeamish over the mouth-to-mouth element of CPR. Some studies even suggest that dropping this recommendation would make it more likely that CPR will be used.
While CPR does seem to improve the patient's short-term outcome, the longer-term prognosis is usually pretty grim. About 40% of patients receiving CPR from a bystander will have their heart begin working again, versus only 15% who do not receive CPR before medical personnel arrive. However, only 4% of those receiving bystander CPR will survive long enough to be discharged from the hospital. While this is certainly better than the 2% survival rate among those who do not receive CPR, it is still a rather low number.
The survival rates are particularly low in comparison with public expectations. Among the general public, the perceived survival rate of patients receiving CPR is about 75%. This perception is true even among the segment of the public that has received CPR training. Television shares some of the blame for this misperception. A study from the late 1990s, when shows like ER were popular, found that CPR was effective about 75% of the time when it was depicted on TV.
Why Bother Learning CPR, Then?
Although the success rate of cardiopulmonary resuscitation is tragically low, there are still some benefits to learning and using CPR. When coupled with training in Automated External Defibrillators (AEDs) - now widely available in public places - individuals can learn some valuable skills that really could save a life.
For those patients who do survive to discharge, bystander CPR can prevent permanent brain damage. Four minutes without oxygen can cause damage to brain tissue, and after seven minutes the damage becomes irreversible. Maintaining circulation of blood to brain tissue, even without artificial respiration, can improve the patient's chances of making a full recovery if they survive.
Cardiopulmonary resuscitation is often touted as a life-saving technique. While this is true in some isolated cases, it is perhaps more accurate to describe it as a death-delaying technique - putting off permanent tissue damage long enough for professional responders to arrive. Those receiving CPR training or considering taking a CPR course should do so knowing the true odds of survival, rather than developing unrealistic expectations.
Sources and Further Information
- CPR Statistics - American Heart Association
Anyone can learn CPR – and everyone should! Sadly, 70 percent of Americans may feel helpless to act during a cardiac emergency because they either do not know how to administer CPR or their training has significantly lapsed.
- Effectiveness of Bystander-Initiated Cardiac-Only Resuscitation for Patients With Out-of-Hospital Ca
Bystander-initiated cardiac-only resuscitation and conventional CPR are similarly effective for most adult out-of-hospital cardiac arrests. For very prolonged cardiac arrests, the addition of rescue breathing may be of some help.
- Cardiopulmonary Resuscitation on Television - Miracles and Misinformation
Television is an important source of information about CPR for patients. We analyzed how three popular television programs depict CPR.
- Public Expectations of Survival Following Cardiopulmonary Resuscitation - Jones - 2008 - Academic Em
The vast majority of people surveyed overestimated the chances of survival following CPR. It appears that, regardless of the source, the public is not receiving accurate information about the effectiveness of CPR.