CPR Expectations and Reality

Every 12 minutes, someone in this country goes in to cardiac arrest. That's nearly 40,000 Canadians. Their survival often depends on bystanders who know cardiopulmonary resuscitation or CPR.  New CPR guidelines came in to effect in 2010. But according a  study just published in the Canadian Medical Association Journal (behind a paywall), those guidelines might be doing more harm than good. 

Under previous guidelines on CPR, non-medical bystanders - the vast majority of people who do the CPR - were taught to perform chest compressions AND rescue breathing.  The  2010 guidelines on CPR eliminated rescue breathing.  In other words, bystanders were taught to just do chest compressions and ignore the victim's airway. Doctors from Kingston General Hospital and from Hong Kong say the change was premature and potentially hazardous to the survival of people who suffer cardiac arrest.

 

The doctors who wrote the article in CMAJ looked at the evidence behind the changes and concluded that it was biased. Studies that showed that rescue breathing offered no added benefit looked only at cardiac arrests in big hospitals and in big cities with quick paramedic response times. These are situations in which rescue breathing is moot because patients get placed on a ventilator quickly. Studies of cardiac arrest in rural areas with longer response times showed that rescue breathing improved survival substantially.  

As well, the doctors argued that all cardiac arrests should not be treated the same.  Heart stoppages may be due to heart problems such as blocked coronary arteries and valve problems.  But cardiac arrests may also be caused by strokes, kidney and lung problems, and cancer. 

If, for example, the patient has a cardiac arrest from a non-cardiac cause such as drowning - that includes many kids - then rescue breathing improves survival.  The authors' conclusion: if the bystander doesn't want to do mouth to mouth, just tilting the victim's head and lifting the jaw will increase the amount of oxygen the victim receives and increases the chance of being saved.  As the authors concluded, with an average survival rate from cardiac arrest of just fourteen percent, anything that improves survival should not be discarded.

The public may be astonished to learn that  studies show the success rate from CPR is as low as 14%. The main reason is that both CPR and defibrillators that shock the heart back into normal rhythm are used in situations in which the chance of success is almost zero. Back in the fifties and early sixties, both CPR and defibrillators were developed to restart the hearts of patients undergoing coronary bypass and other forms of open-heart surgery. These are patients who have witnessed cardiac arrests with all the equipment and personnel on hand to save them. Used  in these sorts of situations, CPR and defibrillators were very successful.  They also have high success rates when someone has a witnessed cardiac arrest at a hockey rink or a casino and there's a defibrillator you can grab off a wall.

Ironically, CPR is least effective when used in hospitalized patients with heart failure, cancer, chronic obstructive pulmonary disease and other serious chronic conditions.  But use it we do because under most ethical codes, we have to try CPR unless the patient or the family signs a form that says "Do Not Attempt Resuscitation."

Patients admitted to hospital and their families are given a realistic picture - that 40% of hospitalized patients who get CPR get their heart going again, but only 10-20% survive long enough to go home.  Despite that,  a recent study found 81% of older people believed they had a better than fifty-fifty chance of going home; 25% believed the odds were greater than ninety percent.  Some think the fault lies with Hollywood.  A  famous study published nearly 20 years ago found that TV series back then showed success rates of 67% - much better odds than reality.  More recent shows like Grey's Anatomy are more accurate.  But  a recent article in the New York Times in the New York Times argues that TV patients tend to be younger than in real life.  And the results on TV are too pat.  TV patients either make a full recovery or die.  But in real life, they might linger in a vegetative state for months and even years. Or, they might have one horrible complication after another. You don't see that on TV.

Fixing misconceptions begins with informing the public. You may recall  the public service ad campaign that taught the public to perform CPR to the beat of Stayin' Alive by the Bee Gees.  Maybe it's time to have a campaign that informs the publics when CPR is likely to be successful and when it isn't.  I think everyone should seek out accurate information from their doctor, the Heart and Stroke Foundation and other reputable sources on survival rates from CPR.  

It would be ideal if everyone thought about whether they want CPR or not when the time comes, but my sense is that many people would rather not think about that, which is too bad in my opinion.

Dr. Brian Goldman is an ER physician and host of White Coat, Black Art, which returns with new episodes this fall.  His latest book The Secret Language of Doctors is published by HarperCollins Canada.