HealthWatch runs every other week as a regular Gazette feature where medical journalist Evra Taylor Levy and emergency physician Eddy Lang help make sense of sometimes contradictory medical research.

"He was only 45 years old, perfectly healthy, and died of a cardiac arrest." Many of us have heard this sad lament and wonder how this could occur. In fact, the phenomenon known as sudden cardiac death results from a malfunctioning heart rendered useless by a lethal arrhythmia. Tragically, this can be the first sign of heart disease in a significant number of otherwise healthy people.

Cardiopulmonary resuscitation, or CPR, is the well-known emergency medical technique used to temporarily restore the flow of oxygenated blood to the brain and heart in the event of a cardiac arrest. This edition of HealthWatch examines a new and simpler approach called hands-only CPR, which nearly anyone can attempt, trained or not, and offers the hope of reducing the tragic burden of sudden cardiac death.

Sudden cardiac death: a deadly mystery
In North America, cardiac arrest is a leading cause of death. Each year, approximately 40,000 Canadians succumb to sudden cardiac death, which the Heart and Stroke Foundation of Canada cites as "the most mysterious and deadly" of cardiac diseases.

Over 80 per cent of sudden cardiac deaths occur outside a hospital; the current odds of survival in these circumstances are only five per cent. Combined with immediate CPR, defibrillation - in which an electric shock is delivered to the heart to restore its normal rhythm - within three minutes can save 49 to 74 per cent of people who suffer a cardiac arrest.

Cardiac arrest is truly a life and death issue, and seconds count: With each passing minute, the probability of survival declines by seven to 10 per cent. Immediate CPR performed by a bystander is the greatest predictor of survival, increasing the likelihood of walking out of the hospital alive and with a normal brain almost fourfold. The title of the recently published scientific statement by the American Heart Association on this issue, A Call to Action, captures the urgency of educating the public on the importance of learning CPR techniques and what this latest development in CPR means.

What exactly does CPR do?
CPR maintains blood flow to the brain as well as in the coronary arteries that feed the heart.

This, in turn, makes the heart muscle more responsive to defibrillation, the primary means of terminating the fatal arrhythmia and restoring cardiac function.
As the name suggests, hands-only chest compressions are performed without the addition of mouth-to-mouth resuscitation, also known as rescue breathing. Conventional CPR, as opposed to the hands-only technique, involves 30 chest compressions for every two rescue breaths in adults.

Understanding low rates of bystander CPR
In Canada, the 2001-2002 rates for CPR performed by a bystander during a case of cardiac arrest range from 14 per cent in Ontario to roughly 25 per cent in metro Montreal, and as high as 46 per cent in Edmonton. These low rates have changed little over the years, despite the wide availability of CPR courses offered by a multitude of agencies. One of the major deterrents to the performance of traditional CPR has been the fear of locking lips with a complete stranger and the risk, which in reality is quite minuscule, of contracting a disease. Also, individuals who have taken CPR in years past might not recall the various steps required, and may lack confidence in their abilities and even fear harming the victim.

The publication:
Michael R. Sayre et al. 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. Circulation: published online before print, March 31, 2008.

Simplified CPR guidelines
Partly in response to dismally low rates of bystander-performed CPR, the American Heart Association has issued new CPR guidelines in the hopes of increasing survival from cardiac arrest. The Heart and Stroke Foundation, which sets CPR guidelines for Canada, has endorsed the association's new scientific statement that hands-only (meaning chest-compression only) CPR is a life-saving alternative that the lay public can more easily - and effectively - perform. Estimates suggest if the number of people willing to attempt CPR after a witnessed collapse is doubled, this would translate into thousands of lives saved annually in Canada.

Does hands-only CPR win hands down?
In most cases, yes. Four recent studies that have compared the streamlined version to the conventional technique have reported them as equivalent. While a small advantage may still exist with rescue breathing, the new thinking is that some CPR is better than no CPR at all. One caveat is that hands-only CPR should not be used for infants or children, for adults whose cardiac arrest is from respiratory causes (like drug overdose or near-drowning) or for an unwitnessed cardiac arrest. In those cases, the individual would benefit most from both chest compressions and breaths in conventional CPR, which is still an important skill to learn.
 
What should you do?
In the case of an adult who is observed collapsing suddenly, the American Heart Association recommends two simple steps. First, call 911 so that an ambulance team equipped with a defibrillator device can be dispatched. Second, lay the victim on their back and, while on your knees and with the palms of your overlapping hands (one on top of the other), start pressing into the centre of the chest just above the base of the rib cage to a depth of about five centimetres (two inches). Use about half of your body weight to lean into these chest compressions to avoid fatigue and maintain the cardiac output until help arrives. Pump hard and fast; the recommended rhythm of 100 pumps per minute roughly matches the beat of the Bee Gees' classic Stayin' Alive.
Effective administration of CPR in a cardiac emergency is one of the interventions virtually every layperson can perform for the heroic purpose of saving someone's life. The Heart and Stroke Foundation (514-871-1551) and St. John Ambulance (514-842-4801) conduct courses in CPR. Contact them for a course in your area.

Signs of cardiac arrest
A person may be experiencing a cardiac arrest when he or she is:
- Suddenly unresponsive, especially when called or tapped on the shoulder.
-Not breathing when you tilt the head back and check for at least five seconds.
Source: Heart and Stroke Foundation of Canada
 

 

© The Gazette (Montreal) 2008