Take-home message:
-A variety of internet posts and e-mail chains have said that when you have symptoms of a heart attack, you should cough vigorously to essentially perform CPR on yourself.
-This idea makes no sense because CPR should only be performed on an unconscious person with no pulse. If you are conscious and can cough, you should not perform CPR.
A friend of mine recently asked me to debunk something they saw on the Internet. It was a facebook post that advised people who were having a heart attack to start coughing strenuously and repeatedly in order to perform CPR on themselves. This idea, known as cough CPR, is not new and seems to go back to a series of mass e-mails back in 1999.
The post usually goes something like this:
How to survive a heart attack when alone
Cough repeatedly and vigorously. A deep breath should be taken before each cough and the cough must be deep and prolonged as when producing sputum from deep inside the chest. The cough should be repeated every 2 seconds until help arrives. Deep breaths gets oxygen into the lungs and cough squeezes the heart and keeps the blood moving.
There are several problems with this idea and it is worth noting that neither the American Heart Association nor the British Heart Foundation recommend it. The British Heart Foundation goes so far as to say “Please avoid spreading this myth any further.” In the end, cough CPR though doesn’t quite make sense for several reasons.
Firstly, you would not perform CPR on someone who is conscious. Anyone who has taken a first aid course will tell you, that you only perform CPR on someone who is unconscious and does not have a pulse. Essentially, a person with no pulse is a person whose heart is not beating. When your heart stops beating, blood no longer flows towards your brain and you lose consciousness. After a few minutes without blood flow and oxygen, brain tissue starts to die. After a critical threshold the damage becomes too severe and extensive for life to continue. The goal of CPR is to provide chest compressions that squeeze the heart and push some blood into the rest of the body, thus providing some oxygen to the brain and forestalling any tissue damage. However, contrary to popular belief (and what is often seen in movies) CPR will not revive someone who is unconscious. Its goal is to minimize brain damage until help can arrive.
Once we understand the purpose of CPR, we can see why the so-called “cough CPR” is somewhat of a paradox. If you are unconscious and need CPR, you cannot cough because you are unconscious. If you are conscious and can cough, then you do not need CPR.
Also, it is somewhat doubtful that coughing, in and of itself, could generate enough pressure on the heart to pump a meaningful amount of blood into the body’s circulation. Most people underestimate the amount of pressure that must be applied when performing the chest compressions of CPR. If the correct amount of force is applied with each compression, you are actually very likely to crack someone’s ribs. The amount of force required for adequate CPR is quite large and it seems unlikely that coughing could generate that kind of pressure.
Finally, the Facebook post about “cough CPR” recommended that people cough and take a deep breath every two seconds. The rationale is that deep breaths get more oxygen into your lungs and then into your bloodstream. This is not actually true. Breathing more deeply and rapidly does not bring more oxygen into your blood; it only allows you to blow off more carbon dioxide. In fact, if you started breathing rapidly in that way and taking a breath every 2 seconds, you would essentially be hyperventilating. When you hyperventilate, you lower the carbon dioxide in your blood, and eventually faint as a consequence. Incidentally, the main way to improve the oxygen levels in your blood is to breathe in air that has a higher percentage of oxygen, which you can only do if you are hooked up to an oxygen tank.
The notion of “cough CPR” does not hold up to scrutiny because much of the physiology is wrong. If you are still conscious you do not need it, if you needed it you would not be conscious, if you did it, it probably would not help, and if you tried it you would probably just hyperventilate and faint.
The public would be best served by deleting any e-mails or Facebook posts surrounding this issue. Learning real CPR would be far more useful, because being trained in first aid and emergency management can potentially save a life. Coughing when you have a heart attack will not.
For those who want to delve deeper into the issue of CPR
Since CPR will not actually bring someone back if they have a cardiac arrest, you might be tempted to ask what will? The one intervention that will actually help is an automated external defibrillator (AED). If you have ever watched a medical show on TV where someone yells “Clear !” and shocks a patient, then AED is basically accomplishing the same thing.
Most patients who suffer a sudden cardiac arrest are actually experiencing a fatal type of arrhythmia that stops their heart from beating. An AED, when attached to a patient’s chest, can analyze their heart rhythm and will automatically deliver a shock to treat the arrhythmia. If done quickly, it can save a patient’s life and might lead to them regaining consciousness (although they should still go to the hospital). AED’s are very easy to use. All a person has to do is turn it on and attach the pads to a person’s chest. The machine will actually do the rest.
CPR is a valuable skill to have and learning first aid is something that everyone should do at some point in their lives. However, the two most important things to do if someone has a cardiac arrest is firstly to call 911 and then to get an AED if one is available. AED’s are much more available now then they were even 5 years ago, however there are still many public locations that do not have one. If your local community centre, gym, or arena does not have an AED on-site, perhaps you should suggest they get one and then encourage everyone to become familiar with its use.
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