Does supplemental oxygen help with a heart attack?

Your question:  The ACLS protocol recommends giving any patient with chest pain or a suspected (or actual) heart attack 2-4lpm of oxygen to ease the oxygen demands of the heart.  If the oxygen saturation is already 96 percent or greater, what use is this suplemental oxygen?  Or is it a simple waste of money?

My humble answer:  This is a great question.  If the patient's spo2 (oxygen saturation) is already 96 percent or greater, that means the blood has an ample supply of oxygen, and the tissues have an ample supply of oxygen.  To put it in simple terms, if 100 percent of hemoglobin are carrying an oxygen molecule, then there are no more empty trains in the station.  Every seat is occupied.  You can put all the oxygen molecules you want into that person's lungs, it will have no place to go but back out into the atmosphere.  So supplemental oxygen in this case is frivolous and a waste of money.  I agree with you.

Yet some will say that even if the oxygen saturation is normal the patient's heart might have infarcted and is not getting good oxygen supply.  Yet with a sat of 96 percent on room air, you know this was not caused as a result of hypoxia (lack of oxygen to the tissues).  It was caused by a blockage in the heart.  You can add all the supplemental oxygen you want, no oxygen is going to get past the blockage.  So, once again, we have shown that you are right and that supplemental oxygen will not benefit the patient in this case.

However, if the heart attack was caused by lack of oxygen in the blood that results in tissue hypoxia, then definitely supplemental oxygen is essential.  Yet so long as you have a good oxygen saturation (or more specifically, a healthy PO2), there is no added benefit to supplemental oxygen.

So pretty much the only reason for giving supplemental oxygen is so you can say you used it in the case of a malpractice suit.  If we got rid of malpractice suits doctors could spare the supplemental oxygen and save a billion dollars a year on just that alone. 

However, medical schools have taught for years that people with chest pain must have oxygen.  This is a myth that may take a while to rid the medical industry of even thought the ACLS recommends not placing ANY patient on supplemental oxygen who has an SpO2 94% or greater.  

Last fall the instructor told our class this, and one old-time doctor said, "I'm still going to put my patient's with chest pain on oxygen, it only makes sense."  The ACLS instructor said, "Not if Medicaid doesn't pay for it you won't."  This is one of the few times Medicaid got something right and the doctors are wrong.

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