Why C - P - R works

Why CPR/Rescue Breathing Works

Many of us are trained to do CPR and use mouth-to-mouth rescue breathing to resuscitate someone who has stopped breathing.  At first it seems to make sense, because the objective is to oxygenate the brain and vital organs by supplying air to the lungs while pumping the blood around.  Wait a minute; you are supplying air that has already been depleted of oxygen because you have already breathed it in before giving it to the victim.

Ambient air contains approximately 20.5% oxygen.  The average human being only takes part of that oxygen from each breath.  Actually our exhaled breath contains approximately 16% oxygen—coincidentally, or not, the stated minimum atmospheric concentration required to sustain life.  This subject is not as simple as putting air in a tire, depending on condition of the lungs, partial-pressure factors and the like; however, generally speaking, our exhaled breath is capable of supplying enough oxygen to maintain brain function and that of other vital organs.

As an enrichment exercise so you can impress your friends and families, maybe win a few dollars on a bet, I offer the following explanation of WHY we need oxygen at all.

Basically producers (plants) capture the sun’s energy and trap it in the form of glucose.  Whether it is converted to starch by the plants, eaten by cattle and turned into fat or protein, or into another form of sugar such as fructose, our bodies must break it down to glucose again (digestion) before that solar energy can once again be released in our bodies to do “stuff.”

When the carbohydrate (glucose—made up of carbon, oxygen, and hydrogen) is broken down, the carbon and the oxygen are released as carbon dioxide (what you exhale) the hydrogen  is running around with this electron—whining and crying like a …well whining and crying.  Enter captain oxygen (what you inhaled) to save the day.  “I’ll take that electron and you and I can form water,” says the oxygen (yes, the one you inhaled).  It takes a lot for the hydrogen to hang on to that electron, not so much for oxygen. 

What happens to that extra energy when hydrogen lets go of the electron?   That is what your body uses to do stuff!

What if you don’t have enough oxygen, can you say “lactic acid,” how about “sore muscles.”