CO2 and hydration

[lovethechaos]

Recently a fellow nurse told me that if someone's CO2 is low it means they are dehydrated. I had never heard this before and was wondering if any of you had, and if so, how the two are related.

[GilaRRT]

Venous CO2 (NOT ABG pCO2) = HCO3 (bicarb) if you don't believe then check out the normal value in chemistry panel for CO2 and HCO3 on ABG value (they are the same). Not sure why they ever named it CO2 since it really indicates HCO3 levels. This needs to be taught in more colleges for nurses since it is the ONE way without drawing an ABG to tell if someone is acidotic or alkalotic. This is SUPER important and one of the most important things I have EVER learned in my career. I think it's because of how the HCO3 is broken down, the end results is CO2 (carbonic break down).

LOW CO2 (since it is really bicarb which is alkalotic) means that the person is acidotic. A low venous CO2 can actually mean the person is dehydrated for SURE!

Every teacher across America should be teaching this! It is useful in every medical arena. This could potentially prevent a code from occurring on your shift. I go to codes (on code team) all day long and it is the #1 asked question by me, b/c their CO2 is many times low and they could have been calling it in to Dr's to get help before the code.

SO in chemistry panel:

Low CO2 --> ACIDOSIS (not enough bicarb in blood HCO3, could be sign of dehydration which is only 1 explanation of many).

ABG CO2 is different and is NOT same as venous CO2 from Chem/SMAC panel.

Bicarbonate is the conjugate base of carbonic acid. Around 80% of CO2 produced in the body will be turned into carbonic acid, hence the reason the venous bicarbonate is often associated with CO2.