Fluids and Electrolytes

shrimpchips, LPN · Feb 16, 2009

Okay, so I'm still learning here. A good mnemonic to learn about metabolic acid/alkalosis and respiratory acid/alkalosis is ROME:

Respiratory Opposite

^ pH, decreased pCO2 = alkalosis

decreased pH, ^ pCO2 = acidosis

Metabolic Equal

^ pH, ^ HCO3 = alkalosis

decreased pH, decreased HCO3 = acidosis.

For the first one, the pH is 7.31 (low) and you also mentioned that the HCO3 is 20 (low) so I would say that is metabolic acidosis. For the second one, the pH is 7.47 (high) and pCO2 33 (low), and I would asy that is respiratory alkalosis.

To my understanding, I thought compensation is when the pH is normal but the pCO2 and HCO3 values are abnormal.

But then again, I'm just learning. I hope I got this right lol

Daytonite, BSN, RN · Feb 16, 2009

there is a specific sequence to reading and analyzing abgs. (1) look at the ph to determine acid or base. this will also tell you if there is compensation. compensation is only occurring if ph is in the normal range and the co2 and/or the hco3 are abnormal. (2) look at the co2. this is the respiratory factor. if it is abnormal you have a respiratory situation going on with the acid/base problem and you need to look no further. if the co2 is normal, move on. (3) look at the hco3. this is the metabolic factor. if it is abnormal you have a metabolic situation going on with the acid/base problem. note: the o2 is not a factor in analyzing abgs.

baby #1 is metabolic acidosis

ph is 7.31 (low) - this is acidosis

paco2 is normal - this is normal so move on to the hco3 and see what it is doing

pao2 101 (high)

bicarbonate 20 (low) - this indicates a metabolic problem

baby #2 is respiratory alkalosis

ph is 7.47 (high) - this is alkalosis

paco2 33 (low) - stop here. this indicates a respiratory problem.

pao2 102 (high)

bicarbonate normal

there is no compensation going on here. if there is compensation the ph normalizes and stays between a normal level of 7.35 - 7.45. that is not happening with either of these two abg results.

there are tutorials that explain reading abgs and some websites with practice problems on post #45 of this sticky thread in nursing student assistance forum https://allnurses.com/nursing-student-assistance/pathophysiology-p-microbiology-145201.html - pathophysiology/ a & p/ microbiology/ fluid & electrolyte resources

melmarie23, MSN, RN · Feb 16, 2009

I just took my quiz on electrolytes (a 92!), and I have nothing substantial to add because as always, Daytonite summed it up beautifully.

I had to look over this quite a few times to understand it, but I promise that you will get it. Good luck with everything!

elprup, BSN, RN · Feb 17, 2009

I agree with the ROME idea!!

"R" Respiratory are "O" Opposite. "M" Metabolic are "E" Equal.

Normals = Ph 7.35-7.45, PCo2 35-45 (see the same 35-45), PO2 80-100, HCO3 22-26

So, for Respiratory, it states they are OPPOSITE.

So, Respiratory Acidosis = Ph 45 b/c the 's are opposite.

So, Respiratory Alkalosis= Ph >7.45, w/ PCO2

Now for Metabolic, the ROME mnuemonic, tells us that anything Metabolic is EQUAL.

So, Metabolic Acidosis = Ph

So, Metabolic Alkalosis= Ph>7.45 w/ HCO3>26, once again the same

As long as I remembered that anything acidosis was any Ph 7.45,just remember ROME and it's a breeze.

You'll also need to look at the PO2 to see if pt is hypoxic ,80

good luck.

MrsIndependent · Feb 17, 2009

Question: Are fluids & electrolytes something that is learned is A&P or in actually Nursing School? I remember this section being in my A&P book but we never covered it. Is this something that I am expected to know once I start NS?

shrimpchips, LPN · Feb 17, 2009

Question: Are fluids & electrolytes something that is learned is A&P or in actually Nursing School? I remember this section being in my A&P book but we never covered it. Is this something that I am expected to know once I start NS?

We covered acid/base balance in A&P, which is actually what this thread is addressing. Fluids & electrolytes deal with the ions (Na+, Cl-, Ca++, etc etc etc) and I didn't start learning about this until nursing school.

shygoofyone · Feb 20, 2009

I'm going to try to make this make sense on here, but it may be hard. We learned by a "tic-tac-toe" method....you draw a box with three columns, labeled "Acid-Normal-Alkaline"...and three rows labeled "ph, HCO3 and CO2".

Write down your normals ranges like this:

PH 7.35-7.45

HCO3 20-26

CO2 45-35 (make it the opposite so that you're acidic values are aligned...really helps!)

Then, you fill in your grid based on the given values:

________ACID____NML____ALK

PH_____________________7.47

HCO3 ___________nml

CO2 _____________________33

Draw your tic-tac-toe with the ph, CO2 and column heading. Since your ph and CO2 are aligned under Alkaline, you have respiratory alkalosis. It is not compensated, because the HCO3 is normal, rather than being acidic to help balance out the ph.

We use this during exams all the time. :) Good luck!

Daytonite, BSN, RN · Feb 20, 2009

I'm going to try to make this make sense on here, but it may be hard. We learned by a "tic-tac-toe" method....you draw a box with three columns, labeled "Acid-Normal-Alkaline"...and three rows labeled "ph, HCO3 and CO2".
Write down your normals ranges like this:
PH 7.35-7.45
HCO3 20-26
CO2 45-35 (make it the opposite so that you're acidic values are aligned...really helps!)
Then, you fill in your grid based on the given values:
________ACID____NML____ALK
PH_____________________7.47
HCO3 ___________nml
CO2 _____________________33
Draw your tic-tac-toe with the ph, CO2 and column heading. Since your ph and CO2 are aligned under Alkaline, you have respiratory alkalosis. It is not compensated, because the HCO3 is normal, rather than being acidic to help balance out the ph.
We use this during exams all the time. :) Good luck!

The links on how to do this are also on the post of the sticky thread I listed above.