ABG's

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can anyone offer some advise on how to keep the abg's staight in your head and how to tell what is resp. alkalosis or acidosis?

thank you for your response!

Specializes in LTC.
OK, I don't have the thing from my instructor. Wish I did, it was really good.

BUT, I did find something in one of my books that is kinda like what she put out.

pH low = Acidosis

pH high = Alkalosis

(duh)

Now determine if its resp or met.

Look at PaCO2

If its respiratory, PaCO2 will be high or low inversely to pH (High PaCO2, low pH)

If its metabloic, PaCO2 will be normal

(This obviously doesn't account for compensation but you get the idea)

Now look at Hco3

Normal limits = respiratory

High = suspect met alk

Low = suspect met acid

BE will be normal for resp, low for met acid, high for met alk

But wait, all you need is the normal values??

well she said that but then she said there will be question about resp alk and resp acidosis and metabolic so i am assuming we are going to need know what is going on if it its high or low...

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Specializes in Nursing Assistant/ Army Medic, LVN.

Oh ok so you're not too far into this ABG thing yet. Sounds like your questions will be pretty straight forward.

Trust me, if you know the normal values and how they affect pH, you'll be just fine. All they want to know is if you can recognize which value is out of whack. Don't sweat this!

pH = 7.35-7.45

PaCO2 = 35-45 (Easy to remember, just take out the 7 from pH)

HCO3 = 22-26

Don't worry about comensated vs. uncompensated and all that other stuff, I doubt that'll be addressed in the exam. Just know what makes pH high or low. Too easy

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Specializes in Nursing Assistant/ Army Medic, LVN.

I don't want you to get ahead of yourself here but I've been having some fun on this and I thought I'd share. Its a practice exam thing and I think it might help you understand what is what and how things work a bit.

Its cool because it briefly explains why you were right or wrong.

If you have to, jot down the normal values and refer to them when you do this. The more you look at and apply the normal values to these questions, the more you'll remember and the easier it will be to make sense of it.

Well it works for me so I hope it works for you too.

Check this out:

http://www.vectors.cx/med/apps/abg.cgi

If you don't get the compensation part right don't sweat it or even worry about it. If all you need to do is recognize the primary mechanism, then just focus on that. Take the rest of it as you feel comfortable.

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An easy way to remember is using the acronym ROME.

R - Respiratory

O - Opposite

M - Metabolic

E - Equal

Meaning,

Resp. Acidosis (opposite - both 'arrows' going in the opposite direction)

pH

PCo2 > 45

Resp Alkalosis

pH > 7.45

PCo2

Met Acidosis (equal - both "arrows" going in same direction)

pH

HCo3 (bicarb)

Met Alkalosis

pH > 7.45

HCo3 > 26

Normal Lab Values:

pH - 7.35-7.45

PCo2 - 35-45

HCo3 - 22-26

And, remember PCo2 deals with respiratory and HCo3 (bicarb) deals with metabolic.

Hope this helps!

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CO2 is going to point towards respiratory, since that is where the body throws off it's excess carbon dioxide. An imbalance in the bicarb is going to point to metabolic.

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Specializes in med/surg, telemetry, IV therapy, mgmt.

there are weblinks on how to do abg analysis 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. please read them. they do a better job of explaining this than we can. i think this "cheat sheet" another student posted explains abg analysis best:

three elements are needed to analyze abgs and determine respiratory or metabolic acidosis/alkalosis or whether or not there is compensation:

  • ph - this determines if you have acidosis, alkalosis or compensation
  • the co2 (carbon dioxide) - this is the respiratory factor
  • the hco3 (bicarb) - this is the metabolic factor

several of the links that are listed explain the step-by-step analysis process and a number of the weblinks have practice abgs to analyze with the answers.

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Specializes in LTC.
an easy way to remember is using the acronym rome.

r - respiratory

o - opposite

m - metabolic

e - equal

meaning,

resp. acidosis (opposite - both 'arrows' going in the opposite direction)

ph

pco2 > 45

resp alkalosis

ph > 7.45

pco2

met acidosis (equal - both "arrows" going in same direction)

ph

hco3 (bicarb)

met alkalosis

ph > 7.45

hco3 > 26

normal lab values:

ph - 7.35-7.45

pco2 - 35-45

hco3 - 22-26

and, remember pco2 deals with respiratory and hco3 (bicarb) deals with metabolic.

hope this helps!

thank you it does~:yeah:

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