Understanding ABG's

Specialties MICU

Published

Hello, I'm new to the world of ITU nursing, in fact i've just finished my 5th shift and am really struggling with understanding ABG's. Can anyone help explain what it all means, please keep it simple

Specializes in Med Surg.

Thanks so much for that land of ABG's link. That really helps out! i have my respiratory test tomorrow!! 99 days til i graduate!! :o) YAAAY!

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Specializes in home care and geriatrics.

can some one explain to me why a dr I spoke with says the following indicates metabolic acidosis. I would think respiratory, he says no. the HCO3 wasn't given, the CO2 was 40, and the PaO2 was 40. pt was vented after being found in a bin after inhaling methan gas, ammonia and had no respirations. was intubated and now on FIO2. ph is 7.25.

I am an lpn to rn student and have always understood the same way dorimar explained it but he says my dx isn't correct.... is he crazy, or am I??

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Specializes in Transplant/Surgical ICU.

He might have known the bicarb value?! Normal Co2 value is usually 35-45. Yours is within normal. The ph however is acidotic which makes me think that since the CO2 (resp) component is normal, then the bicarb must be low causing an acidosis. If its not the CO2 it has got to be bicarb! or maybe your lab just messed up. The PaO2 is low because he was in respiratory distress, however I would expect the Co2 to be higher than the number you reported. If this guy was not breathing, he should be retaining CO2 and become resp acidotic, but that was not the case, hugh? It could be an effect of the methane or just the current settings on the vent. How long after intubation was this gas drawn? I would definetly increase the Fio2 if I had room, and maybe also play with the peep.

You are not crazy and neither is he. Next time if I were you I would call the lab and request a complete report, its unacceptable to report an abg without the bicarb.

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thx so much hrtprness....i only wish i had seen these during nursing school

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Specializes in Critical Care.

It helps to remember "ROME."

Respiratory, Opposite: meaning if the ph is down and the cO2 is up (moving in opposite directions), or vice versa, it's a respiratory cause.

Metabolic, Equal: meaning if ph is up and bicarb is up (moving in equal directions), or vice versa, the cause is metabolic.

That's just a basic explanation, of course.

Someone told me once that it pays to remember the causes and identifications of ph imbalances, because you'll spend all your nursing life treating them in one way or another.

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this is very nice..i learned from this site...

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maybe this will help too...

steps:

1. Draw an H, left side is Metabolic write number 18below, 24 midpoint 30 above. On the right side is Respiratory write number 30 below, 40 midpoint and 50 above

2. Plot the given data bicarbonate, and respiratory

3. Bracket the value to its midpoint, determine which bracket is bigger.

Bigger bracket is the caused of the problem

that's your baby's name...

4.Connect the 2 dots from Left to Right

ascending - acidosis

descending - alkalosis

:bow: just for fun!

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Specializes in PICU/CVICU/Ped Nursing Faculty/TSICU.

movinup

The pao2 is 40 which is very low. It is highly likely that there is some anaerobic metabolism going on because there is decreased 02 leading to the decrease in HCO3 although it wasn't given to us. No O's to the toes which will lead to the metabolic acidosis. hope this helps!

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hi there's alot of threads about ABG's if you'd do a search, but here's one link...I'm sure it will help you... http://realnurseed.com/abg.htm scroll down to "Land of ABG's"...hope it helps

Thank you very much for that website, it helped me ALOT!!!!!!!!!:yeah::typing:heartbeat:up:

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