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ACID-BASE BALANCE..just saw this question from a rview ctr.just wanna know your ans..tnx..
An arterial blood gas result with a pH of 7.31, paCO2 of 39, PO2 of 92 and HCO3 of 18 indicates;
1. Respiratory alkalosis
2. Metabolic acidosis
3. Metabolic alkalosis
4. Respiratory acidosis.
The way I always do it (no mnemonic, sorry) is to evaluate the pH first. If it's acidotic or alkalotic, look for whichever number is also acidotic or alkalotic. If it's CO2, then the lungs caused it. If it's bicarb, then the cause is metabolic.
The opposite system always tries to fix the problem, so a metabolic problem will be compensated for in the lungs and vice versa. If our sample here was partially compensated, we would see low carbon dioxide levels along with our low pH and low bicarbonate because low CO2=lower acidity/higher pH. Full compensation would have a normal pH with wacky bicarb and CO2 levels. You would still match whatever direction the pH was going with the bicarb and CO2 to determine which system caused it and which system fixed it.
The nice thing about this subject is that once you get it, you understand it forever. So keep chipping away. You'll work it out!
This is how I figure it out:
pH of 7.31 Acid 7.35-7.45 Base
paCO2 of 39 Base 35-45 Acid
HCO3 of 18 Acid 22-26 Base
Notice that is alternates Acid, Base, Acid to the right, and opposite for the left. There are two name give for ABGs: Either Acidosis or Alkalosis and Resp. or Metabolic. Ph tells whether it is acid or alk. CO2 no matter if it too high or too low gives the name Resp. And HCO3 no matter if its to high or too low gives the name Metabolic.
SO.... Acid ph of 7.31 Base Acidosis
paCO2 39 Normal
Acid HCO3 Base Metabolic
I actually right the A, B, A down the right of my results and circle as I go! Good Luck!
LindseyRNBSN2011
73 Posts
ROME means Respiratory Opposite Metabolic Eqaul.....with the example from the question, the pH and bicrabonate were both decreased (meaning they were equal) which would indicate that it was metabolic.....had the pH been increased and the bicarbonate decreased (opposite from one another) then it would have been respiratory.......a lot of nursing schools teach the ROME trick, search it and see if you can find a good review about it. Hope this helps!