Interpet this ABG

[smstar1996]

I know all the normal values of ABG's and I also know when it is resp or metabolic as well as acidosis or alkalosis. However I can't interpet the following, I get that it is a mixed ABG.

ph 7.46 (normal acidosis>7.35-7.45

HCO2 63 (normal Alk>35-45

HCO3 34 (normal acid>22-26

Pao2 70 (Hypoxemia)

Sao2 86% (hypoxia)

I'm confused. It starts to look like Metibolic alkalosis, but look at that Co2 level, that is dangerously high. Co2 above 50= Respitory distress and the need for mechanical ventilation. With that said does this cancel out the dx of metabolic alkalosis and the correct interpetation would be Respitory Acidosis? Help!

[fuuchan]

Maybe there is compensation going on?? Sorry, I'm not too good with it myself

[Daytonite, BSN, RN]

when you are interpreting abgs there is a step-by-step sequence to doing this:

1. look at the ph to determine acidosis/alkalosis or compensation
   • ph 7.46 - this is alkalosis, no compensation

[*]look at what the co2 is doing; this is the respiratory effect. if the hco3 is within normal limits then you stop here and the problem is respiratory; if the hco3 is also abnormal you have a metabolic problem, so move on to step #3

• hco2 63 - normal is 35-45, so it is elevated

[*]now, what is the hco3 doing; this is the metabolic effect

• hco3 34 - normal is 22-26, so it is also elevated, so this is metabolic alkalosis

you can verify this using the rome mnemonic (https://allnurses.com/forums/2016253-post25.html)

r

espiratory

o

pposite

• ph

  elevated

  pco2

  diminished

  =

  respiratory alkalosis

  
  

• ph

  diminished

  pco2

  elevated

  =

  respiratory acidosis

  
  

m

etabolic

e

qual

• ph

  elevated

  hco3

  elevated

  =

  metabolic alkalosis

  
  

• ph

  diminished

  hco3

  diminished

  =

  metabolic acidosis

  
  

when assessing abgs the pao2 and sao2 have no significance. you know compensation is occurring when the ph falls within normal range while the co2 and/or the hco3 remains out of balance.

you can get weblinks to sites on abg interpretation including several sites that have practice problems on this post of one of the sticky threads: https://allnurses.com/forums/2488838-post46.html

[kgcStudentRN]

I read it as metabolic alkalosis with partial respiratory compensation. The respiratory system is just starting to compensate, it is not fully compensated because the PH is not in normal limits. It depends how your instructor wants you to read the ABG. Mine wanted us to list every possible detail we could. If she wants it basic, then it is metabolic alkalosis. Do you have any S & S's of the pt.?