Interpreting ABG's

[jschut, BSN, RN]

I understand the basics of this, but I get terribly confused with the compensated and partially compensated.

Then my confusion is tripled when I run across a problem such as:

pH~ 7.37

PCO2~ 25

HCO3~ 14

Can someone explain this in an easy step by step way?

Thank you!

[Daytonite, BSN, RN]

compensated - whenever the ph is within normal limits, but the co2 and/or hco3 are abnormal

partially compensated - the ph is abnormal (there is acidosis or alkalosis) and the co2 and/or hco3 are abnormal

there is a step-by-step way to read and interpret abg's. it is outlined and discussed in a number of the weblinks that are listed on post #43 of this sticky thread: https://allnurses.com/nursing-student-assistance/pathophysiology-p-microbiology-145201.html - pathophysiology/ a & p/ microbiology/ fluid & electrolyte resources and you really should take the time and effort to read through those weblinks and work on some of the practice problems on some of the websites. the rome mnemonic is on post #23 and used for partially compensated abgs. this document arterial blood gases basic principles.doc which is posted on #43 is a handy guideline to analyzing any blood gas result once you have a better understanding of what you are doing and includes tables for assessing compensated and partially compensated abgs.

ph - 7.37

pco2 - 25

hco3 - 14

1. look at the ph to determine:
   
   • acidosis (below 7.35)
     
   • normal or compensated (7.35 to 7.45)
     
     • this is a case where the ph is within normal limits, but at the low end of normal toward the acid reading, so there is compensation going on
       

[*]alkalosis (over 7.45)

[*]what is pa co2 doing? this is the respiratory effect.

• alkalosis, causes high ph or normal low end ph (below 35)
  
• normal or compensated (35 to 45)
  
• acidosis, causes low ph, normal high end ph (over 45)
  
• if a respiratory cause is ruled out, then move on to the next step
  
  • there is no acidosis or alkalosis, per se, although the pco2 (the respiratory component) is 25 which is low
    

[*]what is the pahco3 doing (normal hco3- is 22-26)? this is the metabolic effect.

• high ph is alkalosis
  
• if the paco2 is high it is metabolic; if it is low it is respiratory
  
• low ph is acidosis
  
• if the paco2 is high it is respiratory; if it is low it is metabolic
  
  • there is no acidosis or alkalosis, per se, although the phco3 (the metabolic component) is 14 which is low [when ph goes down, the co2 should go up during compensation but the opposite is happening because of metabolic factors] - this is compensated metabolic acidosis.
    

[jschut, BSN, RN]

Thank you for the info.... by George! I think I've got it! :)

But one more question....

Is Partially Uncompensated and Uncompensated the same thing?

[Daytonite, BSN, RN]

Never heard of partial uncompensated, only compensated and partially compensated. When analyzing you are not going to be asked if the ABGs are compensated or not. You will be asked if you have respiratory or metabolic acidosis/alkalosis or if it is compensated. I've never heard of anything else.

[Dublin37]

compensated - whenever the ph is within normal limits, but the co2 and/or hco3 are abnormal

partially compensated - the ph is abnormal (there is acidosis or alkalosis) and the co2 and/or hco3 are abnormal

there is a step-by-step way to read and interpret abg's. it is outlined and discussed in a number of the weblinks that are listed on post #43 of this sticky thread: https://allnurses.com/nursing-student-assistance/pathophysiology-p-microbiology-145201.html - pathophysiology/ a & p/ microbiology/ fluid & electrolyte resources and you really should take the time and effort to read through those weblinks and work on some of the practice problems on some of the websites. the rome mnemonic is on post #23 and used for partially compensated abgs. this document arterial blood gases basic principles.doc which is posted on #43 is a handy guideline to analyzing any blood gas result once you have a better understanding of what you are doing and includes tables for assessing compensated and partially compensated abgs.

ph - 7.37

pco2 - 25

hco3 - 14

1. look at the ph to determine:
   
   • acidosis (below 7.35)
     
   • normal or compensated (7.35 to 7.45)
     
     • this is a case where the ph is within normal limits, but at the low end of normal toward the acid reading, so there is compensation going on
       

.................

you have absolutely got to consider teaching!

[jschut, BSN, RN]

Never heard of partial uncompensated, only compensated and partially compensated. When analyzing you are not going to be asked if the ABGs are compensated or not. You will be asked if you have respiratory or metabolic acidosis/alkalosis or if it is compensated. I've never heard of anything else.

I apologize. I was on my 2nd day of 12 hour night shifts, and was trying to study a bit.

I meant, is Partially Compensated and Uncompensated the same thing? And since I am in nursing school, I will be asked for this info, along with how to interpret ABG's for my upcoming test.

Thank you again though, for your help.

[Daytonite, BSN, RN]

i meant, is partially compensated and uncompensated the same thing? and since i am in nursing school, i will be asked for this info, along with how to interpret abg's for my upcoming test.

ask your instructors to define these terms exactly how they mean them so there is no confusion.

i can show you how to interpret abgs using the 3-step method which is tried and true and there are several sites that you can go to and get a lot of practice and feedback in interpreting them. print out arterial blood gases basic principles.doc and use the two charts on it to diagnose respiratory/metabolic acidosis/alkalosis and compensated respiratory/metabolic acidosis/alkalosis and you will be good to go. memorize normal ph, co2 and hco3 values. then practice, practice, practice.