acid/base compensation help needed...

[timls3674]

i am studying acid base and i have checked out the info here and several other places and have a good concept of acid base and abg interpretation, however i am having a difficult time understanding the complete, partial compensation, i cant grasp the concept on how you tell if it is compensating or uncompensating based on the values given. i dont have any abg values to list basiclly i would like to figure out the concept so i can look at any abg value and figure it out. i have checked several of the links others have posted in the forums and that info is not helping me much if anyone coulds please explain it more in detail or point me to somewhere that explains it

Thanks

timls3674

[tiggerdagibit]

One of my clinical instructors told me that if the HCO3 or CO2 is out of whack, but the pH is in normal range, that it is compensated.

[Starfish1]

yes, here is a good example...

remember the acronym rome- respiratory opposite metabolic equal

see the following problem

ph 7.29

paco2 17 mmhg

hco3 19 meq/l

the ph indicates acidosis- start of there

the paco2 is low (35-45 is normal) which normally means alkalosis

hco3 is low too (22-26 is normal) which normally means acidosis

since the hco3 corresponds with the ph acidosis thus it is a metabolic cause= metabolic acidosis and since the paco2 is not within range it is partially compensated

sometimes the body can compensate so well that the ph falls within normal ranges.

i hope this example helps...i always start with the ph ( i always write little arrows or acidosis or alkalosis next to it) so it is easier and take each abg reading and mark what it is and then come to a conclusion

i hope this helps! i have done several practice questions to get the hang of the concept and finally grasped it- this problem that is presented here came from the incredibly easy book- and i think it is a good example since all the numbers are out of range

[tiggerdagibit]

That is a great explanation of partially compensated! I never really understood it. That helps alot! Acid base is one of those things that I do ok with when I do them often, but forget really quickly if I don't. lol

[Daytonite, BSN, RN]

the rome mnemonic only applies when the ph is whacked and out of range. the abgs are said to be compensated only when the ph is within normal range of 7.35-7.45. there is a step-by-step way to analyzing abgs just as there is a step-by-step approach to the nursing process. take the steps in the wrong sequence and you take your fate at your own peril. the first thing you do in analyzing abgs is look at the ph. that determines if you have acidosis, alkalosis, or a normalized situation. the second thing you do is look at the co2. that tells you what is going on with the respiratory component. if it is normal, move on. look at the hco3. this is the metabolic component. to determine the degree and type of partial compensation when the ph is normal and the co2 and/or hco3 are out of whack takes experience.

on post #45 of the pathophysiology/ a & p/ microbiology/ fluid & electrolyte resources sticky in this forum (https://allnurses.com/nursing-student-assistance/pathophysiology-p-microbiology-145201.html) are weblinks to tutorials on analyzing abgs as well as practice problems. good tutorials are

• http://www.rnceus.com/course_frame.asp?exam_id=18&directory=abgs - "interpretation of abgs: a four step method"
  
• http://www.wisc-online.com/objects/index_tj.asp?objid=nur6906 - abg interpretation: partially and fully compensated conditions - this audiovisual presentation is also a good tutorial
  
• you might also want to copy and use arterial blood gases basic principles.doc - guide to assessing blood gasses - that was posted by another student on the forums some months ago. it's a really helpful tool for analyzing abgs.
  

then go to http://www.vectors.cx/med/apps/abg.cgi to quiz yourself and get explanations for any wrong answers. this quiz site also explains partially compensated blood gas results.

i will try to work on finding the new urls for vickyrn's worksheets and abg tic-tac-toe sheets. those other urls no longer work since the new software changeover.

-----------------------------------------------------

ph 7.29

paco2 17 mmhg

hco3 19 meq/l

the ph indicates this is acidosis. the co2 is low; the hco3 is also low. using the ro

me

mnemonic, the "me" part applies because

both the co2 and hco3 have shifted in the same direction and are below normal

. that is what "metabolic equal" means in the mnemonic. that means that for this set of abgs "ph

diminished

hco3

diminished

= metabolic acidosis". this set of abgs indicates that the patient is in

metabolic acidosis

.

the rome mnemonic is on post #24 of the

https://allnurses.com/nursing-student-assistance/pathophysiology-p-microbiology-145201.html

-

pathophysiology/ a & p/ microbiology/ fluid & electrolyte resources

sticky.

[Starfish1]

yes, I should have been more clear, my example would be partially compensated.

[timls3674]

i found this from another source is this all correct ?

Uncompensated

pH abnormal (high or low)

One component abnormal (high or low CO2 or HCO3)

The other component is normal

(The component not causing the acid-base imbalance is still normal

Partly compensated

pH not normal (but moving toward normal)

Both CO2 and HCO3 are outside normal range

The component that was normal is changing in order to compensate

Compensated

pH normal

Other values abnormal in opposite directions

One is acidotic the other alkaline

[Dianacabana]

I will try to work on finding the new URLs for VickyRN's worksheets and ABG Tic-Tac-Toe sheets. Those other URLs no longer work since the new software changeover.

These are the ABG Tic-Tac-Toe sheets from VickyRN. My classmates & I have used them and found them very useful! Thank you Vicky and thank you Daytonite!

Good luck.

ALLNURSES ABG Tic-Tac-Toe Part One.doc

ALLNURSES ABG Tic-Tac-Toe Part Two.doc

[Daytonite, BSN, RN]

vicky rn also posted this quiz and its answer sheet to go along with the abg tic-tac-toe grids--found them on one of her other posts. for those of you who are new to allnurses and this forum, vickyrn was (and still is, i believe, a moderator of this forum):

• abg practice quiz.doc - 46 samples to analyze + answers to abg practice quiz.doc
  

also found this interesting thread and weblink in searching allnurses:

• https://allnurses.com/general-nursing-student/abgs-and-compensation-156641.html - abgs and compensation
  
• http://www.accd.edu/sac/nursing/rnsg2331/abgtut.html - discusses compensation
  

[truern]

The tic-tac-toe grid was what really helped me understand acid/base! Nothing seemed to click until I found and used the grid :)

[Daytonite, BSN, RN]

this tutorial also addresses compensation toward the end:

• http://www.m2hnursing.com/abg/index.php - abg and acid/base balance tutorial