Metabolic/ respiratory acidosis and alkalosis

  1. 1
    Call me stupid--but I'm having such a time with determining whether a person is in respiratory or metabolic acidosis/alkalosis based on the ABG levels. I know how to determine the acidosis/ alkalosis part---its the difference between metabolic and respiratory that screws me up. If anyone has any suggestions on how to tell the two apart--please share!!!!
    needlenose45 likes this.
  2. 142,424 Visits
    Find Similar Topics
  3. 35 Comments so far...

  4. 0
    Ummm, I can't help you without "refreshing." That was last semester for me, and I've already forgotten. You don't use it, you will lose it. Ugggg.

    I was able to figure it out back then (like, 4 months ago), but I never understood the dynamics between the 2.

    So, if someone is in Resp Acidosis, what does it mean, what will I objectively see, what will they report, what will I do to help them???

    Metabolic Alkalosis Vs. Resp Acidosis - I have no idea how the sx differ. Ya me.
  5. 0
    Quote from jennielynn
    Call me stupid--but I'm having such a time with determining whether a person is in respiratory or metabolic acidosis/alkalosis based on the ABG levels. I know how to determine the acidosis/ alkalosis part---its the difference between metabolic and respiratory that screws me up. If anyone has any suggestions on how to tell the two apart--please share!!!!
    It is hard sometimes, and one can forget easily with out looking at ABGS frequently.

    acidosis alkalosis

    Ph <7.35 >7.45

    pco2 >45 <35

    co2 <18 >22

    co2 might be hco3 in some labs and the 18 or 22 might be 1-2 numbers different.

    Just write down this down and then circle which ones apply to your ABG results. Then what it is called is the one that caused the acidosis or alkalosis. pco is resp and co2 is metabolic

    ex your pt abgs are Ph 7.30, pco2, 40 co2 10 This is metabolic acidosis.
  6. 18
    Quote from jennielynn
    Call me stupid--but I'm having such a time with determining whether a person is in respiratory or metabolic acidosis/alkalosis based on the ABG levels. I know how to determine the acidosis/ alkalosis part---its the difference between metabolic and respiratory that screws me up. If anyone has any suggestions on how to tell the two apart--please share!!!!
    Our critical care instructor is fantastic -- she just recently *refreshed* our memories from med-surg and drummed this into our heads ...

    First, look at the pH: normal = 7.35-7.45. 7.35-7.39 has an "acidotic lean", 7.41-7.45 has an "alkalotic lean" and 7.40 is *perfect*.

    Next look at the HCO3 (normal = 22-26) and the pCO2 (normal = 35-45). Which one "has the same name" as the pH (acidotic or alkalotic)? If it's the HCO3 then the problem is metabolic, and if it's the pCO2 then the problem is respiratory.

    Example:

    pH 7.33
    pCO2 50
    HCO3 26

    The pH is acidemic, the pCO2 is high (CO2 is acid) and the HCO3 is OK. The pCO2 has the same "name" (problem) as the pH - this is respiratory acidosis.

    Since either of these 2 systems (respiratory system & metabolic - kidneys) will try to compensate for failure of the other, the more complicated problems come in when there is full or partial compensation - the pH will return to normal (but w/the acidotic or alkalotic "lean") and the other value will also be out of whack - the key is to see which matches the "lean" of the pH.

    We call this the who's your daddy method of ABGs ...

    I have a packet with tons of these problems -- if anyone wants a sampler with the answers, just send me a PM.
    sonias, Zz SN, khausig, and 15 others like this.
  7. 9
    A trick we learned was ROME. Respiratory=Opposite, Metabolic=Equal.
    I'll use this on the example from teh above post
    pH 7.33
    pCO2 50
    HCO3 26
    Your pH is low. Your PCO2 is high. high/low is opposite. So its respiratory, and you know its acidosis b/c the pH is low.

    and now, this one
    pH-7.52
    pCO2-40
    HCO3-30

    pH is high, HCO3 is high. high/high is equal, so its metabolic. pH is high, so its alkalosis. metabolic alkalosis.

    make sense?
  8. 2
    We learned "the family tree of ABGs"

    Okay, an example (normal ranges: pH - 7.35-7.45; CO2 - 35-45; HCO3 - 23-27):

    pH 7.48
    CO2 (which refers to respiratory) - 30
    HCO3 (which refers to metabolic) - 26

    Okay, first look at pH - you first need to determine if it's compensated or uncompensated. If it's within normal limits, it's compensated. This is outside the normal range, so it's UNCOMPENSATED. And you know by the value that it's alkalotic.

    Okay - CO2 - it's outside the normal range, and is also alkalotic

    HCO3 - within normal range

    So, you know that the pt. is uncompensated, and based on the pH, is alkalotic. Then you look at the other two values for the alkalosis "match" to determine if it's metabolic or respiratory. The CO2 value is what matches the pH (because it's also alkalotic like the pH), so you know you're dealing with RESPIRATORY alkalosis.

    Another example:

    pH: 7.30
    CO2: 34
    HCO3: 29

    pH is outside normal limits, so it's UNCOMPENSATED. Because of the value, you also know it's ACIDOSIS

    CO2: outside normal limits, based on the value you know it's alkalosis

    HCO3: outside normal limits, based on the value you know it's acidosis

    So you know, based on the pH, that the pt. has UNCOMPENSATED ACIDOSIS. Now you need to determine if it's respiratory or metabolic. Because the metabolic value (HCO3) is the one that matches the pH (because it's also acidosis), then you know it's METABOLIC. So the answer is UNCOMPENSATED METABOLIC ACIDOSIS

    Does this help at all?
    kya2728 and KristeyK like this.
  9. 0
    I had problems with this earlier this semester when we had our exam over it, I asked for help on here and got some great responses..... it really helped me out and cleared it up for me. Check out this thread:
    http://allnurses.com/forums/showthread.php?t=93156
  10. 2
    Quote from jennielynn
    its the difference between metabolic and respiratory that screws me up. If anyone has any suggestions on how to tell the two apart--please share!!!!
    To tell whether it's a respiratory problem or a metabolic problem look at the CO2 and the bicarbonate (HCO3).

    Normal CO2 is 35-45, look at it and see if it falls within that range, if it does NOT fall within that range then, it's abnormal and therefore the problem is respiratory acidosis/alkalosis.

    Normal HCO3 is 22-26, look at it and see if it falls within that range, if it does NOT fall within that range, then it's abnormal and therefore the problem is metabolic acidosis/alkalosis.
    NewBeee and Vida like this.
  11. 0
    This link has an excellent ABG review!
    http://www.rnceus.com/course_frame.a...directory=abgs
  12. 0
    I agree with this method. This is how I remember it. ABG's are very easy using this method once you get the hang of it.





    Quote from RNinMay2005
    A trick we learned was ROME. Respiratory=Opposite, Metabolic=Equal.
    I'll use this on the example from teh above post


    Your pH is low. Your PCO2 is high. high/low is opposite. So its respiratory, and you know its acidosis b/c the pH is low.

    and now, this one
    pH-7.52
    pCO2-40
    HCO3-30

    pH is high, HCO3 is high. high/high is equal, so its metabolic. pH is high, so its alkalosis. metabolic alkalosis.

    make sense?


Top