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Does anyone understand the ABG compensation thing? I understand the basic concept of metabolic acidosis and alkalosis and respiratory acidosis and alkalosis. But when there are 3 values given.... Ph, PCO2, and HCO3 and then you have to decide whethere its metabolic or respiratory then acidosis or alkalosis THEN if its compensation or not I get so confused. Can anyone help??
ortess1971
528 Posts
Here's some examples from a worksheet we were given to practice with...
PH: 7.45 The Ph is within normal range but is tending towards
PO2: 80 alkalosis. I then look at the CO2- It is higher than normal
PCO2: 60 and the HCO3 is higher than normal as well. Applying the
HCO3: 36 R.O.M.E. trick, you can see than the HCO3, is "Equal," or
moving in the same direction as the PH. This tells you that
this example is metabolic alkalosis. It's compensated
because the PCO2 is abnormal as well. It's fully
compensated because the PH is within normal limit
PH: 7.15 The ph is abnormal(acidotic).The PCO2 is higher than
PO2:88 normal or "opposite" of the PH. This is respiratory acidosis.
PCO2:60 The HCO3 is within normal limits so there is no
HCO3:24 compensation going on.
PH:7.61 This is alkalosis. The PCO2 is lower than normal or
PO2:55 "opposite" of the PH-therefore, this is resp. alkalosis. The
PCO2:22 HCO3 is lower than normal so there is compensation by
HCO3:15 the metabolic system. However, it's only partially
compensated as evidenced by the abnormal PH.
It's difficult at first but then one day it all makes sense. Hope this helps!