A nurse taught me an easy way to read ABGs.
First, normal values:
Look at pH first. If it is normal, it is fully compensated. If it is abnormal, it is not.
Disregard the last two values. You don't care about them. Well, you might, but you don't need to evaluate them to determine acid/base status.
The pH is lower than normal, so it is more acidic than normal. We know already it is not fully compensated.
The PCo2 is 25, that is also lower than normal. However, a low value of Co2 means that it is more alkalotic than normal, not more acidotic. A value of higher than 45 is acidotic.
So far we have an acidotic pH and an alkalotic Co2.
Ok, the bicarb is 8, that is much lower than the normal value of 22-26. We can safely say that is acidotic, a number higher than 26 would be alkalotic, or basic.
So we have an acidic pH and an acidic bicarb level. We can presume that the Co2 is basic to compensate for the acidotic state, so this is:
partially compensated metabolic acidosis
it is not fully compensated because the pH is abnormal
if the pH was abnormal, and the Co2 was normal, then it would be uncompensated.
Does this make sense to anyone?
I usually look at it, and draw an arrow next to the values as to whether its normal or abnormal, acid or base, and go from there. Its really fairly simple.
Hopefully this will help you. If you need anything else let me know. If it confuses you more, just ignore it.
You'll learn all this from your own nursing instructors next year.