Acidosis & alkalosis

Here is a glossary of these terms, which is useful for understanding some of the blood buffer systems. There are basically four abnormalities with regards to the acid-base balance in blood. You should ask yourself three questions:

1. Is the pH high or low? - low pH= acidosis and high pH = alkalosis.
2. Is CO₂ abnormal? - if 'yes':

• • Is this in keeping with the pH change? - i.e. when pH↑, CO₂↓ OR pH↓, CO₂↑. These changes point to a respiratory acidosis/alkalosis. If the change is not there, then it is a compensatory change.

1. Is the HCO₃^- abnormal? - if 'yes'

• • Is this change in keeping with the pH change? - i.e. (opposite to CO₂ changes) when pH↑, HCO₃^-↑ OR pH↓ HCO₃^-↓