Acid Base Balance

Understanding the cause of an acid-base imbalance is the key to treating it.

So now, lets combine the two formulae to describe the carbonic acid - bicarbonate buffer system.

The two headed arrows indicate that the process is reversible

CO2 + H2O <--> H2CO3 <--> (HCO3-) + (H+)

Instant Feedback:
It takes only minutes for the kidneys to change the amount of bicarbonate in the blood.

You see how either mechanism (respiratory or metabolic) can cause an acidosis or an alkalosis.

The task of ABG interpretation is to determine the cause of an acid-base (carbonic acid-bicarb) imbalance and correct it.

Points to remember:

  1. Either mechanism (respiratory or metabolic) can cause either alkalosis or acidosis.
  2. It is normal for each mechanism to compensate the other.
  3. You have to find the cause.
  4. Treat the cause not the compensation.

Instant Feedback:
If you treat the cause of the problem, the compensatory mechanism should correct itself.

Click here to enter the Tulane Univ. School of Medicine, Dept. of Anesthesia Acid-Base balance tutorial.