HCO3 (Bicarbonate in Blood): ABG interpretation

We have discussed the partial pressure of oxygen and carbon dioxide in blood in previous lessons, now let's talk about the Bicarbonate in blood and its functions to maintain the pH of blood in the buffer.
Bicarbonate, also known as HCO3, is a byproduct of your body's metabolism. Your blood brings bicarbonate to your lungs, and then it is exhaled as carbon dioxide. Your kidneys also help regulate bicarbonate.
Bicarbonate is excreated or reabsorbed by your kidneys. This regulates your body's pH or acid balance. Bicarbonate also works with sodium, potassium, and chloride, which are electrolytes in the blood.
The normal range of HCO3 in the blood is between 22 to 26.
In this video, we will look at the significance of Bicarbonate in ABG along with interpretation of various metabolic disorders.
The higher level of Bicarbonate in the blood causes metabolic Alkalosis, a condition in which the pH of blood rises above normal, that is above 7.45.
Normally, pH of blood is Between 7.35 to 7.45.
Now, look at this example, here the pH of blood is more than 7.45 means the patient is in Alkalosis and the HCO3 levels are decreased, indicating metabolic Alkalosis.
Metabolic alkalosis can happen due to the loss of acid from your body, such as through vomiting and dehydration. It may also be related to conditions including anorexia and chronic obstructive pulmonary disease.
A low level of bicarbonate in your blood may cause a condition called metabolic acidosis, or too much acid in the body. A wide range of conditions, including diarrhea, kidney disease, and liver failure, can cause metabolic acidosis. Here the pH of blood drops below Normal, which is 7.35.
Normally patients with low levels of bicarb in ABG suffer from metabolic acidosis due to constant loss of HCO3 from the body, resulting in reduced pH.
But our body compensates for this loss by Reducing the level of carbon dioxide in the blood.
This condition is called compensated metabolic acidosis where the Partial pressure of carbon dioxide is dropped below normal and both Bicarbonate and pH rise towards normal.
The compensation can be either partial or full.
If the body is able to maintain the pH within normal range it will be called fully compensated metabolic acidosis or if it fails to regulate pH within normal range, it will be partially compensated metabolic acidosis.
Same in case of metabolic Alkalosis, the CO2 rises in order to maintain the pH of blood and compensate for increased levels of bicarbs.
Now we know the function of bicarbs in arterial blood gas and it's compensation mechanism.