Bicarbonate (HCO,)

Bicarbonate plays an important role in the blood buffer system, which
helps maintain the normal blood pH of 7.4. Simply put, the blood buffer system
is activated by a buildup of positively charged hydrogen ions in the
body. When this buildup occurs, bicarbonate, a negatively charged ion,
combines with the hydrogen to produce a weak acid, or buffer, called carbonic
acid. After a series of chemical reactions, an equilibrium is established
and pH levels are held within the normal range. Variations in bicarbonate
concentrations will affect the pH levels in blood.
Bicarbonate also serves as a transport mechanism to move carbon dioxide
(CO2.) from the body tissues to the lungs where it is exhaled. Carbon
dioxide is a waste product and must be removed from the bloodstream .
Normal Range
22-26 mEq/L
Variations from Normal. Decreased bicarbonate concentrations results in
acidosis, a blood pH of 7.35 or less. Acidosis is seen in renal failure, a variety
of respiratory diseases in which the lungs retain carbon dioxide, and
poorly controlled diabetes mellitus.
Increased bicarbonate concentrations results in alkalosis, a blood pH
greater than 7.45 . Alkalosis is associated with hyperventilation, excess intake
or retention of bicarbonate, and loss of gastric acid due to vomiting or
potassium depletion.