Metabolic Acidosis

Acidosis refers to an increased concentration of H+ in the blood.

Metabolic acidosis is acidosis that results from a primary decrease in HCO3- , as might be caused by an accumulation of acids in the blood, such as after tissue hypoxia or in the state of diabetic ketoacidosis. Refer to the web notes on the Renal-Respiratory System and on bicarbonate for more information on how changes in blood HCO3- result in changes in blood pH.

Because it is a disease state, the body takes actions to restore things back to normal. This is an example of homeostasis .

Because bicarbonate is somehow involved in the cause of the disease state (it's a metabolic acidosis), a typical response is compensation by the lungs, increasing the rate at which CO2 is blown off, out of the body.

The respiratory system compensates by increasing the respiratory rate. This increases the rate at which CO2 is removed from the body.

The response is not usually enough to fully return blood pH to 7.4. The extent of compensation can be determined from base deficit.

West gives a description of base deficit on page 84.

For more information on this topic, please refer to West , page 83.

Also, check out the following links that may be helpful:

• Biochemistry I - Buffers and Ionization of Amino Acids
• Acid-Base Terminology
• Acid Base Disorders in Critical Care MEDSTUDENTS-INTENSIVE CARE
• And, as always, if you have questions, or if you can suggest a helpful link, please e-mail me.