Metabolic Alkalosis

Alkalosis refers to an decreased concentration of H+ in the blood.

Metabolic alkalosis is alkalosis that results from an increase in HCO3- , as might be caused by vomiting or the ingestion of alkalis. 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 HCO3- is somehow involved in the cause of the disease state (it's a metabolic alkalosis), a typical response is compensation by the lungs.

The respiratory system compensates by decreasing ventilation, thereby decreasing the rate at which CO2 is blown off, out of the body.

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

West gives a description of base excess 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.