Respiratory Acidosis

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

Respiratory acidosis is acidosis that results from an increase in PCO2 , as might be caused by a decreased breathing rate or an increase in the PCO2 of the surrounding atmosphere.

Refer to the web notes on the Renal-Respiratory System and on bicarbonate for more information on how changes in blood CO2 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 the lungs are somehow involved in the cause of the disease state (it's a respiratory acidosis), a typical response is compensation by the kidneys.

The kidneys compensate by conserving HCO3-.

The renal response is not usually enough to fully return blood pH to 7.4. The extent of renal 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.