There are two main types of pH imbalances in the body: acidosis and alkalosis. An increase in H+ ion levels in the blood causes pH levels to fall resulting in acidosis. A decrease in H+ levels causes pH levels to rise, making the blood more basic, or alkaline. These conditions can be caused by two kinds of disturbances to the buffers that control the body’s pH levels, which alter the acid-base balance. Metabolic and respiratory acidosis and alkalosis are the results of disruptions to the bicarbonate and carbonic acid components of the chemical buffers.
Metabolic and respiratory acidosis result when pH levels fall due to an increase in H+ ions or a loss of bases causing the bodily fluids to become slightly acidic. Insufficient bicarbonate levels lower the pH levels of fluids in the digestive tract, resulting in metabolic acidosis. Respiratory acidosis is caused by excessive carbonic acid in the respiratory system, which lowers pH levels through the retention of CO2.
Alkalosis is the result of opposite changes to the acid-base balance: excessive bicarbonate levels in the digestive system increases pH as H+ ion concentrations decrease, which causes fluids to become more basic. Insufficient carbonic acid levels are caused by excessive exhalation of CO2, resulting in respiratory alkalosis.
Treatment for metabolic and respiratory acidosis and alkalosis varies depending on the underlying cause of the imbalance. Respiratory acidosis caused by hypoventilation can be treated with oxygen therapy and the help of breathing machines to help restore normal oxygen/carbon dioxide exchange, allowing the kidneys time to increase production of bicarbonate and reestablish the acid-base balance of the blood. Respiratory alkalosis caused by hyperventilation can be treated with inhalation of carbon dioxide, such as breathing in a paper bag, which returns excessively exhaled CO2 to the respiratory system.
Metabolic acidosis can be caused by many different underlying disorders, but general treatment of metabolic acidosis is aimed at reducing the acid in the digestive and circulatory systems, often through administration of sodium bicarbonate to rebalance the pH levels. The body can usually resolve acid-base balance following metabolic alkalosis caused by excessive vomiting, without medical help; however, increased fluids administered via IV will help speed the process. In some cases of chronic alkalosis medication may be needed to maintain the pH balance in the digestive tract.
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U.S. National Library of Medicine. (2012a). Respiratory alkalosis. Retrieved from http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001170/
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