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Disturbances of Acid-Base Balance Essay

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Disturbances of Acid-Base Balance
If an acid-base disturbance shifts the pH outside of the physiologic range, various control measures are activated to resist the change in pH. Compensatory mechanisms try to preserve the normal 20:1 ratio of bicarbonate to carbonic acid to keep the pH at normal range. The body works to maintain normal ratios through a compensation mechanism using renal and respiratory methods (Crowley, 2010).
Metabolic Alkalosis
Metabolic alkalosis is seen by an increase in the concentration of plasma bicarbonate relative to the concentration of carbonic acid, which shifts the pH to the alkaline side of the physiologic range (case study- pH 7.5). The main causes of metabolic alkalosis are loss of gastric juice or
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Excessive use of antacids (case study-using more than the recommended dose) may also cause metabolic alkalosis by neutralizing gastric acid, which has the same effect as loss from vomiting. Ingesting sodium bicarbonate as an antacid to neutralize gastric acid has the same effect as any other antacid. Any sodium bicarbonate ingested that exceeds the amount required to neutralize the gastric acid will be absorbed, contributing further to metabolic alkalosis.
Chloride depletion also results from loss of GI secretions caused by severe vomiting (case study) or diarrhea. Chloride and bicarbonate are the two main anions in the plasma, and their concentrations vary inversely. When the plasma chloride falls, plasma bicarbonate rises to keep the total concentration of anions in the extracellular fluids in check.
An excess secretion of adrenal corticosteroids that regulate salt and water metabolism (mineralocorticoids) often causes metabolic alkalosis, and potassium depletion. A major site of action of corticosteroids is the distal renal tubule, where the hormone promotes absorption of sodium in exchange for potassium, which is secreted into the tubular filtrate. An excess of mineralocorticoids increases absorption of sodium in
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