Acidosis

Metabolic acidosis occurs when bicarbonate is lost from extracellular fluid or noncarbonic acids increase and it can happen quickly or over an extended period. The body’s buffering systems usually maintain arterial pH and compensate for excess acid. According to Huether and McCance, “When acidosis is severe, buffers become depleted, cannot compensate, and the ratio of bicarbonate to carbonic acid decreases to less than 20:1” (p. 116). Metabolic acidosis is manifested by changes in the function of the cardiovascular, gastrointestinal, respiratory and neurologic systems. Lethargy and headache are early symptoms and progression to severe acidosis includes coma. Kussmaul respirations are deep and rapid and are and effort to compensate for increased metabolic acids. These occur as an attempt by the body to rid itself of carbon dioxide, which decreases carbonic acid, therefore increasing pH. Other symptoms include abdominal discomfort, diarrhea, vomiting, nausea, anorexia, arrhythmias, hypotension and even death.

A decrease in alveolar ventilation in relation to the metabolic production of carbon dioxide produces respiratory acidosis by an increase in carbonic acid (Huether & McCance, 2008, p. 117). An excess of carbon dioxide in the blood occurs with depression of ventilation. Causes include bronchitis, asthma, emphysema, pulmonary edema, pneumonia, broken ribs, respiratory muscle paralysis, and depression of the respiratory center from drugs or head injury. Signs and symptoms include coma, convulsions, tremors, muscle twitching, disorientation, lethargy, restlessness, breathlessness, blurred vision and headache. Skin may appear flushed and warm due to vasodilation caused by elevated carbon dioxide. Respiratory rate is rapid at onset and slowly becomes depressed as the respiratory center adapts to increasing levels of carbon dioxide.

REFERENCES

Huether, S. & McCance, K. (2008). Understanding Pathophysiology (4th Ed). St. Louis, MO: Mosby...