Any process that causes a decrease in the pH of the body as a result of the retention of acids or the loss of bicarbonate buffers. Metabolic acidosis is usually categorized by the presence or absence of an abnormal anion gap. The anion gap metabolic acidoses include diabetic, alcoholic, and lactic acidoses; the acidosis of renal failure; and acidoses that result from the consumption of excess acids e.g., salicylates, methanol, or ethanol). Non-anion gap metabolic acidoses occur in diarrhea, renal tubular acidosis, and multiple myeloma.

ETIOLOGY
Possible causes include excessive ingestion of acids, salicylates, methanol, or ethylene glycol; failure of the kidneys to excrete acids (e.g., in renal failure or renal tubular acidosis); ketoacidosis (diabetic, alcoholic, owing to starvation); severe dehydration; diarrhea; rhabdomyolysis; seizures; and shock.

PATIENT CARE
A history is obtained, focusing on the patient's urine output, fluid intake, dietary habits (including recent fasting), associated disorders (e.g., diabetes mellitus and kidney or liver dysfunction), and the use of medications (including aspirin) and alcohol. Arterial blood gas values, serum potassium level, and fluid balance are monitored. The patient is assessed for lethargy, drowsiness, and headache, diminished muscle tone, and deep tendon reflexes. The patient is also evaluated for hyperventilation, cardiac dysrhythmias, muscle weakness and flaccidity, and gastrointestinal distress (e.g., nausea, vomiting, diarrhea, and abdominal pain). Prescribed intravenous fluids, medications such as sodium bicarbonate or insulin, and other therapies such as oxygen or mechanical ventilation are administered. The patient is positioned to promote chest expansion and repositioned frequently. Frequent oral hygiene with sodium bicarbonate rinses will neutralize mouth acids, and a water-soluble lubricant will prevent lip dryness. A safe environment with minimal stimulation is provided, and preparations should be available if seizures occur. Both patient and family are given oral and written information about prescribed medication and managing related diseases.
See: Nursing Diagnoses Appendix

Main entry:
acidosis