endocrine and metabolic disorders
Metabolic Acidosis
Diagnosis of Metabolic Acidosis
Arterial blood gas (ABG) and serum electrolyte measurement Anion gap and delta gap calculated Winters formula for calculating compensatory changes Evaluation for cause Recognition of metabolic acidosis and appropriate respiratory compensation are discussed in Diagnosis . Determining the cause of metabolic acidosis begins with the anion gap. The cause of anelevated anion gapmay be clinically obvious (eg, hypovolemic shock, missed hemodialysis), but if not, blood testing should include BUN (bloodureanitrogen) Creatinine Glucose Lactate Possible toxins Salicylate levels can be measured in most laboratories, but methanol and ethylene glycol frequently cannot; their presence may be suggested by presence of an osmolar gap. Calculated serum osmolarity (2 [sodium]+[glucose]/18+BUN/2.8+blood alcohol/5, based on conventional units) is subtracted from measured osmolarity. A difference>10 implies the presence of an osmotically active substance, which, in the case of a high anion gap acidosis, is methanol or ethylene glycol. Although ingestion ofethanolmay cause an osmolar gap and a mild acidosis, it should never be considered the sole cause of a significant metabolic acidosis. loss, which most commonly occurs in renal tubular acidosis ( Diagnosis is discussed elsewhere). Calculation of the anion gap None 