Management of High Anion Gap Metabolic Acidosis

Initial Resuscitation and Stabilization

Administer 0.9% normal saline at 15-20 mL/kg/hour to restore intravascular volume and renal perfusion in adults with high anion gap metabolic acidosis, according to the American College of Medical Toxicology 1, 2, 3
Continue aggressive fluid resuscitation as the cornerstone of initial management regardless of etiology, as recommended by the American College of Emergency Physicians 1, 2
Obtain arterial blood gas, serum electrolytes with calculated anion gap, plasma glucose, serum ketones, lactate, BUN/creatinine, osmolality, and urinalysis to identify the underlying cause, as suggested by the Society of Critical Care Medicine 1, 3

Immediate hemodialysis is mandatory if anion gap >27 mmol/L with suspected ethylene glycol or methanol poisoning, according to the European Society of Intensive Care Medicine 4, 1, 2
Consider hemodialysis if anion gap is 23-27 mmol/L, as recommended by the American College of Medical Toxicology 4, 2
Use intermittent hemodialysis rather than continuous renal replacement therapy when available, as suggested by the International Society of Nephrology 4, 2

Correct life-threatening hyperkalemia immediately, particularly in bowel infarction or severe acidosis, according to the American Heart Association 3
Correct serum sodium for hyperglycemia by adding 1.6 mEq for each 100 mg/dL glucose >100 mg/dL, as recommended by the Endocrine Society 3

Therapeutic endpoints include capillary refill ≤2 seconds, normal mental status, urine output >1 mL/kg/hour, ScvO2 >70%, and pH normalization, as suggested by the Society of Critical Care Medicine 5, 2

Do not rely solely on anion gap magnitude without clinical context, as recommended by the American College of Emergency Physicians 1, 2
Be aware that anion gap may overestimate severity with concomitant AKI or ketoacidosis, or underestimate severity with hypoalbuminemia, according to the National Kidney Foundation 1, 2
Remember that elevated glycolate can falsely elevate plasma lactate on some analyzers, as suggested by the American Association for Clinical Chemistry 1

Stop hemodialysis when anion gap <18 mmol/L, ethylene glycol/methanol concentration <4 mmol/L, or acid-base abnormalities are corrected, according to the European Society of Intensive Care Medicine 4