Expected sodium change per liter of IV fluid (Adrogué-Madias)

What goes into the Sodium change per liter (Adrogué-Madias)

• Serum sodium (mEq/L)
• Infusate: 3% saline; 0.9% saline; Lactated Ringer's; 0.45% saline; D5W or free water
• Weight (kg)
• Patient: Man < 65; Woman < 65; Man ≥ 65; Woman ≥ 65

How to interpret the result

• Hyponatremia: limit correction to ≤ 8 mEq/L in 24 h in patients at high risk of osmotic demyelination
• Hypernatremia: lower by about 10–12 mEq/L per 24 h in chronic cases

Clinical pearls

• The formula ignores ongoing losses and urine output and often underestimates the rise, especially when ADH secretion stops (e.g., after hypovolemia is corrected).
• Check sodium every 2–4 hours during active correction; have D5W and desmopressin ready for overcorrection.
• Severe symptomatic hyponatremia: 100–150 mL 3% saline boluses aiming for a 4–6 mEq/L rise.

Evidence

1. Adrogué HJ, Madias NE. Hyponatremia. N Engl J Med. 2000;342:1581-1589.

Related workups

Related calculators