Adrogué-Madias: expected Na change per liter of IV fluid.
ΔNa = (Infusate Na − Serum Na) / (TBW + 1). TBW ≈ weight × 0.6 (men) or 0.5 (women). Correct hyponatremia ≤ 8–10 mEq/L in 24 hours to prevent osmotic demyelination syndrome. For symptomatic hyponatremia, 3% saline may raise Na 1–2 mEq/L per hour initially.