A sodium deficit may be seen in all forms of dehydration, although it is most pronounced in hyponatremic patients.

Formula used:

Na deficit = 0.6 × wt(kg) × [desired Na (mEq/L) - Measured Na (mEq/L)]

Reference:

Isakow W. Common Equations and Rules of Thumb in the Intensive Care Unit. In: Kollef M, Isakow W, eds. 2nd ed. The Washington Manual of Critical Care. Philadelphia, PA: Lipincott Williams & Wilkins; 2012:641-645.