Clinical Note: For chronic hypernatremia, the recommended correction rate is typically 0.5 mEq/L/hr (max 10-12 mEq/L per 24 hours) to prevent cerebral edema.
Adult Male (0.6)
Adult Female (0.5)
Elderly Male (0.5)
Elderly Female (0.45)
Children (0.6)
D5W (0 mEq/L)
0.45% Normal Saline (77 mEq/L)
0.9% Normal Saline (154 mEq/L)
0.2% Normal Saline (34 mEq/L)
Total Body Water (TBW):–
Free Water Deficit:–
Na+ Change per 1L Infusate:–
Required Infusion Rate:–
Total Volume to Target:–
Understanding Hypernatremia Correction
Hypernatremia is defined as a serum sodium concentration exceeding 145 mEq/L. It represents a deficit of total body water relative to total body sodium. Correcting this imbalance requires a delicate approach, particularly in chronic cases, to avoid the risk of cerebral edema caused by a rapid shift of water into brain cells.
The Adrogue-Madias Formula
This calculator utilizes the Adrogue-Madias formula to estimate the effect of 1 liter of a specific intravenous fluid on the patient's serum sodium level. The formula is:
Change in Serum Na+ = (Infusate Na+ – Serum Na+) / (Total Body Water + 1)
Important Considerations
Acute Hypernatremia: (Developed in < 48 hours) Can be corrected more rapidly (approx. 1 mEq/L/hr).
Chronic Hypernatremia: (Developed in > 48 hours) Must be corrected slowly at a rate of 0.5 mEq/L/hr or 10-12 mEq/L per day.
Free Water Deficit: This represents the amount of pure water needed to return the sodium to a normal level (usually 140 mEq/L).
Example Calculation
A 70 kg male with a serum sodium of 160 mEq/L. We want to lower it to 145 mEq/L using D5W (0 mEq/L sodium).