Calculation of Table Salt in 3% Hypertonic Saline
One liter of 3% hypertonic saline contains approximately 5.13 teaspoons of table salt.
Understanding 3% Hypertonic Saline Composition
- 3% hypertonic saline contains 513 mmol/L of sodium (Na+) as shown in the physico-chemical properties table 1
- This concentration is significantly higher than normal saline (0.9%), which contains only 154 mmol/L of sodium 1
- The osmolarity of 3% saline is 1026 mOsmol/L, making it hyperosmolar compared to plasma 1
Calculation Method
To determine the amount of table salt (NaCl) in 3% hypertonic saline:
- 3% saline means 3 g of NaCl per 100 mL of solution
- Therefore, 1 L (1000 mL) contains 30 g of NaCl 1
- The molecular weight of sodium chloride (NaCl) is approximately 58.44 g/mol
- One teaspoon of table salt weighs approximately 5.85 grams 1
- 30 g ÷ 5.85 g/teaspoon = 5.13 teaspoons
Clinical Relevance of 3% Hypertonic Saline
3% hypertonic saline is commonly used for:
The primary mechanism of action is through osmotic fluid shifts from intracellular to intravascular space 1
Administration Considerations
- 3% hypertonic saline can be safely administered peripherally at rates up to 999 mL/hr in emergency situations 3
- For treatment of hyponatremia, careful monitoring is required to prevent overly rapid correction 1, 2
- Alternative formulations with sodium acetate buffer can reduce chloride load while maintaining hyperosmolarity 4
Safety Considerations
When using 3% hypertonic saline for neurologic emergencies:
- Monitor serum sodium levels regularly 5
- Target correction rates should not exceed 0.5-1 mmol/L/hr for chronic hyponatremia 1
- Faster correction (up to 2.4 mmol/L/hr) may be appropriate for acute, symptomatic hyponatremia 2
- Using a sliding-scale protocol can help maintain sodium in target range (136-145 mEq/L) 5
Potential complications include hypernatremia and osmotic demyelination syndrome, though these are rare when appropriate protocols are followed 1