To calculate the Electrolyte Free Water (\(EFW\)):
\[ EFW = TBW \times \left(1 - \frac{S}{D}\right) \]
Where:
Electrolyte free water is the portion of water in the body that is free of electrolytes. It is an important concept in medicine, particularly in the management of patients with electrolyte imbalances. Electrolyte free water is used to correct hypernatremia (high sodium levels) by diluting the sodium concentration in the body. It is calculated based on the total body water, serum sodium, and desired sodium levels. Understanding and managing electrolyte free water is crucial for maintaining proper hydration and electrolyte balance in patients.
Let's assume the following values:
Using the formula:
\[ EFW = 40 \times \left(1 - \frac{150}{140}\right) = 40 \times \left(1 - 1.0714\right) = 40 \times -0.0714 \approx -2.86 \text{ liters} \]
The electrolyte free water is approximately -2.86 liters (indicating a need to remove water).
Let's assume the following values:
Using the formula:
\[ EFW = 50 \times \left(1 - \frac{145}{140}\right) = 50 \times \left(1 - 1.0357\right) = 50 \times -0.0357 \approx -1.79 \text{ liters} \]
The electrolyte free water is approximately -1.79 liters (indicating a need to remove water).