# What is a free water deficit?

## What is a free water deficit?

The Free water deficit is the amount of free water a patient has lost. How do you know how much water a patient has lost? Much of the water is stored in the intracellular space and we can’t easily measure that. Sodium Concentration becomes a good surrogate for how much free water a patient has lost.

## How do you calculate a free water deficit?

Background: The water-deficit equation {WD(1) = 0.6 × B(m) × [1 – (140 ÷ Na(+))]; B(m) denotes body mass} is used in medicine and nutrition to estimate the volume (L) of water required to correct dehydration during the initial stages of fluid-replacement therapy.

What is a free water?

“Free water” refers to the excess water excreted in the urine above the amount of water needed to rid the osmolar load in the same concentration of plasma.

### What is free water?

Definition of free water : water that is free: a : water that will settle from oil rapidly. b : water in ore analysis that is not in chemical combination with mineral matter. c : ground water free to move in response to gravity. — called also gravitational water.

### How do you calculate free water deficit in hyponatremia?

V. Calculation: Free Water Deficit (Hypernatremia)

1. Free Water Deficit (FWD in L) = (Normal TBW) – (Current TBW)
2. Free Water Deficit (FWD in L) = (Normal TBW) * (sNa – 140) / 140.
3. Free Water Deficit (FWD in L) = (Normal TBW) * (sNa/140 – 1)
4. Adjustments to Total Body Water.

What is free water IV fluids?

The physician’s concern with giving sodium or dextrose to a patient with CHF and a high blood sugar led to an order to change the patient’s peripheral IV to “free water” at 100 mL/hr. “Free water” refers to water not associated with organic or inorganic ions.

#### What is bound water and free water?

Water that can be extracted easily from foods by squeezing or cutting or pressing is known as free water, whereas water that cannot be extracted easily is termed as bound water.

#### How do you calculate free water in tube feeding?

Free Water Calculation

1. Formula A is 70% free water.
2. Total volume of formula prescribed is 1300 mL.
3. Estimated patient fluid needs = 1600 mL per day.
4. 1300 mL x 0.70 = 910 mL free water available to meet patient fluid needs.
5. 1600 mL – 910 mL = 690 mL additional free water needed to meet 100% estimated fluid needs.

What is normal free water clearance?

With diminished ADH secretion and normal renal function, a substantial volume of free water is cleared in response to hypotonic stimuli. A positive free water clearance > 0.4 L/day in hypertonic conditions or a negative free water clearance during hypotonicity confirms an abnormal ADH-renal axis response.

## How is pediatric sodium deficit calculated?

VI. Protocol: Calculate Sodium Deficit and Sodium Requirement

1. Calculate Deficit. Formula: 0.6 x (weight kg) x (135 – Serum Sodium) Where 0.6 is volume of distribution (per kg)
2. Add Maintenance. Formula: 3 meq/kg/day x (weight kg)
3. Subtract Replacement given Phase 1. Phase 1 Fluid bolus.

## How much free water is in LR?

IV Fluids: Choosing Maintenance Fluids