Oral Rehydration Volume Calculator

How to calculate Oral Rehydration Volume?

The mL-per-kilogram method is the gold standard for clinical rehydration. It calculates the specific fluid volume required based on the individual's body weight and the severity of fluid loss. By multiplying the patient's weight by a standardized target volume (measured in mL/kg), clinicians can ensure the patient receives enough fluids to restore balance without risking over-hydration.

Total Volume (mL) = Weight (kg) × Target (mL/kg)

Using the Volume Calculator: an example

To illustrate, consider a child who weighs 10 kg and has been diagnosed with moderate dehydration. The clinical recommendation for moderate dehydration is typically a target of 75 mL/kg to be administered over a 4-hour period.

Step-by-step calculation

1. Identify weight: The child's weight is 10kg.
2. Select target: For moderate dehydration, the target is 75mL/kg.
3. Multiply: 10kg × 75mL/kg = 750mL total volume needed.
4. Divide by 4 hours: 750mL ÷ 4 hours = 187.5mL per hour.

Frequently Asked Questions

What is ORS?
Oral Rehydration Salts (ORS) is a mixture of clean water, salt, and sugar. It is used to replace fluids lost due to diarrhea or vomiting, preventing dehydration. It works by using the glucose in the sugar to help the intestines absorb the salt and water more effectively.

When to seek emergency care?
You should seek immediate medical attention if a person shows signs of severe dehydration, such as extreme lethargy or unconsciousness, very sunken eyes, an inability to drink or swallow, or if the person has a very weak pulse or rapid breathing.

What is the difference between mild and moderate dehydration?
Mild dehydration typically involves increased thirst and slightly dry mucous membranes. Moderate dehydration presents more clearly with signs such as decreased urine output, a rapid heart rate, and decreased skin turgor (the skin takes longer to return to its original position when pinched).