Oral rehydration therapy (ORT) is a safe and effective way to treat dehydration caused by conditions like diarrhea and vomiting. The foundation of ORT is the oral rehydration solution (ORS), a simple mixture of water, salts, and sugar that helps the body absorb fluids more effectively than water alone. Proper volume is determined by the patient's weight, the severity of dehydration, and ongoing fluid loss.
Step 1: Assess the Level of Dehydration
Before you can calculate the appropriate volume, you must assess the patient's level of dehydration. This can be done by observing key signs and symptoms.
- Mild Dehydration: Signs may include increased thirst, slightly dry mouth, and normal urine output. In children, a sunken fontanelle might be slightly noticeable. Fluid loss is estimated at less than 5% of body weight.
- Moderate Dehydration: Symptoms include greater thirst, a very dry mouth, reduced or dark urine, and possibly sunken eyes. The patient may also feel dizzy or tired. Fluid loss is estimated at 5–10% of body weight.
- Severe Dehydration: This is a medical emergency and requires immediate intravenous (IV) fluid administration. Signs include lethargy or unconsciousness, very dry mucous membranes, low blood pressure, and a weak pulse.
Step 2: Calculate the Initial Rehydration Fluid Volume
The initial rehydration phase typically takes place over a 4-hour period. The amount of ORS given is based on the patient's body weight and the degree of dehydration.
- For Mild Dehydration: A guideline is to administer a certain volume of ORS per kilogram (kg) of body weight over 4 hours.
- For Moderate Dehydration: A guideline is to administer a different volume of ORS per kilogram (kg) of body weight over 4 hours.
Step 3: Account for Ongoing Fluid Loss
After calculating the initial rehydration volume, it is crucial to replace fluids lost from continued diarrhea or vomiting to prevent a return to a dehydrated state. This is called the maintenance phase.
- For Diarrheal Stools: For each watery or loose stool, give an additional amount of ORS. While a guideline exists, age-based recommendations are often used.
- Age 2–9 years: Specific volumes are typically recommended after each watery stool.
- Age 10 years or older: Larger volumes are typically recommended, or as much as wanted after each loose stool.
- For Vomiting Episodes: Wait a short period after a vomiting episode, then resume giving ORS in smaller, more frequent amounts. A general replacement estimate is often based on body weight for each episode.
Practical Administration and Monitoring
Administering ORS correctly is as important as calculating the volume. Give the solution in small, frequent amounts to reduce the risk of vomiting. For children, a spoon or syringe is effective. Continuous monitoring of the patient's condition is essential to ensure rehydration is successful.
Comparison of ORS Administration Methods
| Feature | Small, Frequent Sips (Oral) | Nasogastric (NG) Tube | Intravenous (IV) Therapy |
|---|---|---|---|
| Best For | Mild to moderate dehydration; patients who can drink voluntarily. | Patients who refuse to drink or have persistent vomiting. | Severe dehydration or shock; immediate medical emergency. |
| Administration | Spoon, syringe, or cup; often in small increments initially. | Slow, continuous drip via a tube inserted through the nose into the stomach. | Fluid infusion directly into a vein; fastest method. |
| Supervision | Can be done at home with caregiver oversight. | Requires trained medical personnel to insert and monitor. | Must be performed in a clinical setting by healthcare professionals. |
| Effectiveness | Highly effective for non-severe dehydration, low risk. | Effective for patients who cannot tolerate drinking by mouth. | Most rapid rehydration for life-threatening dehydration. |
Conclusion: Prioritizing Safe Rehydration
Mastering how to calculate oral rehydration therapy is a critical skill for managing dehydration in non-severe cases. By accurately assessing the level of dehydration and determining the appropriate volume based on body weight, caregivers can effectively restore fluid balance. Ongoing monitoring and replacement of continued fluid losses are key to a full recovery. For cases of severe dehydration, medical attention and intravenous fluids are necessary. Always prioritize patient safety, and when in doubt, consult a healthcare professional. Remember that a properly calculated and administered oral rehydration solution can be a game-changer in restoring health. For more on the clinical guidelines, see the World Health Organization's resources.
How to Make a DIY ORS Solution
If commercial packets are unavailable, the WHO has outlined a simple recipe for a homemade oral rehydration solution.
- Ingredients:
- 1 liter of clean, boiled, and cooled water
- Sugar
- Salt
- Instructions:
- Wash hands and all utensils thoroughly.
- Add the salt and sugar to the water in the specified proportions and stir until fully dissolved.
- Use within 24 hours. The mixture should be slightly diluted for safer use, following specific guidance.
Recognizing When ORT Isn't Enough
While ORT is highly effective for mild to moderate dehydration, it is not a substitute for professional medical care in all situations. Be aware of signs that indicate the need for immediate medical intervention, such as persistent vomiting that prevents drinking, worsening dehydration signs, or lethargy. A low consciousness level or evidence of intestinal blockage are also contraindications.
