1. What is the 4-2-1 Maintenance Fluid Rule?

The 4-2-1 rule (also known as the Holliday-Segar method) is a formula for calculating maintenance fluid requirements in pediatric and adult patients. It provides an estimate of the hourly fluid needs based on body weight.

2. How Does the Calculator Work?

The calculator uses the 4-2-1 rule:

Example Calculation:

• 5 kg patient: 5 × 4 = 20 ml/h
• 15 kg patient: (10 × 4) + (5 × 2) = 40 + 10 = 50 ml/h
• 25 kg patient: (10 × 4) + (10 × 2) + (5 × 1) = 40 + 20 + 5 = 65 ml/h

3. Importance of Maintenance Fluid Calculation

Details: Accurate fluid calculation is essential for maintaining proper hydration, electrolyte balance, and preventing complications of both dehydration and fluid overload, especially in pediatric patients and critical care settings.

4. Using the Calculator

Tips: Enter patient weight in kilograms. The calculator will provide both hourly fluid rate and 24-hour total volume. Always consider clinical context and adjust based on individual patient needs.

5. Frequently Asked Questions (FAQ)

Q1: When is the 4-2-1 rule typically used?
A: It's commonly used for pediatric patients but can be applied to adults as well for estimating maintenance fluid requirements.

Q2: Are there situations where this rule shouldn't be used?
A: Yes, in patients with renal impairment, heart failure, electrolyte imbalances, or those requiring specialized fluid management, this rule may need modification.

Q3: What fluids are typically used for maintenance?
A: Isotonic solutions like 0.9% saline or balanced crystalloids are commonly used, often with dextrose for pediatric patients.

Q4: How should this be adjusted for fever or other conditions?
A: Additional fluids may be needed for fever (approximately 10-15% increase per degree Celsius above normal), diarrhea, vomiting, or other ongoing losses.

Q5: Is this rule appropriate for all age groups?
A: While developed for pediatric patients, the principle can be applied to adults, though clinical judgment should always be exercised.