Maintenance Fluids Calculations
Maintenance Fluids (4-2-1 Rule)
kg
Hourly Rate:
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mL/hr
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–
Calculates maintenance fluid requirements by weight.
Why Use
Weight-based dosing of fluids is important given the fact that a patient's total body water (and blood volume) are based on their weight.
When to Use
Determining IV fluid rates for patients who are not taking oral fluids (either from vomiting or being NPO). Determining IV fluid requirements for patients who are dehydrated or have insensible losses or third spacing.
Formula
Calculated using the “4-2-1” Rule: For 0-10 kg: 4 mL/kg/hr For >10-20 kg: 40 mL + 2 mL/kg/hr for every kg >10 kg For >20 kg: 60 mL + 1 mL/kg/hr for every kg >20 kg
Advice
Past, current, and future hydration status should always be considered when prescribing maintenance fluids, as under-dosing will lead to dehydration and renal insufficiency, and over-dosing may lead to fluid overload and edema in some patients.