Maintenance Fluids (4-2-1)
Maintenance Fluids (4-2-1) - a deterministic tool in Sophie Well's Clinical Math & Conversions group.
Open the Maintenance Fluids (4-2-1) → Runs in your browser. No signup, no tracking.
What this is
Compute pediatric maintenance IV fluid rate using the Holliday-Segar 4-2-1 rule: 4 mL/kg/hr for the first 10 kg, 2 mL/kg/hr for the next 10 kg, and 1 mL/kg/hr for every kilogram thereafter. Sophie Well takes a weight in kilograms and returns the hourly rate along with the daily volume (the 100-50-20 daily equivalent), so a clinician can prescribe either an hourly drip or a 24-hour total without recomputing.
When to use it
Use this when prescribing maintenance fluids for an admitted pediatric patient, when checking that an existing order matches the weight on chart, or when a resident wants to confirm a back-of-envelope calculation before the order goes into the EHR. The 4-2-1 rule assumes a euvolemic patient at baseline; bolus replacement, ongoing losses, and dextrose strategy live outside this tool. Modern practice favors isotonic maintenance fluids (per AAP 2018 guidance) over the historical hypotonic default - the rate is the math; the fluid composition is a clinical decision.
References
Holliday MA, Segar WE. Pediatrics 1957. 4-2-1 maintenance rule.
Worked example: Maintenance: 110 mL/hr (40 + 20 + 50)
Sophie Well is a reference and educational tool. Not medical, legal, or financial advice. Does not replace clinician judgment, professional billing review, or legal counsel.