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Maintenance IV Fluid Rate (4-2-1 Rule)
Input
Maintenance Fluid Rate
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Daily Maintenance Volume
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About
The 4-2-1 rule (Holliday-Segar method) is the standard method for calculating maintenance intravenous fluid requirements. It estimates the hourly fluid rate needed to replace normal daily fluid losses from metabolism, respiration, and urinary output. This is the baseline rate; additional fluids may be needed for ongoing losses (e.g., fever, burns, surgical drains).
Formula
First 10 kg of body weight: 4 mL/kg/hr
Next 10 kg (11–20 kg): 2 mL/kg/hr
Each additional kg (>20 kg): 1 mL/kg/hr
Example: 70 kg patient = 40 + 20 + 50 = 110 mL/hr
Interpretation
| Weight Range | Rate | Example |
|---|---|---|
| 0 – 10 kg | 4 mL/kg/hr | 8 kg → 32 mL/hr |
| 11 – 20 kg | 40 + 2 mL/kg/hr | 15 kg → 50 mL/hr |
| > 20 kg | 60 + 1 mL/kg/hr | 70 kg → 110 mL/hr |
FAQ
Disclaimer
For educational and informational purposes only. Not intended to replace professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare professional.