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Maintenance IV Fluid Formula:
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The maintenance IV fluid calculation for adults estimates the hourly and daily fluid requirements needed to maintain normal hydration and electrolyte balance in patients who cannot take fluids orally.
The calculator uses the standard maintenance fluid formula:
Where:
Explanation: The formula provides a range of 30-40 mL per kg body weight per day, which is then converted to hourly rates for IV administration.
Details: Accurate fluid calculation is essential for preventing dehydration or fluid overload, maintaining electrolyte balance, and supporting normal physiological functions in hospitalized patients.
Tips: Enter patient weight in kilograms and select the appropriate fluid rate factor (30, 35, or 40 mL/kg) based on clinical assessment and patient needs.
Q1: When should I use 30 vs 40 mL/kg?
A: Use 30 mL/kg for elderly patients or those with cardiac/renal impairment. Use 40 mL/kg for younger patients with normal organ function. 35 mL/kg is often used as a standard starting point.
Q2: Are there adjustments for special conditions?
A: Yes, adjust for fever (add 10-15% per °C above 38°C), sweating, burns, or gastrointestinal losses. Reduce for heart failure, renal failure, or SIADH.
Q3: What about electrolyte replacement?
A: Maintenance fluids typically contain sodium (50-100 mmol/L) and potassium (20-40 mmol/L) in addition to the calculated water volume.
Q4: How often should fluid rates be reassessed?
A: Fluid requirements should be reassessed daily based on clinical status, intake/output measurements, and laboratory values.
Q5: Is this calculation suitable for all adults?
A: This is a general guideline. Individualize based on clinical condition, comorbidities, and ongoing fluid losses. Not suitable for pediatric patients.