How much fluid does an infusion of 100 mL per hour over 24 hours deliver, and is that volume appropriate for a 38‑kg pediatric patient?

Fluid Volume Calculation for 100 mL/hr Infusion

An infusion rate of 100 mL/hr delivers 2,400 mL (2.4 liters) over 24 hours, which is calculated by multiplying 100 mL/hr × 24 hours. 1

Mathematical Calculation

• 100 mL/hr × 24 hours = 2,400 mL total volume 1
• This equals 2.4 liters over the 24-hour period 1

Clinical Context for a 38-kg Pediatric Patient

Maintenance Fluid Requirements

Using the standard pediatric maintenance fluid calculation (4-2-1 rule): 2

• First 10 kg: 4 mL/kg/hr = 40 mL/hr 2
• Second 10 kg: 2 mL/kg/hr = 20 mL/hr 2
• Remaining 18 kg: 1 mL/kg/hr = 18 mL/hr 2
• Total maintenance rate = 78 mL/hr or 1,872 mL per 24 hours 2

Assessment of 100 mL/hr Rate

The rate of 100 mL/hr (2,400 mL/24 hours) is appropriate for maintenance fluid therapy in a 38-kg child, as it provides approximately 128% of calculated maintenance requirements. 2 This slightly higher rate may be reasonable depending on clinical context (ongoing losses, fever, increased insensible losses). 2

Critical Distinctions: Maintenance vs. Resuscitation

When 100 mL/hr is NOT Appropriate

Do not use maintenance rates like 100 mL/hr for acute resuscitation scenarios. 2, 3 In shock, sepsis, or severe dehydration:

• Administer 20 mL/kg boluses rapidly (760 mL for a 38-kg child) 2, 3
• Each bolus should be given over 5-15 minutes, not as a slow infusion 3
• Reassess after each bolus and repeat as needed up to 40-60 mL/kg in the first hour if intensive care is available 3
• This would be 1,520-2,280 mL in the first hour for a 38-kg child, far exceeding what 100 mL/hr would deliver 3

Continuous Infusion Recommendations

For parenteral nutrition or lipid emulsions in neonates and infants, continuous infusion over 24 hours is recommended rather than cyclic administration. 1 This principle supports steady-state delivery for certain therapies. 1

Common Pitfalls to Avoid

• Do not confuse hourly rates with bolus volumes - 100 mL/hr is a maintenance rate, not a resuscitation bolus 2, 3
• Do not use maintenance calculations during acute hemodynamic instability - these patients require rapid boluses with frequent reassessment 3
• Do not exceed 60 mL/kg/day (2,280 mL for 38 kg) of crystalloid in trauma patients, as higher volumes are associated with worse outcomes 1, 3
• Monitor for volume overload, especially in patients with cardiac or renal disease, even at maintenance rates 2, 3