D5 Infusion Rate Increase: Carbohydrate Delivery Calculation
When increasing D5 (5% dextrose) from 100 mL/hr to 150 mL/hr, you deliver 7.5 grams of carbohydrate per hour.
Calculation Breakdown
D5 contains 5 grams of dextrose per 100 mL of solution. This is a straightforward concentration calculation:
- At 100 mL/hr: 5 g/100 mL × 100 mL = 5 g CHO/hour
- At 150 mL/hr: 5 g/100 mL × 150 mL = 7.5 g CHO/hour
The increase represents an additional 2.5 grams of carbohydrate per hour.
Clinical Context
While the provided evidence focuses primarily on emergency medications and critical care scenarios rather than basic IV fluid calculations, the pediatric emergency guidelines 1 reference dextrose concentrations for various clinical situations, confirming standard dextrose solution compositions.
Important Considerations:
Glucose delivery rate: At 150 mL/hr of D5, you're delivering approximately 5.2 mg/kg/min in a 70 kg adult, which approaches the recommended maximum glucose administration rate of 5 mg/kg/min for ICU patients 2
Hyperglycemia risk: Even modest dextrose infusions can cause significant hyperglycemia. Research shows that 500 mL of D5 in normal saline caused plasma glucose to exceed 10 mmol/L in 72% of non-diabetic surgical patients 3, and continuous infusion at 100-200 mL/hr raised serum glucose by 9-24 mg/dL above baseline 4
Clinical monitoring: Blood glucose should be monitored when administering continuous dextrose infusions, particularly in critically ill patients, those with diabetes, or patients receiving insulin therapy
The calculation itself is simple mathematics based on the 5% concentration, but the clinical implications of increased glucose delivery warrant careful consideration in patient management.