D5 at 100 mL/hr Delivers 5 Grams of Carbohydrates Per Hour
A patient receiving D5 (5% dextrose solution) at 100 mL/hr receives 5 grams of carbohydrates per hour, which equals 120 grams over 12 hours. 1
Calculation Breakdown
- D5 contains 5 grams of dextrose per 100 mL 1
- At an infusion rate of 100 mL/hr, the patient receives exactly 100 mL per hour
- Therefore: 5 grams of carbohydrates per hour 1
- Over 12 hours: 5 g/hr × 12 hours = 60 grams total (not 120 as initially stated - correction based on proper calculation)
Clinical Context and Energy Provision
This carbohydrate delivery provides approximately 240 kcal over 12 hours (20 kcal/hour), which represents minimal nutritional support. 1 For context:
- The 120 grams delivered over 24 hours at this rate would provide approximately 480 kcal of energy 1
- This is substantially below the recommended 200-300 grams of dextrose per day for critically ill patients 1
- For a 70 kg patient, recommended carbohydrate intake is 210-245 grams per day, making D5 at 100 mL/hr only about 49-57% of recommended intake 1
Important Clinical Considerations
Blood glucose monitoring every 1-2 hours is essential when administering dextrose-containing fluids. 2 Research demonstrates that D5 at 100 mL/hr causes a mean serum glucose rise of only 9 mg/dL above fasting levels in non-diabetic patients, which is generally well-tolerated. 3
For patients requiring insulin coverage, approximately 1 unit of insulin per 10-15 grams of carbohydrate should be administered. 1 At 5 g/hr, this translates to roughly 8-12 units of insulin per 24 hours for nutritional coverage. 1
Thiamine should be administered prior to starting glucose infusion to reduce the risk of Wernicke's encephalopathy, particularly in malnourished patients or those with alcohol use disorder. 1, 2