In the PN scenario, how many grams of dextrose are included?

• A. 250 g
• B. 300 g
• C. 350 g
• D. 400 g

Answer: (B)

In PN calculations, you convert the carbohydrate portion of total daily energy into grams of dextrose using the energy yield per gram of dextrose. If the plan specifies that 60% of total energy comes from carbohydrate and the total daily energy is 1700 kcal, then carbohydrate calories are 0.60 × 1700 = 1020 kcal. Dextrose provides about 3.4 kcal per gram in PN calculations, so the grams of dextrose needed are 1020 ÷ 3.4 = 300 g. So the PN would include 300 g of dextrose. If you used an energy value of 4 kcal/g (for dextrose anhydrous), you’d get 255 g, which shows why 3.4 kcal/g is the standard in this context.