The next step is to determine the CHO percentage. CHOs should make up 50-100% of the NPCs. Infants usually start at 80:20 CHO:lipids and advance to 70:30 for the final concentration. Older children can often be started at 60:40 and stay on the same substrate composition as the NPCs are advanced to goal. The exact substrate composition may be adjusted for clinical factors such as insulin resistance or hypertriglyceridemia. The dextrose concentration to order can be calculated as follows: NPCs x %CHO / 3.4 Kcal/gm = gm dextrose in TPN bag (IV dextrose only has 3.4 cal/gm because of extra water) gm dextrose x 100 / total cc fluid = final dextrose concentration Example: NPCs of 500 with 60% CHO in total volume of 850 cc 500 x 0.6 / 3.4 = 88 gm dextrose 88 x 100 / 850 cc = 10% dextrose final concentration The dextrose concentration should not increase by more than 2-5% per day and usually should not exceed 20% Finally determine the glucose infusion rate (GIR) in mg/kg/min.