If the prescriber orders heparin sodium injection of 10,000 units subcutaneously and the only dose on hand is a 20,000 units/ml syringe, the amount that should be given is 0.5ml (10,000 units, which is the prescribed dose) of the 20,000 units/ml syringe.
Patient is prescribed 10g of Glucose. The glucose is presented as a 5% solution in 500ml Saline. How much of the 5% dextrose saline solution do you need