Question

JL is a 77 yr old male who has just undergone abdominal surgery for an obstruction of the duodenum. The surgeon has ordered TPN for this patient and has asked Pharmacy to prepare it according to the “recipe” below: The final concentration of TPN is 4.25% amino acids and 25% dextrose in a total volume of 1000mls. The surgeon would like an additional 25mEq of Sodium per Liter of TPN. The pharmacy stocks NaCl 23.4% solution. Answer the following questions:

1. What is the volume of NaCl 23.4% solution that should be added to make the 25mEq/L of Sodium? (MW of NaCl = 58.5) ______________________________.

2. If the physician orders 1000ml per day, what is the infusion rate in “ml/hr”? ___________________________.

3. Calculate the amount of Kcal (kilocalories) provided by the dextrose in 1000ml of solution. ___________________________.

4. Calculate the amount of Kcal (kilocalories) provided by the amino acids in 1000ml of solution. ____________________________.

Answer 1

1.

23.5 % Na Cl means 23.5 grams per liter / 58.5 grams per mole =0.401 moles per liter

=401mEq/L of Na+ and Cl-

Therefore

1 L of 23.5% of NaCl = 401 mEq/L

x = 25 mEq/L

x= 25/401* 1L

=0.062*1000ml

=62 ml

62 ml of 23.5% of Nacl is to be add to make 25m Eq/L of Sodium

2.

1000ml per day= 1000/24 hrs

= 42 ml/ hr

3.

1 gm of dextrose = 3.4 kcal

25% Dextrose = 25 grams per 100 ml

250 gm in 1000 ml= 250*3.4 kcal

= 850 kcal

4.

1gm of amino acid = 4 kcal

4.25% amino acid = 4.25 grams per 100 ml

42.5 gm in 1000 ml=42.5*4

=170kcal