Pharmacy Tech Study

Question about TPN:

by melanie
(florida)

Question about (Total Parenteral Nutrition)TPN: A TPN order calls for these amounts to be made from the items on hand. The total volume is to be 1000ml. how much of each ingredient, additives, and sterile water do you need to prepare this TPN?:

AMINOSYN 4.25 % + Dextrose 20%

On hand are aminosyn 8.25% 1000ml
Dextrose 50%, 500ml

The TPN order for additives are:
KCL 24 mEq
MVI 5 ml
NACL 24 mEq
while on hand are KCL 2mEq/ml 20 ml
mvi 10 ml
nacl 4.4 mEq/ml 20 ml

please show the solution and explanation....showing the amounts for aminosyn, dextrose, KCL, MVI, NaCl, and sterile water.

thank you very much.......

Comments for
Question about TPN:

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Aug 26, 2010

answer
by: Barb

The following formula is one method which can be used to determine the amount of one mixture required to make a mixture of lesser strength.

amount needed/% wanted = amount prescibed/% have

aminosyn: x/4.25% = 1000 mL/8.25%
8.25x = 4250
x = 515 mL

dextrose: x/20% = 1000 mL/50%
50x = 20,000
x = 400 mL

When determining the amount needed of ingredients which have concentrations expressed in mEq/mL, it may be easier to set up a proportion instead of trying to use the formula. In this case, using proportions:

KCL: 24/x = 2/1
x = 12 mL

NaCl: 24/x = 4.4/1
x = 5.5 mL

MVI: 5 mL

the total volume so far for the TPN is
5 + 5.5 + 12 + 400 + 515 = 937.5 mL
so you will need to add 62.5 mL

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