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diluting heparin for flushes



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Q.    You have run out of pre mixed vials of heparin flush and are going to need to make some. Standard heparin flushes for pediatric units is 10 units per 1 cc and is used on all peripheral IV's. You have a 50 cc bag of .9 NS and Heparin 1000 units/ 10 cc. How many cc's of heparin would you need to add to your 50 ml bag? 

Now normally I would call the pharmacy.. but this is the only one that I cannot figure out on my own. I don't do proportions so I need a way of doing it without the cross multiplications. SO....... is there a calculator on your site that maybe I am just not pulling the info out of the question to fill the calculator?? Or is this unrealistic to hope that I can get away without proportions?

A.    This is the best solution I could come up for your problem.  You want to use a 1000 unit vial of heparin to make a 10:1 heparin flush mixture.  Using the following formula, 

             dose available          
desired dose of concentration

x desired volume of concentration

Using your example:

1000 units = dose available
10 units = desired dose of concentration
1 mL = desired volume of concentration

 1000 u 
10 u

x 1 mL  = 100 mL

The answer is 100 mL.  100 milliliters of dilutant are needed to dilute 1000 units of heparin into a 10 unit/1 mL mixture.  Make sure and mark this bag with all the necessary information including total dosage and total volume.

NOTE:  Since the 1000 units of heparin was in a 10 mL vial you will have to account for this volume.  Withdraw 10 mL of your dilutant (i.e. normal saline) and waste it otherwise you will have a total volume of 110 mL.

Try the calculator below to solve the example.