Dosage Calculation Question

Ok, Im suppose to use DA for this and Im a bit confused about how to set it up:
Ordered: Heparin gtt 21 u/kg/hr
Supplied: 28,000 u/300ml
Weight: 170lbs
How many ml/hr will be administered?
I have a feeling I am way overthinking this since mL/ hr is usually just total volume / # hrs to infuse. The persons weight equals 77 Kg. There are 100 units per 1 mL. The 21 units become 0.21 mL. The 0.21 mL * 77 kg= 16 mL total to give to patient.
Im stuck at what to do at this point. Any help? 

Sep 29, '13I'm just a student, too.
I get 17ml/hr because I didn't round until the end. I may be wrong 


Sep 29, '1321x77=1617units/hr
28,000u 1,617u
 = 
300ml 17.325ml
17ml/h
The 28,000u/300ml is where you get 100u/ml (but I didn't round it like that) 

Sep 29, '13Quote from PedsHopefulThere are not 100 units/mL. There are 28,000 units of heparin in 300 mL of fluid which is 93 u/mL.Ok, Im suppose to use DA for this and Im a bit confused about how to set it up:
Ordered: Heparin gtt 21 u/kg/hr
Supplied: 28,000 u/300ml
Weight: 170lbs
How many ml/hr will be administered?
I have a feeling I am way overthinking this since mL/ hr is usually just total volume / # hrs to infuse. The persons weight equals 77 Kg. There are 100 units per 1 mL. The 21 units become 0.21 mL. The 0.21 mL * 77 kg= 16 mL total to give to patient.
Im stuck at what to do at this point. Any help?
You are to administer 21u/kg/hr to a patient who weighs 77 kg.
21 u/kg/hr x 77 kg x 1 mL/93 units = 17 mL/hr. 
Sep 30, '13Once you get kg amount (77.27)...The rest is easy..
Want
 x Volume.
Have
What you want is 1623 units a hour (77.27 x 21) rounded
What you have is 28,000
divide 1623 by 28000 then times it by your volume. Answer is 17.38 or 17 mls/hr 