Dimensional Analysis - Math Problem


Heparin bolus 60 units/kg IV. Weight 98 kg.  Heparin comes 10,000 Units/ml in a 5 ml vial.  How many ml of heparin should the nurse draw into the syringe?   Answer is to the nearest tenth.

Can someone solve this using dimensional analysis?

I know the answer, we have an answer key but no explanation.

I feel like I am missing a step. I calculated 50,000 since there are 10,000 units in a ml and we are using a 5 ml vial, I just don't know how to show it on the dimensional analysis.

Here is my dimensional analysis:

5ml/50,000 units x 60 units/kg x 98 kg/ 1 = 29400/50000 = 0.6 ml


Your answer is correct, and the problem is properly formatted.  If it were me, I would have used 1 mL/10,000 units, but that is just personal preferance.

If you are unfamiliar with dimensional analysis, you might find the attachments to the first two posts in this thread helpful.

Best wishes, and thank you for showing us what you had already done.

Honyebee, CNA

Specializes in Customer service.

60 units/kg IV. Weight 98 kg.  Heparin comes 10,000 Units/ml in a 5 ml vial.

I'd do it this way: 



Rionoir, ADN, RN

Specializes in Mental Health.

You are confused because you are trying to incorporate a distractor into your math. 5 mL vial, 100 mL vial... it doesn't matter.

1 mL / 10,000 units