# Heparin math question

Hi all, I have a heparin math question. I have been practicing my drug calc because I go back to school in a few weeks and we have an exam on the first day. The infamous 100% or fail math exam. The instructors sent a study guide which included heparin math. I have a question on how my instructor got a certain answer doing a step they did.

This is the question:

6. A patient is on a Heparin drip of 25,000 units of Heparin in 250mL of D5W. The Heparin drip has been set at 14 mL/hr. The PTT comes back at 75. The order reads: I the PTT is between 71 and 90, decrease the drip by 3 units/Kg/hour. The patient weights 220 pounds. Based on this order, you reset the pump at __________ mL/hour.

This is my instructors work:

6. Amount you have: 25,000 units/250ml = 1000 units per ml

Desired amount: decrease current rate by 3units/100kg/hour = 3000 units

Pt weighs 220lbs/2.2 = 100 kg

Pump currently running at 14ml/hr or 14000 units per hour

14000 unit - 3000 units = 11000 units or 11ml/hr

The bolded part is the only thing that doesn't make sense to me. Mathematically it = 100. I worked it out using 100 and i understand the process, I just don't understand how they can get 1000. Is there some secret to the heparin math? I didn't see anything online when i googled heparin math...

Thank you in advanced for your responses.

Specializes in Critical Care.

You are correct, your instructor is wrong. Your instructor has apparently just flunked themselves out of nursing school.

Thank you, I was driving myself crazy!

Specializes in Critical Care, ED, Cath lab, CTPAC,Trauma.

You are correct, your instructor is wrong. Your instructor has apparently just flunked themselves out of nursing school.

Is there some secret to the heparin math?
there's no such thing as heparin math... there's just plain old math... there is algebra and trigonometry and geometry... but those tools apply universally to any subject...

there's nothing special about the math involved in performing dosage calculations... which is really just dilutions and flow rates.

there's no such thing as heparin math... there's just plain old math... there is algebra and trigonometry and geometry... but those tools apply universally to any subject...

there's nothing special about the math involved in performing dosage calculations... which is really just dilutions and flow rates.

This. People seem to flip their lids about "med math" and "dimensional analysis" like it's a mysterious beast from the planet wonkalonka LOL It is the same math you did in math class, dimensional analysis is just math and is the same math you did in math class (and chem class), it's all just math :)

(Not saying OP flipped their lid...I have seen people over and over question what they know is the right answer because the book answer is wrong. Always remember the book could be wrong! "Made by humans" is the disclaimer (or at least SHOULD be) for any textbook LOL

I hadn't done any math problems relating to heparin before and wasnt sure if there was a special formula to use. That is what I meant by special heparin math. Since I hadnt ever done this before I questioned myself rather than the teacher who had been doing this for many years.

:]

I hadn't done any math problems relating to heparin before and wasnt sure if there was a special formula to use. That is what I meant by special heparin math. Since I hadnt ever done this before I questioned myself rather than the teacher who had been doing this for many years.

:]

When we did heparin problems it was introduced as "heparin math", which made everyone go bananas LOL! Actually all "nursing math" seems to make people go nuts because most of our instructors made it out as some mysterious new way of calculating.

Good luck on your math comp!!

dimensional analysis is just math and is the same math you did in math class (and chem class)
And it's not even DIMENSIONAL analysis.

Dimensions are length, mass, temperature, etc.

Kilograms, milliliters, teaspoons, etc are NOT dimensions, they are UNITS.

And it's not even DIMENSIONAL analysis.

Dimensions are length, mass, temperature, etc.

Kilograms, milliliters, teaspoons, etc are NOT dimensions, they are UNITS.

That's so funny that you say that because I always wondered how they came up with "dimensional analysis" because the first time I heard the term I wondered what dimensions we were analyzing LOL! I've always thought it was such an odd term to use.

That's so funny that you say that because I always wondered how they came up with "dimensional analysis" because the first time I heard the term I wondered what dimensions we were analyzing LOL! I've always thought it was such an odd term to use.
A few lives ago I was introduced to dimensional analysis as it pertained to derivation of dimensionless numbers with physical applications (e.g., Reynolds number for flow analysis [laminar v. turbulent], Mach number for the speed of sound, etc).

In chemistry (which is really the field to which "med math" belongs), we are not typically concerned with dimensional analysis but rather consistency of units of measurement.

This stuff is just foundational and basic mathematics and chemistry.

I'm of the opinion that the biggest obstacle faced by most students is simply their own belief of themselves that they are unable to comprehend the topic.