# Unit IV Math help!

Published

• Specializes in OB/Peds. Has 4 years experience.

So I understand most IV math help and have pracitced it on my homework but after looking futher ahead there are other problems that i am getting hung up on. They are the same concept but different....

A client is to receive Heparin 25,000 u in 500mL of D5W at 7mL/hr. How many units per hour will the pt receive?

*** So my papers say the answers 350u/hr, but I dont know how to going about the set up when it says 7mL/hr?

27 Posts

Specializes in Telemetry, ER. Has 5 years experience.

looking for units/hour

25,000 units/500ml x 7ml/hour = 175,000 u/500 = 350 units/hour

(the two "ml's" will cancel each other out and you are left with units/hour)

15 Posts

Specializes in OB/Peds. Has 4 years experience.

THANK YOU!!!!

27 Posts

Specializes in Telemetry, ER. Has 5 years experience.

You are very welcome! :typing

15 Posts

Specializes in OB/Peds. Has 4 years experience.

Okay So I am trying to work out this problem and show my work and I am not sure how you came up with 175,000 u.

Thank you so much for your help again. I am really struggling with this units stuff and we werent taught it in school.

THANK YOU THANK YOU THANK YOU

15 Posts

Specializes in OB/Peds. Has 4 years experience.

Okay so I just got it... you times it by 7. Sorry!!!! :)

27 Posts

Specializes in Telemetry, ER. Has 5 years experience.

The way I was taught to is to see what the question is looking for in the answer. (like ml/hour or gtt/min, etc) Then you set the problem up by putting what you need on top for you answer first and on top, then what you need on bottom for you answer next and whatever info is left and any conversions that may be needed. Anything with same units (ml, units) on opposite sides will cancel each other out. You should only be left with units that you need in your answer. (hope that makes sense) And then you just do the math by multiplying everything on top and then everything on bottom and then dividing the two of them.

500ml x 1200 = 600,000

25,000 x 1 hr = 25,000

then divide 600,000 by 25,000 to get 24

27 Posts

Specializes in Telemetry, ER. Has 5 years experience.

Oops...sorry....I put an explanation to your other problem up.

Same concept though.

25,000 x 7 = 175,000

500 x 1 hr = 500

175,000 divided by 500 = 350

15 Posts

Specializes in OB/Peds. Has 4 years experience.

So help again. LOL :)

I am working on a problem now that is same concept.

* Pt is getting Heparin drip at 7ml/hr. The concentration is 25,000u in 250mL of D5W. The doc changes the order to increase the drip to 500units/hr. At what rate would you set the pump at in mL/hr?

so do I set it up differently? I know the answer is 12mL.hr but I dont get how the come to this answer in the book.

THANKS AGAIN PPL. Trying to learn this stuff before Tuesday for test.

27 Posts

Specializes in Telemetry, ER. Has 5 years experience.

Does the question possibly say the dr is increasing the drip BY 500units/hr?

100units = 1 ml

The patient is already getting 7ml (or 700 units) per hour, if you increase it BY 500 units (or 5ml) then the answer would by 12ml/hour (7ml+5ml).

15 Posts

Specializes in OB/Peds. Has 4 years experience.

i think it does. i will check!!!! thanks again

4 Articles; 14,603 Posts

Specializes in med/surg, telemetry, IV therapy, mgmt. Has 40 years experience.

pt is getting heparin drip at 7ml/hr. the concentration is 25,000u in 250ml of d5w. the doc changes the order to increase the drip to 500units/hr. at what rate would you set the pump at in ml/hr?

(1) you must determine how many units per hour the patient is receiving.

7 ml/hour
(infusion rate)
x 25,000 units/250 ml
(dose on hand)
=
700 units/hour
(current dose of heparin that the patient is getting)

(2) calculate the new hourly dose of heparin (doctors order continuous iv heparin as units/hour).

700 units + 500 units =
1200 units

(3) determine the new rate for the iv pump for this new dose of heparin (1200 units/hour) with an iv concentration of 25,000 units in 250 ml of d5w.

1200 units/hour
(dose desired)
x 250 ml/25,000 units
(dose on hand)
=
12 ml/hour
(infusion rate)

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