Heparin Drip decreased Calculation

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Please help me. Can someone show me how to calculate the following heparin calculation?

The nurse provides care for the client diagnosed with a pulmonary embolism. A heparin drip of 100 units/mL is infusing at 130 mL per hour. The health care provider asks the nurse to decrease the rate by 1000 units per hour. The nurse sets the intravenous rate to how many milliliters per hour to achieve the new dose? (Record your answer using a whole number. Do not round.)

MunoRN, RN

8,058 Posts

Specializes in Critical Care.

Since you need to translate a change in units to mls, how many mls would equal 1000 units?

mrsboots87

1,761 Posts

Specializes in Neuro, Telemetry.

Side note. This is an incredibly high dose for heparin. Make sure if you ever see this in real life, you question it. I'm sure these numbers are just made up for the sake of a math problem though.

heavenleegh1

7 Posts

OK, I know its too much but this is a question on my Kaplan. Perhaps a typo. The real question if this was a real scenario how would I decrease by 1000 U? Am I to assume that the Heparin comes in 25000U/500ml? Can anyone please show me a step by step to solve the calculation?

Anonymous865

483 Posts

OK, I know its too much but this is a question on my Kaplan. Perhaps a typo. The real question if this was a real scenario how would I decrease by 1000 U? Am I to assume that the Heparin comes in 25000U/500ml? Can anyone please show me a step by step to solve the calculation?

It doesn't matter how Heparin comes.

The question told you that your drip has 100 units in 1 ml. All the information you need to solve the problem is included in the problem.

Muno told you how to solve the problem. If 1 ml contains 100 units, how many mls contain 1000 units?

heavenleegh1

7 Posts

It doesn't matter how Heparin comes.

The question told you that your drip has 100 units in 1 ml. All the information you need to solve the problem is included in the problem.

Muno told you how to solve the problem. If 1 ml contains 100 units, how many mls contain 1000 units?

Yes, I got that far. It would be 100 ml's but the answer is 120 ml/hr this answer I do not get.

chare

4,232 Posts

Yes, I got that far. It would be 100 ml's but the answer is 120 ml/hr this answer I do not get.

You have been provided the concentration: 1 mL = 100 units. You can use this relationship to convert units to mL (1 mL/100 units) or mL to units (100 units/1mL). Either way you use this ratio, it is equal to 1. It changes the units displayed, without changing the value. I will demonstrate a similar problem.

Heparin, 75 units/mL is infusing at 50 mL/hour. The physician writes an order to decrease the infusion by 975 mL/hour. What is the new infusion rate?

To solve this, both the current infusion rate and (50 mL/hour) and the ordered decrease (975 units/hour) have to be expressed in like units. You can either convert the infusion to units/hour, or the ordered decrease to mL/hour.

If you convert the rate:

  • 50 mL/hour × 75 units/mL = 3750 units/hour
  • 3750 units/hour – 975 units/hour = 2775 units/hour.

You now need to convert the infusion to mL/hour:

  • 2775 units/hour × 1 ml/75 units = 37 mL/hour

If you convert the ordered decrease:

50 mL/hour – (975 units/hour × 1 mL/75 units/hour

= 50 mL/hour – 13 mL/hour

= 37 mL/hour

Mavrick, BSN, RN

1,578 Posts

Specializes in 15 years in ICU, 22 years in PACU.
Side note. This is an incredibly high dose for heparin. Make sure if you ever see this in real life, you question it. I'm sure these numbers are just made up for the sake of a math problem though.

The incorrect answer is also made up too. Two typos for the price of one! Kaplan = FAIL.

KelRN215, BSN, RN

1 Article; 7,349 Posts

Specializes in Pedi.
Yes, I got that far. It would be 100 ml's but the answer is 120 ml/hr this answer I do not get.

Your infusion is running at 130 mL/hr. You have 100 units heparin/mL. 1000 units/100 units/mL = 10 mL, not 100 mL. Subtract that from your current rate of 130 mL/hr since you are decreasing the rate by 1000 units/hr which you just figured out is 10 mL and you have your new rate.

Mavrick, BSN, RN

1,578 Posts

Specializes in 15 years in ICU, 22 years in PACU.
The incorrect answer is also made up too. Two typos for the price of one! Kaplan = FAIL.

Well, shoot. Mavrick = FAIL. I mis-remembered the original question.

KelRN has got it.

Heparin drip 100 units/mL infusing at 130 mL/hr. Decrease rate by 1000 units/hr. Set IV rate at how many mL/hr to achieve the new dose?

To solve this you need to use a conversion factor. You are given this in the problem, which is 100 units/mL. In order words 100 units = 1 mL. You use the conversion factor in whatever order you need it to solve the problem because no matter what it equals 1. So you can write it as 100 units/1 mL or 1 mL/100 units - either way it equals 1. Just like another conversion factor - 60 mins/1 hr or 1 hr/60 mins.

So you first need to figure out how many units per hour are running CURRENTLY. Before the rate change. You have a heparin drip of 100 units/mL infusing at 130 mL/hr.

So you set it up with what you have - 130 mL/hr - now you use the conversion factor. You need to know how many UNITS are running per HOUR. So, you need to cancel out the mL. You can only cancel diagonally. mL are in the numerator of the 130 mL/hr, so you need mL in the denominator of the conversion factor. So it will be 100 units/mL (rather than 1 mL/100 units). So, now you can cancel out the mL in each fraction, and you are left with units in a numerator (of the conversion factor) and hr in the denominator (of the first fraction), which gives you what you need - units/hr. So, you calculate across the numerators and across the denominator (in this case isn't necessary), and you get 13,000 units/hr.

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You now know you are running it at 13,000 units/hr currently. The order is to decrease rate by 1000 units/hr. The units match up - you are running 13,000 units/hr and you need to decrease by 1000 units/hr.

So you take 13,000 units/hr - 1000 units/hr = 12,000 units/hr.

So, you now know what you need the new infusion to run at with the adjustment for the decreased rate. But how do you get back to mL/hr?

You need to run it at 12,000 units/hr.

You have a heparin drip of 100 units/mL.

If you look at the units for these you have units/hr and units/mL. REMEMBER - You can only cancel out units diagonally. So how do you set up the problem?

You need mL/hr, so you need to be left with mL in the numerator of a fraction and hr in the denominator of a fraction. You have to cancel out the units from each fraction to be left with mL/hr. To get hr in the denominator, you need to set up the first fraction as 12,000 units/hr. Now, you need to cancel the units out (which is in the numerator), and you can only do this diagonally, so the next fraction will need units in the denominator. So, it will be mL/100 units.

Again, you calculate across the numerators and across the denominators, and are left with 12,000/100 = 120 mL/hr.

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Hope this helps you see each step you need to go through.

heavenleegh1

7 Posts

Thank you so very much for spelling it out. I truly appreciate you and it.

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