Want to know the best two words a nurse can hear? IV PUMP.
Okay, so maybe it’s not at the top, top of the list. I imagine “sinus rhythm” or “no bleeding” might be higher up there.
But it must make at least the top 10. And why wouldn’t it?!
IV Pumps make your life SUPER simple. Just plug in the medication and the rate over time and you’re good to go! No more muss or fuss with manually setting the drip rate. SCORE!
Another bonus: IV pump drip rates are easier to calculate than manually set drip rates, because the units are in mL/hr, so no IV tubing drip factor conversion is needed! (One less step? YES PLEASE!)
So let’s walk through a problem together, shall we?
Example: Your elderly patient, Andy, in room 404 has been prescribed 100mL of Lactated Ringers to help increase his electrolytes. The doctor prescribed the solution to run over 30 minutes. You have IV tubing that says it’s a drop factor of 10gtts/mL. How many milliliters per hour will Andy receive?
Step 1: What do you need?
At first glance, you might think you need to calculate the drops per minute for your patient. But the question is actually asking for milliliters (mL) per hour.
It’s good to read the entire question before jumping to conclusions on what the question is actually asking. Some of your exam questions may be misleading, so read carefully!
You’ll want to write mL per hour on the very right hand side of your paper, so you know that’s what you need to end up with in the end.
Step 2: What is your order?
This question tells you that the doctor ordered 100mL of Lactated Ringers to run over 30 minutes. You’ll want to write this on the left hand side of your paper.
Step 3: What conversions do you need?
The question gives you a conversion factor related to the IV tubing (10gtts/mL). Your second conversion factor is time: 60 min/1 hr.
Feel free to write both of these in the middle of your paper if you’re unsure if they’re necessary or not. The dimensional analysis method makes it really easy to see which conversions to use or not.
Now that your equation is set up, you can see that you can’t use the 10gtts/mL drip factor because you need mL to be on the top of the equation. This conversion would cancel it out, leaving you with drops (gtts) per hour, which is not what the question is asking for.
But when you use just the time conversion, you end up crossing minutes out and are left with mL on the top and hours on the bottom, which is exactly what Step 1 says you need! See, piece of cake! (I’ll take chocolate, please!)
Step 4: Solve the problem.
To solve the problem, you simply multiply across the top row, multiply across the bottom row, and divide these two numbers.
Did you get 200? BAM, look at you go!!
Step 5: Round appropriately.
Remembering your rounding rules from this post, you know that you (almost) always round IV rates to whole numbers. And since your answer is already a whole number, no rounding is needed.
One major BUT: If your IV pump allows for you to input the mL/hr to the tenth decimal place, and you have a calculation that contains a tenth decimal (our example does not), then you should input it for a more accurate measurement. This is especially important when calculating pediatric or high risk medication dosages. And of course, always follow your clinical sites policy.
Step 6: Check your answer.
Even though you’re obviously a dose calc PRO, mistakes can still happen. So make sure to check your work by following steps 1-5 a second time, just to be safe.
Okay, you can have that chocolate cake now, you earned it!
Seriously though, if you follow these steps exactly how they’re laid out, you are going to be flyin’ through your dosage calculation test.
Get ready to leave that exam with a little extra pep in your step, my friend!
Comment below and tell me your favorite soul food indulgence before an exam.