Whoa, whoa, whoa. Look at you go, girlfriend!
You are just plowin’ on through this dosage calculation series and ready to rock that exam (and maybe show off a little at clinical).
Today we’re talking about calculating intravenous (IV) drip rates.
There are two main reasons that it is super important for you know how to calculate drip rates accurately:
1. Many of the medications you will give in a hospital setting will be through the patient’s IV.
2. IV’s are direct access to the bloodstream, so miscalculating a drip rate can cause dangerous issues very, very quickly.
Luckily for you, drip rates are where the dimensional analysis method really shines!
It makes it super easy to convert multiple units at one time and get to the correct answer quicker. If you’re not convinced, check out this post.
Just a little reminder: Be confident!
As long as you follow the dosage calculation steps I laid out for you here, you will be good to go! Even though drip rates have multiple conversions, the same steps still apply. You’ve got this!!
Calculating Basic Drip Rates
Take this scenario for example:
Margret, your patient in room 110, has not been drinking enough water to satisfy Dr. Feelbetter. He orders 1000mL of normal saline fluid to run over 8 hours. Your tubing is 15gtts/mL. How many drops per minute will the patient receive?
Step 1: What do you need?
You need to figure out what the question is asking you for first in order to make sure you use the right order and conversion factors. This question says you need to calculate the drops per minute. This should go on the very right hand side of your paper.
Step 2: What is your order?
The doctor ordered 1000mL to run over 8 hours. We know this is the order we are calculating because it is the only one listed. Sometimes, exam questions may contain multiple orders and expect you to pick out the right one. This is why you should always start with what the question is asking from you first (step 1).
Write your order on the left hand side of your paper.
Step 3: What conversions do you need?
There are usually at least 2 conversions you need for basic drip rates: the IV tubing size and time. This scenario gives you an IV tubing size of 15gtts/mL. The second conversion you need to use is 1 hr/60 min.
Write your conversion factors in the middle of your paper.
Step 4: Solve the problem.
To double check to make sure your conversions are correct, you can put a line through the units that cancel each other out (one on the top row, and one on the bottom row). Which leaves you with gtts/min.
Once you have your conversions set up in your equation, all you need to do is multiply all of the numbers across the top row, multiply all of the numbers across the bottom row, and divide those two numbers.
Did you get 31.25? AWESOME!
Step 5: Round appropriately.
I’m about to throw a rounding rule at you…are you ready??
Drip rates are ALWAYS rounded to whole numbers!
This makes sense if you think about it: you would look a little silly trying to count a quarter of a drop coming out of the drip chamber. That would take you forever to set correctly! So no, none of that nonsense, thankfully!
You simply use basic rounding rules: If it’s less than 5, round DOWN; If it’s 5 or greater, round UP.
In this case, your decimal is .25, which is less than .5, so you would round down to the nearest whole number: 31.
Therefore, your drip rate should be 31 drops per minute.
Step 6: Check your answer
Use these same 5 steps to solve the problem again. You are a nursing ROCK STAR and I know the last thing you want to do is make a medication error. So re-checking your work will help to prevent that (Can I get a “Woot-Woot!!”)
And there you have it, my friend! The easiest way to get your drip rates right every time!