Hi. Welcome to our video series on dosage calculations.
In this video, we're going to look at how to figure IV flow rates.
Now, don't let the math scare you.
We're going to give you some very clear direction
and some really fun practice problems.
Okay, let's start with the IV itself first.
There's a primary line and a secondary line.
Now, the fluid that we hang on a primary line,
it's usually a larger volume, 500 milliliters or a thousand milliliters.
Now, to give you a frame of reference, a thousand milliliter IV bag
is about half the volume of a two-liter bottle of Pop.
Well, it's exactly half the volume
of a 2000 milliliter or a two-liter bottle of Pop.
So that we have a bigger bag
and it connects directly to the patient's IV line.
So you follow the primary bag, the fluid, the line,
there’s a tubing,
all the way down, it will connect right to the patient.
Now, it can go to all sorts of things.
We'll talk about those in our other video series.
But just know for now, primary line has a larger volume,
has a long line that goes from that bigger bag
all the way down to the patient
because the primary tubing is longer than the secondary IV tubing.
Look at the graphic there.
You see there's a much bigger box around the bigger bag
and the primary tubing because it's longer.
So, it can connect easily right to the patient.
The secondary tubing is much shorter.
Now, the primary tubing will have a drip chamber.
That's at the very top right where it enters the bag.
That's where you can see the little drips.
That's going to be the fun part of our practice questions.
So, stay tuned for that and we're going to give you
some actual drip chamber questions that you can count.
Now, the drip chamber will be there.
There will also be injection ports.
Thankfully, most of our tubing is needle-less.
So that means you can take a syringe
full of whatever you need to inject to the patient
and connect it directly to the port
without risk of sticking yourself when you're done.
It also will have a roller clamp.
Now, that's just a little roller that will clamp down on the tubing.
The farther down you roll it, the tighter it clamps on that tubing
and the slower the drops will drip.
There are slide clamps that just slide across the tubing
and that's another way to stop the flow of the liquid.
Now, finally there might be a cartridge.
If this tubing is intended to go into an IV pump,
which many IVs do,
there'll be a special cartridge that fits the type of pump
that is used in that facility.
Okay, so let's start at the top one more time.
Usually, we have a larger volume bag.
A primary IV line could be 500 milliliter or a thousand milliliter.
That connects to primary tubing which connects directly to the patient.
Remember, primary tubing is much longer than secondary tubing.
There'll be a drip chamber, injection ports for medication,
a roller clamp to control how fast the drops drip,
a side clamp to completely shut it off or open,
and a cartridge on the tubing if it's intended to be used in an IV pump.
Now, secondary tubing, that's the little guy.
More like my size, right? It's a shorter one.
Secondary tubing is shorter than primary tubing
because it's just going to connect
right from the pull to the top of the IV tubing.
It doesn't go all the way down to the patient.
Now, the medication in that secondary fluid
is going to go through the primary line
and it will enter the patient.
But we don't have to connect the tubing directly to the patient.
That's why it can be shorter. So, it will also have a drip chamber.
It will also have a roller clamp. It may also have an injection port.
If you look at the one in our picture, sometimes as nurses,
you'll have to mix an IV piggyback or this secondary fluid volume.
So it has a port where you can inject something in.
It might also be done in the pharmacy.
They may make this IV piggyback for you.
But you've got an injection port in the secondary tubing.
Sometimes at the top of the bags, you can inject
whatever medication needs to go into that fluid directly into the bag.
Okay, so secondary tubing is shorter
but it will have a drip chamber, a roller clamp, and an injection port.
Now, the secondary IV lines are hung higher than the primary fluid.
So take a look at that picture.
You see that we have placed an extender there.
That's just a little plastic hanger.
You hook it through the top of the bag and put it on the IV pole.
That allows the primary tubing to be lower
than the secondary tubing.
That's really important because that way,
when it's time to hang the secondary IV bag, it will drain out first.
When it's done, then the primary fluid will just continue to drain
because the fluid that's hanging higher has more pressure
and it will empty first.
Then that primary IV solution will continue to infuse
after the IV piggyback or the little bag is done.
Now, an IV piggyback is we call it that because it's a smaller bag
and it has a lower amount of solution in it.
So you'll often see people say, “Give this medication IVPB.”
That means IV piggyback.
The cool part about this is boy, it's a lot of volume.
So, we can give medications over a slower period of time,
lots of other fluid to kind of dilute it.
Otherwise, I'd have to stand there forever with a syringe
and slowly, slowly, slowly push it in.
So that's what we use IV piggybacks for.
They're used for intermittent medications.
It can be anything from antibiotics,
maybe it's a little bit of potassium,
any type of medication that we give
like maybe every six hours or every eight hours.
Now, you always want to make sure
that you work with your pharmacist
and make sure that whatever medication
you're hanging in that secondary bag,
or that IV piggyback is compatible
with the solution that's in the primary IV.
That's really important because if you hang an IV piggyback
that is not compatible with your primary solution,
it could cause precipitate
or it could cause an interaction in the medications.
If it causes a precipitate,
you're going to end up with that putting right into the patient
which could cause problems with clots.
So, you want to make sure they're compatible,
that the medications won't work against themselves,
and it won't develop something like a precipitate.
Now, these volumes are usually smaller than a primary.
They are always smaller than a primary.
It might be as small as a 25 milliliter,
50, 100, 150, 200, or even 250 milliliters.
It will connect to the patient's primary IV tubing through the injection port,
kind of near the top, but it's underneath the primary drip chamber.
Remember, the injection port on an IV piggyback
is right there in the bag.
Often, primary IV bags will also have an injection port.
But when we connect that IV piggyback tubing to the primary line,
it will be below the drip chamber in an injection port.