IV drip - example one

we have an  order for : NS 150cc/hr continuous.

What we want to know is :

 

 

Our ordered dose is 150ml/hr. Since I know there are 60 min. in an hour, I know this is the same as 150ml/60min. Now being the lazy person I am, I usually use the second - it saves me from later having to add in a conversion factor for hr <> min.  Remembering to orient our first factor so a unit matches what we want to know,  we have :

 

 

Now comes the available part. This is where a little nursing judgment comes in. I look at the supply shelf and which  tubing am I going to pick ? In this example, we going to use two different tubing  15 gtt/min  and 60 gtt/min so you can see the difference. Let's use a drop factor of 15 to start  - remember to orient the next factor so the units cancel (ml) :

 

 

Looking the equation over, you can see when we cancel, the remaining units will match "what we want to know". Canceling & solving gives:

 

 

We round that UP to 38 gtt/min  

Let's do this problem again - this time using a drop factor of 60 gtt/min to see the difference it makes ....

 

 

 

 

 

Factoring  & solving :

 

 

This drip rate looks like:   

Try to count those drops ! Well, maybe some of you, ah, less age challenged folk can, but this nurse .... I'll pass! You can see why the ordered rate and the choice of tubing makes a difference though. As a general rule, microdrip tubing is a good choice when you need to deliver something slowly.  It is also useful with pediatric rates and somtimes with our aged clients too. For any rate greater than 120 cc per hour (and that's pushing it!) use a larger tubing.

IV Drip Shortcut:

If you are using Microdrip tubing (60 gtt/min) :  ml/hr EQUALS gtt/min. This means you don't have to do any math if you are using Microdrip tubing!  If the order is for IV fluid at 50cc/hr, the drip rate will be 50 gtt/min.  If the ordered rate is 30cc/hr the drip rate is 30 gtt/min.

 

 ©1997-2006 Dale Sampson, RN