Dosage Calc Question

Why don't you show us what you hove done so far? This lets us see where you are having problems, and will allow us to better help you understand what you are doing.

I'm not really sure where to even begin. I though I would multiple the mL by the gtt and then divide by 60 minutes. But i'm not sure where the drop factor comes into play

Does anyone else find this order to be weird? OP: Are you positive that the order is in gtts/min? Most dr orders are mg or mL per hour or min.

For example, 7 mcg/min or 100 mL/hr.

However, maybe your instructor is simply trying to trip you up. At the end of the day, you do have the components to solve the problem, and working it out, it does come out to round numbers, so if I tell you that the drop factor tells you that 1 mL is delivered for every 15 drops, does that help?

In the real world, I don't think you will ever come across an order like this. lol.

I'm not really sure where to even begin. I though I would multiple the mL by the gtt and then divide by 60 minutes. But i'm not sure where the drop factor comes into play

If there are 15 gtt/mL, how many mL did the patient receive in 1 hour?

If your IV is infusing at X mL/hour, how long will the infusion take?

I'm with you. This is a weird order and took me a minute to wrap my head around it. Why are they even bothering with this kind of thing? It's like teaching the apothecary system. Nobody uses it and it's just a ginormous waste of time.

No, it's not a ginormous waste of time. What did hospitals do after Katrina and Sandy? I'm in the northeast and apparently nurses didn't know how to calculate IV rates and set them up manually. We need to know what to do in the case of a disaster (man made or natural) where we don't have the luxury of IV pumps that do all the work for us.

No it's not a ginormous waste of time. What did hospitals do after Katrina and Sandy? I'm in the northeast and apparently nurses didn't know how to calculate IV rates and set them up manually. We need to know what to do in the case of a disaster (man made or natural) where we don't have the luxury of IV pumps that do all the work for us.[/quote']

Saying that an IV is infusing at x gtt/min is no different than saying it is infusing at y mL/hour.

And I can't agree with you more regarding the importance of knowing how to set up and calculate infusion rates.

With dimensional analysis it helps to figure out what you want in the end. In this case it is time since you need to know how long the IV will infuse.

Take a look at all the components you have:

20gtt/ 1 min

15 gtt/ 1 ml

500 ml

I like dimensional analysis since you just have to rearrange your values until everything crosses out except the unit (in this case minutes) that you want. I find when starting out it helps to put "1 ml" instead of just "ml".

Take a stab at it, there's only so many combinations. I have the problem all worked out.

he doctor orders 500mL at 20 gtt per min. The drop factor is 15. How long will the IV infuse? If the infusion started at 6am, when will it finish?

You have 2 numbers in gtt and 1 number in mL. Let's get them all in the same units. 1mL is 15gtt. 20/15=1.33mL per minute. 1.33x60=80mL per hour. 500/80=6.25 hours. If started at 6am, it will finish at 12:15PM. (0.25h is 1/4h is 15 minutes)