Pediatric med calculations problems

[lainith]

So I was speeding through my pharm calculations from my Peds course pack before school starts next week and I found a section that has me stumped. I can't find anything like it in my pharm or Math for Meds book so I can't find a formula or way of solving these. Anyone have some insight on how I am supposed to figure these out? It'd be mighty helpful!

Ticarcillin is stable in solutions at room temperature for 1 hour. It can be give IV bolus over 10 minutes. If administered by burette, the flow rate for pediatric microdrip is: gtt/minute = mL/hour (60gtt = 1mL), Thus 60gtt/minute = 60mL/hour (or 60mL/60 minutes)"

6 - You're about to give the required dose using microdrip tubing. Considering the stability of ticarcillin and the volume to be infused, what's the minimum flow rate for safe administration? (From the previous problem I solved the volume is 12mL.)

7 - Given the time limit for the IV bolus method (10 minutes), what's the maximum flow rate you can use to deliver 12mL of ticarcillin with a concentration of 1Grams/5mL?

Flow rate consideration: You'll determine the appropriate IV flow rate based on several considerations, including the minimum amount of solution needed to infuse the drug, the patient's fluid restrictions, and how quickly the drug must be infused. You'll also take into account the patient's activity, any discomfort at the IV site, and other drug orders.

8 - You must administer 600mg of ticarcillin. What's the range for the IV flow rate?

9 - What's the time restriction on administering 600mg of ticarcillin to this child?

10 - How long would it take to infuse 600mg of ticarcillin in 12mL at a flow rate of 40gtt/minute?

11 - How long would it take to infuse 600mg in 15mL at a flow rate of 40gtt/minute?

12 - If you decide to give 600mg in 12mL over 20minutes, which flow rate would you use?

And they go on and on. Am I missing something? Am I supposed to be able to look up the IV flow rate range and stuff somewhere? There's lots more questions and this is NOTHING we went over in Pharm so I'm lost. Any direction would be helpful and thank you so much in advance!!!

[NotReady4PrimeTime, RN]

These are all basic math questions and really have little to do with the drug. you could substitute any drug name in there and it wouldn't matter.

6. The drug is stable for an hour and can be given safely over 10 minutes. You have to consider the volume of the tubing in this question. It's probably about 20 mL and you'll need that volume as a flush afterwards to ensure all the drug is infused within your hour's stability window. So you'll have to run your infusion at a minimum of ? (32 mL/ hr or 32 drops per minute: the volume of the drug is 12 mL+20 mL for the dead space in the tubing)

7. You want to deliver the med in 10 minutes or 1/6 of an hour; 12 mL of med plus your 20 mL dead space gives you a total volume to be infused of 32 mL (same answer we got above). 32 x 6 (intervals of 10 minutes in an hour) = 192 mL/hr or 192 drops per minute. Making sense?

8. What is the concentration of your med? 1 gm in 5 mL or 200 mg/ mL. What will your volume be? Use the formulae in the previous two questions.

9. That information is in your explanation. Stability and maximum rate of administration.

10. You know that your drip rate is 1 mL/second, so 40 drops per minute is a rate of ?

11. See 10.

12. I bet you can figure this one out now.

This may not be the exact way your instructor wants these problems calculated, but that is how I'd figure them out. People tend to forget about the volume of the tubing and factor it into their flwo rates when they have a med with a limited shelf life. It doesn't do much for the patient when it's sitting in the tubing. BUT... in peds we run all this stuff on a pump, and on my unit we'd use a syringe pump with a tubing volume of

[kgh31386, BSN, MSN, RN]

I calculated them basically the same way, except I left out the 20ml. Also when you say flow rate, did they want ml/hr gtt/min microgtt/min?

[NotReady4PrimeTime, RN]

I'm just guesstimating the dead space as 20 mL, as most of the IV sets I've used over the last 15 years have had about a 20 mL priming volume.

Generally speaking, when writing tests like this there's a pattern in the questions. Use the pattern. They're defining flow rate as gtts/min. Burettes always deliver 60 gtts/mL by design. So to be thorough you could include the drip rate and the mL/hr rate.