Pediatric Infusion Rate Calculation

NCRNMDM, ASN, RN · Dec 14, 2011

The way I see it, and this could be wrong, you have 570 mg of medication in 10 ml of fluid. You want to administer that 10 ml, with the 570 mg of medication, in thirty minutes. If you divide 10 by 60, you get the flow rate for if you wanted to give it in an hour. 10/60= 0.167. If you multiply this by two, you get the rate that it would take to administer the dose in thirty minutes. 0.167x2= 0.334. I think this is the correct answer, but I'm not sure. 10/0.334= 29.940, so I think that 0.334 ml/hr is correct. Once again, this could be wrong, and I haven't had much practice with pediatric dosage calculations, but I would go with this answer.

student126 · Dec 14, 2011

Sorry, just realized I never posted the answer (according to the answer key). It's 31.4 ml/hr, no clue how to get that. But I really do appreciate your help. Thank you!

NCRNMDM, ASN, RN · Dec 14, 2011

Wow, I was way off. I'm usually really good at dosage calculations (adult ones, at least). We are going to start pediatric dosage calculations next semester, so I guess I will learn all of that then. I will look at my math again, and see if I did something wrong. If I find how to get the correct answer, I will add a reply with the correct way to work it out. However, I am totally clueless at this point, so I don't know if that will happen. Sorry I couldn't help you.

student126 · Dec 14, 2011

Thank you for your help though, and good luck next semester!!!

3boys_n_a_dog · Dec 30, 2011

That answer seems impossible. If the med is in 10mL of solution and needs to be administered in 30 minutes, the only logical rate would be 20mL per hour. If 10 is given in 30 then 20 would be given in an hour. Here is how i set the problem up.

10mL 1140mg 11,400

_____ X _______ = _______ = 20mL/hr

570mg 1 hr 570

If 570 is given in 30 min then it would be 1140 if ran for an hour with the concentration of the solution. milligrams cancel and you are left with mL/hr.

KelRN215, BSN, RN · Dec 30, 2011

This is how you get 31.4 mL/hr.

What you have available is ampicillin 100 mg/mL. Your drug volume is 5.7 mL and then your problem tells you to further dilute the 570 mg in 10 mL sterile water. So your total volume to be administered is 15.7 mL. If that's going in over 30 minutes, twice as much (or 31.4 mL) goes in over an hour.

In the real world of pediatrics, you'd take your 5.7 mL of ampicillin, put it on a syringe pump and program it to give 5.7 mL over 30 minutes. Ampicillin isn't stable for very long after it's re-constituted so it's one of those drugs that comes up from Pharmacy as a powder and we mix it ourselves. We always mix it to a concentration of 100 mg/mL and I've never once further diluted it with sterile water.

nurseprnRN, BSN, RN · Dec 30, 2011

just look at that initial response #1. if you have 10 cc of fluid and you're giving it at one-third of a cc per hour, that will take thirty hours to go in. does that make any sense at all? pedi or not?

this is why when you have completed a calculation, look at the answer for reasonableness. if it's asking you to get sixty-two vials of something, or give 84,000 units of something, or, as in this example, give something over an impossible period of time, step back and look at it again, ok?

NCRNMDM, ASN, RN · Dec 30, 2011

Thanks for that. It was humorous and it made me realize how ridiculous that answer sounded. Usually I'm good at math, but obviously I wasn't thinking when I attempted that calculation. Shortly after I posted my reply I realized how to get the correct answer, but, by then, it had already been explained.