Help with pharm question

[swansonplace]

A client who tested positive for group B streptococcus has an order for 2 g ampicillin I.V. in 100 ml normal saline to be administered over 20 minutes. The nurse would set the infusion to run at how many drops per minute using tubing that delivers 10 drops/minute?

answer is 50

Hello. I was hoping someone could help me out with how to solve the above pharm question. We use dimensional analysis at my school.

[nurseprnRN, BSN, RN]

well, i've always thought it helpful to look at what is important before rushing to plug numbers into a formula. what are they really asking? first, in this question, it doesn't matter what's the matter with this patient or what drug is in the mini bag. what matters is that you have to get 100cc into him in 20 minutes. how many cc/minute is that? maybe... five?

100cc/20min = 5cc/min

that tubing doesn't deliver 10 gtts/minute, it's 10gtts/cc. so, if there are 10 gtts in one cc, how many gtts are there in 5 cc?

that would be...fifty. so. you will be giving 5cc/minute = 100cc/20 minutes if you give 50 gtts/min.

hope that helps you figure it out.