intravenous medication/secondary infusion

[nemoemo]

The physician has prescribed secondary IV of regular insulin 50 units in 500ml of 1/2NS to infuse at a rate of 6 units per hour. Available are mulitdose vials labeled 1 ml= 100units of regular insulin. The drop factor of the secondary infusion set is 60.

1)How many ml of regular insulin should be added........answer: 0.05ml

2) How many drops per min should infuse to deliver the required amount of drug?....answer: 60 gtt/min

3) What will be the hourly rate to deliver the ordered dose of regular insulin?....answer: 60 ml/hr

Can anyone explain why the answer is 60 for problem 2 and 3?

[noyesno, MSN, APRN, NP]

2.

(60 ml/hr)*(1 hr/60 min)= 1 ml/min

gtts factor of 60 gtts/ml, so: (60 gtts/1 ml) * (1 ml/ min)= 60 gtts/min

3.

(50 U/500 ml)*(1 hr/6 U)= 50 hr/3000 ml

Flip the 50 hr/3000 ml over to get 3000 ml/50 hr.

Now reduce this fraction to get: 60ml/hr

[RNTutor, BSN, RN]

It's just one of those mathematical "quirks." Whenever the drop factor of the set you are using is 60gtt/min, then the number you calculate for gtt/hr will ALWAYS be the same as the number you calculate for ml/hr. I could go into why, but it's hard to type out math formulas here :)