The way this second problem is presented, isn't too clear. Exactly WHAT do you need to know for this problem? Do you need to need how many hours it is to run for the entire infusion and then gtt/ minute or just gtt/ minute?
In order to figure gtt/ minute
on the 2nd problem, all you need is the gtt/ml and ml/hr. The other information (1000 ml of D5 .045% NS) is superfluous, meant to throw you off. You have to learn to sort out the unnecessary information from the absolutely critical information. Afterall, this is the way it is in "real life." Always ask yourself - WHAT is the problem asking? WHAT parameters do I need to work out this problem? Then throw out the rest.
To figure gtt/ minute, start with dose desired (gtt):
X 50 ml
X 1 hr
= 50 gtt
ml 1 hr 60 min min
(Or 60 gtt/ml X 50 ml/1 hr X 1 hr/60 minutes = 50 gtt/ minute)
However, if you also need to know HOW MANY HOURS of infusion (1000 ml D5 0.45% NS @ 50 ml/ hr), again you need to know what information you need and which is unnecessary. You don't need to know the D5 0.45% NS. All you need to know is 1000 ml and 50 ml/hr.
To figure hours of infusion, start with dose desired (hr):
X 1000 ml
= 20 hours of infusion
50 ml infusion
(Or, 1 hr/50 ml X 1000 ml/ infusion = 20 hours of infusion)
Hope this helps