Help with a med calculation.

This is very basic and I am ashamed that im drawing a blank. I know the answer and I can do it in my head, but I can't remember what formula I should use.
Any help?
4. Order: Ancef 1 gram over 30 minutes. The drip factor is 20gtts/mL
Drug label: Ancef 1 gram in 50 mls of NS.
The nurse would set the pump rate at how many mL/hour? 

Jan 19, '07My first instict is to do 1000 x 20 / 30. But that's wrong. I'm really lost, lol.
BUT I know the answer, I can very easily do it in my head. 
Jan 19, '07Flow rate (gtt/min) is used if you are regulating the IV infusion by gravity. If you are using a pump, you simply set the pump to ml/hr.
You have 50 ml (includes the 1 g of Ancef that is required) that needs to be administered over 30 minutes. Pump setting must be ml per hour, so set it up:
50 mL/.5 hr = 100mL/hr 

Jan 19, '07How about this one then?
Order: Ancef 1 gram over 30 minutes. The drip factor is 20gtts/mL
Drug label: Ancef 1 gram in 50 mls of NS.
The nurse would set the rate at how many gtts per minute when administering the Ancef by gravity? 
Jan 19, '07I'll take a stab at that one...crossing my fingers I don't have it wrong LOL
You would set it up using the total infused/time X drop factor = drops per minute
So that would be 50 mls/30min X 20 drops/mL = 33.3 or 33 gtts/min
Hope that helps! 
Jan 19, '07Quote from Bonny619you can also work it out the "logical" way...How about this one then?
Order: Ancef 1 gram over 30 minutes. The drip factor is 20gtts/mL
Drug label: Ancef 1 gram in 50 mls of NS.
The nurse would set the rate at how many gtts per minute when administering the Ancef by gravity?
1 gram of Ancef in 50 ml and it will drip at 20 drops per ml. That means each ml will equal 20 drops. 50 ml x 20 drops = 1000 drops. You have 30 minutes to run in those 1000 drops, so 1000 drops divided by 30 min = 33 drops per minute.
always work it backwards too. 33 drops per minute for 30 minutes = 990 drops in 30 minutes. Every 20 drops is equal to 1 ml so 990 divided by 20 = 49.5 ml. 49.5 ml "matches" the 50 ml you started with. 

Jan 19, '07Quote from Bonny619This is very basic and I am ashamed that im drawing a blank. I know the answer and I can do it in my head, but I can't remember what formula I should use.
Any help?
4. Order: Ancef 1 gram over 30 minutes. The drip factor is 20gtts/mL
Drug label: Ancef 1 gram in 50 mls of NS.
The nurse would set the pump rate at how many mL/hour?
20/1 X 50/30 = 33.3 or 20 x 50 =1000/30=33.3 
Jan 20, '07Quote from bonny619most iv pumps are set at a rate of ml per hour, so the only thing you need to determine for this problem is how many ml would you be giving over a one hour period of time? the answer is 100ml. that is determined by taking the 50ml which is what you are actually going to give over a 30 minute period and multiplying it by 2 because there are two 30 minute intervals in a 60 minute, or one hour, time period.ancef 1 gram over 30 minutes. the drip factor is 20gtts/ml. ancef 1 gram in 50 mls of ns. the nurse would set the pump rate at how many ml/hour?50ml x 2 = 100ml per hourthe rest of the information in the question isn't needed for the calculation.
Quote from bonny619using dimensional analysis, or factor label method, you want to end up with the labels on a fraction, or ratio of gtts/min. to do that you can still use a form of the dose desired divided by the dose on hand formula and set it up by dimensional analysis this way:order: ancef 1 gram over 30 minutes. the drip factor is 20gtts/ml drug label: ancef 1 gram in 50 mls of ns. the nurse would set the rate at how many gtts per minute when administering the ancef by gravity?50ml/30min (dose desired) x 20gtts/1ml (drop factor of iv tubing on hand) = 33gtts/min (after canceling out repeated labels, doing the math and rounding off)