Help with a med calculation.

  1. 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?
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  2. 9 Comments

  3. by   Bonny619
    My 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.
  4. by   Rosa2Little
    Flow 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
  5. by   Bonny619
    Thank you! I wasn't thinking in terms of .5
  6. by   Bonny619
    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?
  7. by   SanskeetRN
    I'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!
  8. by   jov
    Quote from Bonny619
    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?
    you can also work it out the "logical" way...

    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.
  9. by   Bonny619
    Thank you guys!
  10. by   tookewlandy
    Quote from Bonny619
    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?

    20/1 X 50/30 = 33.3 or 20 x 50 =1000/30=33.3
  11. by   Daytonite
    Quote from bonny619
    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?
    most 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.
    50ml x 2 = 100ml per hour
    the rest of the information in the question isn't needed for the calculation.
    Quote from bonny619
    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?
    using 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:
    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)

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