I am confused and need some help with this math question. I am confused and need some help with this math question. | allnurses

I am confused and need some help with this math question.

  1. 0
    The client with lung cancer is 1 day post-op lobectomy and demonstrates symptoms of infection. The health care provider orders 900 mg of Nafcillin. There is powder in a vial labeled "Nafcillin 1 gram" with instructions "to dilute with 3.4 mL of sterile water to produce 1 gram in 4 mL.".

    How many milliliters does the nurse administer? (Round to the nearest tenth and write only the number.)

    **please let me know some simple steps on how you got the answer. Maybe i am studying too much and my brain is burning out
  2. 12 Comments

  3. Visit  SaoirseRN profile page
    A simple ratio calculation would work here

    1000mg/4ml = 900mg/x
  4. Visit  NursingBro profile page
    this is what it says :
    (4 mL/1 gram) X (1 gram/1000 mg) X (900 mg/1) = 3600/1000 = 3.6 mL

  5. Visit  SaoirseRN profile page
    Yes, that's the answer I got.

    To make this really simple, you need to find out how many mg/ml the solution is.

    1000mg/4ml equals 250mg/ml

    You need 900mg. How many times does 250 go into 900?

    900/250= 3.6
  6. Visit  NursingBro profile page
    I dont know what is wrong with me sometimes I just cant see it.

    one way i was doing it is 900 / 1000 = 0.9 0.9 x 4 = 3.6

    another weird way is 900 x 4 = 3600 3600/1000 = 3.6

    do you know a website that can help me out with the math? It is tough for me to see it in my mind.
  7. Visit  PalmHarborMom profile page
    I am in nursing school at the University of South Florida. We use the book Calculating with Confidence 5th Edition by Gray Morris. The book has a website There is some great info on doing calculations and practice problems. You do need to register.
    Last edit by Esme12 on Nov 27, '12 : Reason: TOS/link removed
    loriangel14 likes this.
  8. Visit  loriangel14 profile page
    I use Doc (what the doctor ordered) over stock ( what you have on hand) 900/1000 = 0.9.Multiplied by the volume(4) = 3.6
    NursingBro likes this.
  9. Visit  NursingBro profile page
    thanks i will check it out
  10. Visit  Esme12 profile page
    NursingBro likes this.
  11. Visit  NursingBro profile page
    Quote from Esme12
    Great website! thanks!
    Esme12 likes this.
  12. Visit  Esme12 profile page
    You're welcome!
  13. Visit  mariebailey profile page
    Some simple steps:
    1. Don't forget to convert your g to mg.
    2. Remember the Mass/Liquid for Liquid Formula (found on site previously posted)
    Ordered X Volume have = Liquid Required
  14. Visit  BloomNurseRN profile page
    I use a similar method to Loriangel14.

    Desired dose/Have * Quantity = X (D/H * Q = X)

    Desired (900 mL)/Have (1000 mL) * 4 mL = 3.6 mL

    Good luck!