Calculation about dilution

  1. Hi everyone~I am a semester 2 student nurse, I am quite confusing with dilution of medication.
    Question:You need to serve your patient 2mg morphine, you have 10mg/1ml morphine. (you need to dilute morphine with 10ml NS) How many ml morphine you need to serve?
    10mg/1ml morphine dilute with 10ml NS that means after dilution I will have 10mg morphine in 11ml or 10mg morphine in 10ml???
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    16 Comments

  3. by   sallyrnrrt
    Neither,

    What does high school math warrant...

    Hint what do you have on hand, so how much on hand to you need to mix. In the 10ml saline flush...
  4. by   Khoo Sereen
    I'm confused as my lecturer told us if 10mg/1ml IV morphine we need to dilute with 9ml of NS to make it total 10ml. If I calculate the question with this concept, I will have 11ml after dilution as 10ml NS added with 1ml morphine.
  5. by   Wuzzie
    Quote from Khoo Sereen
    I'm confused as my lecturer told us if 10mg/1ml IV morphine we need to dilute with 9ml of NS to make it total 10ml. If I calculate the question with this concept, I will have 11ml after dilution as 10ml NS added with 1ml morphine.
    What does 9ml of NS+1ml of morphine=?ml
  6. by   Khoo Sereen
    total volume will be 10ml, is there any mistakes?
  7. by   Wuzzie
    Quote from Khoo Sereen
    total volume will be 10ml, is there any mistakes?
    No. I'm just trying to figure out where you came up with 11ml.
  8. by   Khoo Sereen
    oh~it comes from 10ml of NS+1ml of morphine
  9. by   Wuzzie
    Quote from Khoo Sereen
    oh~it comes from 10ml of NS+1ml of morphine
    But your instructor told you to dilute it in 9ml of NS.
  10. by   sallyrnrrt
    Quote from Wuzzie
    But your instructor told you to dilute it in 9ml of NS.
    I generally don't do home work

    You have on hand10mg/1ml. Morphine, you need to give( not serve) 2mg. Morphine diluted in saline flush

    Each 1ml of 10 mg morphine, contains 1mg of morphine per 0.1ml...... There fore to give 2mg, you would add to the flush
    0.2ml of the stock 10mg / 1 ml of morphine......

    If you added 1ml of your stock solution to even 100mls. normal saline, regardless of the dilution, you would be giving 10mg morphine, instead of 2 mg.......

    Geezer. This is high school math
    Last edit by sallyrnrrt on Mar 20 : Reason: sp
  11. by   Wuzzie
    Quote from sallyrnrrt
    I generally don't do home work

    You have on hand10mg/1ml. Morphine, you need to give( not serve) 2mg. Morphine diluted in saline flush

    Each 1ml of 10 mg morphine, contains 1mg of morphine per 0.1ml...... There fore to give 2mg, you would add to the flush
    0.2ml of the stock 10mg / 1 ml of morphine......

    If you added 1ml of your stock solution to even 100mls. normal saline, regardless of the dilution, you would be giving 10mg morphine, instead of 2 mg.......
    The way I was taught was to pull the entire 1ml of MS and dilute it in 9ml of NS which would have resulted in a 1mg/1ml concentration. Then to administer 2mg I would give 2cc. My practice has always been to dilute meds that way. Now most of my practice has been peds so that may be why. I'm not sure the OP is grasping the point of the exercise.
  12. by   Khoo Sereen
    I know the math part but I'm confused with the question,I will ask my lecturer when I'm back to university, thanks you very much for spending to answer my question ^^
  13. by   MunoRN
    It's actually a very legitimate question, since based on the question you would be ending up with a final volume of 11mls. This is often how the question is phrased in nursing school: "dilute with 10ml NS", which is different than "dilute with NS to produce 10mg/10ml". Leaving aside that seems to be perpetuating the myth that these medications need to be diluted at all, the correct answer to the question as written would be that you would have a concentration of 10mg/11ml, and to give 2mg you would give 2.2 ml, which if course is silly and why the more correct answer is that the instructor who wrote this question is not to bright.
  14. by   Wuzzie
    Quote from MunoRN
    It's actually a very legitimate question, since based on the question you would be ending up with a final volume of 11mls. This is often how the question is phrased in nursing school: "dilute with 10ml NS", which is different than "dilute with NS to produce 10mg/10ml". Leaving aside that seems to be perpetuating the myth that these medications need to be diluted at all, the correct answer to the question as written would be that you would have a concentration of 10mg/11ml, and to give 2mg you would give 2.2 ml, which if course is silly and why the more correct answer is that the instructor who wrote this question is not to bright.
    What's confusing me is first he said the instructor said to dilute it in 10 mls then it was 9 so I'm not sure what the original question was. As for diluting, in peds/neo we do have to dilute so we get accurate and measurable amounts. Not so much with adults.

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