Dimensional Analysis Calculation Help

  1. good day all:

    i need help calculating the problem below using dimensional anlaysis:

    dopamine 800 mg in 250 ml d5w is infusing at 12 ml/h in a patient weighing 195 lbs. you would document that the patient is receiving _______ mcg / kg / min.

    i understand that i need to factor the mg to mcg, the lbs to kg, and the h to min.

    i tried to solve the problem but i am not coming up with the same answer the book has of 7.22 mcg/kg/min?

    thanks!
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    About Want2baGoodRN

    Joined: Feb '09; Posts: 7
    from US

    3 Comments

  3. by   CrufflerJJ
    Quote from iamruthann
    good day all:

    i need help calculating the problem below using dimensional anlaysis:

    dopamine 800 mg in 250 ml d5w is infusing at 12 ml/h in a patient weighing 195 lbs. you would document that the patient is receiving _______ mcg / kg / min.

    i understand that i need to factor the mg to mcg, the lbs to kg, and the h to min.

    i tried to solve the problem but i am not coming up with the same answer the book has of 7.22 mcg/kg/min?

    thanks!
    aren't these sorts of problems fun (not)? nearly as much fun as word problems..."if a train leaves tokepa heading east at 7am, and a roller derby queen leaves boston at 2pm,blahblahblah"

    i've set this up as a bunch of sequential multiply/divides. hope it gets formatted ok when you view it.

    (800 mg/250 ml) * (1000 mcg/1 mg) * (12 ml/1 hr) * (1 hr/60 min) * (1/195 lb) * (2.2 lb/1 kg)

    = 7.2205 mcg/kg/min
  4. by   Want2baGoodRN
    Thanks! I figured out from your post what I was doing wrong. I had the weight as 195/1 instead of 1/195.
  5. by   CrufflerJJ
    Quote from Iamruthann
    Thanks! I figured out from your post what I was doing wrong. I had the weight as 195/1 instead of 1/195.
    The "wrong" answer of 1407 mikes/kilo/min would be a LOT more exciting! It would probably result in impressively high BP & heart rates, until something bad happened.:uhoh21:

    Glad I could help!

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