Dopamine Calculations

  1. Can someone please help me, I'm lost.

    The order is to infuse Dopamine at 10 mcg/kg/min to maintain cardiac output. The IV solution was prepared by adding 0.4 g of Dopamine to D5W. The final solution contains a total volume of 250 ml. Your patient's current weight is 135 lbs.

    Calculate the flow rate in ml/hr for the infusion pump:________________________
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  3. by   chare
    The formula for calculating this problem is: (dose x weight x 60) / concentration. Obviously the dose, weight, and concentration will vary, however 60 is a constant. When setting up this problem you need to ensure that both the dose and concentration are expressed in the same unit. In this case, they should be in micrograms.

    You can extract the following information from the problem:
    Dose: 10 mcg/kg/minute
    Weight: 61.4 kg (135 lbs)
    Concentration: 1600 mcg/mL (1.6 mg/mL)
    (10 x 61.4 x 60) / 1600
    36,840 / 1600 = 23.025

    Your instructor should tell you how many decimals you should be rounding to. In practice however, I would round to the number of decimal places the infusion device I am using will allow me to enter.

    I hope this information was helpful.
  4. by   Daytonite
    See below.
    Last edit by Daytonite on Aug 29, '09
  5. by   chare
    In the original post the dopamine concentration was 0.4 gram/250 mL (1.6 mg/mL), while you used 4 gram/250 mL (16 mg/mL) in your calculations. This is where the difference in our responses stems from.

    In the PICU where I work, we use either the Abbott Plum A+ infusion pump or the Medfusion 3500 syringe pump depending upon patient weight and/or medication being infused.

    The Abbott Plum A+ is capable of being programmed to 0.1 mL/hour using either the manual rate entry or the pre-programmed medication library.

    The Medfusion 3500 is capable of being programmed to 0.01 mL/hour when manually entering the rate. When using the pre-programmed medication library the infusion rate is displayed to three decimal places.
  6. by   Daytonite
    My mistake. Then the answer will be:
    10 mcg/kg (dose desired) 250 mL/0.4 gram (dose on hand) x 135 pounds (patient weight)/minute (other part of dose desired fraction that needs to be included in the calculations) x 1 gram/1,000,000 mcg (conversion factor) x 1 kg/2.2 pounds (conversion factor) x 60 minutes/1 hour (conversion factor) = 23.011363 mL/hour, rounded off to 23 mL/hour (infusion rate to set the pump on - NOTE: infusion pumps can only be set in whole numbers)