OB Math Calculations


A patient is being treated for eclampsia with Mag Sulfate ordered for anticonvulsant therapy. The order reads: Administer Mag Sulfate 4 g IV over 15-20 min. The concentration is 50% (1g/2mL). How many mLs would be administered? You have placed the dose in a 50mL bag for piggy back into the main line. What rate is your pump set at to deliver the medication in the time ordered?

Answer: So far I have - 8mL for the first question

x mL/4g : 2mL/1g


How do I solve the second part? the timing and the 50mL bag is confusing me. Does anyone know how to do this correctly?

Thank you.


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How many mL will you need to administer, after preparing it for administration?

use the 15 min timing since it's easiest...

15 min is how much of an hour? then calculate the rate to figure out how many mL/hr it would take to infuse the 50 mL in 15 min.