Help with math

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Hello,

There are some math problems I have done prior to class beginning (required) but I am stuck on a few that I'm not sure if I did them properly or not. I worked them out anyways, but would like help on them.

1. the nurses admits a woman in active preterm labor. the perinatologist orders Magnesium Sulfate IV: stat 4 gram bolus to run over 20min; followed by maintenance infusion at rate of 2 grams per hour. Pharmacy supplies a 10% solution (50 grams in 500 ml D5W). How much of this solution should run in for the bolus at what pump rate setting? When the bolus I complete, to what rate should the pump be adjusted?

500mL/20min = 25mL/min bolus

500mL/10min = 50mL/hour

I did the second part like this because it says the maintenance is now 2 grams per hour, so half the initial ordered amount. So I cut the time in half.

2. The physician writes an order for Diazepam 10mg IV to be given now. You have in supply 5mg/2mL. the drug book says to give 5mL per min. How many mL(s) would you give? Over how many minutes would you infuse the dose?

10mg/5mg x 2mL = 4mL

I would give 4mL(?) .. and over 1min(?) since that's all I have on hand? I'm not sure.

3. You are to give 8mL of Acetaminophen with Codeine to your 16kg patient. The elixir available is mixed Acetaminophen 300mg and Codeine 30mg per 12.5mL. How many mg of Acetaminophen is the patient receiving?

Now .. this one I have NO clue where to start! But let me give it a shot. I apologize if I did this poorly lol

12.5 - 8 = 4.5mL

300mg/12.5mL = 24mg/mL x 8 = 192mg

Sorry! I really was stuck on this one.

4. Your patient's IV is infusing at 76mL/hour. The patient's medication needs to infuse over 30 minutes. How many mL(s) will you be infusing over 30min?

This one seems so simple, but I feel like I'm just overthinking it

76mL/30min = 2.5mL infused over 30min

Or .. is it just 76mL infused over 30min?

Please let correct me if I did any of them wrong. I'd really appreciate it 🤓

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Specializes in OR, Nursing Professional Development.

Your first question is not correct. You have 50g in 500mL. You are giving 4g. Therefore, you cannot give the full 500mL in the first 20 minutes. What do you think is the first step you need to take? Hint: It has to do with giving only 4 of the 50g you have been sent. You also input rates into the pump in mL/hr, not mL/min. You also do not simply take the time and halve it when moving from 20 minutes to 1 hour- it is separate from the dose in grams and involves a completely new calculation.

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Specializes in OR, Nursing Professional Development.

Second question: amount is correct. Time, you could technically calculate it out as to how many seconds you can push each mL. However, 1 minutes is relatively close.

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Specializes in OR, Nursing Professional Development.

Question 3: Your first step is 100% irrelevant to the question- what you have left over is meaningless. You gave 8mL. You correctly calculated how many mg are in each mL and multiplied it times the dose.

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Specializes in OR, Nursing Professional Development.

Question 4: You are giving 76mL in 1 hour. How many minutes are in an hour? In that portion of the hour, how many of those 76mL will infuse?

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Specializes in OR, Nursing Professional Development.

OP, have you tried working out those that weren't correct?

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So I got this.

4g/ 40mL so 40mL/20min*60=120mL in 20min

then maintenance is 2g/20ml so 20mL/60min*60=20mL/hr

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For number 4. 38mL in 30min?

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