Loading dose and maintenance dose of an Iv

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Hi,

I need help with the following nursing problem:

Physician orders for a 32 week patient with preterm labor, include Magnesium sulfate 40 grams in 100 ml D5 1/4NS. Loading dose of 4 grams over 30 minutes, then maintain magnesium sulfate at 2 grams per hour.

Set up the the IV Pump for the loading dose

Set up the IV Pump for the maintenance dose.

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Specializes in Critical Care, ED, Cath lab, CTPAC,Trauma.

Hi! Welcome to AN! The largest online nursing community!

We are happy to help with homework but we will not do it for you.....I need to see what you ahve so far so I can best help you and know what you aren't understanding for nurses do drug conversions multiple times during every shift they work.

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Hi,

I need help with the following nursing problem:

Physician orders for a 32 week patient with preterm labor, include Magnesium sulfate 40 grams in 100 ml D5 1/4NS. Loading dose of 4 grams over 30 minutes, then maintain magnesium sulfate at 2 grams per hour.

Set up the the IV Pump for the loading dose

4000mg/30min=133.3mg/min

Set up the IV Pump for the maintenance dose.

2000mg/60min=33.3mg/min

Is this correct?

Thank you,

0 Votes
Specializes in Critical Care, ED, Cath lab, CTPAC,Trauma.

DosageHelp.com - Helping Nursing Students Learn Dosage Calculations

Physician orders for a 32 week patient with preterm labor, include Magnesium sulfate 40 grams in 100 ml D5 1/4NS. Loading dose of 4 grams over 30 minutes, then maintain magnesium sulfate at 2 grams per hour.

Set up the the IV Pump for the loading dose

Set up the IV Pump for the maintenance dose.

First is the total IVF really only 100cc's for this is typically mixed in 1000cc of fluid. If it is really only 100cc of IVF then the calculation would be as follows. This problem has several steps. https://allnurses.com/nursing-student-assistance/med-math-examples-786141.html

Every dosage problem has essential steps.....First KNOW your conversions..........Then answer for every problem

Desired dose

Concentration

Volume on hand

Any conversions: Lbs/Kg, grams/mg, mg/mcg

looking for:

administration set up:

1) If you have 40 grams in 100cc's....how many mg's is there in 100cc's.....you multiply 40grams by 1000......there is 40000mgs/100cc right?

2) If you have 40000mgs/100cc how many mg do you have per cc? There is 400mg/cc right? 40000/100 (40000 divived by 100)

3) How many cc's are needed to be given to total 4000mgs? )4000/400 =) 10cc equals 4000mgs.

4) What does the pump need to be set at to deliver 10cc over 30 min?

If however the 40grams of MgSO4 in 1000cc the calculations would be completely different......

1) Then there would be 40gms in 1000cc of fluid....which means there is 40000mg in 1000cc's. How many mg's is there per cc? 40000/1000 =

2) It is then 40mgs/cc. If you have 40mgs/cc how many cc's will it take to give you 4000mg?

3) You need 100cc of fluid to infuse over 30 min.....what would your pump setting be to infuse 100cc's over 30 min? 100cc/30min x 60gtt factor=200cc/hr for 30 min.

4) Now you need 2gm/hr or 2000mg/hr...every hour. How many cc's of fluid do you need to contain 2000mgs.

5) If 50cc of fluid contains 2000mgs on MgOS4...how fast do you need to set the pump to deliver the 50cc in 1 hour? 50cc/60min x 60= 50cc/hr.

0 Votes
Specializes in Critical Care, ED, Cath lab, CTPAC,Trauma.

Know your conversions

The Short List 1 cup © = 8 ounces (oz)

1 dram (dr) = 60 grains (gr)

1 dram (fl dr) = 60 minims

1 gallon (gal) = 4 quarts (qt)

1 glass = 8 ounces (oz)

1 grain (gr) = 64.8 milligrams (mg)

1 gram (g) = 15.43 grains (gr)

1 inch (in) = 2.54 centimeters (cm)

1 kilogram (kg) = 2.2 pounds (lb)

1 liter (L) = 1.057 quarts (qt)

1 milliliter (mL) = 16.23 minims

1 minim = 1 drop (gt)

1 ounce (oz) = 2 tablespoons (tbsp)

1 ounce (oz) = 8 drams (dr)

1 ounce (fl oz) = 29.57 milliliters (mL)

1 pint (pt) = 16 ounces (oz)

1 pound (lb) = 16 ounces (oz)

1 quart (qt) = 0.946 liters (L)

1 quart (qt) = 2 pints (pt)

1 tablespoon (tbsp) = 3 teaspoons (tsp)

1 teacup = 6 ounces (oz)

1 teaspoon (tsp) = 4.93 mL

The Long list

1 central = 45,359 grams (g)

1 centimeter (cm) = 10 millimeters (mm)

1 cubic centimeter (cc) = 1 milliliter (mL)

1 cup © = 8 ounces (oz)

1 drachm = 3.55 milliliter (mL)

1 dram (dr) = 60 grains (gr)

1 dram (fl dr) = 60 minims

1 gallon (gal) = 4 quarts (qt)

1 gill = 4 ounces (oz)

1 glass = 8 ounces (oz)

1 grain (gr) = 64.8 milligrams (mg)

1 gram (g) = 1,000 milligrams (mg)

1 gram (g) = 1,000,000 micrograms (mcg)

1 gram (g) = 15.43 grains (gr)

1 hand = 4 inches (in)

1 inch (in) = 2.54 centimeters (cm)

1 kilogram (kg) = 1,000 grams (g)

1 kilogram (kg) = 2.2 pounds (lb)

1 liter (L) = 1000 milliliters (mL)

1 liter (L) = 1.057 quarts (qt)

1 meter (m) = 1,000 millimeters (mm)

1 meter (m) = 100 centimeters (cm)

1 milligram (mg) = 1,000 micrograms (mcg)

1 milliliter (mL) = 1 cubic centimeter (cc)

1 milliliter (mL) = 15 drops (gt)

1 milliliter (mL) = 16.23 minims

1 minim = 1 drop (gt)

1 ounce (fl oz) = 2 tablespoons (tbsp)

1 ounce (oz) = 20 pennyweights (dwt)

1 ounce (oz) = 24 scruples

1 ounce (oz) = 31.1 grams (g)

1 ounce (oz) = 480 grains (gr)

1 ounce (oz) = 8 drams (dr)

1 ounce, fluid (fl oz) = 29.57 milliliters (mL)

1 palm = 3 inches (in)

1 pennyweight (dwt) = 24 grains (gr)

1 pint (pt) = 16 ounces (oz)

1 pint (pt) = 4 gills

1 pound (lb) = 16 ounces (oz)

1 pound (lb) = 350 scruples

1 quart (qt) = 0.946 liters (L)

1 quart (qt) = 2 pints (pt)

1 scruple = 20 grains (gr)

1 stone = 0.14 cents

1 tablespoon (tbsp) = 3 teaspoons (tsp)

1 teacup = 6 ounces (oz)

1 teaspoon (tsp) = 60 drops (gtt)

1 teaspoon (tsp) = 4.93 mL

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Found on allnurses

0 Votes
2000mg/60min=33.3mg/min

Is this correct?

Thank you,

Pumps set cc/hr, not mg/min. Your question asks you to solve for cc/hr, not for mg/min. So no, that is the wrong answer. If you see a question like this in your exams, the common distractor (wrong answer) would be the one you gave, because they know some people will use the wrong units.

Let's look at this again. Did you notice there are three problems to solve here?

1. Loading dose. This is an IV rate, cc/hour question. 40gm in 100cc. So... 4gm is how many cc? You must be able to look at that and say, gee, 1/10 of 40gm is 4gm, and 1/10 of 100cc is 10cc, so my loading dose of 4gm is in 10cc to give over 30 minutes. That would be 4gm/40gm x 100cc = 10cc

Having gotten that, 10cc/30 minutes would be 20cc/60minutes (one hour), so you set your pump for 20cc/hour to start, but you make sure it stops after 10cc is delivered or 30 minutes is past, whichever your pump allows.

2. Maintenance dose. This is an IV rate, cc/hour question too, but it has two parts. 40 gm in 100cc. That means 0.4gm/cc. Maintenance dose is 2gm/hour. That looks like 5cc, right? So maintenance is 5cc/hour. 40gm/100cc = 0.4gm/cc. THEN 2gm / 0.4gm/cc = 5cc

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I found a really easy way of solving this:

For loading dose: 4g/min x 60min/hr x 100ml/40g = 20 ml/hr

For maintenance dose: 2g/hr x 100ml/40g = 5ml/hr

0 Votes
I found a really easy way of solving this:

For loading dose: 4g/min x 60min/hr x 100ml/40g = 20 ml/hr

For maintenance dose: 2g/hr x 100ml/40g = 5ml/hr

This is definitely the easiest way! You're using dimensional analysis here...I LOVE dimensional analysis...you follow along the path from what you have (g) to what you need (mL) and cancel out what you don't need along the way - you go from g/min to mL/hr in the loading dose and g/hr to mL/hr in the maintenance dose.

I just think dimensional analysis makes things so much easier!!

I solved the equation just like you and got 20 mL/hr and 5 mL/hr as well

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Specializes in Public Health, TB.

I kinda miss apothecary measures, drams, and grains, and minims, oh my!

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