Order magnesium sulfate 20g IV in LR 500 ml. Start with bolus of 2g to infuse over 30 min, then maintain a continuous infusion at 1g/hr.

1. Calculate the ml/hr for bolus

2. Calculate ghe ml/h for comtinuous infusion. Magnesium Sulfate Continuous Infusion Assignment

**Question 1**

Step 1: Write down the information provided in the question

- The orders are: 20 g IV (intravenous) in LR (Ringer lactate) 500 ml
- Bolus should be given as – 2g over 30 min = 2g/30 min
- Continuous infusion – 1 g/hr

Step 2: Re-write in information under the following headings:

- Dose at hand – 20 g
- Quantity at hand – 500 ml
- Dose required – 2 g (as the rate should be 2g/30 min for the bolus)
- Quantity required – x

Step 3: Write down the universal formula

- Dose at hand / Quantity at hand = Dose required /quantity required
- Quantity required = Dose required x Quantity at hand / Dose at hand

- Explanation for step 1

Enter the values in the formula

- 2 g x 500 ml / 20 g

Cancel the common units in the numerator and denominator

- 2 x 500 ml / 20

Cancel the common factor of 2 and 20.

50010

Cancel the common factor of 500 and 10.

50ml

So 50 ml will provide 2g of magnesium sulfate

So, 2 g/30 min = 50 ml / 30 min

Step 4: Convert minutes to an hour

- 1 hour = 60 min
- 1 min = 1/60 hour

50 ml/ 30 min = 50 ml / 30 x (1/60) hr

Now re-arrange the fraction

Cancel the common factor of 50 and 30.

5×603

Cancel the common factor of 60 and 3.

5×20

Multiply 5 by 20.

100ml/hr

So, the bolus should be

**100 ml/hr****Question 2**

The infusion rate for the continuous infusion should be 1g/hr

Step 1: Write down the information under the following heads:

- Dose at hand – 20 g
- Quantity at hand – 500 ml
- Dose required – 1g (as the rate should be 2g/30 min for the bolus)
- Quantity required – x

Step 2: Write down the universal formula

- Dose at hand / Quantity at hand = Dose required /quantity required
- Quantity required = Dose required x Quantity at hand / Dose at hand

- Explanation for step 2

Step 3: Insert the values into the formula

- 1 g x 500 ml / 20 g

Cancel the common units in the numerator and denominator

- 1 x 500 ml / 20

Cancel the common factor of 500 and 20.

1×25

Multiply 25 by 1.

25ml/hr

The continuous infusion should be provided at the rate of

**25 ml/hr.**The

__bolus rate__should be**100 ml/hr**and the__continuous infusion rate__should be**25 ml/hr.****Magnesium Sulfate Continuous Infusion Assignment**