Dosage Calculation HELP!

Nursing Students General Students

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Question: Explain how you would prepare each of the following hydrogen peroxide (solute) and normal saline (solvent) irrigation orders:

1L of 1/4 strength solution

1L= 1q = 32 fl oz = 2pt = 960 mL (is this correct?)

The question is asking for an answer in mL.

The book's answer is:

250 mL hydrogen peroxide (solute) + 750 mL normal saline (solvent) = 1,000 mL (1L) of the 1/4 strength solution.

How does 1,000 mL = 1L when I calculated 32 fl oz x 30 mL = 960 mL?

for my answers I got: 240 mL solute (hydrogen peroxide) and 720 mL solvent (normal saline) = 960 mL total solution = 1L right?

I'm really confused with these calculations.

Specializes in NICU, ICU, PICU, Academia.

Because one ounce is approximately 30 mL. In reality, one ounce is 28.something mL. When you go between two systems of measurement, you will end up usually approximating. You made a faulty assumption that 1 liter = 1 quart. They are not equivalent.

Because one ounce is approximately 30 mL. In reality, one ounce is 28.something mL. When you go between two systems of measurement, you will end up usually approximating. You made a faulty assumption that 1 liter = 1 quart. They are not equivalent.

My book has a chart of equivalents and 1 liter = 1 quart is a equivalent given.

Specializes in psych, addictions, hospice, education.

Is the information about quarts in the question? If so, it's just a distractor. It seems all you need to do is stay in the metric system. Agreed, one liter is ABOUT one quart, but a difference of 40 ml could be significant. There's no need to convert from one system to another in this problem.

Specializes in Med/Surg, Ortho, ASC.
Is the information about quarts in the question? If so, it's just a distractor. It seems all you need to do is stay in the metric system. Agreed, one liter is ABOUT one quart, but a difference of 40 ml could be significant. There's no need to convert from one system to another in this problem.

This! You really confused everything by adding that unnecessary conversation into quarts.

the quarts thing isn't confusing me, just the fact that my book has a chart on the inner binder saying 1L = 32 fl oz, but when i calculate 1L = 960 mL where as in the solution section of the question , it's saying 1 L = 1,000 mL, just not sure why it wouldnt have a higher fl oz equivalent if they want 1,000 mL to equal 1L, you understand what i mean?

Specializes in psych, addictions, hospice, education.

your book rounded to the nearest ounce

Question: Explain how you would prepare each of the following hydrogen peroxide (solute) and normal saline (solvent) irrigation orders:

1L of 1/4 strength solution

1L= 1q = 32 fl oz = 2pt = 960 mL (is this correct?)

The question is asking for an answer in mL.

The book's answer is:

250 mL hydrogen peroxide (solute) + 750 mL normal saline (solvent) = 1,000 mL (1L) of the 1/4 strength solution.

How does 1,000 mL = 1L when I calculated 32 fl oz x 30 mL = 960 mL?

for my answers I got: 240 mL solute (hydrogen peroxide) and 720 mL solvent (normal saline) = 960 mL total solution = 1L right?

I'm really confused with these calculations.

1- Your book is wrong.

2- Why on earth would you convert it to ounces and back?

3- Since 1 ml will always be 1/1,000 of 1 liter, 960 ml will never ever equal 1 liter. The metric system is really simple, and you should learn the principals to avoid errors.

1 oz = 30 ml is a handy rough estimate. That way when the pt has an 8 oz glass of OJ, you don't have to document " PO intake 236.5882375 ml fluid."

If you want to pass the test, you need to discuss the equivalency question with your instructor.

Not on an internet forum.

If you want to pass the test, you need to discuss the equivalency question with your instructor.

Not on an internet forum.

Well being it's summer break for me I'd rather get advice and answers from people who may know the answer??

Specializes in Medical and general practice now LTC.

Moved to the General Student discussion forum

Specializes in 15 years in ICU, 22 years in PACU.
the quarts thing isn't confusing me, just the fact that my book has a chart on the inner binder saying 1L = 32 fl oz, but when i calculate 1L = 960 mL where as in the solution section of the question , it's saying 1 L = 1,000 mL, just not sure why it wouldnt have a higher fl oz equivalent if they want 1,000 mL to equal 1L, you understand what i mean?

The chart in your book is giving you approximate conversions of liters to ounces. 1L is actually 33.8140227 oz but that is too hard for most student nurses to remember.

If the desired answer to the question is in ml then the measurements should be in ml.

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