Med Math please read need help

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Hey guys. PLEASE help me solve the following questions. Please show all work.

#1

The client was receiving a premixed Magnesium Sulfate solution of 40grams per

liter infusing at 22cc/h via an IV pump. The nurse should record how many

milligrams per minute the client is receiving?

#2

The client has an I.V. of Normal Saline solution infusing at the rate of 40gtts/minute. The dro factor is 10 gtts/ml. How many milliliters per hour is the client receiving?

Thank you

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Specializes in med/surg, telemetry, IV therapy, mgmt.

the client was receiving a premixed magnesium sulfate solution of 40 grams per liter infusing at 22 cc/hour via an iv pump. the nurse should record how many milligrams per minute the client is receiving?

22 cc/1 hour
(dose being given)
x 40 grams/1 liter
(dose on hand)
x 1 hour/ 60 minutes
(conversion factor)
x 1000 mg/1 gram
(conversion factor)
x 1 liter/1000 cc
(conversion factor)
= 14.6666 mg/minute
, rounded up to
15 mg/minute
(dose being given)

the client has an i.v. of normal saline solution infusing at the rate of 40 gtts/minute. the drop factor is 10 gtts/ml. how many milliliters per hour is the client receiving?

40 gtts/minute
(drip rate)
x 1 ml/10 gtts
(drop factor of iv tubing)
x 60 minutes/1 hour
(conversion factor)
=
240 ml/hour
(infusion rate)

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Daytonite, thank you. I understand what you did for problem 2 but im confused what you did for problem 1. is that dimensional analysis? cuz if it is, i have NO idea how to use it.

Can you please explain, IN DETAIL, how you did problem 1 or maybe you can show a simpler way of doing it (maybe ratio and proportion)??

Please someone help me with question #1.

Thank you :(

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Specializes in med/surg, telemetry, IV therapy, mgmt.

I did both by dimensional analysis.

Problem #1 is simply 40 grams/Liter which is = to 40,000 mg/1000 mL. That is 40,000 mg divided by 1000 mL which is = to 40 mg/mL. At 22cc/hour the patient is getting (22cc)(40mg) or 880 mg/hour. Since there are 60 minutes in an hour, divide the 880 mg by 60 minutes to get 14.6666 which you can round off to 15 mg/minute.

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can you explain the dimensional analysis way again. this was confusing, sorry and thanks again.

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Specializes in med/surg, telemetry, IV therapy, mgmt.
can you explain the dimensional analysis way again. this was confusing, sorry and thanks again.

I've shown you 2 ways to work the problem. I don't know any other ways to work it for you. Have you tried to work the problem on paper yourself doing both ways? Maybe you need to take a break and come back to the problem later.

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i suck at dimentional analysis...actually i'm mathmatically challanged so i'll try and break it down step by step like a wonderful friend had to do for me. :bugeyes:

“the client was receiving a premixed magnesium sulfate solution of 40grams per

liter infusing at 22cc/h via an iv pump. the nurse should record how many

milligrams per minute the client is receiving?”

(helpful hint:always underline what they are asking for and double check yourself after you’re done with the problem so you don’t get a problem wrong just because you forgot to convert something!!! i don’t know how many times i could have kicked myself :banghead: for a stupid mistake until my friend gave me that bit of advise.)

without breaking it down my problem would look like this:

40g:1l = 40,000mg:1,000ml

1h = 60min

40,000mg:1000ml = x: 22ml (cc)

1000x = 880,000

x = 880mg

880mg/60min = 14.666666666 = 14.6mg/min

breaking it down:

first convert grams and liters to mg and ml (cc)

(because the question wants to know how many mg your pt is receiveing)

40g:1l = 40,000mg:1,000ml (cc)

breaking it down further if you need:

1g = 1,000mg so

1g: 1,000mg = 40g: x (crossmultiply)

1x = 40,000

x = 40,000mg

1l=1,000ml (hope don’t have to break this one down :bugeyes:)

then convert hours to minutes because the question wants to know how many mg per minute the client is receiving.

1h = 60min

then you put it together:

if 40,000mg are in 1,000ml then how many mg (x) are in 22ml?

40,000mg:1000ml = x: 22ml (cc)

1000x = 880,000

x = 880mg

so your variable x = 880mg (in other words 40,000mg:1,000ml = 880mg:22ml)

then you have to figure out how many mg per minute the client is receiving

so you divide 880 by 60min = 14.6666

800/60 = 14.666666666

the correct answer (14.666, 14.6, or 15) depends on if or where your instructer wants you to round up to.

i’ve had instructers who’ve asked for different answers when asking for mg/min or mg/hr type questions but gtts/min or ml/hr we always round to the whole number. (i kept them straight by thinking if it’s fluid it’s whole)

i hope i didn't confuse you more! i know my way is long and complicated but seeing everything written out always helped me keep things straight and helped when i went back to double check myself.

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