Math calculations test next week, HELP ME!

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Hi everyone! I have just finished my first semester in Foundations of Nursing and begin next week in Adults 1 (Med-surg1). In order for us to start clinicals we have to pass this math calculations test the first day of class and I am a human wreck trying to figure out some of these problems. If anyone is interested, can you please help me figure them out?

1. Acyclovir 400mg in 100ml of D5W is ordered to infuse over 0.25 hours. The IV tubing delivers 10gtt/ml. The rate of the infusion will be how many gtts/min?

2. A Heparin drip is ordered: 500ml DW with 50,000 unit of Heparin to infuse at 1100units/hour. How many ml/hr will the pt receive?

*p.s. can you explain to me the procedures for figuring out units?

3. 500ml of D5W with 0.5G Theophylline is ordered to infuse at 50ml/hr. How many mg will the pt received per hour?

Thank you so much for your patience, this will really help.

Hi everyone! I have just finished my first semester in Foundations of Nursing and begin next week in Adults 1 (Med-surg1). In order for us to start clinicals we have to pass this math calculations test the first day of class and I am a human wreck trying to figure out some of these problems. If anyone is interested, can you please help me figure them out?

1. Acyclovir 400mg in 100ml of D5W is ordered to infuse over 0.25 hours. The IV tubing delivers 10gtt/ml. The rate of the infusion will be how many gtts/min?

2. A Heparin drip is ordered: 500ml DW with 50,000 unit of Heparin to infuse at 1100units/hour. How many ml/hr will the pt receive?

*p.s. can you explain to me the procedures for figuring out units?

3. 500ml of D5W with 0.5G Theophylline is ordered to infuse at 50ml/hr. How many mg will the pt received per hour?

Thank you so much for your patience, this will really help.

Hope you are getting this in time. Just another way to do the same problems, I found this ways is easier and you can do it with any problem you have!

#1

100ml x 10 gtt/ml

15 min

Divide 100 over 15 then multiply the answer by 10. This gives you 66.66 = 67gtt/min

#2

50,000U : 500ml :: 1100U/hr : xml

do this like any proportion, multiply the middle numbers together...

500x1100=550,000

then mulliply the outer two numbers together

50,000 x X = 50,000x

so your problem lookes like this

550,000=50,000x

now isolate your variable (x) by dividing

550,000 = x

50,000

x = 11ml/hr

#3

500mL : 500mg :: 50mL/hr : x mg

do the same as above, the two inner, the two outer

500x50=25,000

500 x X = 500x

25,000 = 500x

25,000 = x

500

x= 50mg/hour

Child 5 lbs, you are ordered to give 10 mg/kg of Tylenol. You have infant drops available in a concentration of 80 mg/0.8 ml dropper. How much do you give?

I have the weight conversion down, 2.3 kg. I am just not sure what to do there.

The other question is an infant weighs 32 lbs and needs Tylenol for pain relief, 15 mg/kg. The concentration available is 160 mg/5 ml.

2.3 kg x 10 mg= 20 mg

80 mg 20

______ _____

0.8 ml X ml

0.8 x 20 divided by 80 = 0.04 ml.

This is what I have been self teaching myself. I think that is correct. I just started. use the same formula for the other problem.

Tracy

Achoo, I am glad we can work through this together! This is what I get:

23 mg x 0.8 ml/ 80 mg = 0.23 ml

For the second one, I get the weight as 14.5 kg

14.5 kg x 15 mg/kg = 217.5 mg

217.5 mg x 5 ml/ 160 mg = 6.8 ml 6.8 ml would be the dose!

Would these be right?

If these would be correct, it just clicked! Thanks so much everyone for all your help!

Specializes in med/surg, telemetry, IV therapy, mgmt.
Child 5 lbs, you are ordered to give 10 mg/kg of Tylenol. You have infant drops available in a concentration of 80 mg/0.8 ml dropper. How much do you give?

The equation you will set up using dimensional analysis is as follows:

10 mg Tylenol/1 kg (
desired dose
)
x
1 kg/2.2 lb (
conversion ratio
)
x
0.8 ml/80 mg Tylenol (
dose on hand
)
x
5 lbs./1 (
child's weight
)

Simplify and cancel out labels on the numbers which leaves you with:

(10 x 1 x 0.8
ml
x 5)
/
(1 x 2.2 x 1 x 80)
=
0.227 ml which is rounded to
0.2 ml

An infant weighs 32 lbs and needs Tylenol for pain relief, 15 mg/kg. The concentration available is 160 mg/5 ml.

The equation you will set up using dimensional analysis is as follows:

15 mg/1 kg (
desired dose
)
x
1 kg/2.2 lb (
conversion ratio
)
x
5 ml/160mg (
dose on hand
)
x
32 lbs/1 (
child's weight
)

Simplify and cancel out labels on the numbers which leaves you with:

(15 x 1 x 5
ml
x 32)
/
(1 x 2.2 x 1 x 160)
=
6.8181 ml which is rounded to
7 ml

Specializes in Urgent Care.
Achoo, I am glad we can work through this together! This is what I get:

23 mg x 0.8 ml/ 80 mg = 0.23 ml

For the second one, I get the weight as 14.5 kg

14.5 kg x 15 mg/kg = 217.5 mg

217.5 mg x 5 ml/ 160 mg = 6.8 ml 6.8 ml would be the dose!

Would these be right?

If these would be correct, it just clicked! Thanks so much everyone for all your help!

PM me and we can brainstorm together! :)

Tracy

Hi-

RE: Child 5 lbs, you are ordered to give 10 mg/kg of Tylenol. You have infant drops available in a concentration of 80 mg/0.8 ml dropper. How much do you give?

I have the weight conversion down, 2.3 kg. I am just not sure what to do there.

The other question is an infant weighs 32 lbs and needs Tylenol for pain relief, 15 mg/kg. The concentration available is 160 mg/5 ml.

You have been given the answer to the above in several posts, but here is a way to remember it:

I use this ALL THE TIME and it is so simple: Remember D/HxQ

just remember: Desired over Have multiplied by Quantity (D/H x Q)

in your first question--> D or what is "desired" is: 23 mg of Tylenol. H is what you Have: 80 mg, Q is the quantity of the Have: .8 ml

so 23mg divided by 80mg x .8ml is .23 mls

in the next example-> D/HxQ

you have D=217.5 mg (by multiplying 15mg/kg by 14.5 kg), H=160mg, Q = 5ml

217.5 mg divided by 160 mg = 1.36

1.36 x 5ml = 6.8 ml

just remember this: D/HxQ you will use it the most!

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