Calculation problem

CrufflerJJ, BSN, RN, EMT-P · Jul 26, 2009

Could someone please tell me how to do this calculation. "A resident is ordered 15mg/ml of morphine, 10mg/ml of maxalon and normal saline, to be made up in 10ml syringe over a 24 hour period. Calculate the amount of drug and normal saline that would need to be prepared. Syringe Drivers - Terumo 10ml syringe=9.4ml equals stroke length of 48mm. What is the total morphine volume, total volume of maxalon, total vol of normal saline and what is the total volume to prepare in the syringe" many:bow: thanks - just starting this calculations stuff.

That is a STRANGELY worded math problem. It gives no info about the starting concentration of morphine or Maxolon. If I'm reading it correctly, you need to end up with 9.4ml of total solution to fill the "10ml" syringe.

IF I'm reading it correctly, your total volume will be 9.4ml. Amount of morphine in the syringe will be 9.4 x 15 = 141mg. Amount of Maxolon in the 9.4 ml syringe will be 9.4 x 10 = 94mg. Whatever volume is left in the syringe would need to be made up with normal saline to a final volume of 9.4ml.

Without being given the starting concentration of morphine & Maxolon, I can't tell you the volume of each drug to be added to the syringe. If the concentrations in the word problem (15mg/ml, 10mg/ml) are supposed to be initial concentrations for morphine & Maxolon, the freakin' problem doesn't tell you the ultimate (diluted) concentration of each drug to be generated in the final mixture. Sorry - it's a very poorly worded, confusing question. Your professor gets an F for clarity.

Bluecap · Jul 26, 2009

Thank you for trying and I got stuck on the same issues. Cheers

chare · Jul 26, 2009

I agree that this is a poorly worded problem. However, with the information provided you can make the following assumptions:

- Total morphine dose is 15 mg

- Total Maxolon dose is 10 mg

- Maximum allowable volume for the 10 mL Terumo syringe on the available syringe pump is 9.4 mL

Using these assumptions leads to the following volumes:

- Morphine: 1 mL

- Maxolon: 1 mL

- Normal saline: 7.4 mL

You end up with the following concentrations:

- Morphine: 1.595 mg/mL

- Maxolon: 1.063 mg/mL.

To infuse this over 24 hours your infusion rate would be 0.208 mL/hour.

I hope this information was helpful. :specs:

CrufflerJJ, BSN, RN, EMT-P · Jul 27, 2009

I agree that this is a poorly worded problem. However, with the information provided you can make the following assumptions:

I hate making assumptions with med related stuff. I even double-checked to see if morphine & Maxolon were compatible in mixtures. Yes, I'm anal. Then again, I hate making mistakes (even theoretical ones) involving meds being delivered to a patient.

allnurses Guide · Aug 2, 2009

I agree that this is a poorly worded problem. However, with the information provided you can make the following assumptions:
- Total morphine dose is 15 mg
- Total Maxolon dose is 10 mg
- Maximum allowable volume for the 10 mL Terumo syringe on the available syringe pump is 9.4 mL
Using these assumptions leads to the following volumes:
- Morphine: 1 mL
- Maxolon: 1 mL
- Normal saline: 7.4 mL
You end up with the following concentrations:
- Morphine: 1.595 mg/mL
- Maxolon: 1.063 mg/mL.
To infuse this over 24 hours your infusion rate would be 0.208 mL/hour.
I hope this information was helpful.

How can you assume that morphine 15mg or maxolon 10mg = 1ml? It says the final concentration should be 15mg/ml, it does not say that is the stock strength....?? Maybe I'm missing something.

beth66335, BSN, RN · Aug 2, 2009

I would like to hear what Daytonite thinks of this problem! :rolleyes:

chare · Aug 3, 2009

i have previously stated that this was a poorly worded problem. if i had received this order, i would have called the physician for clarification prior to implementing it.

first, let me state that my response was poorly worded as well. when i stated that you could make certain assumptions, i should have stated that all information required to solve the problem was provided in the original post although not clearly stated:

- 15 mg morphine, in 1 ml (highlighted in red)

- 10 mg maxolon, in 1 ml (highlighted in blue)

- diluted to 9.4 ml with normal saline (highlighted in green)

could someone please tell me how to do this calculation. "a resident is ordered 15mg/ml of morphine, [color=#3366ff]10mg/ml of maxalon and [color=#339966]normal saline, to be made up in [color=#339966]10ml syringe over a 24 hour period. calculate the amount of drug and normal saline that would need to be prepared. [color=#339966]syringe drivers - terumo 10ml syringe=9.4ml equals stroke length of 48mm. what is the total morphine volume, total volume of maxalon, total vol of normal saline and what is the total volume to prepare in the syringe" many thanks - just starting this calculations stuff.

i hate making assumptions with med related stuff. i even double-checked to see if morphine & maxolon were compatible in mixtures. yes, i'm anal. then again, i hate making mistakes (even theoretical ones) involving meds being delivered to a patient.

i agree with you. assumption is the mother of all foul ups. i previously stated that this was a poorly written problem, which would have prompted a call to the ordering physician for clarification. and verifying compatibility is not anal, it’s common sense.

that is a strangely worded math problem. it gives no info about the starting concentration of morphine or maxolon.

this information was clearly provided in the original post.

if i'm reading it correctly, your total volume will be 9.4ml. amount of morphine in the syringe will be 9.4 x 15 = 141mg. amount of maxolon in the 9.4 ml syringe will be 9.4 x 10 = 94mg. whatever volume is left in the syringe would need to be made up with normal saline to a final volume of 9.4ml.

following your math, you are now up to 18.8 ml, this would be quite and accomplishment in a 10 ml syringe. talk about assuming facts not in evidence.

without being given the starting concentration of morphine & maxolon, i can't tell you the volume of each drug to be added to the syringe. if the concentrations in the word problem (15mg/ml, 10mg/ml) are supposed to be initial concentrations for morphine & maxolon, the freakin' problem doesn't tell you the ultimate (diluted) concentration of each drug to be generated in the final mixture. sorry - it's a very poorly worded, confusing question. your professor gets an f for clarity.

again, all of this information was provided in the original post, and final concentrations of both medications are easily calculated.

how can you assume that morphine 15mg or maxolon 10mg = 1ml? it says the final concentration should be 15mg/ml, it does not say that is the stock strength....?? maybe i'm missing something.

again, refer to the original post. you are provided the amount of medication to be added as well as starting concentration. crufflerjj was the one making the assumption that the final concentration should be 15 mg/ml, not the original poster.

hopefully this has clarified my response:specs:

kgh31386, BSN, MSN, RN · Aug 3, 2009

i can do math problems all day and night, but this one just doesn't make any sense. however it is 2:30 and i'm sitting here charting at work, so i checked maxolon on the computer here, and it said..."i.v. (for severe gastric statis): 10 mg over 1-2 minutes; 10 days of i.v. therapy may be necessary for best response". so if a doc gave me that order, i'd call and question it for sure and ask for more info. i think that would be an iv push, not some long 24 hour infusion...perhaps a mini-infusion as a piggyback in a 10cc syringe(which i've seen and hung in clinical)??? some info is missing from the op. :typing

allnurses Guide · Aug 10, 2009

i have previously stated that this was a poorly worded problem. if i had received this order, i would have called the physician for clarification prior to implementing it.
first, let me state that my response was poorly worded as well. when i stated that you could make certain assumptions, i should have stated that all information required to solve the problem was provided in the original post although not clearly stated:
- 15 mg morphine, in 1 ml (highlighted in red)
- 10 mg maxolon, in 1 ml (highlighted in blue)
- diluted to 9.4 ml with normal saline (highlighted in green)
i agree with you. assumption is the mother of all foul ups. i previously stated that this was a poorly written problem, which would have prompted a call to the ordering physician for clarification. and verifying compatibility is not anal, it's common sense.
this information was clearly provided in the original post.
following your math, you are now up to 18.8 ml, this would be quite and accomplishment in a 10 ml syringe. talk about assuming facts not in evidence.
again, all of this information was provided in the original post, and final concentrations of both medications are easily calculated.
again, refer to the original post. you are provided the amount of medication to be added as well as starting concentration. crufflerjj was the one making the assumption that the final concentration should be 15 mg/ml, not the original poster.
hopefully this has clarified my response:specs:

wow, you're quite defensive about this!! we are all working together to try and help the op.

i still don't agree with your logic - the original question states that there is 15 mg/ml of morphine, not 15mg in 1ml. it also states that there is 10mg/ml of maxolon, not 10mg in 1 ml. stating a concentration is not the same as stating the starting volume or the final concentration.

in fact, i would read it as the patient is ordered 15mg/ml of morphine - meaning that from the final syringe, they should be receiving 15mg/ml of morphine. using your calculations, they would only be getting 1.5mg/ml (total 15mg in 10 mls - or slightly higher conc if you reduce total vol to 9.4mls).

in any case op, i hope you can see this is not an easy question, because it's very badly written.

[color=#3366ff]

beth66335, BSN, RN · Aug 10, 2009

Wow, you're quite defensive about this!! We are all working together to try and help the OP.
I still don't agree with your logic - the original question states that there is 15 mg/ml of morphine, not 15mg in 1ml. It also states that there is 10mg/ml of maxolon, not 10mg in 1 ml. Stating a concentration is not the same as stating the starting volume or the final concentration.
In fact, I would read it as the patient is ordered 15mg/ml of morphine - meaning that from the final syringe, they should be receiving 15mg/ml of morphine. Using your calculations, they would only be getting 1.5mg/ml (total 15mg in 10 mls - or slightly higher conc if you reduce total vol to 9.4mls).
In any case OP, I hope you can see this is not an easy question, because it's very badly written.

Actually, that is exactly what " / " means...it means "per mL". I think this question is worse every time I look at it! :confused:

chare · Aug 10, 2009

I apologize if I seemed defensive or offensive in my posts; that was not my intent. I was merely attempting to explain my understanding of the original problem and how I obtained the information that I used, obviously not very clearly.

These differences of interpretation highlight the necessity of calling the ordering physician for clarification on any order that is not 100% clearly worded and understood.