Advanced calculation problem. Help!!!

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Hello, I am in the third semester now and we are doing the advanced calculations. I can do all of them except I am having troubles with the ones that have 3 or more steps.. I didnt know if anyone had an easier way to look at this.. I am pulling my hair out.. this is how it goes

Order: morphine sulfate 6mg IV push q3hr p.r.n. pain. On hand is morphine sulfate 10mg/ml, with drug reference recommendation for IV infusion not to exceed 2.5mg/min. How many ml will the nurse push every 15 seconds.

I get it up to the 0.6 ml but then I cant figure out what is next and so on.. thanks in advanced. I have the answer but just trying to figure out if there is another way to do this that I may understand.

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2.5 mg = 0.25 ml. Divide that by 4 (4 blocks of 15 secs per minute)= .06 ml.

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

See below.

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but recommendations are not to exceed 2.5 mg/min

if 0.6 mL is given in one minute then that would be giving 6 mg/min

(10 mg/mL works out to 2.5 mg/ 0.25 mL)

0.25 mL would be the maximum to be given in one minute (because = 2.5 mg)

0.25 mL divided by 4 doses per minute works out to 0.0625 mL

(rounded to 0.06 mL)

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

OK. Let me re-calculate this:

STEP #1

6 mg
(dose desired)
/
10 mg
(dose on hand)
x
1 mL
(amount on hand)
=
0.6 mL
(dose to give)

STEP #2

6 mg
(dose desired)
/
2.5 mg
(limited dose you can give)
x
1 minute
=
2.4 minutes
(time it will take to inject the 6 mg dose)

STEP #3

0.6 mL
(dose to give)
/
2.4 minutes
(time required to inject the dose)
x
1 minute
/
60 seconds
(conversion factor)
=
0.6 mL/144 seconds
=
0.004166 mL/second

STEP #4

60 seconds
/
4
(intervals per minute)
=
15
(seconds per interval)

STEP #5

0.004166 mL/second x 15
=
0.06 mL per every 15 seconds

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but recommendations are not to exceed 2.5 mg/min

if 0.6 mL is given in one minute then that would be giving 6 mg/min

(10 mg/mL works out to 2.5 mg/ 0.25 mL)

0.25 mL would be the maximum to be given in one minute (because = 2.5 mg)

0.25 mL divided by 4 doses per minute works out to 0.625 mL per dose q 15 seconds (rounded to 0.6 mL)

(must recheck that decimal point: 0.25 mL divided by 4 doses = 0.0625 mL

rounded to 0.06 mL)

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