drug calculation help!

FarmgrrlRN · Dec 12, 2004

where were you'all in aug.?
I am just finishing up pharm and i have to say that i am just now really starting to understand the math...............especially the recalculation times for IV's........uck!!!!!
Its very frustrating at times!----especially when you start to talk to RN's whom are all,"I don't know why they require you to know all of the conversions. We have chrts to look them up when we need to."
Plus in my state there are colleges where pharm is not required, at all.
'I am a stronger person for it, i am a stronger person for it, i am a stronger person for it'............................................
good luck to all whom still have finals to get through!!!!!!!!!!!!!!!!!!!!

Yes, but pharm is required for NCLEX....those colleges that don't require it probably incorporate it into the curriculum

janetrette · Dec 13, 2004

hey kudra would you be able to give an example of a titration problem?

Pediatric Critical Care Columnist · Dec 13, 2004

In our unit, many of our patients are fluid restricted and may only have a few ml per hour of fluid to play with. So we mix our infusions so that we can run them at a standard, recognized, miniscule rate to maintain our fluid restrictions. The patient I had today is a 16 day old 3.3 kg baby who had an arterial switch procedure and VSD closure a couple of days ago. His sternum is open with the skin sutured closed over it. In order for us to close his sternum, he must have a negative fluid balance for 48 hours, to ensure that there will not be edema in the chest wall or mediastinal contents. Otherwise we risk cardiac tamponade from forcing the heart to beat in a space too small for it. He is fluid restricted to 50% of maintenance, which for him is 165 ml for 24 hours, or 6.9 ml per hour. (Maintenance for peds is 100 ml per kg for the first 10 kg, 50 ml per kg for the next 10 kg and 20 ml per kg for the rest of their weight. This patient weighs 3.3 kg so 100 % for him would be 3.3 X 100 = 330.) His lines (arterial = 1.5 ml, CVP = 1 ml and left atrial= 1 ml) use up 3.5 ml per hour of that total, leaving us 3.4 ml per hour for all his other infusions. So his dopamine is mixed such that I can run it at 1 ml per hour and he will get 5 mcg per kg per minute. He is on a morphine infusion both for sedation and analgesia. It is mixed so that 1 ml per hour gives him 50 mcg per kg per hour. His dose is 40 mcg, so that one runs at 0.8 ml per hour. We're then left with 1.6 ml per hour that we can make up with some D10NS with a bit of KCl in it to maintain his glucose and K+ within normal limits. While we're at it we must also add in all meds and flushes we may need during the 24 hour period and subtract that volume from our total so we're still within his 50%. He gets Lasix 3 mg q6h, which with the flush amounts to 4 ml. I made allowances for that by running his D10NS/KCl at 1.5 ml and going over his total fluid intake by a little bit. Starting to make sense?

lucy_w · Dec 13, 2004

nevermind.

andi2634 · Dec 13, 2004

We run alot of our drips mcg/kg/min and this is the easiest way for me to figure it out.

If the order says to start Dopamine at 5 mcg and the pt. weighs 70 kgs:

To find the rate if you know the dose (amt. desired).

Amt drug (mg/units)

--------------------- x 1000 = A

Amt solution (cc's)

Amt desired divided by A x wt (kg) x 60 (for min)

400

----- x 1000 = 1600

250

5 divided by 1600 x 70 x 60 = 13 cc

You would set the pump for 13 cc/ hour.

Now if you go to asses your patient and you see that dopamine is running at 13 cc- you want to double check to make sure it is at the right dose ordered.

To find the dose if you know the rate.

Amt drug(mg/units)

------------------- x 1000 x rate divided by wt. divided by 60

Amt solution (cc's)

400

---- x 1000 x 13 divided by 70 divided by 60 = 5mcg/kg/min

250

Hope this helps

aruray · Dec 18, 2004

............his D10NS/KCl at 1.5 ml and going over his total fluid intake by a little bit. Starting to make sense?

Yes it makes sense now. I had to read it at least 3 times but yes I do understand it! I fee like I can work in PICU tomorrow now. jk..

aruray · Dec 18, 2004

............his D10NS/KCl at 1.5 ml and going over his total fluid intake by a little bit. Starting to make sense?

Yes it makes sense now. I had to read it at least 3 times but yes I do understand it! I fee like I can work in PICU tomorrow now. jk..

aruray · Dec 18, 2004

We run alot of our drips mcg/kg/min and this is the easiest way for me to figure it out.
If the order says to start Dopamine at 5 mcg and the pt. weighs 70 kgs:
To find the rate if you know the dose (amt. desired).
Amt drug (mg/units)
--------------------- x 1000 = A
Amt solution (cc's)
Amt desired divided by A x wt (kg) x 60 (for min)
400
----- x 1000 = 1600
250
5 divided by 1600 x 70 x 60 = 13 cc
You would set the pump for 13 cc/ hour.

This problem was actually in my final. Same exact one, although I dont remember if I got the right answer, lol.

aruray · Dec 18, 2004

We run alot of our drips mcg/kg/min and this is the easiest way for me to figure it out.
If the order says to start Dopamine at 5 mcg and the pt. weighs 70 kgs:
To find the rate if you know the dose (amt. desired).
Amt drug (mg/units)
--------------------- x 1000 = A
Amt solution (cc's)
Amt desired divided by A x wt (kg) x 60 (for min)
400
----- x 1000 = 1600
250
5 divided by 1600 x 70 x 60 = 13 cc
You would set the pump for 13 cc/ hour.

This problem was actually in my final. Same exact one, although I dont remember if I got the right answer, lol.

Pediatric Critical Care Columnist · Dec 18, 2004

Yes it makes sense now. I had to read it at least 3 times but yes I do understand it! I fee like I can work in PICU tomorrow now. jk..

Come on down!!!! We could use a hand today.

celticqueen · Jan 12, 2005

hi, does anyone know microgram/kg/min?
i had done calculation with mg/kg/min but microgram? i'm not even sure of the conversion of it either!
please help!:balloons:

Hiya. I was told to always covert big to small, i.e if you had a calculation of needing 65.5 micrograms and the stock amount is 0.5Mg's then you need to multiply the 0.5Mg by 1000 to convert it into micrograms aswell. This makes it easier to calculate.

hope this helps (hope i wasn't rambling on!!!!!)

emma