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IV Microdrop flow rate question.

by Germaine
(LA)

IV Microdrop Calculation

IV Microdrop Calculation

Please show how to calculate this IV problem:

The medication order is to administer dobutamine hydrochloride (Dobutrex) at 5.2 mcg/kg/min. The patient weighs 150 lbs. The IV solution has been prepared by adding Dobutrex 250 mg to 200 mL of D5W. Calculate the flow rate in microdrops (60 drops per mL).

Comments for IV Microdrop flow rate question.

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IV Question Answer
by: ANA

PATIENT SHOULD ADMINISTER:
.354mg/min (.0052mg *68.18 kg)
we have 250mg /200 ml
so,345mg found in 283 ml
the drop factor = 60 gtt/ml
so we have 17.07gtt/283 ml
so the flow rate is 17gtt/min
help
by: Anonymous

doesnt make sense? :(
hope this helps
by: Anonymous

First step convert mcg to mg. 5.2mcg to .0052mg. Then convert lbs. to kg 150/2.2= 68.18(to convert lbs. to kg divide by 2.2)
Next .0052mg x 68.18kg= .354ML
Plug that into your concentration 250mg/200mlx .354=.283

now micro drip is 60. so multiply .283 by 60

.283x60=
hope this helps
by: Anonymous

First step convert mcg to mg. 5.2mcg to .0052mg. then convert lbs. to kg 150/2.2=68.18 (to convert lbs. to kg you must divide lbs. by 2.2)
next .0052mgx 68.18kg=.354ml
Plug that into your concentration 250mg/200mlx.354=.283

Now micro drip is 60. So .283x60=17
17gtts/min
microdop flow rate
by: Anonymous

First step convert mcg to mg. 5.2mcg to .0052mg. then convert lbs. to kg 150/2.2=68.18 (to convert lbs. to kg you must divide lbs. by 2.2)
next .0052mgx 68.18kg=.354ml
Plug that into your concentration 250mg/200mlx.354=.283

Now micro drip is 60. So .283x60=17
17gtts/min
Drop factor calculation
by: Anonymous

You need to use like (same units):
150 lbs * (1kg/2.2lbs) = 68.2 kg

Multiply the ordered rate in mcg/kg/min by patient weight:
68.2 kg * 5.2 mcg/kg/min= 354.64 mcg/min
Convert mcg to mg:
(Move decimal 3 places to left or:)
364.64 mcg/min * (1mg/1000mcg)= 0.365 mg/min

Need to use concentration of bag to convert dose to ml:
0.365 mg/min * (200 ml/250mg)= 0.292 ml/min

Convert ml/min using drop factor:
0.292 ml/min * (60 drops/1ml) = 17.5 drops/min
really confused
by: Anonymous

This is one of the most confusing ones what is a easier way to remember the formula
hope this helps
by: Johnson Meloottu CPhT

First of all, we need to convert two things.

-First one is mcg to mg.
That is 5.2mcg/1000 = 0.0052mg

-Second pound to kg.
That is 150/2.2 = 68.18kg

The total mL = .0052mg(68.18kg)= 0.354mg
Concentration given is 250mg/200 ml.
so 200
----(.354) = 283ml
250
micro drip is 60gtt/mL
So the flow rate = .283mL(60)= 17gtt/min
All in one step method
by: Brad Wojcik, Pharm D

You can do this all in one step using dimensional analysis. You are starting with a rate of 5.2 mcg/kg*min for a 150 lb pt and have to end up with microdrops/min.
150 lb(5.2 mcg/kg*min)(1 kg/2.2 lb)(200 mL/250 mg) 1 mg/1000 mcg)(60 microdrops/mL) = 17 microdrops/min.
I like this method because you can cancel out all the unwanted units making sure that you are ending up with the correct units before you do any calculations.

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