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Calculating
Flow Rate (ml /hr):
Key elements:
- Dosage
must be given.
- This
may be expressed as "amount"/kg/min, units/hr, mg/min, etc.
- Time
is constant (60 min/hr).
- Weight
of the client is expressed in kilograms.
- Concentration
of the infusion.
- When
using a dosage of mcg/kg/min, the end concentration must be expressed
in mcg/cc. (Convert mg to mcg.).
- You
will need to use R & P to find how many units of a medication
in a ml. (See below.)
- Rule
is: To calculate, one must have like amounts in dose and concentration.
Formula to
calculate flow rate:
Dose
("unit"/kg/min) X wt in kg
X 60 (min/hr)
concentration of infusion ("unit" / ml)
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Example:
For
the client whose weight is 130 lbs and has dopamine ordered at 8 mcg/kg/min,
what rate should the infusion pump be set for a solution of 400 mg dopamine
in 250 ml D5W?
Critical
information:
- Client's
weight: 130 lbs
- Dosage:
8 mcg/kg/min
- Solution:
400 (mg) in 250 (ml)
Tip:
1)
Convert wt to kg. 130 / 2.2 = 59.09 kg
2) Find concentration of dopamine in 1 cc.
400
mg
250 ml |
= |
x
mg
1 ml |
| 250x |
= |
400 |
|
x
|
= |
1.6 |
3)
Concentration is 1.6 mg /cc. Convert the mg to micrograms.
1.6
(mg) x 1000 (mcg per 1 mg) = 1600 mcg/cc.
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Now
that you have gathered all the information, plug it into the formula:
8
("unit"/kg/min) X 59.09 (wt
in kg) X 60 (min/hr)
1600 ("unit" / ml)
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= |
28363.32
1600
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x
|
= |
17.727 |
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17.727
or 18 ( ml/hr) will dialed on the pump.
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