Download - Beginning Calculation of Infusion Rates
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Dosage Calculations
Beginning Intravenous Therapy
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Flow Rate
Order usually as mL/hr or set amount over a
given length of time
Examples:
20 mL/hr or 125 mL/hr
500 mL over 10 hours
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Flow Rate
Calibration factors vary
Minidrop set is always 60 gtts/ml
Macrodrop set can be 10gtts/mL, 12gtts/mL, 15gtts/mL, or
20gtts/mL
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Flow Rate
Formula
Total mL (per hour) X drop factor
time in minutes (if per hour amt = 60)
Your answer is always labeled gtts/min
**note gtts/min is always rounded to a
whole number***
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Flow Rate Example One:
125 mL is ordered to infuse over 30 minutes
using a calibration factor of 12 gtts/mL,
calculate the flow rate.
125 mL X 12 gtts/mL = 50 gtts/min
30 minutes
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Flow Rate Example Two:
250 mL is ordered to infuse over 6 hours.
Calculate the flow rate using a microdrop
set.
First find the mL/hr to be infused
Then plug information into the formula
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Flow Rate Example Two:
250 ml to infuse over 6 hours
mL = mL/hr
hr
250 mL = 41.6 mL/hr
6 hrs
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Flow Rate Example Two:
41.6 mL/hr X 60 gtts/mL = 41.6
60 minutes
41.6 rounds to 42 gtts/min
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Flow Rate Example Using dimensional
Anaylsis: 500 mL NS is ordered to infuse over 5 hours.Find the flow rate using 10gtts/mL drop factor.
500 mL X 1hr X 10 gtts = 60 gtts/min
5 hrs 60 min 1 mL
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Re-timingF
low Rate Sometimes IVs will infuse slower or faster
than desired and the nurse will need to
adjust the rate to complete the IV on time.
NOTE: if an increase in rate is required
assess your patient to make sure they cantolerate the increase vascular fluids
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Re-timingF
low Rate You will use the flow rate formula
Find the mls left and time left for the
infusion and use these numbers
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Re-timingF
low Rate Example: An IV of 250 mL over 6 hours
has been infusing for 2 hours. How ever,
100 cc has already infused and thereforeinfusing too fast. Re-time the flow rate tocomplete this infusion on time using a 10gtts/mL factor.
Time left = 4 hours
Fluid left = 150 mL
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Re-timingF
low Rate Find mL/hr
150 mL left = (37.5 mL/hr
4 hours left
37.5 mL/hr X 10 gtts/mL = 6.25
60 minutes
6.25 = 6 gtts/min
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Calculating IV rate from flow
rate
Example: An IV running @ 20 gtts/min has
a drop factor of 20 gtts/mL. How many
ml/hr will the patient receive?
Start with flow rate
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Calculating IV rate from flow
rate20 gtts X 60 min = 1200gtts
min hr
1200 gtts divided by 20gtts (drop factor)
hr
gives 60 mL/hr
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Calculating IV rate from flow
rate Example: An IV of 0.45 NS is infusing at
30 gtts/min. Using a microdrip set calculate
the infusion rate.
30 gtts/min X 60min = 1800 gtts/hr
1800 gtts/hr = 30 mL/hr
60 gtts/mL
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Can Also Use Flow Rate Formula
Example: An IV of 0.45 NS is infusing at
30 gtts/min. Using a microdrip set calculate
the infusion rate.
?mL/h x 60 gtt/mL = 30 gtt/min
60 minutes
X = 30 mL/h