Volume/Time - IV Drop Rate Questions
Given a certain amount of liquid, a time period, and a drop factor (gtts/mL),
what is the necessary IV flow rate in gtts/min? Measurement used when IV is
regulated manually. Because it is not possible to give a patient a fraction
of a drop, it is typical to round answers for these problems up or down
to the nearest whole number.
Formula:
Example: Calculate the IV flow rate for
1200 mL
of NS to be infused in
6 hours. The infusion
set is calibrated for a drop factor of
15 gtts/mL.
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x Drop Factor (gtts/mL) = Y (Flow Rate in gtts/min)
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Convert 6 hours to minutes.
- min ← hr ( x by 60 )
- 6 hr x 60 = 360 min
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x 15 gtts/mL = 50 gtts/min
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Example: Calculate the IV flow rate for
200 mL
of 0.9% NaCl IV over
120 minutes. Infusion set
has drop factor of
20 gtts/mL.
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x Drop Factor (gtts/mL) = Y (Flow Rate in gtts/min)
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x 20 gtts/mL = 33 gtts/min
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