Post on 14-Apr-2018
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TO CALCULATE RATE USING MINUTES
volume x calibrationminutes
= gtt/min
TO CALCULATE RATE USING HOURS
volume x calibrationhours x 60
= gtt/min
1) Give a 50cc IVPB over 30 minutes using IV tubing with a calibrationof 10. How many drops per minute should this IVPB be set for? Seethe example below.
select "x = minutes"x = 30volume = 50calibration = 10
Actual formula:
50 x 1030
= 16.7 or 17 g
2) Using IV tubing alone (calibrated at 60), prepare an IV to infuse 1liter over 8 hours. How many drops per minute should the IV be setfor? See the example below.
select "x = hours"x = 8
volume = 1000calibration = 60
Actual formula:
1000ml x 608 x 60
= 125 gtt/min
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Note, when using microdrip tubing (calibration = 60), the drip rate will bethe same as mL/hr. This will save you the time of calculating the driprate if asked to give the rate in mL/hr.
3) The doctor orders an IV to infuse at 125cc/hr. Calculate the flow rateusing 10 drop/min IV tubing.
select "x = milliters/hour"x = 125calibration = 10
Actual formula:
125cc x 1060 = 20.8 or 21 gtt/min
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How to calculate IV flow rates:
Intravenous fluid must be given at a specific rate, neither too fast nor too slow. Thespecific rate may be measured as ml/hour, L/hour or drops/min. To control or adjust the
flow rate only drops per minute are used.
The burette contains a needle or plastic dropper which gives the number of drops per ml(the drop factor). A number of different drop factors are available (determined by the
length and diameter of the needle).
Common drop factors are:10 drops/ml (blood set), 15 drops / ml (regular set), 60 drops / ml (microdrop).
To measure the rate we must know:(a) the number of drops
(b) time in minutes.
The formula for working out flow rates is:
volume (ml) X drop factor (gtts / ml)---------------------------------------------
time (min)
= gtts / min(flow rate)
Example:
1500 ml IV Saline is ordered over 12 hours. Using a drop factor of 15 drops / ml, howmany drops per minute need to be delivered?
1500 (ml) X 15 (gttss / ml)---------------------------------------------------
12 x 60 (gives us total minutes)= 31 gtts / minute
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