How to calculate IV flow rates:
Intravenous fluid must be given at a specific rate, neither too fast nor too slow. The specific 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)
————————————————– = gtts / min (flow rate)