Calculating IV drug Infusion Rates

Another Example

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)
———————————————
time (min)
= gtts / min
(flow rate)

Example:

1500 ml IV Saline is ordered over 12 hours. Using a drop factor of 15 drops / ml, how many 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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Author
Anna Curran. RN, BSN, PHN

Anna Curran. RN, BSN, PHN
Clinical Nurse Instructor

Emergency Room Registered Nurse
Critical Care Transport Nurse
Clinical Nurse Instructor for LVN and BSN students

Anna began writing extra materials to help her BSN and LVN students with their studies and writing nursing care plans. She takes the topics that the students are learning and expands on them to try to help with their understanding of the nursing process and help nursing students pass the NCLEX exams.

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