Published
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:
[TABLE=class: MsoNormalTable]
[TR]
[TD]
volume (ml) X drop factor (gtts / ml)
_____________________________
time (min)
[/TD]
[TD]
= gtts / min (flow rate)
[/TD]
[/TR]
[/TABLE]
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?
[TABLE=class: MsoNormalTable]
[TR]
[TD]
1500 (ml) X 15 (gtts / ml)
_______________________
12 x 60 (gives us total minutes)
[/TD]
[TD]
= 31 gtts / minute
[/TD]
[/TR]
[/TABLE]
I find that a there is a much simpler way of doing this...
First: Get flow rate. Your flow rate is what you would be setting your pump to. You get this number by dividing the volume of your diluent by the TIME IN HOURS that you want to see it go in over.
So, 100 cc to infuse over 30 minutes is 100/0.5. (200cc/hr)
200 cc to infuse over 90 minutes = 200/1/5. etc.
Now once you've got that number and you need to calculate gtts per minute (because now, you do not have a pump or you want to check accuracy of your on-line-regulatory device like a dial-a-flow) take that flow rate and if your tubing is:
10gtts/ml - divide flow rate by 6
15gtts/ml - divide flow rate by 4
20 gtts/ml divide flow rate by 3
Mini or micro gtt -divide the flow rate by 1 (micro gtt tubing is 60gtts/ml)
It is that simple. And really not that much memorization either as there are 6 - 10 second increments in a minute, 4 - 15 second increments, 3 - 20 second increments etc. Just think of a clock.
vj2jam
1 Post
i want to know how to compute the IV and calculate, to solve the formula regarding the exact number of drops to be apply for the patients needs for the safety to maintain the safety of the patients...