The drip factor is not calculated; it's a known characteristic of the IV tubing being used. You use the drip factor to calculate the IV drip rate. Let's clarify the difference.
Understanding Drip Factor
The drip factor (also known as drop factor) represents the number of drops (gtt) it takes to deliver 1 milliliter (mL) of fluid through a specific IV tubing set. It's measured in gtt/mL (drops per milliliter). The drip factor is usually printed on the IV tubing packaging. Common drip factors include:
- Macrodrip: 10, 15, or 20 gtt/mL (used for delivering larger volumes quickly)
- Microdrip: 60 gtt/mL (used for delivering small volumes slowly)
Calculating IV Drip Rate
To calculate the IV drip rate (the number of drops per minute needed to deliver a specific volume of fluid over a specific time), you use the following formula:
IV Drip Rate (gtt/min) = (Total Volume (mL) x Drop Factor (gtt/mL)) / Time (minutes)
Let's break down the formula and provide an example:
- Total Volume (mL): The total amount of fluid you need to infuse.
- Drop Factor (gtt/mL): This is the drip factor of your IV tubing (as discussed above).
- Time (minutes): The total infusion time in minutes.
Example:
A doctor orders 1000 mL of IV fluid to be infused over 8 hours. You are using IV tubing with a drop factor of 15 gtt/mL. What is the required IV drip rate in drops per minute?
- Total Volume: 1000 mL
- Drop Factor: 15 gtt/mL
- Time: 8 hours * 60 minutes/hour = 480 minutes
Calculation:
IV Drip Rate = (1000 mL x 15 gtt/mL) / 480 minutes = 15000 / 480 = 31.25 gtt/min
Therefore, you would set the IV drip rate to approximately 31-32 drops per minute.
In summary, you don't calculate the drip factor; it is provided by the tubing manufacturer. You use the drip factor, along with the total volume to be infused and the infusion time, to calculate the IV drip rate.
