Fundamentals of Nursing Q 381
The physician orders an IV solution of dextrose 5% in water at 100ml/hour. What would the flow rate be if the drop factor is 15 gtt = 1 ml?
A. 5 gtt/minute
B. 13 gtt/minute
C. 25 gtt/minute
D. 50 gtt/minute
Correct Answer: C. 25 gtt/minute
100ml/60 min X 15 gtt/ 1 ml = 25 gtt/minute. When the nurse has an order for an IV infusion, it is her responsibility to make sure the fluid will infuse at the prescribed rate. IV fluids may be infused by gravity using a manual roller clamp or dial-a-flow, or infused using an infusion pump. Regardless of the method, it is important to know how to calculate the correct IV flow rate.
Option A: When calculating the flow rate, determine which IV tubing you will be using, microdrip or macrodrip, so you can use the proper drop factor in your calculations. The drop factor is the number of drops in one mL of solution, and is printed on the IV tubing package.
Option B: Macrodrip and microdrip refers to the diameter of the needle where the drop enters the drip chamber. Macrodrip tubing delivers 10 to 20 gtts/mL and is used to infuse large volumes or to infuse fluids quickly. Microdrip tubing delivers 60 gtts/mL and is used for small or very precise amounts of fluid, as with neonates or pediatric patients.
Option C: To calculate the drops per minute, the drop factor is needed. The formula for calculating the IV flow rate (drip rate).. total volume (in mL) divided by time (in min), multiplied by the drop factor (in gtts/mL), which equals the IV flow rate in gtts/min.