Answer:
Let’s look at an example of an IV piggyback medication… 1 gram of Ancef in 100 mL of normal saline is to be infused over 30 minutes. You have macrodrip tubing with a drop factor of 10 gtt/mL. Calculate how many gtt/min to set as the IV drip rate. Use the formula, with 100 mL divided by 30 min, multiplied by 10 gtt/min, which equals 33.3, rounded to 33 gtt/min.
If you need to set this up on an IV infusion pump, use the formula, volume (mL) divided by time (min), multiplied by 60 min over 1 hour. This equals the IV flow rate in mL/hr which is the standard method of setting infusion rates on IV pumps. Using this formula, 100 mL divided by 30 min, times 60 min in 1 hr, equals 199.9, rounded to 200 mL/hr.
Once the infusion has started, monitor the rate closely to be sure it is infusing at the correct rate and check the patient’s IV site for signs of infiltration or inflammation.