16_Curren_1401831222- CHAPTER 16 Objectives IV Flow Rate CalculatioN

C H A P T E R 16 IV Flow Rate CalculatioN Objectives The learner will: 1. identify the calibrations in gtt/mL on IV administration sets 2. calculate flow rates using ratio and proportion 3. calculate flow rate using the rate formula method 4. calculate flow rates by the division factor method 5. recalculate flow rates to correct off-schedule infusions There are a number of ways to calculate IV flow rates, and this chapter presents three: ratio and proportion, a formula method, and the division factor method. Use whichever method you are most comfortable with. Large volumes of intravenous fluids are most often ordered on the basis of mL/hr to be administered, for example 125 mL/hr. With the widespread use of electronic infusion devices that can be set to deliver a mL/hr rate, simply setting the rate ordered on the device and making sure it is working properly is all that is required for most infusions. Some infusion devices can also be set at a gtt/min (drop per minute) rate, which is much less frequently ordered than the mL/hr rate. The most common calculation, which is necessary when an infusion device is not being used, involves converting an IV order to the gtt/min rate necessary to infuse it. This calculation may be required for large-volume orders written designating a mL/hr rate, for example, 1000 mL to infuse at 125 mL/hr; for infusions of mL per multiple hours, for example, 3000 mL/24 hr; or for small-volume orders, usually involving medication administration, for example, 100 mL/40 min. IV TUBING CALIBRATION The size of IV drops is regulated by the type of IV set being used, which is calibrated in number of gtt/mL. Unfortunately, not all sets (and their drop size) are the same. Each hospital uses at least two sizes of infusion sets, the standard, or macrodrip set, calibrated at 10, 15, or 20 gtt/mL, which is used for routine adult IV administrations; and a mini, or microdrip set, calibrated at 60 gtt/mL, which is used when more exact measurements are needed, for example, to infuse medications, or in critical care and pediatric infusions. IV adMiNistratioN sets are calibrated iN gtt/ML