The prescription calls for an IV infusion of a medication at a rate of 120 mL/hr using tubing with a drop factor of 15 gtt/mL. What is the IV flow rate in drops per minute (gtt/min)?

When an infusion pump is unavailable, nurses must calculate the manual flow rate in drops per minute (gtt/min). This requires integrating the drop factor—the specific number of drops a tubing set produces per milliliter—to ensure the patient receives the correct volumetric hourly intake. Rationale: A. A rate of 12 gtt/min is mathematically incorrect and would result in an infusion speed that is far too slow. This would cause the patient to receive only 48 mL per hour, leading to subtherapeutic dosing. Accuracy is essential to maintain steady plasma levels. B. Step 1: Identify formula gtt/min = (mL/hr × drop factor) ÷ 60 Step 2: Insert values = (120 × 15) ÷ 60 Step 3: Calculate = 1800 ÷ 60 = 30 gtt/min Final Answer: 30 gtt/min C. A flow rate of 45 gtt/min would deliver 180 mL per hour, which is a 50% overdose relative to the order. This increase in velocity could lead to circulatory overload or adverse reactions to the medication. Following the formula prevents these iatrogenic risks. D. Selecting 60 gtt/min would double the intended infusion speed. This rate would deliver 240 mL/hr, which is twice the prescribed rate and could lead to severe hemodynamic instability or acute fluid volume excess, especially in patients with compromised renal or cardiac function.