A RL 1000 ml is ordered for a client to run in 8 hours. A drop set with a drop factor of 15 per ml is used. What is the flow rate to be set?

Appeared in: PGIMER Chandigarh NO - 2015

Explanation

determined by using the standard formula for calculating IV flow rates: Flow Rate (gtt/min) = (Total Volume in mL × Drop Factor) / Time in minutes.
First, convert the infusion time from hours to minutes: 8 hours × 60 minutes/hour = 480 minutes.
Next, plug the values into the formula: (1000 mL × 15 gtt/mL) / 480 minutes.
This calculation results in 15000 / 480 = 31.25 gtt/min.
Since flow rates must be set in whole numbers, 31.25 is rounded to the nearest whole number, which is 31 drops/minute.

Option A: A flow rate of 51 gtt/min is too fast. It would infuse the 1000 mL in approximately 3.2 hours, not the prescribed 8 hours.
Option C: A flow rate of 41 gtt/min is too fast. It would infuse the 1000 mL in approximately 4 hours, significantly less than the ordered 8 hours.
Option D: A flow rate of 21 gtt/min is too slow. At this rate, it would take approximately 12.7 hours to infuse the 1000 mL, failing to deliver the fluid within the prescribed 8-hour timeframe.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain IV flow rate calculation as background academic context rather than a clinical decision trigger.
Accurate IV flow rate calculation is a critical nursing skill to prevent complications. Administering fluids too quickly can lead to fluid overload, especially in patients with cardiac or renal conditions. Administering them too slowly can delay treatment and lead to dehydration or inadequate medication delivery.
Nurses must always verify the drop factor on the IV tubing package, as different manufacturers produce macrodrip sets with varying drop factors (10, 15, or 20 gtt/mL).
What if? If the nurse used a microdrip set (60 gtt/mL) by mistake? The flow rate would be (1000 x 60) / 480 = 125 gtt/min. Setting the rate to 31 gtt/min with a microdrip set would result in a dangerously slow infusion, taking over 32 hours.

How to Approach the Question

First, identify the question type. This is an analytical/calculation question requiring a specific formula.
Identify all the necessary components from the question: Total volume (1000 mL), total time (8 hours), and drop factor (15 gtt/mL).
Recall the correct formula: Flow Rate (gtt/min) = (Volume × Drop Factor) / Time in minutes.
Notice the time unit mismatch. The formula requires time in minutes, but the order is in hours. Convert hours to minutes (8 hours × 60 = 480 minutes).
Substitute the values into the formula: (1000 × 15) / 480.
Perform the calculation and round the result to the nearest whole number, as partial drops cannot be administered. Select the option that matches your calculated result.

Concept Tested & Keywords

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E6 Pharmacology Nurses Shanbhag 3e p. 54-56

E6 Nursing Fundamentals Potter Perry 12e Part 5 p. 93-95

Practise the full PGIMER Chandigarh NO - 2015

Attempt every question from this paper in a timed mock, then review the full solution for each one.