If 2000 ml fluid is to be infused in 18 hours and the drop factor is 15, what should the flow rate be?

RRB Staff Nurse Mumbai-2015

Nursing Foundation

Hard

Appeared in: RRB Staff Nurse Mumbai-2015

Explanation

determined by calculating the flow rate in drops per minute.
The formula is: Flow Rate (gtt/min) = [Total Volume (mL) × Drop Factor (gtt/mL)] / Time (minutes).
First, convert the time from hours to minutes: 18 hours × 60 minutes/hour = 1080 minutes.
Next, plug the values into the formula: (2000 mL × 15 gtt/mL) / 1080 min.
This equals 30,000 / 1080, which is approximately 27.77 gtt/min.
Rounding to the nearest whole number gives 28 gtt/min. The closest option provided is 27 gtt/min.

Option A: A flow rate of 18 drops/min is too slow and would result in the infusion taking much longer than the prescribed 18 hours.
Option B: A flow rate of 35 drops/min is too fast and would deliver the 2000 mL of fluid in less than the prescribed 18 hours, potentially leading to fluid overload.
Option C: A flow rate of 24 drops/min is close but incorrect. This rate results from a miscalculation, possibly by rounding down prematurely or using incorrect values.

Visual 1: Diagram: A flowchart showing the step-by-step process of calculating IV drip rates, from identifying variables to the final calculation.
Visual 2: Infographic: A comparison of Microdrip and Macrodrip IV tubing sets, highlighting their drop factors and common clinical uses.

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 fundamental nursing skill critical for patient safety. Incorrect rates can lead to fluid overload, dehydration, or ineffective medication delivery.
Nurses must always double-check their calculations, especially for high-risk medications or vulnerable patients (e.g., pediatric, elderly, cardiac patients).
What if the patient was a child requiring a much smaller volume, like 200 mL over 18 hours? The calculation would be (200 * 15) / 1080 = 2.77 gtt/min. In this case, a microdrip set (60 gtt/mL) and an infusion pump would be essential for accuracy, as counting such a slow drip rate manually is unreliable.

How to Approach the Question

First, identify the question type. This is a calculation-based question requiring a specific formula.
Identify all the necessary components from the question: Total volume (2000 mL), total time (18 hours), and the drop factor (15 gtt/mL).
Recall the correct formula: Flow Rate (drops/min) = (Total Volume in mL × Drop Factor) / Total Time in minutes.
Notice the units. The formula requires time in minutes, but the question gives it in hours. Convert hours to minutes (18 hours * 60 min/hour).
Substitute the values into the formula and perform the calculation.
Compare your calculated answer to the given options and select the closest one, as rounding is often necessary.

Concept Tested & Keywords

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