Question

Calculate the IV flow rate in \(\mathrm{gtt} / \mathrm{min}\) for the following IV administrations, unless another unit of measure is stated. An IV of \(500 \mathrm{~mL}\) of \(0.9 \% \mathrm{NS}\) is to infuse in \(6 \mathrm{hr}\) at a rate of \(14 \mathrm{gtt} / \mathrm{min}\) (14 macrogtt/min). Drop factor: \(10 \mathrm{gtt} / \mathrm{mL}\) The IV was started at 7 AM. You check the IV at 8 AM, and 250 mL has infused. Recalculate the rate in \(\mathrm{gtt} / \mathrm{min}\) for the remaining solution. Determine the percentage of change and state your course of action.

Short answer

The new rate is 8 gtt/min, which is a 42.86% decrease from the original rate.

Step-by-step solution

Determine remaining volume

The IV started with 500 mL at 7 AM. At 8 AM, 250 mL has infused. Calculate the remaining volume: \[ \text{Remaining volume} = 500 \, \text{mL} - 250 \, \text{mL} = 250 \, \text{mL} \]

Calculate remaining time

The initial infusion time was 6 hours starting from 7 AM, ending at 1 PM. At 8 AM, 1 hour has passed, so the remaining time is:\[ 6 \, \text{hours} - 1 \, \text{hour} = 5 \, \text{hours} \]

Calculate new flow rate in gtt/min

Use the formula to calculate flow rate: \[ \text{Flow Rate (gtt/min)} = \frac{\text{Total Volume to Infuse} \times \text{Drop Factor}}{\text{Time (min)}} \] Fill in the values: \[ \frac{250 \, \text{mL} \times 10 \, \text{gtt/mL}}{5 \, \text{hours} \times 60 \, \text{min/hour}} = \frac{2500 \, \text{gtt}}{300 \, \text{min}} = 8.33 \, \text{gtt/min} \] Round it to the nearest whole number, which is 8 gtt/min.

Determine the percentage of change

The original rate was 14 gtt/min, and the new rate is 8 gtt/min.Calculate the percentage change using:\[ \text{Percentage of Change} = \frac{\text{Old Rate} - \text{New Rate}}{\text{Old Rate}} \times 100 \% \] Substitute the values:\[ \frac{14 \, \text{gtt/min} - 8 \, \text{gtt/min}}{14 \, \text{gtt/min}} \times 100 \% \approx 42.86 \% \] The rate decreased by approximately 42.86%.

State course of action

Since the flow rate needs to be adjusted to achieve the intended completion time but is now lower than prescribed, it's necessary to adjust the IV pump settings accordingly or manually regulate to meet the new rate of 8 gtt/min so the remaining infusion is completed on time.

Key concepts

Understanding Drop Factor

The drop factor is crucial in determining how many drops make up a given volume of intravenous (IV) fluid. In simple terms, it's the calibration of the drip chamber. Each IV setup will have a specific drop factor, which refers to the number of drops (gtt) needed to make up 1 milliliter (mL) of fluid. For example, in the problem above, the drop factor is given as 10 gtt/mL.
Understanding the drop factor helps us accurately convert the flow rate from milliliters per hour (mL/hr) to drops per minute (gtt/min), which is often necessary for manual IV setups. Remember, a higher drop factor means fewer drops are needed to deliver 1 mL, which affects the calibration and monitoring of the infusion.

• Helps in adjusting the IV drip speed
• Ensures the accuracy of medication delivery
• Critical for manual IV infusion setups

Calculating Infusion Time

Infusion time is the total time required for the IV fluid to completely enter the patient's bloodstream. Initially, in our problem, the infusion time was set for 6 hours. However, once you begin observing the infusion, you might notice changes that require recalculations to meet the initial completion timing.
For instance, when half of the volume was infused in 1 hour instead of the expected 3 hours (250 mL of 500 mL in an hour, when originally planned for half of the content to be infused in about 3 hours), the remaining time needs adjustment. You need to subtract the elapsed time from the original plan to determine how to modify the flow rate accurately.
Efficiently adjusting the infusion time ensures that treatments maintain their intended timings without over or under-infusion during the set period.

• Initial infusion design may require adjustment
• Ensures patient safety and adherence to treatment protocols
• Keeps track of elapsed and remaining time

Volume Measurement in IV Therapy

Proper volume measurement determines how much fluid remains and affects recalculating the infusion rate. In our case, the task began with 500 mL, with 250 mL used up by a certain point in time. Hence, the measurement of remaining volume becomes critical for adjusting the rate to match the treatment schedule.
Volume measurement is straightforward here; simply subtract the dispensed amount from the original volume. This straightforward calculation assists in recalibrating subsequent flow rates. Without accurate volume measurement, infusion schedules can become inaccurate, affecting patient care.

• Initial and remaining volume calculations are vital
• Affects flow rate recalibration critically
• Crucial for administering correct medication quantity

Determining Percentage Change

Calculating the percentage change provides insights into adjustments needed from the original plan. It's a mathematical way to explain whether we need to reduce or increase the flow rate significantly from the initial setup. From our problem, the change occurred where the initial rate was 14 gtt/min, and the recalculated rate was 8 gtt/min.
The percentage change formula helps determine how much different the new rate is compared to the old one. In our example, the rate decreased by about 42.86%. Such a significant shift indicates a major adjustment to avoid over-infusion, ensuring that the medical plan stays on course. Understanding percentage change allows healthcare providers to fine-tune interventions to meet the planned infusion timeline.

• Helps understand deviation from the original plan
• Enables accurate adjustments to the IV flow rate
• Ensures ongoing therapy aligns with prescribed treatment