A nurse is preparing to administer potassium chloride 20 mEq.
The amount available is potassium chloride liquid 40 mEq/15 mL. How many mL should the nurse administer? (Round the answer to the nearest tenth.
Use a leading zero if it applies.
Do not use a trailing zero.).
The Correct answer and Explanation is:
To determine the volume of potassium chloride (KCl) liquid needed to administer 20 mEq, we use the formula for calculating the dosage based on the concentration of the available solution:
Formula: Volume (mL)=(Desired Dose (mEq)Concentration (mEq/mL))\text{Volume (mL)} = \left( \frac{\text{Desired Dose (mEq)}}{\text{Concentration (mEq/mL)}} \right)Volume (mL)=(Concentration (mEq/mL)Desired Dose (mEq))
Step-by-Step Calculation:
- Identify the Desired Dose and Concentration:
- Desired Dose (D): 20 mEq
- Concentration (C): 40 mEq/15 mL
- Convert the Concentration to mEq/mL: The concentration of the available KCl solution is 40 mEq in 15 mL. To find the concentration per mL: Concentration (mEq/mL)=40 mEq15 mL=2.67 mEq/mL\text{Concentration (mEq/mL)} = \frac{40 \text{ mEq}}{15 \text{ mL}} = 2.67 \text{ mEq/mL}Concentration (mEq/mL)=15 mL40 mEq=2.67 mEq/mL
- Apply the Formula: Plug the values into the formula to find the required volume in mL: Volume (mL)=Desired Dose (mEq)Concentration (mEq/mL)=20 mEq2.67 mEq/mL≈7.5 mL\text{Volume (mL)} = \frac{\text{Desired Dose (mEq)}}{\text{Concentration (mEq/mL)}} = \frac{20 \text{ mEq}}{2.67 \text{ mEq/mL}} \approx 7.5 \text{ mL}Volume (mL)=Concentration (mEq/mL)Desired Dose (mEq)=2.67 mEq/mL20 mEq≈7.5 mL
- Round the Answer: The calculated volume is approximately 7.5 mL. We round to the nearest tenth, so the final answer is 7.5 mL.
Explanation:
Potassium chloride is often administered in liquid form for various clinical reasons, including electrolyte imbalances. It’s essential to accurately measure and administer the correct dose to avoid complications such as hyperkalemia (high potassium levels), which can have serious consequences including cardiac arrhythmias.
To ensure proper dosage, we convert the concentration of the available solution into mEq per mL. Using this conversion, we can accurately determine how much of the solution is needed to provide the desired amount of potassium.
This calculation is crucial in clinical settings to ensure patients receive the exact amount of medication required, and rounding is performed according to standard practices to avoid dosing errors. Always double-check calculations and verify with established protocols or guidelines.