The healthcare provider prescribes a loading dose of digoxin 0.6 mg intravenously (IV) for a client with heart failure (HF). The nurse obtains digoxin Injection 500 mcg in 2 mL vial from the electronic medication system. How many mL should the nurse administer? (Enter numeric value only. If rounding is required, round to the nearest tenth.)
The correct answer and Explanation is :
To determine the volume of digoxin to administer, follow these steps:
- Convert the prescribed dose to the same units as the vial concentration.
- The prescribed dose is 0.6 mg.
- Convert mg to mcg (micrograms) because the vial concentration is in mcg:
[
0.6 \text{ mg} \times 1000 \text{ mcg/mg} = 600 \text{ mcg}
]
- Determine the concentration of the digoxin vial.
- The vial contains 500 mcg of digoxin in 2 mL.
- Therefore, the concentration is:
[
\frac{500 \text{ mcg}}{2 \text{ mL}} = 250 \text{ mcg/mL}
]
- Calculate the volume needed to administer the prescribed dose.
- The prescribed dose is 600 mcg.
- Using the concentration of 250 mcg/mL, the required volume can be calculated by:
[
\text{Volume} = \frac{\text{Prescribed Dose}}{\text{Concentration}}
]
[
\text{Volume} = \frac{600 \text{ mcg}}{250 \text{ mcg/mL}} = 2.4 \text{ mL}
]
Explanation:
The process of determining the volume to administer starts with ensuring that the units of the dose match those of the vial concentration. In this case, converting milligrams to micrograms aligns the prescribed dose with the vial’s concentration, both of which are measured in micrograms.
Once the units are aligned, you use the formula (\text{Volume} = \frac{\text{Dose}}{\text{Concentration}}) to find out how much of the solution you need to administer. This involves dividing the total amount of medication required (600 mcg) by the concentration of the medication in the vial (250 mcg/mL).
By dividing 600 mcg by 250 mcg/mL, you get 2.4 mL. This is the exact volume of the digoxin solution that needs to be administered to provide the prescribed loading dose of 0.6 mg.
So, the nurse should administer 2.4 mL of the digoxin solution.