A client who weighs 60 kg receives a prescription for dalteparin 200 units/kg subcutaneously once a day for a month. The medication is available in 25,000 units/mL vial. How many mL should the nurse administer? (Enter numerical value. If rounding is required, round to the nearest tenth.)
The Correct Answer and Explanation is:
To determine the volume of dalteparin to administer, follow these steps:
- Calculate the Total Dose Required: The prescribed dose is 200 units/kg, and the client weighs 60 kg. First, calculate the total number of units needed:Total Units=200 units/kg×60 kg=12,000 units\text{Total Units} = 200 \, \text{units/kg} \times 60 \, \text{kg} = 12{,}000 \, \text{units}Total Units=200units/kg×60kg=12,000units
- Determine the Volume to Administer: The medication is available in a vial with a concentration of 25,000 units/mL. To find out how many mL contain the required 12,000 units, use the formula:Volume (mL)=Total UnitsConcentration (units/mL)\text{Volume (mL)} = \frac{\text{Total Units}}{\text{Concentration (units/mL)}}Volume (mL)=Concentration (units/mL)Total UnitsSubstitute the values:Volume (mL)=12,000 units25,000 units/mL\text{Volume (mL)} = \frac{12{,}000 \, \text{units}}{25{,}000 \, \text{units/mL}}Volume (mL)=25,000units/mL12,000unitsCalculate:Volume (mL)=0.48 mL\text{Volume (mL)} = 0.48 \, \text{mL}Volume (mL)=0.48mL
Thus, the nurse should administer 0.5 mL of dalteparin, rounding to the nearest tenth.
Explanation
Understanding the Problem:
The client’s prescription requires a specific dose of dalteparin based on their weight. To administer the correct amount, you must first calculate the total dose needed based on the weight, and then convert this dose into a volume using the concentration of the medication.
Steps Explained:
- Total Dose Calculation: The dose is calculated by multiplying the prescribed dose per kg by the client’s weight. This gives the total units of medication needed for one day.
- Volume Calculation: Given the concentration of the medication (units per mL), you convert the total dose needed into a volume. This is done by dividing the total units by the concentration. This result tells you how many mL of the medication contains the required number of units.
Why Rounding is Necessary:
The final result might be a decimal that needs rounding to fit standard medication administration practices, ensuring that doses are practical and safe for administration. In this case, 0.48 mL rounds to 0.5 mL, a more manageable amount for practical injection.
By following these calculations, you ensure the client receives the correct dosage of medication according to the prescription and the available drug concentration.