A patient is receiving an IV of 500 mL D5W (dextrose 5% in water). How many grams (g) of dextrose are contained in this IV solution?
A.
10 g
B.
25 g
C.
50 g
D.
100 g
The Correct Answer and Explanation is:
To determine how many grams of dextrose are contained in a 500 mL IV solution of D5W (dextrose 5% in water), we need to understand the composition of the solution. The “5%” in D5W indicates that the solution contains 5% dextrose by weight/volume.
Here’s a step-by-step explanation of how to calculate the grams of dextrose:
- Understand the Concentration: The term “5% dextrose in water” means that 5% of the weight of the solution is dextrose. This percentage is based on the weight/volume (w/v) ratio, which in this case means 5 grams of dextrose per 100 mL of solution.
- Convert the Volume: Since the volume of the IV solution is 500 mL, we can use the percentage concentration to find out how many grams of dextrose are in this volume.
- Calculate the Amount of Dextrose:
- First, determine how many grams of dextrose are in 100 mL of the solution: 5 grams.
- To find out how many grams are in 500 mL, use a proportion. Since 100 mL contains 5 grams, 500 mL will contain: Amount of dextrose=5 grams100 mL×500 mL\text{Amount of dextrose} = \frac{5 \text{ grams}}{100 \text{ mL}} \times 500 \text{ mL}Amount of dextrose=100 mL5 grams×500 mL
- Perform the Calculation:Amount of dextrose=5 grams×500 mL100 mL=25 grams\text{Amount of dextrose} = \frac{5 \text{ grams} \times 500 \text{ mL}}{100 \text{ mL}} = 25 \text{ grams}Amount of dextrose=100 mL5 grams×500 mL=25 grams
So, in a 500 mL IV solution of D5W, there are 25 grams of dextrose.
Correct Answer: B. 25 g
This calculation is essential for ensuring proper dosing and understanding the nutritional and caloric intake provided by intravenous fluids. Accurate measurements are crucial for patient safety and effective treatment.