A stock solution of inulin has a concentration of 500mg/ml. From this stock 0.50ml is diluted with 0.50ml of sterile saline. After 30 min blood is sampled and produces a result of 50ug/ml. What is total extravascular volume?
To calculate the total extravascular volume, we need to determine the amount of inulin that was added to the blood sample and then divide it by the concentration of the inulin in the blood sample.
First, let's calculate the amount of inulin added to the blood sample:
In the stock solution, the concentration of inulin is 500mg/ml.
From this stock solution, 0.50ml is taken and added to the blood sample.
The amount of inulin added to the blood sample can be calculated by multiplying the volume of the stock solution taken (0.50ml) with the concentration of inulin in the stock solution (500mg/ml):
Amount of inulin added to blood sample = 0.50ml * 500mg/ml
= 250mg
Next, let's calculate the concentration of inulin in the blood sample:
In the blood sample, the result is given as 50ug/ml.
The concentration of inulin in the blood sample is 50ug/ml.
Finally, let's calculate the total extravascular volume:
Total extravascular volume = Amount of inulin added to blood sample / Concentration of inulin in blood sample
Total extravascular volume = 250mg / 50ug/ml
Before calculating, we need to convert the units to be consistent. Since 1mg = 1000ug, we need to convert the amount of inulin added to the blood sample to micrograms (ug):
Amount of inulin added to blood sample = 250mg * 1000ug/mg
= 250,000ug
Now, let's calculate the total extravascular volume:
Total extravascular volume = 250,000ug / 50ug/ml
= 5,000ml
Therefore, the total extravascular volume is 5,000ml.