Question

A patient requires potassium chloride 7 mE in a 1000 mL bag of

lactated Ringer's solution. The pharmacy has on hand potassium
chloride for injection 40 mEg in 20 mL vials. How many mL will be
needed i

Answer 1

To calculate the amount of potassium chloride (KCl) needed in mL, we can use the concept of dilution. The volume of the stock solution needed is 3.5 mL.

Step-by-step explanation:

To calculate the amount of potassium chloride (KCl) needed in mL, we can use the concept of dilution. We have potassium chloride for injection with a concentration of 40 mEq in 20 mL vials. The desired concentration is 7 mEq in 1000 mL of lactated Ringer's solution.

Using the formula C1V1 = C2V2, where C1 is the concentration of the stock solution, V1 is the volume of the stock solution used, C2 is the desired concentration, and V2 is the final volume, we can calculate the volume of the stock solution needed.

Here's how:

1. C1 = 40 mEq / 20 mL = 2 mEq/mL (concentration of the stock solution)
2. C2 = 7 mEq / 1000 mL = 0.007 mEq/mL (desired concentration)
3. V2 = 1000 mL (final volume)

Plugging in the values into the formula, we get:

2 mEq/mL * V1 = 0.007 mEq/mL * 1000 mL

Solving for V1:

V1 = (0.007 mEq/mL * 1000 mL) / 2 mEq/mL

Therefore, V1 = 3.5 mL.