First, we need to find out how many mg of warfarin are in one vial. Since the vial is labeled 5 mg/single-use, we can assume that it contains 5 mg of warfarin.

Next, we need to find out how many mL of solution are in one vial. Since the instructions say to reconstitute with 2.7 mL of sterile water for injection to yield 2 mg/mL, we can use the following formula:

Amount of solution= amount of water + amount of warfarin

Substituting the given values, we get:

Amount of solution = 2.7 + 5 =7.7 mL

Now, we need to find out how many mL of solution contain 2 mg of warfarin, which is the prescribed dose for the patient. We can use the following formula:

mL of solution = mg of warfarin/ concentration of warfarin

Substituting the given values, we get:

mL of solution = 2/2 = 1 mL

Therefore, the nurse should administer 1 mL of solution to the patient.