A nurse is preparing to mix short-acting insulin with NPH insulin from two vials. Which of the following actions should the nurse take?

A. Use two separate syringes to mix the insulin: Using two syringes is unnecessary and is not the standard procedure. Short-acting and NPH insulin can be mixed in the same syringe as long as proper technique is followed to avoid contamination. B. Ensure the NPH insulin is drawn into the syringe first: The short-acting insulin should always be drawn up first to prevent contaminating its vial with the cloudy NPH insulin. Drawing NPH first risks altering the action of the short-acting insulin. C. Administer the insulin within 20 min of preparing it: Mixed insulin should typically be administered immediately after preparation, especially when short-acting insulin is involved. Waiting up to 20 minutes may alter its effectiveness. D. Inject air into the vial to withdraw the short-acting insulin: Injecting air into both vials is essential for pressure balance. Air is injected into the NPH vial first (without drawing insulin), then into the short-acting vial, from which the insulin is drawn first. This prevents cross-contamination and ensures dosing accuracy.