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

Correct answers: C Rationale: A. Administering the insulin within 20 minutes is not the standard clinical requirement for mixing these specific types. Most guidelines suggest injecting the mixture within 5 to 15 minutes to prevent the NPH from altering the short-acting insulin's peak. B. Drawing NPH insulin first is incorrect and risks contaminating the regular insulin vial with protamine. The "clear before cloudy" rule mandates drawing short-acting insulin first. This practice ensures the purity of the rapid-acting medication remains intact for future doses. C. Injecting air into the vial before withdrawing the short-acting insulin is necessary to maintain pressure. The nurse must first inject air into the NPH vial, then air into the regular vial. This prevents the formation of a vacuum during aspiration. D. Using two separate syringes is inefficient and increases the number of subcutaneous injections for the patient. Mixing in a single syringe is the preferred method for combined therapy. This approach improves patient comfort and adheres to standard nursing protocols.