A nurse is mixing a short-acting insulin and an intermediate-acting insulin in the same syringe for a client who has diabetes mellitus.

A nurse is mixing a short-acting insulin and an intermediate-acting insulin in the same syringe for a client who has diabetes mellitus.

Which of the following actions should the nurse take first?

A.
Draw the intermediate-acting insulin into the syringe.

B.
Draw the short-acting insulin into the syringe.

C.
Inject air into the intermediate-acting insulin vial.

D.
Inject air into the short-acting insulin vial.

The Correct Answer and Explanation is:

The correct answer is C. Inject air into the intermediate-acting insulin vial.

Explanation:

When mixing two types of insulin in one syringe, particularly a short-acting (e.g., regular insulin) and an intermediate-acting insulin (e.g., NPH insulin), specific steps must be followed to ensure accuracy and maintain the integrity of the insulins. The sequence is essential to avoid contaminating the insulin vials and to ensure that the correct dose is administered to the client.

1. Inject Air into the Intermediate-Acting Insulin Vial (NPH): The first step is to inject air into the intermediate-acting insulin vial. This is because NPH insulin is a suspension and needs to be mixed well before drawing it into the syringe. By injecting air into the vial first, you equalize the pressure inside the vial, making it easier to draw the insulin out later.
2. Inject Air into the Short-Acting Insulin Vial: Next, you should inject air into the short-acting insulin vial. Since this insulin is clear and not a suspension, you should be careful not to contaminate it with the intermediate-acting insulin.
3. Draw the Short-Acting Insulin: After injecting air, draw the short-acting insulin into the syringe. This ensures that if any mixing does occur, it will be the short-acting insulin that remains uncontaminated by the intermediate-acting insulin, maintaining the integrity of the dose.
4. Draw the Intermediate-Acting Insulin: Finally, draw the intermediate-acting insulin into the syringe. Since it is being drawn after the short-acting insulin, it will not affect the clarity or potency of the short-acting insulin.

This method of drawing up insulin is sometimes remembered with the acronym “Cloudy before Clear” (for injecting air) and “Clear before Cloudy” (for drawing up the insulin). This sequence is crucial for avoiding contamination of the short-acting insulin with the intermediate-acting insulin, which could alter the efficacy and predictability of the insulin therapy. Following this method ensures that the client receives the correct dosage and minimizes the risk of errors in insulin administration, which is critical for maintaining proper blood glucose control in clients with diabetes mellitus.