A patient is being discharged home with insulin lispro and insulin isophane suspension (NPH). Which information does the nurse include when providing discharge teaching to the patient?

Choice A rationale When mixing insulin lispro (rapid-acting) with NPH (intermediate-acting), it is a standard and crucial procedure to draw the clear rapid-acting insulin first, followed by the cloudy NPH insulin. This is to prevent the contamination of the rapid-acting vial with the NPH suspension, which could alter the rapid-acting insulin's predictable onset and peak. Choice B rationale While unopened insulin vials should be stored in the refrigerator, the patient's current in-use vials can be stored at room temperature for up to 28 days to make injections more comfortable. Injecting cold insulin can cause discomfort and lipohypertrophy at the injection site. However, the refrigerator is where all unopened vials are stored. Choice C rationale Shaking the insulin for a full minute is not recommended. Vigorous shaking can cause foaming and bubble formation, which can lead to inaccurate dosing. NPH insulin, a suspension, should be gently rolled between the palms to ensure uniform mixing and proper suspension of the particles, which prevents clumping and allows for accurate dosing. Choice D rationale Administering an injection at a 30-degree angle is not standard practice for subcutaneous insulin injections. Insulin is injected into the subcutaneous fat layer. A 90-degree angle is commonly used for most patients, and a 45-degree angle may be used for very thin individuals or for injections into the arms. A 30-degree angle is not correct.