Infusion Sets

An infusion set is the device that connects the pump to your body. Insulin is delivered from the cartridge in your pump to your infusion site through thin tubing (the infusion site is where your health care provider inserts the tubing inside the skin). The infusion set should be changed every 2-3 days (blood glucose levels increase for each additional day you wear the same infusion set, which may lead to hyperglycemic episodes), and it’s easy to disconnect and reconnect again. Keep in mind that delaying your set change makes you four times more likely to get infusion site problems such as pain, swelling, bruising or itching. Also using an infusion set for a longer time than suggested may lead to set problems like leakage or poor adhesion.

Selecting the right infusion site is very important as your body will absorb insulin differently depending on where you infuse it and what activities you do. Your healthcare provider will help you to select the best site for you based on your lifestyle. The abdomen, for example, absorbs insulin the fastest and is the site used by most people, especially adults. The upper arms, buttocks and thighs are also usable sites. The buttocks are usually suggested for children, but have slower absorption timing.

Do not ever change an infusion site right before going to sleep unless you are having a problem with your current one. The infusion set needs to be changed at least 3 hours before going to sleep as you must be able to check whether or not it is working properly.

It is advised to check the infusion site, set and tubing a couple of times per day in order to make sure that there are no signs of infection, that the infusion set is safely attached and that no air has gotten inside the tubing.

Change your infusion set and site every 2-3 days, as suggested by your doctor or health care provider. It is important not to use the same site too often. Re-using the same site can lead to the subcutaneous tissue under your skin becoming hard and bumpy (lipohypertrophy). This may cause the insulin to not be absorbed uniformly in these areas and can lead to unexpectedly high or low blood sugar levels. Rotating the infusion sites gives your skin the possibility to recover, helps the insulin to be absorbed easily and reduces the risk of infections. Just remember to use a simple visual scheme, like a circle drawn around your bellybutton or any regular pattern. The important is to distribute the insulin evenly. Pregnant women may need to change their set and site every day. Always consult with your doctor first.

When changing the set:

• Have all set parts ready on a clean surface;
• Wash and dry your hands properly;
• Wash and dry the skin site carefully;
• Always check the infusion set package to make sure it is sealed properly and not damaged;
• Avoid touching the needle, cannula or other parts that come in to contact with insulin;
• After use, dispose of the infusion set needle properly.

An insulin pump provides continuous delivery of short-acting insulin all day long. The insulin pump replaces the need for long-acting insulin. A pump also replaces the need for multiple daily injections with a continuous insulin infusion, and also helps to regulate your blood sugar levels.

There is a high risk for the patient to develop ketones on pump therapy. This happens because long-acting insulin is not usually administered, and rapid-acting insulin is generally given only in extremely small amounts. If the basal insulin administration is interrupted for more than an hour, always remember to check your blood sugar and ketones. If you continue to not receive the amount of insulin you should receive, your blood glucose and ketone levels could increase dangerously, putting your health at risk.

Insulin pump-related ketone increase may be caused by different reasons, such as:

• Damaged infusion set;
• Problems at the infusion site;
• Air in tubing (resulting in loss of insulin);
• Extended pump suspension or disconnection (for more than 1-2 hours);
• Pump dysfunction;
• Insulin leakage (at insertion site or at infusion set connection site);
• Signs of illness or infection;
• Vomiting or dehydration;
• Bad insulin.

The presence of ketones while using an insulin pump can be a sign of a severe medical emergency. Seek medical attention in order to prevent diabetic ketoacidosis in case of an unexplained and/or persistent increase in your blood sugar, or if you have nausea and/or vomiting. Keep in mind that ketoacidosis develops more commonly in pump users. In that case you should stop injecting insulin through the pump and replace it with normal injections via pen or syringe, change the infusion set, and monitor your blood sugar level. If ketones are positive, you may need to seek for emergency medical care.

Remember that ketoacidosis is a medical circumstance that requires an immediate medical check. Always carry with you an insulin vial and syringe/pen with needle for backup. Talk to your doctor and always have a backup plan in case of pump dysfunction.

There are different types of infusion sets, but we can categorize them mainly into two groups: angled sets and straight sets.

Angled sets are usually inserted at a 30-degree angle under the skin and the cannula, as well as the needle, may vary in length. Straight sets are inserted perpendicularly at a 90-degree angle. The cannula may be in different lengths as well.

Infusion sets are a very important part of successful pump therapy as they are able to provide safe and constant insulin delivery. A cannula that gets damaged, for example, can interrupt or obstruct insulin delivery and result in dangerously high blood sugar levels and ketone formation: using infusion sets can prevent this risk.

The most commonly used infusion sets are made of polyvinyl chloride (PVC). The main reason for using PVC-based materials is their endurance and flexibility, transparency, ease of sealing, resistance to sterilization procedures, and relatively low cost.