Tunneling, also known as insulin pump infusion set tunneling, occurs when insulin leaks along the path of the infusion cannula under the skin, leading to unpredictable insulin absorption. This issue is especially common with Teflon infusion sets and often affects active individuals, such as golfers, tennis players, and runners. The only noticeable sign of tunneling may be unexplained high blood sugar levels, and in some cases, insulin may leak onto the skin surface following a large bolus.

What Causes Insulin Pump Infusion Set Tunneling?

Tunneling is more likely to occur with Teflon infusion sets because of their smooth, inert material. When an infusion set remains in the same spot for several days, the surrounding tissue may begin to “heal” around it, forming a fibrous capsule. Any physical movement or bumping of the infusion site can disrupt the contact between the Teflon cannula and the tissue, allowing insulin to follow the insertion track back to the skin’s surface instead of being properly absorbed.

Preventing Insulin Leaks from Infusion Sets

The key to preventing insulin leaks from infusion sets is proper site selection, securement, and consistent rotation of the infusion set. Below are proven strategies:

Choose the Best Infusion Sets for Active Pump Users:

Low-profile sets with flexible cotton bases are less likely to shift during physical activity.
Metal needle sets, such as the 90-degree Rapid, are small, comfortable, and less prone to tunneling because they maintain firm contact with the tissue.

Secure the Infusion Set Properly

Use a “plastic sandwich” technique:
- Apply a piece of IV3000 or similar adhesive material under the infusion set.
- Place a second piece of adhesive over the top of the set to reduce catching and movement.

Rotate Infusion Sites Regularly

Avoid using the same site too frequently. Allow previously used areas time to heal fully.
Steer clear of areas with lipohypertrophy, scar tissue, or signs of irritation.

Maintain Good Site Hygiene and Technique

Clean and dry the skin thoroughly before insertion.
Avoid using lotion or oils near the site.
Choose areas on the body that are less affected by bending or external pressure.

Key Takeaway

Preventing insulin pump infusion set tunneling is especially important for physically active individuals. By choosing the best infusion sets for active pump users, securing them properly, and maintaining excellent site management, you can minimize the risk of insulin leaks from infusion sets and help maintain more consistent blood sugar control.

Read Pumping Insulin, now in its 7th edition, for easy steps to succeed with your insulin pump.