Considering that insulin pumps are new to more than a third of the population with type 1 diabetes in Canada, we continue to learn new positives as well as challenges in use of the therapy. An emerging challenge is long term infusion site health as it relates to absorption of insulin. In my experience, about one in four pump users have insulin absorption issues which ultimately affect overall Diabetes control (A1c).

Signs and observations:

  • increase in total daily dose of insulin over past year or more >/= 25%.
  • increasing A1c
  • new onset insulin resistance diagnosis or medications (applies to those without significant weight gain)

In other words, if you have been on a pump for a while, and have noticed it takes more insulin to bring your glucose down then it used to and your A1c is not in range, this issue may apply.

What are the contributing factors? 

Compared to injecting, placing an infusion set is tricky. Site rotation becomes limited to what you can reach with both hands. Usually, you need to see what you are doing clearly. This means pump users likely use half of 'injection-approved' site areas. (injection approved like the back of arms, lower back or side of upper thigh.)

Add to this the demand on the tissue for 3 days worth of absorption and the challenge emerges:

  • most adult pump users alternate between sides of the abdomen.
  • the abdomen has the most consistent absorption and therefore is the most used whether injections or infusion sites.
  • the cost of replacing an infusion set means sets can be left in too long.

All of the above set the groundwork for the development of scar tissue which ultimately affects the absorption of insulin.

Assessment

During a self-assessment of your infusion sites, you may notice:

  • differences in one side of the abdomen from the other when gently pinching up along your infusion areas.
  • you have more than 2 past sites still trying to heal.
  • your infusion set gets damp or seems to leak as it gets closer to day 3. 
  • the recommended cannula prime amount is not enough- usually have to take a non- food bolus to get the insulin absorption of your site "going".
  • more than one site infection requiring a course of antibiotics.

Treatment

As with injecting, areas of scar tissue are to be left alone / avoided. A challenge when using a pump! Development and frequency of site infections can also relate to the individual's immune defences. Leaving in painful , red looking infusion sets in beyond the 3 days increases the risk o site infection- leading case of scar tissue.

If you wish to try new areas for infusion placement, be aware you may need to lower your insulin amounts as much as 25% to prevent hypoglycaemia. You could try a temporary basal rate lowering with the usual meal bolus for simplicity until you are satisfied your usual rates apply in the new site area. More frequent glucose checks may be required while monitoring this change.

Routine use of a topical antiseptic ointment can help limit the risk of site infection beyond the basics of good hand washing and clean process of set placement. Expand the areas of use in your site rotation plan. Monitor your glucose response when using 'fresh' infusion areas. Talk to your diabetes team for tips or treatments to help you.

Hair removal may be used to find new ‘fresh’ infusion areas on hairy men.

Some hair removed on belly

Some Hair Removed

Hair removed on entire belly with Veet wax strips

All Hair Removed

Jill Milliken RN, is a Diabetes Nurse Educator in private practice who has been developing educational programs for people using insulin pumps since 1999. Ms. Milliken contributor to Pumping Insulin (Walsh) and Diabetes for Dummies for Canadians.