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Time for a Change
Changing Your Infusion Sets
Common advice is to change the infusion set every 2-3* days if you are using a set with a flexible cannula (and at least 24 hours before the duration at which your blood glucose tends to rise).
However, there is growing evidence that consistent insulin absorption gets sketchy after 2 days, and so stretching the period between set changes even to 3 days may lead to unpredictability in glucose readings. Also, the longer a given set is left in one place, the greater the chance of skin problems.
Infusion sets with a metal (fixed) cannula should be changed more often than those with a flexible cannula. Common advice is to leave them in place for a maximum of 48 hours; less if you notice problems with blood glucose swings or discomfort.
Of course, there is always the matter of economics. With the high price of insulin pump supplies, many users (especially those who do not have coverage under a provincial government plan or a private extended health care plan) may feel the pressure to stretch their dollars by stretching the time between infusion set changes. We cannot make this decision for your family, however, we encourage you to monitor blood glucose closely after the second day of a given set, looking for trends of rising blood glucose or increased swings. We also encourage you to consider in your decision the “cost” of high blood glucose, the stress of unpredictability, and the hassle of putting out diabetes-related fires. In the end, changing a set every two days may be of more benefit than cost.
A Fresh Start
It makes sense in most cases to change the insulin in the pump reservoir/cartridge at the same time as you change the infusion set: every 2 (maximum 3) days. And there is more than just convenience at stake here. Insulin, when held in a plastic container, is not stable beyond a few days; it begins to lose its effectiveness. If you are in the habit of changing the infusion set every 2 days, but want to conserve insulin, you can still *opt to change the insulin in the pump reservoir/cartridge every 3 days; it will simply be out-of-sync with every second set change (and in sync with alternate set changes, every 6 days).
*Note: This is true only for infusion sets in which the tubing and/or cartridge can be disconnected from the cannula housing, which is not true for patch pumps (such as Omnipod), as the insulin reservoir is contained within the infusion set.
You may also consider the amount of insulin you load into a pump reservoir/cartridge. Some users prefer to do a full fill every time (fill the pump reservoir/cartridge to the maximum amount), as it reduces the chance that you will run out of insulin between set changes, and may also reduce the chance of air bubble trouble. Other users opt for a partial fill, loading into the pump reservoir/cartridge only the amount of insulin that they anticipate using before the next set change. This latter strategy reduces insulin wastage and, depending on your Total Daily Dose (and therefore the amount of insulin you are likely to use over 3 days), may not detract from convenience at all.
(Left: partial fill of an insulin pump cartridge)
(Right: full fill of an insulin pump cartridge)
If you’re like me, it can be a challenge to remember to complete a regular task such as infusion set changes. But changing the set on time every time is a critical part of being a safe and effective insulin pump user.
Some families find that putting a note or star on a wall calendar to highlight set change day helps them remember when it’s time to change their child’s infusion set. Others use an electronic calendar tied to their email, or in their smart phone or tablet. Or, there’s an app called “Set Change” that gives you gentle reminders when your set change is due and then increases its nag-factor if you miss your set change. Also, many pumps include a Reminder function in which your child’s insulin pump beeps or sings at a set time. At each set change (if it allows you to set it at least 2 days later), you could set it for when the next set change is due.
Or you could develop a system for set changes that links set changes with another regular activity, such as bath night, or Cub Scouts, Brownies, or gymnastics. Whatever rotates on a 2-3 day schedule.
Rotation, Rotation, Rotation…
So you have a set change schedule down, but how do you avoid using the same site again and again? Check out these rotation tips: Choosing a Site Location.
If an infusion set is left in too long, or a particular site is overused, then poor absorption, infection, tissue damage/scarring, and lipohypertrophy could develop.
Infections are more likely to occur at infusion sites than with injections, as the infusion set is left in place for 2-3 days. It’s wise to check the infusion site often (not just when you change the set) for signs of redness, swelling or bleeding. Let your child know that if the area feels itchy, painful, or hot, they should tell you. If any of these traits appear, contact your child’s health care team for assessment.
Scar tissue from a previous wound or surgery can interfere with insulin absorption, leading to lack of absorption or unpredictable absorption. Therefore, it is best to avoid areas with scar tissue.
Lipohypertrophy, or the formation of fatty lumps under the skin, are a result of overuse of a particular area, which may happen because of inadequate rotation of sites or too many days between set changes. Kids often have a “favourite spot” for infusion set insertions, which they may be able to reach easily, or which may hurt less. But if they stick too much to that spot, fatty lumps will develop. If this area is used subsequently, insulin absorption will likely be ineffective or unpredictable, making it even more difficult to manage blood glucose. If you notice, when using a certain area for infusion sites, your child experiences unexplained high blood glucose, or greater-than-usual blood glucose swings, then it may be wise to feel the area with your fingertips, looking for lumps under the skin. If you have any question that lipohypertrophy has developed, please consult your child’s diabetes health care team. And avoid using that area for infusion sites in the meantime.
In short, the risks of poor absorption, infection, tissue damage/scarring, and lipohypertrophy can be reduced by systematic rotation of infusion sites. Any changes in the appearance of the skin in areas used for infusion sites, including dimpling, irritation or lumps, are best checked out by your child’s diabetes health care team.
On the Outs
Removing an infusion set is much like removing a band-aid: most people are fine with it, some dread the process. If your child complains of pain or discomfort when you are removing an infusion set, consider the use of Remove™ wipes. They come in single-use packets (like alcohol swabs) and are soaked with a chemical that breaks down the sticky adhesive, so that the tape can be pulled off without pulling on the skin. You could also try applying olive oil to the tape to loosen the adhesive; another possibility is to remove infusion sets after a bath or shower, when the adhesive may be weaker.
More on removing infusion sets and sensors easily and painlesslysee Step 13
Once the infusion set is off, take a look at the skin underneath to see how it’s faring. A healthy former site should not be red, irritated or itchy, and the spot where the cannula entered the skin should not be enlarged, oozing, overly red or itchy. If you see any of these signs, it may be wise to have your child’s diabetes health care team assess.
More on reducing skin reactions and irritation:15 Steps to Avoid Skin Irritation and Keep D-Tech Stuck On
The above information was significantly modified, with permission, from The Alberta Children’s Hospital Diabetes Clinic information handouts.
The above information was reviewed for content accuracy by clinical staff of the Alberta Children’s Hospital Diabetes Clinic.
This material has been developed from sources that we believe are accurate, however, as the field of medicine (in particular as it applies to diabetes) is rapidly evolving, the information should not be relied upon, as it is designed for informational purposes only. It should not be used in place of medical advice, instruction and/or treatment. If you have specific questions, please consult your doctor or appropriate health care professional.
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