Insulin Pump
Infusion Sets.

When you first think of getting a pump that is what you tend to think of and concentrate on - the pump itself.

Fair enough, it's an expensive object and you do not want to make a mistake. However you really need to give some consideration to the pump's little helper, the infusion set. After all this is the bit that is going to be living right up close and personal with you, in fact right in there with you, and you want to be sure to get one that not only does it's job of getting the insulin into you reliably but does it in a painless and comfortable way.

One pump will last you for a long time, years in fact, but your infusion set is disposable (the sets need to be changed every 3 days) and you will use about 120 in a year, so you want to have the right ones.

So what are infusion sets?
These consist of the thin plastic tubing which comes in varying lengths, from 23-43inches (60-110cm), and a needle or soft cannula. The cannula is a plastic tube coated with Teflon to stop it sticking to the tissue.

The needle or cannula is inserted just under the skin, usually in the abdomen, thigh, buttocks, hip or arm.

If you are using a soft cannula it comes within an introducer needle which is removed once the cannula is in place.

You have a choice of inserting the cannula manually or using an automatic inserter. This is easier and less intimidating for some people.

Some sets come with needles that require to be inserted at 90 degrees while others want to be put in at an angle, of say 30 or 45 degrees.

The needles are much bigger than those used on insulin syringes, especially the ones that are inserted at an angle, and can hurt when inserted.

For some holding an ice cube against the skin for a few moments will numb it enough to prevent the pain.

For others, especially children, there are numbing creams (known as topical anaesthetics). In the US they go under the trade names of L.M.X.4 and EMLA. EMLA, Ametop Gel and Cryogesic spray (Ethyl chloride) are used in the UK.
EMLA is also available in Australia, Canada and Europe.
In some countries a script is required for these creams.

Which infusion set with which pump?
You will get an infusion set with your pump when it arrives, and it may, it may not, be the greatest and best. Economics rears it's ugly head here and the pump manufacturer may use the infusion set from the company that offers them the best deal financially. Also people vary, as always, and what works well for some may not work for others. If you are one of the lucky ones the set that comes with your pump will be just the one for you but if not you will have to find out in the usual way - trial and error.

The tubing has to connect to the pump in some way. This is usually done via a standard Luer Lock connection and any infusion set can be used with any pump, with the exception of two pumps.
The exceptions are the Dana Diabecare II pump, which uses a proprietary connection, though you can buy an adapter that then allows you to use any set with the standard Luer lock connection and the Medtronic MiniMed Paradigm which utilises a unique connector and so can only use the infusion sets especially made for it. I believe Simple Choice now offers an alternative infusion set, rather like the Silhouette one from MiniMed, for Paradigm pumps.

The length of the needle you need depends on the amount of subcutaneous fat you have. Most sets come with a choice of needle lengths.
90 degree sets usually use 6 mm long needles for infants, 8 mm for children, 10 mm for the average adult, and 12 mm for the larger adult.
The gauge (diameter) of set needles does not vary much. Most are in the 25-27g range.

At the site of insertion you will have the needle or cannula, a connection hub, the adhesive section that holds it in place and the tubing. You will want to disconnect
from the tubing at various times.

Some sets allow disconnecting right at the infusion site, leaving just the adhesive, connection hub and cannula behind while others let you disconnect away from the site, leaving the adhesive, connection hub and cannula plus a small tail of tubing - usually about 4 inches (10mm) - behind.

The ability to disconnect away from the site is useful for those with poor vision or dexterity problems as there is less chance of pulling the needle or cannula out.

Problems and their solutions.
Yip, as always nothing is perfect and once again we have to find out what goes wrong and what we can do about it - you are enjoying your new role as trouble-shooter aren't you?

1. Needle/cannula bending.
I put this at the top of the problem list as it is one that comes up often in the forums.
There can be various reasons for this happening. Obviously the one we would all like to blame is lousy needles/ bad manufacture and this does happen, but we must also consider other factors pertaining more to ourselves than to the sets themselves.
Most of us come to pumps after years of normal injections and have developed scar tissue at the insertion site or possibly lipohypertrophy or lipoatrophy.

For the puzzled lipoatrophy is a lack of fatty tissue that is caused by frequent insulin injections (and sometimes is just an inherited factor) while lipohypertrophy is the exact opposite, deposits of too much fatty tissue, caused by exactly the same things - ain't life grand?!!

You may have to experiment a bit to find a site that is good.
You may also not be putting the needle in correctly, though this is rare in folk who have been doing very similar stuff for years. Automatic inserters may help anyway.

If you do have trouble with a bent needle or cannula you will not only have pain but the insulin will either not be delivered at all or be poorly absorbed.

2. Allergy.
This can be to either the adhesive or to the needle or cannula.
If you are allergic to the adhesive on one type of set you can try another (or get hold of the manufacturer and try and find out if they use the same adhesive or not - good luck!). Barring that you can try barrier creams or special patches.
The main allergic reaction associated with needles is a nickel allergy and that is usually solved by changing over to the plastic cannula.
In a reverse situation those who are allergic to the Teflon on the cannula can use the needles instead.
And if you are allergic to all of these I am afraid it is bear with it or it is back to the old fashioned syringe for you.

3. Poor absorption.
As stated before, this can be from a bent needle or cannula but it can also be a result of an immune reaction to the cannula, as in the above allergic reaction.
Some sites absorb worse than others, possibly due to the number of blood vessels at the site. The result can be really strange and erratic BG readings. Try another set and/or another site.

4. Lack of adhesion to skin.
It is necessary to have good adhesion because otherwise the dashed thing can fall out at very inconvenient times - mind you no time is ever really convenient when you consider having to stick yet another needle in yourself!
Also it can leave the site open to infection.

Adhesives stick better to some skin types than others. If you are having a problem getting yours to stick try an intravenous prep solution (Smith and Nephew make one) that not only sterilises the skin but also leaves a sticky film behind that may help.

Sometimes it may be enough to change your brand of soap - many have added moisturisers these days - or your fabric softener which may leave deposits on your skin. I am assuming here that you are too sensible to use a lotion or cream on the part of the body you are about to try inserting a set into.

If you like water sports or long hot soaks you will need to experiment until you find one with an adhesive that clings come hell or, literally, high water.

There are liquid adhesives made that you apply to your skin before you insert the infusion set. Most of these require special adhesive removers.

5. Length of tubing.
This is an easily solved problem really - just buy the right length. However if you are new to this and unaware of what is out there you may not realise you have this option.

Short tubes are better for those who like to wear their pumps close to their insertion sites, waist band to tummy or under bra to arm. You can buy something that allows you to wrap a longer tube around it (sort of like a mini hose reel) that is probably better than trying to stuff all that spare tubing in your underwear but does leave you with yet another item to try and conceal.

If you are one of those folk who wear slacks or trousers (men) and like to use Leg Things or tuck the pump into your sock then you will need the long tubing.
Long tubing can also be better at night as it allows you to move around more - and think what fun and laughs you and your partner can have as you try to disentangle yourself from the 'ties that bind'!

6. Air bubbles in tubing.
This occurs because air bubbles have got into the pump reservoir when you filled it. You can help prevent this by allowing your insulin to get to room temperature before filling the cartridge.
It is possible that the connector is leaking so check this out and change the infusion set if necessary.
Disconnect the set and prime the bubbles out.

7. Kinks in tubing.
This can occur, especially at night if you chance to twist the tube while tossing and turning in your sleep. Straighten the tube if you can, otherwise change the set.

8. Blood in tubing.
If the insulin in the tube takes on a rosy glow you need to change the set and the site. It is possible that the needle/cannula did not go in at quite the right angle.

9. Insulin leak.
Getting a damp patch on your clothes or a strange' trickly' feeling? It is possible that the connector is leaking. If the leak is not easily visible you can try wrapping a bit of tissue or toilet paper around the connector and seeing if it gets damp. Needless to say if it does you will need to change the set.

Varieties of infusion sets.
When researching this topic I was very surprised to find, on the Unomedical website, what appeared to be Medtronic infusion sets. After a lot of head scratching and mouse clicking I eventually came to this conclusion -
Although you will find infusion sets sold under a variety of different names most are made by one company that specialises in making infusion sets - the Danish firm Unomedical.

So whether it is a Accu-Chek, a Medtronic or an Animas it comes from the same place. Undoubtedly it will differ depending on the requirements of the company ordering it.

There were other manufacturers out there, like Clinico, Dana Diabecare, Avail and Smiths Medical MD and then there is SimpleChoice, a division of SpectRx, Georgia, which also produces what could be termed generic disposable infusion sets - However the latter products are not 'endorsed' by the pump manufacturers so you are told that you use them "at your own risk".

Which set to use?
There are so many out there you will just have to try them out to find the one that works best for you. If you want a little help you may get it from the data below:-

The website www.diabetes123.com conducted a poll in June 2005 to find out which infuser set was the most popular. Though this did not cover all makes of infusion sets available world-wide it does give some idea.

The results were as follows:-
1. Quick-set by Medtronic MiniMed
2. Silhouette by Medtronic MiniMed
3. Comfort by Unomedical
4. Animas Inset by Unomedical (an 'all-in-one' infusion set and inserter .)
5. Sof-Set by Medtronic MiniMed
6. Tender by Accu-Chek (Disetronic)
7. Ultraflex by Accu-Chek (Disetronic)
8. Rapid or Rapid D by Accu-Chek (Disetronic)
9. Polyfin or Classic by Medtronic MiniMed
10. Other teflon infusion set
11. Other steel needle infusion set

To find out more about the particular infusion sets you can visit the websites below:-
Unomedical.
Accu-Chek (Disetronics).
Medtronic MiniMed.
SimpleChoice (SpectRx).
ICU Medical.
Animas.

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