How Insulin Pumps Work + Pump Terminology

The basic concept of how an insulin pump works is that it delivers a small, slow trickle of insulin 24-hours a day closely mimicking the way that the normal human body works.

As well as getting to grips with how to use it, you need to know how to talk about using it. It’s here that the ‘new lingo’ required can take some getting used to.

The problem is not that the words are hard, it’s that many of them are so similar that those new to what is simply called ‘pumping’.

How an insulin pump works

To use the pump, the insulin cartridge is filled with fast-acting insulin and fitted inside the pump. The needle or cannula is inserted under the skin and held in place with an adhesive patch, which fixes to the surrounding skin.

The other end of the tube is connected to the pump which then delivers insulin through this infusion set according to its programming.

The pump does not measure blood glucose levels, nor does it and produce insulin automatically.

You will still have to do blood tests and you set your own programmes in the pump yourself but insulin pump therapy is the most natural form of insulin treatment available today.

Using the pump

To use the pump, the cartridge is filled with fast-acting insulin and fitted inside the pump. The needle or cannula is inserted under the skin and held in place with an adhesive patch, which fixes to the surrounding skin.

The other end of the tube is connected to the pump which then delivers insulin through this infusion set according to its programming.

  • Read more: Insulin pump product guides

There are far more pump users in the USA - the UK is behind on pump uptake due to the cost of pumps. The cost is roughly £2,500 for the pump and infusion sets; reservoirs and batteries are ongoing costs to the effect of about £200 a year.

Pump distribution

Only since May 2009 has NICE product guidelines for pump distribution, effectively giving the go-ahead for their use in the UK based on evidence that pump use can improve HbA1c results and therefore reduce the likelihood of unpleasant consequences (and expensive treatment) of badly controlled sugar levels over the long term.

Infusion sets and insertion devices

There are infusion sets and insertion devices. Then there are basal rates and boluses.

What is the infusion set?

The infusion set is the long tubing that runs from the pump where it’s attached to the reservoir to your body, where it’s held in place by an integral plaster. In the middle of this plaster is the ‘business end’ – the needle or canula (a sort of soft plastic needle) through which the insulin is put into your body just below the skin.

Each manufacturer has a few choices of infusion sets, with variations used in materials, whether it’s a needle or canula, the depth of that needle or canula as well as variations in the length of tubing. These allow some scope for different sizes and shapes of bodies to get the best fit.

What is an insertion device?

Another factor that might affect your choice of infusion set will be the insertion device. Put very simply, this is how you bang the business end in.

The devices are fundamentally similar to a lancing device - you tend to have to pull it back to charge the device and when you press go it bangs the set into place.

That’s putting it crudely and the devices can be quite sophisticated, but in essence that’s the point of the insertion device.

Depending on your dexterity or other concerns (you might simply not like the set up) you might be swayed to choose an infusion set based on the ease-of-use of the insertion device.

Some infusion sets can simply be put in manually. As you’re replacing multiple injections with an infusion set that only needs replacing every 3 days, the whole art of infusion set application is one that only needs to practiced every 72 hours.

What is the basal rate?

The basal rate is the tiny, precise doses that the pump delivers at very frequent intervals. You and your healthcare team determine your basal rates based on what doses of long-acting (or 24-hour) insulin you were on before.

The rate can be set at different levels for different times of the day to match with your body's requirements – for instance it’s normal to have a slightly higher basal rate set for the morning with a reduce rate through the night.

What is a bolus?

A bolus is the same as having an insulin shot from an insulin pen. So you’ll give yourself a dose (a bolus) when you eat your meals. You should blood test as normal and take into consideration any exercise you might take, set your bolus and set the pump to deliver.

Once you get the hang of the basic terms and get used to playing with your pump, these things fade from memory, but at the early stages it helps to get to grips with the lingo to aid easier uptake of pump practice.

Reference: www.diabetes.co.uk