What is Insulin Pump Therapy?

Web Resource Last Updated: 28-05-2024

The aim of the insulin pump is to replicate the function of the pancreas.  In people without diabetes, the pancreas continuously releases a low level of insulin throughout the day and night (known as basal insulin production), with boosts of insulin released at mealtimes.


The pump is programmed to deliver a continuous background amount of insulin; similar to the basal insulin production of the pancreas and matched to your own requirements. This is called the “basal rate”.

The speed of insulin delivery may be programmed to differ at different times of the day and can be altered to match your activity levels.

In addition, a bolus dose of insulin is delivered by pressing buttons on the pump, a handset or phone to cover carbohydrates in food eaten or to give a correction if the blood glucose is high.

The pump uses quick-acting insulin (called analogue insulin); such as Novorapid, Humalog, and Apidra.

As insulin pumps give rapid-acting insulin continuously all of the time, there is no need to use an injection of long-acting insulin as well. The basal rate of the insulin can be adjusted at any time. When you eat, you give a bolus dose of insulin through the pump.



Benefits and challenges of using an insulin pump

Benefits of using an insulin pump

Challenges of using an insulin pump

  • A reduction in hypos and return of hypo awareness
  • The ability to manage exercise and activity more accurately
  • Improved control and flexibility
  • No daily injections
  • More accurate insulin delivery
  • Small basal rates 0.025 unit increments and bolus 0.1 unit increments can be achieved
  • Built in calculators help calculate the insulin dose at mealtimes (bolus calculator and correction dose functionality) – your healthcare team will help you programme this. This includes pre-programmed insulin: carb ratios (ICRs), insulin sensitivity factors (ISF), to help calculate mealtime and correction doses, and “active insulin” feedback to assist in dose calculation
  • An infusion set change is required every 2–3 days
  • Risk of site infection
  • The pump may malfunction and infusion set can block
  • Risk of Diabetic Ketoacidosis (DKA) which can occur sooner than with insulin injections
  • Must monitor blood glucose 4–6 times daily
  • Must have a good knowledge of carbohydrate counting
  • The Pump must be worn 24hrs a day, every day
  • The Pump can be disconnected but only for a maximum of 1 hour at a time
  • Complications such as lipohypertrophy (lumpy injection sites) can still occur using the pump.


Wearing your pump

Wearing your insulin pump can take a bit of getting used to at first, however, there are a few things that you should know to help get you started:


It can take some time to work out the best place to put it. The pump can be attached to any belt, or waistband, or just carried in your pocket. You must make sure it is secure, so it is not likely to fall out of your pocket. There are a number of different cases and belts available to keep your pump safe and secure

Remember: you need to wear the pump most of the time. You can ‘come off’ your pump for short periods. This is usually no longer than an hour at a time. If you need to remove the pump for longer periods, you will need to speak to your diabetes team.

When you come off your pump, you will need to disconnect at your cannula site. This is quite easy to do and you will be shown how. You can leave your pump running after it has been disconnected. Place it in a clean Tupperware box or something similar, lined with kitchen paper. Always put your pump in a safe place. Where possible lock it away. Your insulin will automatically begin infusing once you have reconnected.

For most activities, where the pump is off for less than an hour, it is not necessary to make any adjustments to your insulin dose. If, however, it is longer than an hour, you may have to give a correctional bolus. Discuss this with your diabetes team.

A patch pump can be worn on your tummy, your legs or your arms. You would only remove a patch pump when you are changing to your next patch pump.



Your infusion site

Your infusion site is the patch of skin where the cannula attached to your insulin pump administers insulin. Most people prefer to use their abdomen as their infusion site


However, you can use many different places that have a bit of padding such as your lower back, thighs, upper buttock, or the back of your arms – see areas highlighted in green on the image. Some people prefer to stand up when setting a site up.

There are some sites you should avoid such as:

  • ‘lumpy’ or heavily used infusion sites
  • areas at which your skin folds
  • directly on the beltline or under your waistband.


Changing infusion sites

You should change your infusion set and infusion site every 2–3 days. It is important to rotate infusion sites to avoid the development of lumpy skin (also known as ‘lipohypertrophy’). You should make sure that your new site is at least 5 cm away from your last one.

You should always check your blood glucose level 1–2 hours after inserting your cannula to make sure it is working. It is also sensible to leave your old infusion set in place until the new one is in place and some people leave it in place for up to 2 hours. 

The best time to change your infusion site is after a bath or a shower. It is important to make sure your new infusion site is working correctly and that insulin is being delivered once you’ve changed it.

DO NOT change it late at night before you go to sleep: if there is a problem, you will not know about it as you are asleep. Failure to absorb insulin overnight can result in diabetic ketoacidosis.

Another good time to change your infusion site is before a meal so that the meal bolus ensures the clearing of any blood or tissue left in the cannula. 

You should also examine your cannula after removal to check for any kinking or bending. Consult your diabetes team if this happens regularly.

For hybrid closed loop users, it is particularly important to change the cannula regularly and use new sites each time. The systems rely on good insulin absorption and a well functioning cannula to make adjustments to the insulin and to learn how your glucose varies across the day.


Infusion sites are sometimes painful after insertion. If your infusion site is still painful one hour after set-up then it is best to change the infusion set and site. You may experience a slight stinging sensation. Tea tree cream may be useful following the removal of the infusion set to help with healing.

You should wash your hands before opening any packaging and before and after touching the old infusion site – this will help reduce the chance of infection. Generally, you should change your infusion set at the first sign of pain, redness, or discomfort. 

More resources:

A hybrid closed loop system automatically adjusts the delivery of insulin based on real-time glucose levels. It is also sometimes known as an ‘artificial pancreas’.  You can find out more in our hybrid closed loop resource.