An insulin pump:
- is a little smaller than a deck of cards – some are much smaller
- delivers short acting insulin every few minutes in tiny amounts, 24 hours a day
- the insulin flows through a cannula which sits in the subcutaneous tissue (which is where you inject) and is changed by the pump user every 2 or 3 days
- basal (background) insulin is programmed to meet your needs (this replaces long acting insulin such as Lantus or Levemir)
- bolus insulin is delivered at the touch of a button to cover food or bring down a high blood glucose level
- only rapid-acting insulin is needed and provides all your insulin requirements.
Note: insulin pumps do not measure blood glucose levels, but some pumps can read the signal from a separate glucose sensor.
What sort of insulin pumps are there?
There are two types of insulin pump:
- A ‘tethered’ pump uses a fine tube to connect the pump to the cannula; the pump is worn in a pocket or clipped to a belt.
- A patch pump or micro pump has no tubing or a very short tube, and the pump is usually stuck on to the skin.
To find out what insulin pumps are currently available in the UK, visit Pumps and Infusion Sets Available in the UK
Why use an insulin pump?
For people with type 1 diabetes, keeping blood glucose levels in normal range is the best way to prevent or delay complications of type 1 diabetes, but tight control can increase the risk of hypoglycaemia.
When a pump is used well it can help keep tight control without increasing the risk of hypos because it is so adaptable. Once long-acting insulin has been injected you cannot turn it off or slow it down, but basal insulin delivered by a pump can be slowed, stopped or increased for a few minutes or a few hours.
Boluses for snacks, meals and to correct high blood glucose levels can be delivered all at once, spread over a few minutes to a few hours, or split so some is given straight away and the rest is delivered over a span of time.
Pumps deliver insulin much more precisely than any available pen or syringe. Basal rates are adjustable down to lower than a tenth of a unit per hour, depending on the make of pump. The tiny doses of Insulin from a pump are more consistently absorbed than a larger amount from an injection where it is sometimes not absorbed properly causing glucose levels to run low or high for several hours.
Injected long-acting insulin can be absorbed differently every day-sometimes too quickly, sometimes too slowly, and sometimes only in part. This leads to variable control. With a pump and rapid acting insulin continuously delivering in tiny drops, absorption is much more reliable and your diabetes more stable and predictable.
What are the advantages?
Insulin pump users like managing their type 1 diabetes this way for lots of different reasons. Some of the most common reasons are:
- feeling like you are more in control
- having the flexibility to have a lazy morning, skip a meal or eat late
- delivering food boluses in the most appropriate way, eg spreading it over 7 hours for pizza
- setting a temporary basal increase or decrease when ill, having your cycle, or stressed
- managing the dawn phenomenon
- only needing one needle every 2 or 3 days (other than finger pricks)
Insulin pump users may also find the following things easier:
- managing blood glucose levels around planned or spontaneous exercise
- treating hypers with precise correction doses (from 0.05 unit upwards)
- treating hypos with just fast-acting carbohydrate
- managing changing shift work patterns
- managing toddlers’ meal-time battles
- keeping good control through growth spurts and hormonal changes in adolescence
What are the disadvantages?
There are some disadvantages and things that can put people off pump use:
- being attached to something 24/7 (you can take it off for up to an hour for showers, sports, etc)
- increased risk of DKA (that’s why you need to test blood glucose levels at least 4 times a day)
- risk of site infections (especially if you leave the cannula in longer than the recommended 2 or 3 days)
Will an insulin pump be right for me?
Pumps are not right for everyone. You have to be motivated enough to use this tool properly. That means:
- mindfully managing your type 1 diabetes on a day to day basis
- counting carbohydrates and adjusting insulin doses
- checking glucose levels at least four times a day
- checking that your basal rates are correct by occasionally missing meals
- checking your insulin-to-carbohydrate ratios
If you are having to deal with highs and lows despite your best efforts on multiple daily injections (MDI), or you have frequent hypos that affect your day-to-day choices, then a pump may help you.
National audits published in 2018 show that just over 15% of adults with type 1 diabetes in England, and just over 32% of children and young people in England & Wales are using an insulin pump.