Insulin pumps have come a long way since the 1970s and we continue to regularly see new technology.
Insulin pumps deliver insulin through a tiny cannula inserted just under the skin, usually on the abdomen, hip, or upper arm. Most pumps feature plastic tubing that connects the cannula to a reservoir of insulin situated within the pump and the pump is then carried in a pouch or clipped to clothing. There are also tubeless micropumps that adhere to the body without needing a pouch or carry case for the pump.
All insulin pumps provide a continuous flow of short-acting insulin, known as a basal rate. With a standard pump, these rates are pre-programmed into the pump. While you can program different rates for different times of the day, the basal rate doesn’t alter in response to real-time changes in blood glucose levels. Pump users also give a bolus of insulin when they eat or to correct a blood glucose level that is above target.
What is closed loop technology?
Closed-loop technology (sometimes referred to as an artificial pancreas) means that insulin delivery is fully automated, that the insulin pump would be determining the amount of insulin a person needs without any need for the pump user to press buttons. These systems are integrated with a continuous glucose monitor (CGM) which is constantly sending information about the glucose level to the insulin pump. A complex algorithm is then used to predict what the blood glucose level will be in the near future and how much insulin has already been delivered, to then alter the rate of basal insulin delivery accordingly. In addition, the system can also automatically deliver correction blouses of insulin when the glucose levels are predicted to be above target and reduce or temporarily pause insulin infusion when hypoglycaemia (low blood glucose level) is predicted. Information regarding carbohydrate intake still needs to be entered into the pump and recommended bolus doses for food need to be accepted.
It may be worth noting that these pumps do rely on the information from a sensor to determine the rate of insulin delivery, so if anything happens to interrupt the signal from the sensor to the pump, the user will need to do some trouble shooting. The cannulas will still need to be changed every 2-3 days; the insulin reservoirs will still need to be filled and alarms will still need to be managed. While the automated insulin delivery will reduce the burden of managing diabetes, the pump user will still need to have some active involvement.
While we are very close to seeing this technology in Australia, we aren’t quite there yet. Currently we have some hybrid closed-loop systems available on the market. They are a stepping stone to a closed loop system but are known as hybrid closed-loop systems because they still require input from the user. These are also sensor-augmented pumps that allow the continuous glucose monitor to ‘talk to’ the insulin pump so it can make adjustments to the basal insulin rate based on real-time glucose data. These pumps can suspend the basal rate when the blood glucose levels are dropping and resume the insulin infusion again once glucose levels have increased. You still need to tell the pump how much carbohydrate you are going to eat and approve the suggested meal-time bolus. Also manual input is required to factor in sick days and exercise. These pumps alter the basal rate according to the sensor information and can prevent/correct hypoglycaemia, but don’t automatically give any bolus correction doses for predicted above target glucose levels.
Affordability is probably one of the biggest limitations to sensor-augmented pumps. Private health funds can cover the cost of the actual pump but then there are ongoing monthly consumable costs of around $30/month (cannulas, tubing, insulin etc). On top of that, the hybrid closed- loop or closed-loop systems need a continuous glucose monitor, which aren’t covered by private health insurance. Some people with type 1 diabetes may be eligible to receive a fully subsidised CGM through the NDSS. For more information on eligibility, click here.
The ability for different pumps and continuous glucose monitors to work together is referred to as interoperability and means that information can be transferred and shared between devices. However in most cases, the insulin pumps will only ‘talk to’ certain sensors. This means that your pump of choice may not be able to be integrated with your sensor of choice. You may need to potentially forgo certain features of either the pump and/or sensor to get the main features you want. Or you may choose to use devices that aren’t interoperable and manually enter information into the pump instead. The insulin pump would then be used in manual rather than automated mode.
Different hybrid closed-loop insulin pumps use different algorithms to determine the automated basal insulin adjustment and may also have different factory settings that cant be overridden, eg target blood glucose level targets. Some people may prefer to have more control over setting these targets and deciding on insulin doses. There are many pump choices in Australia, including using the hybrid closed loop pumps in manual mode, if this is your preference. However, research does indicate that people who use a hybrid closed loop or closed loop system, tend to spend more time with their glucose level in target and have a reduced number of hypoglycaemic episodes.
Some people who use the hybrid closed-loop insulin pumps can find the idea of letting the pump do most of the work a bit scary or daunting to start with and it can take time to ‘trust’ the algorithm and the technology. Trying to ‘override’ the system can affect the algorithm and reduce the effectiveness of the automated system.
Buying an insulin pump is a bit like buying a car. A family sedan is going to suit some people and others will be looking at a sports car. While insulin pump therapy remained quite stagnant in Australia for a long time, over the last few years we have seen a lot more options become available. There is not one pump that is going to suit everyone so just like buying a car, it’s good to do some research. Perhaps look at information on the web for the pumps currently available in Australia; Ypsomed MyLife YpsoPump, Medtronic 670G and 770G, Tandem t:slim X2 and the tubeless varieties Omnipod Dash and Accu-Chek Solo Micropump. Its looking like other pumps will be available in the near future.
The Diabetes WA Type 1 Tech Night is a great opportunity to talk to each of the pump companies and have a look and physically touch the devices. Click here for more information or to register for our November Type 1 Tech Night.