Off Label Pump Programming or Looping

There is a movement known as ‘We Are Not Waiting’ (#wearenotwaiting). This movement uses the expertise of people with diabetes to develop and share new technology sooner than industry can. As an example, ‘Nightscout’ (www.nightscout.info) provided people with the ability to share CGM data with others by uploading data to the cloud, before this was offered by CGM companies.

The movement also offers methods of partial closed-loop insulin pumping; this is done through an effort called ‘OpenAPS’ (Open Artificial Pancreas System’ https://openaps.org/) also referred to as ‘looping’ (https://loopkit.github.io/loopdocs/ ). 

Partial (hybrid) closed loop insulin pumps are integrated with CGM devices. The artificial intelligence algorithms in these pumps use the data from CGM to make some decisions and to automatically adjust insulin without the user’s interaction. Currently (2019), partial closed-loop pumps can automatically increase, decrease or turn off basal insulin multiple times in an hour, even during sleep. However, they cannot automatically bolus for food. The user must still indicate grams of carbohydrate eaten.

The algorithms used for each hybrid (partially closed loop) pump differ. OpenAPS, the Looping website and current industry pumps with hybrid abilities all have different alogrithms. Industry algorithms (e.g Medtronic 670G, Tandem in the U.S.) are not available to view as they are proprietary, whereas the OpenAPS and Looping ones are available for public viewing and public use.

The ‘We Are Not Waiting’communities offer directions online for people to set up their own system. The required code is accessed through Github. Required items inlcude an older model insulin pump, CGM and a small device that runs an algorithm to change the basal rate on the pump in real time.

People who build their own system are choosing to take on the risk of that themselves. There are no warranties or liabilities assumed by the community. 

Role of Educators in Off-Label Pump Programming


As a healhcare provider, it’s important not to promote the system to patients, but to support the people who decide to take this on. 
To support your patients:
  • Educate on the basics of diabetes control as you normally would for exercise, glycemic control and carbohydrates, including rate of absorption ( the ‘Looping’ algorithm offers the option of 2, 3 or 4 hour carbohydrate absorption times when bolusing for meals)
  • Assist in determining pump settings: active insulin time, basal rates when not using the algorithm, adjustemnt of insulin to carbohydrate ratios
  • Consider that the max basal rate using OpenAPS likely needs to be greater than double the highest normal basal rate.
  • Learn from your paitients. People who pursue this will likely be paying close attention, and will be able to teach you a lot about what works for them. Avoid generalizing what patients tell you, as algorithms differ. Accept there are differences between algorithms  (e.g. one of the open looping algorithms will use 60-70% of daily insulin as basal whereas the Health Canada approved Medtronic Hybrid closed loop uses closer to 40% , but requires larger meal boluses).  Ask for explanations when you hear information that is unknown to you or sounds contrary to your knowledge. e.g. Could you explain to me why that  _____ (insulin action time, max basal rate) is used? 

Resources