Status of closed loop pump trials

Trying to find out what pump brands expect to be on the market in the next year. I don’t like dealing with Medtronic, because I find them to be dishonest about the flaws in their designs. Big example is the buildup of bubbles in the reservoirs during the few days following changing out each reservoirs. I’ve complained to them for 3 years, no action except to blame me. I said others have the same problem, no reply. I even complained (filed report) to FDA. That turned out to be a dead horse. Typical slow to stop speed of a regulatory agency.

Hello Davyboy,
The latest issue of Diabetes Forecast has an EXCELLENT article about the current
work being done on closed-loop and artificial pancreas. The May/June 2017 issue.
There are other companies working on these. I also have LOTS of problems with
bubbles in my reservoir using a Medtronics 530G. If you live in a warm climate
it can be made worse with the warmer temperatures. Here where I live gets
to be in the 110 to 116 degrees in the summer months.

Are you in Phoenix, by chance? I live in Prescott, hits 100 a few days in Summer, temps run about 20 degrees cooler than Phoenix.

A lot of people have the bubbles. According to Medtronic, it must be all our fault, since the reservoirs always meet their design (I sent several in for testing). Of course, what they don’t admit to is that the design itself is bad.

i found a technique that drastically reduces bubbles, as follows:

  1. pull insulin into reservoir as normal, except rotate the plunger while pulling it back. This often releases a few little bubbles around the rubber O-ring
  2. Leave the plunger in the reservoir, with new tubing attached. Hold tubing in the air, so that insulin will flow upward from the reservoir
  3. Holding reservoir on the counter top, slowly press the reservoir downward onto the plunger, which pushes the insulin up the tube, until you see a bubble emerge from the needle (just like using the pump to push up the seal and drive insulin up the tube.)
  4. insert reservoir into pump and follow the rest of the steps as normal. As pump pushes its little driver into the reservoir, let it press out one bubble, then proceed to insert the Inset and add insulin to the tube, filling the cannula. All done.

What I believe is different is that the pump built-in plunger rotates as it moves up into the reservoir, so that the rubber seal is also being rotated, while it is being pushed. I examined the rubber rings. They are round, not square, but the cutouts for them are square. I believe the pump action distorts the rubber a little bit, creating very small routes for air to enter the reservoir.

Since Medtronic refused to research the cause of bubbles getting into the reservoir, I filed a complaint with the FDA in 2014. So far they have taken no action to get it resolved. So this problem will only get fixed by having every diabetic who gets bubbles complain to both Medtronic and to the FDA.

Thanks for the tips on filling the reservoir. Hopefully you can get a copy of the Diabetes Forecast and get some info on the other progress being made for artificial pancreas and closed loops. I live in the Mojave desert in California. Good luck with the information gathering.

I’ve been pumping with Medtronic for 17 years and have never had a problem with bubbles in the reservoir. Maybe it’s due to your climate in AZ?

Insulet Omnipod is currently working towards an AP. They are actually recruiting for clinical trials right now, so if you are open to that and want to use it ASAP that is an option. You can find the details on

I know Tandem is also working towards an AP, but they are a little further behind. It will be a few years before they have one hit the market.

How do you wear your pump with regard to where the tubing comes out? Pump below tubing, above tubing, or? And which Medtronic pumps have you had?