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| The Medtronic 640G launches Feb 2015 |
Those familiar with Medtronic's Veo may have come across the term 'Low Glucose Suspend', the facility where overnight the Veo (when used with Enlite CGM sensors) can automatically stop basal insulin supply if the pump detects a predetermined low glucose threshold has been passed. This has been shown to significantly reduce the severity and duration of overnight hypoglycaemia in clinical trials and was welomed (particularly by parents of T1 children) as a major step forward towards developing the 'artificial pancreas'.
The MiniMed 640G takes this approach to a whole new level with 'Smartguard', an algorithm that begins to take effect significantly before you have hit your 'low' level, attempting to dodge some of those pesky hypos altogether. The sensors are Enlites again, but with a new (and apparently much improved) 'Guardian Link' transmitter to boost performance.
More on that later, but first a quick overview:
- Colour screen which apparently reads easily in sunlight
- Waterproof (yay!) including swimming
- Reservoirs available in either 180u and 300u
- Up to 5 different basal patterns with up to 48 rates per 24 hours each.
- Pairs with Contour Next Link USB (new 2.4 version)
- Limited bolus options via meter, full bolus wizard on pump
- Completely re-worked interface with many more 'user-friendly' options and updates
- More customisable alarms (and at louder volumes)
- Already licensed for use by children
- Size-wize it's very similar to the Veo, just a few millimeters taller, wider and deeper
The thing Medtronic were clearly most excited about was obviously 'Smartguard', so it's probably worth trying to note down what I can remember about how that works. Smartguard builds significantly on the premise of Low Glucose Suspend by making the whole thing much more predictive. While Low Glucose Suspend only kicks in when you are already registering low, Smartguard acts earlier trying to head off the low by temporarily stopping basal (in much the same way I started doing while wearing a Libre sensor - see 'new technique'). They had a snazzy graph in the presentation to explain how it works, which I've attempted to recreate here. On the pump you set a 'low' limit that you do not wish to fall below - anywhere between 2.8 and 5.0 in 0.2mmol/L increments. Above that the pump sets additional 1.1mmol/L and 3.9mmol/L guides. Smartguard is triggered if sensor glucose values fall below that upper line (3.9 above your low limit) AND are falling sharply enough that you are predicted to fall below the 1.1 line within 30 minutes. All insulin is stopped for at least 30 minutes from that point (including basal and any partial dual or square waves still in progress). If your numbers stay down, the insulin stays off for a maximum of 2 hours. Basal delivery (only) automatically resumes once you have risen above the 1.1 line AND are predicted to remain there for the next 30 minutes. Users can, of course, cancel the Smartguard intervention at any point (eg if they would prefer to treat the impending low with some tasty fast-acting carbs. Rather neatly you can also choose whether or not the 640G alarms or alerts at any of those points and even tailor what times of the day (or night) to switch Smartguard on or off. Alternatively you can simply run the system as the current Low Glucose Suspend works.
It was claimed that in the 'Pilgrim' study, the same algorithm that powers Smartguard was able to avoid 80% of potential hypoglycaemic events both day and night. If those results could be reproduced 'in the wild' it would be nothing short of groundbreaking. A handful of people have recently been able to use the 640G on a trial basis at Kings College Hospital and two of them (including @desangsue) shared their experiences. Responses from other hands-on users are also very encouraging and seem to suggest that many found Smartguard alone was sufficient to cope with moderate exercise. After a short while to build trust, many were also happy to simply let Smartguard do its thing silently and alarm-free, only realising when checking the pump later that they had been spared a low-level dip here or there by some automated basal jiggery-pokery. The only mandatory alarm that sounds would be if your sensor glucose fell below your 'low limit'. This is a good thing. But the customisability of those alarms, while preventative action is automatically taken without confirmation being required seems to go a long way to prevent CGM 'alarm fatigue'.
Fancy new meter
The 640G pairs with a Bayer meter that looks just like the existing Contour Next USB, but this souped-up '2.4' version has some extra cleverness under the hood. For starters you can use it to deliver a quick manual bolus of any number of units you choose without having to fish the 640G out of your pocket. You can also create up to 8 bolus presets (which can include predetermined square or dual-wave options and doses) on the 640G that can be fired from the meter. Frustratingly you cannot vary the doses of these presets from the meter itself at the point of delivery - which would make this much more useful for me - and neither can the meter act as a fully fledged bolus wizard as it does with Roche pumps. However *some* meter bolus options are certainly better than none, and I can see that these could be very useful for snacks and preset mini-corrections or standard preboluses. The new BG meter also acts as the USB conduit for uploading data to the Carelink software package which (mercifully) is also getting a complete overhaul very soon.
Sensors schmensors
That's all very well you may say, but I'm about as likely to get funding for full time sensors as I am to become the next Pope - is this all about Smartguard, or is there anything here for non-CGMers?
It is true that Medtronic are putting a lot of emphasis on Smartguard - they are keen to describe the 640G as a 'system' rather than just a pump. It seems they are trying to work with Healthcare Professionals and NICE, seeking to allow more people to access this sensor augmented, 'virtual pancreas' approach. Swift murmerings were made about price points and volume but no real detail given as to if (and how much) sensor cost may fall if there is a greater uptake.
However even without all that sci-fi automation there is much here to please regular pumpers.
A colour screen is pretty much a given these days, but the layout and icons here are well thought through and in themselves allow quick access to a detailed and drillable overview, similar to but richer than the 'back button' on old MiniMed pumps. Bolus and basal adjustments are available direct from the 'home' screen, and everything is navigated by the 4-way/OK controller plus two other buttons - one for 'menu', the other for 'back'. Pleasingly, pressing and holding the 'back' button takes you directly to the home screen however deeply you are embedded in within menu options, which is a nice touch.
A great deal of attention seems to have been paid to the available options to make the pump more customisable and personalisable for individual users. For many things (such as basal patterns) you can now choose named versions eg 'work day' or 'illness' that make them more self explanatory to use, alternatively you can still opt for the more usual numbered options. You also have the option of setting all sorts of presets, including temporary basal rates of predefined length/intensity (again with named alternatives). Whatever you choose to populate from the available options in setup screens get shown in the selection menus, but you don't have to wade through dozens of items that you never use if you don't want to set them up. So you might choose to set just two of eight available TBR presets one for 'moderate activity' and another for 'light activity', then when setting a TBR you can choose either of those or dial in a custom one. Overall it felt logical, intuitive and that several regular tasks would be faster to achieve. The added complexity might mean an additional button-press here or there for one or two things, but in the hour or so we had to play with the 640G most things I wanted to access within a few presses I could.
Battery life is anticipated to be around 2-4 weeks, depending on use. The 640G needs the slightly larger AA batteries (rather than the Veo's AAAs) to power the colour screen. In the top menu bar the battery (and other) icons re-colour to indicate their status. On the battery front, as well as the usual 'low battery' warnings at 25% and again (if I remember right) at 5% there is also an inbuilt 'get out of jail' rechargeable battery that will allow the pump to limp on for up to 8 hours if you find yourself stranded in a motorway traffic jam or somewhere with no shops over a Bank Holiday having paid no attention to the icons/alerts when you set off. I also unwittingly tested the "what happens if you need to change battery in the middle of things" situation and a trial TBR I had set running happily carried on after I took the battery out to have a look. Another neat trick is that the standard-issue belt clip can be swiftly detached and is moulded in such a way that it can be used instead of a coin to unscrew the battery cap. Just a nice bit of attention to detail which speaks highly of the amount of effort Medtronic have put into the design of things.
Infusion sets and reservoirs are exactly the same ones used in the Veo, but special mention must go to the 'Infusion set change' alarm which you can set as a reminder. This particularly caught the imagination of Paul B who said that as a feature, it was pretty much enough to win him over on its own.
My biggest disappointment on the day was to discover that those infernal (and entirely useless) TBR hourly chimes are still present on the MiniMed 640G and it doesn't look like you can turn them off either. After all the effort that has clearly gone into usability and user-experience... The mind boggles.
To be honest I'm going to have to stop there - it's suddenly got rather late and I had thought I was just jotting down some quick notes. It was a very interesting day and there were other snippets (such as the iPort) that will have to follow later.
In short, I will have had Artoo for 4 years in November this year at which point the warranty runs out and my robot counterpart begins to live on borrowed time. While I'm not champing at the bit for a new pump, I had absently been wondering what I might look at next. I am still interested to find out more about Roche's Insight pump. Until today I was fairly certain that the Animas Vibe was my front runner because of Dexcom integration. I know that for may the lack of a fully functioning remote handset will be a dealbreaker, but the 640G has given me much to think about and very clearly sets itself apart in the market by doing something that absolutely no other pump can do.
Disclosure. Medtronic generously paid my train fare and laid on a tasty lunch. I was not asked and have not been paid to write this post or publicise their products in any way, but thought you lot might be interested.
