YpsoPump experiences – December 2020

Regular readers may know that my personal insulin pump has been an Accu-Chek Combo for a few years now. But lately I’ve been experimenting with a different pump. I’ve experimented with the YpsoPump before, but now I’ve had a chance to use it “in-depth” for an extended period. As a result I’ve become aware of some of the pump’s pros and cons that a cursory review might not highlight.

Some background:
As well as a few years using the Combo, I have in the past also spent many years using Animas Vibes, over a year using various Medtronic pumps, a few weeks using a Tandem t:slim X2, and a few weeks using a DANA R. My experiences with other insulin pumps have been relatively short experiments.

Not a thorough YpsoPump review

This is not a complete review of the pump, but instead an exploration of some pros and cons I’ve noticed through actual use. It is not intended as something to convince potential purchases for or against this pump.

Ypsomed have a “YpsoPump Explorer App” on both the Android and Apple app stores if you want to experiment further, although it is an approximation as to the look and feel of the pump.

Size

Just like you’ve probably heard before, the YpsoPump is a small and neat pump. Easy to carry neatly tucked away in an inner pocket (or “running belt”, etc).

Compared to my Combo pump, it’s narrower, thinner, and shorter. The tubing doesn’t poke straight out the end of the pump, making it easier than the Combo to slide in and out of a pocket without catching or kinking the tubing.

The YpsoPump takes one AAA battery and holds up to 160U of insulin, but more on those later.

Touch screen

There are two controls on the pump. The “function button” on the end which wakes it up (and can be configured for “blind boluses” similar to the way this works on Medtronic Paradigms). And the touch screen which we interact with through taps and left/right swipes.

There are no words on the display as it’s the same product for all languages, so we do have to get used to the symbols. They don’t take long to get used to, although some of the pictograms still try to trip me up. For example this icon is showing that the pump is in “run” mode. It’s not saying “press this button to put me in run mode”!

If it was in stopped mode we would see this icon. Tapping on that does bring up a confirmation screen for the action we’re about to do (put the pump into run mode) so any confusion doesn’t last long, but I still do the occasional double-take when operating the menus.

Infusion sets

I have been using it with the Orbit micro (steel) and Orbit soft (teflon) infusion sets (which I’ve also been using on my Combo pump for some time) and also with the YpsoPump Inset (which is equivalent to the Animas Inset II, Medtronic Mio, and Tandem AutoSoft 90 which I’m very familiar with).

These three are the only infusion sets currently available for the YpsoPump. A decent variety of tubing lengths is available through NDSS, from 45cm to 110cm.

Each set is slightly different (see my earlier article about the Orbits) but so far I’m fairly ambivalent about which I use.

Filling infusion sets

In almost all the other pumps I’ve used, the fill process is fairly manual. We start the fill, keep flicking it to make sure any bubbles come out, and manually stop it when all the bubbles have gone through the tubing and insulin is dripping out the end.

But not the YpsoPump. It has some very nice Swiss engineering involved. Unlike the luer-lock connection of the Combo, the YpsoPump’s connection between the tubing and the reservoir seems to have virtually no dead space, and I have had NO issues with bubbles getting trapped there while filling the line. The fill is simple and straightforward.

The manuals that come with the infusion sets tell you exactly how much you need to tell the pump to use to fill each line length. Attach the tubing to the pump, program in that number, certify that the site isn’t connected to you, and the pump will fill the line exactly: finishing with a droplet of insulin just starting to form at the end of the tubing/needle. Nice and neat!

tubing length	Orbit	Inset
45/46cm	10U	10U
60cm	12U	12U
80cm	15U	14U
110cm	18U	18U

Some people are so used to seeing larger drops at the end of the tubing (maybe from experience with other pumps) that they use fill volumes a little larger than the Ypsomed advice, but I think that’s fine. Sure it wastes a tiny amount of insulin and isn’t necessary, but it doesn’t really do any harm.

There is then of course a cannula-fill function, and again the manuals tell you exactly how much with which to fill new sites. It ranges from 0.001 mL (0.1U) for a 6mm YpsoPump Inset, up to 0.004 mL (0.4U) for a 9mm Orbit soft. Like the Mio/etc before it, I have found that an extra 0.2U is required for YpsoPump Insets that have been inserted with an un-filled line (of course that usage isn’t in any official manual).

PumpCart

The YpsoPump reservoirs are glass (unlike the plastic used by all the other pumps) and in fact basically they’re just shorter versions of the Novo Penfill format called PumpCart.

Novo supplies both NovoRapid and Fiasp in pre-filled PumpCart format in Europe, but not here yet. In Europe two pumps use PumpCart: the YpsoPump and the Accu-Chek Insight. But filling the YpsoPump reservoirs is easy (including with Humalog, Apidra, etc) so the lack of pre-filled PumpCarts here isn’t a hardship. Incidentally, in Europe some users of the Insight pump have been using YpsoPump reservoirs filled with their favourite insulin instead of the standard pre-filled NovoRapid option.

With Lilly’s recent announcement that the YpsoPump will be the delivery engine for their closed-loop system in the US, maybe Humalog and Lyumjev will one day be available in pre-filled PumpCart format too? Incidentally Ypsomed has agreements in place with many organisations, and the Lilly deal is not the only commercial closed-loop deal: for example on Ypsomed’s public product map for several years away is their own “MyLife Loop”.

Pre-filling

Because they’re glass the insulin can sit stably in the reservoirs for longer than with other pumps: officially you can fill reservoirs up to a month ahead of using them. This photo is of the convenient reservoir holder Ypsomed provides.

So taking a fresh reservoir with me (grabbing it from the fridge on my way out the door) and then dropping it into the pump whenever needed during the day has been a straightforward operation. Especially when I don’t have to replace or re-prime the tubing/site at the same time.

Even if a reservoir only lasted me a day, I expect that would not be a major hardship.

Replacing reservoirs

After we’ve rewound the pump and put in a new reservoir, the next step is to fill the tubing (as above). This first advances the pump’s piston to the plunger in the reservoir. There’s no extra manual step required there (although filling is a required step before the pump will resume delivering insulin).

If I haven’t replaced the tubing (e.g. I’m only replacing the reservoir because my site still has days left) then I haven’t needed to flush the line. With the Combo I’d have to re-fill the entire tubing to get rid of the bubbles introduced at the luer connector. But with the YpsoPump because of the design of the pump connector, this doesn’t seem to be necessary. I’ve never seen bubbles appear there!

I do still need to do a fill (minimum 1U) so the pump will seat the reservoir (and then report on the available supply). But that doesn’t take long (with the tubing temporarily disconnected from the site of course!).

Some people express concern about the size of the YpsoPump reservoirs, but we should put it in context:

Pump	Capacity
Cellnovo (defunct)	150U
YpsoPump	160U
Medtronic Paradigm/Veo 5xx	180U
Animas Vibe (defunct), Accu-Chek Solo	200U
Medtronic Paradigm/Veo 7xx, 640G/670G/770G	180U or 300U
Tandem t:slim X2, DANA R/RS/i	300U
Accu-Chek Combo	315U

So small, but not “tiny” to most people. And even more important: it’s easy to drop in a new full one when it gets low!

Fiasp

In the Combo my use of Fiasp has had to involve carefully flushing out bubbles while priming the setup, and again flushing new bubbles after less than a day.

But in the YpsoPump I have experienced almost no issue with Fiasp bubbles! I occasionally find one small bubble in an almost-empty glass reservoir after 6 days, and filling new tubing is simple and straightforward as mentioned above.

Waterproofing

Like many other pumps the YpsoPump has an IP68 ingress rating, meaning it should survive a swim in the pool for example. But like most other pumps the manual is very clear: they can’t guarantee that it remains waterproof (for example sometimes microfractures can develop in materials especially after rough handling). The advice (which I follow with my Combo also) is to remove the pump for swimming/etc, but I still have some confidence the pumps will survive if I fall in a pool for example.

The battery cap at the base has a rubber O-ring and we’re advised to replace the battery cap every few months.

My Combo pump has a similar level ingress rating, but I do feel the YpsoPump is probably a little more robust. It has a touch screen and a single function button that’s hopefully more robust over time than the Combo’s four rubber buttons (which in some old Combos have cracked and ended up as an entry point for water). But also the YpsoPump’s insulin compartment is apparently waterproof.

The Combo has a second rubber O-ring that seals the top of the reservoir compartment, and people who have spilt insulin and other liquids inside that compartment have unfortunately found that the inside of the Combo is not waterproof.

But the YpsoPump’s compartment is different. Because of the design of the reservoir and the tubing attachment, that connection does not need to get a water-tight seal around the rim. Even if the glass reservoir was to crack and leak insulin (something I remember from my days of using pens) it should be possible to clean out the compartment (carefully!) and keep on trucking.

Delivery speed

As is seen in the data in my article about pump speeds, the YpsoPump is the current “pocket rocket”. It delivers bolus insulin at only about half the full speed of the old Animas Vibe, but about twice as fast as the current Medtronic pumps in their “Quick” mode. 33.3 U/minute, and it’s not adjustable.

This might affect some people’s use of the pump especially with large doses, unless they use extended boluses. Larger volumes delivered quickly by pumps can be noticeable. But I’ve not noticed any issue with the YpsoPump.

Although I’ve been used to the 12 U/minute delivery speed of the Combo, and I’m currently using Fiasp (which some people find can exaggerate any “stinging” feeling), it’s very unusual for me to notice any feeling of the insulin going in. I have felt it with some previous pumps and cannula types. However, this might also be related to the volumes I currently use and the way I dose it.

My average total daily dose at the moment has dropped to below 25U. Five years ago it was >60U/day: the change is due both to corrected dosing (I’m sure my rates were wrong) and probably because I’ve gained a lot of fitness and lost extra weight.

Most of my insulin is delivered as either small boluses or as increased basal insulin. It’s unusual for me to bolus many units in one go (or in fact bolus manually at all) but that’s probably a story for a different article.

For people who notice the sensation of insulin being delivered, extended/combo boluses may be useful. And/or selection of the most appropriate cannula type/location.

Battery life

The pump likes 1.5V batteries, and the only batteries supported for it are alkaline AAAs. It doesn’t like lithium or rechargeable batteries.

With the plain YpsoPump, a battery like an Energizer Max lasts about a month. In my experiments where I’ve been doing a LOT of Bluetooth communication with the pump I was expecting to see that shorten dramatically. But in reality I’ve so far been getting at least 3 weeks without triggering the “1-bar” low-battery warning!

Even if I had to change battery every 3 weeks I think that would be acceptable. Especially as they’re relatively-inexpensive alkaline AAAs (which Ypsomed currently supplies to users anyway!).

Changing the battery

Unlike with other pumps, I don’t need to stop the pump before replacing the battery! There’s an internal rechargeable battery that takes over insulin delivery and Bluetooth communications for up to 5 minutes while the AAA is being replaced. At the same time the screen shows a convenient reminder of which way around the new battery goes.

I don’t need to arrange down-time: I just change the battery when I need to.

If I intend to take the battery out and leave it out, I just need to have the pump in “stop” mode before removing the battery. Otherwise after 5 minutes it starts complaining. Loudly!

On-pump warnings/alarms

There are various alerts and alarms that the pump can give us, but there’s one worth mentioning at this point: Temp basal ended. Or in Ypsomed terms, the “Temporary basal rate function completed” warning. The pump will issue a vibrate+audible warning at the end of a TBR, reminding you it’s gone back to normal operation. Do note that this is just a warning, not an “alarm”. The pump continues to work, although the short-term bleeping alert can be disruptive.

I would prefer this to be configurable in the current product, as a TBR to help manage an evening meal should not then wake you up just as you’re finally drifting off to sleep. I have heard from some parents that this warning is very frustrating.

Conclusions

The tiny little YpsoPump is a very impressive piece of engineering, starting from the hardware upwards. I do think it has a few shortcomings for me in its current form (see my comments about the “Temporary basal rate function completed” warning for example) and anyone choosing a pump would have to consider all these issues. But then finding a perfect device is hard!

There is a reasonably-active YpsoPump user group on Facebook: YpsoPumpers Australia.

Disclosures

Ypsomed has not asked me to write any of this.
Just to be clear: I am not an employee of Ypsomed. They are funding a clinical trial being conducted by the Baker Heart and Diabetes Institute (who employ me on a part-time basis). Also in 2018 I was one of several loopers invited to Ypsomed’s headquarters where we discussed the requirements of remote control with their engineers.

Feel free to consider those things in the biases that might be affecting me. But regardless I am genuinely impressed by the engineering behind the little YpsoPump!