Finding the chase and cutting to it

NB this is not teaching you what pumping is and expects you to be familiar with some of the terms.  It is a breakdown of the operational and design features of some of the insulin pumps on the market with an in depth view on the Accu-chek DTron, Early Medtronic Paradigm and Animas Vibe pumps.

After my operation in February, my DTron insulin pump reached the end of its life. While I was recovering (and not working) I returned to multiple daily injections.

I did this for a number of reasons, not least because it was the first time in 12 years I had not used the pump (!!!). In those twelve years, I used the DTron for the first four years then changed to a DTron plus. I did try a Medtronic Paradigm with a combined continuous glucose meter system (CGMS) during that time.

The DTron and its successors were beautifully designed, from the ease of swapping out the cartridge to getting the status of any of the actions I had completed.  It was simple with

• a four button control interface (and the alarm codes on the back) that you can use with your eyes closed (or if you had retinopathy)
• a battery which lasted 8-10 weeks
• it was reasonably water-proof, I certainly used it in the pool for days at a time
• from realising I wanted to change to the cartridge to gathering all the items and plugging in the new cannula set took less than five minutes – no further prep necessary
• the 3ml glass pen compatible cartridge provided all three millilitres to me: I once swapped out a cartridge early for a trip, but used the remaining 10 units as back up in my Humalog pen
• a great size, smaller than my hand and beautifully curved.

I am gutted that Roche have stopped making it.

Hey, what about the Medtronic Paradigm?

Plenty of people love the Paradigm combined pump from Medtronic: I am not one of them.  I used it for eight weeks.

Compared to the DTron, the Medtronic had a 1.5ml “syringe” cartridge.  This meant you have to fill up a syringe and then load it in to the pump before priming (filling with insulin) the tubing and the cannula (the tube that sits under your skin).

I injected with both pens and syringes from 1977 to 2002 and nothing is as fiddly as the syringes used by insulin pumps.  Where-as a syringe used for insulin has a mechanism for gripping and holding the syringe while you draw up the insulin (and inject), a pump cartridge syringe has no such help (that may be a little mean, they do provide a detachable extender, but they always fall off, especially if you are trying to shake out air bubbles).  If I get a small air bubble in for an injection, it is no big deal and easy to resolve.  A small air bubble in a pump cartridge can mean not having any insulin for a couple of hours which leads to extremely high blood sugars.  But in December 2007, that was what I was trying.

Now though, this process is being performed twice as often.  Joy (or not).  The worst thing about this system is that you end up losing a lot of usable insulin so that you are not performing this hideous process at an inopportune moment (Dtron, change cartridge over at 3am, not an issue, trying to get the fiddly cartridge in at 10pm, nightmare).

But it would be worth it for the CGMS.  Or not.

The other big difference between the two pumps was how frequently the basal was delivered.  I use a very small amount of insulin mid-afternoon.  In the DTron, every 3 minutes the pump gave me 0.005 units of insulin.  The Paradigm didn’t, it gave me a 0.17 unit dose 10 minutes apart.  I felt grotty, which wasn’t something I was used to having got the pump set up back in 2002.

But it would be worth it for the CGMS.  Or not.

The CGMS was OK: when you learn to use the pump, you are taught the values it provides are a guideline only, available for three days.  For me, I have a little trouble spotting a fast drop in insulin (typically experienced with an infection say).  I am aware I am in the hypo, but because of the speed of the change in blood sugar, one minute every thing’s fine the next I have a hypo which needs treating quickly.

This was the reason I wanted CGMS, to provide that cut off in the change of blood sugar levels where I could spot the hypo and where I couldn’t.  It would also give me an idea of the changes going on over night to prove the over night basal rates.

Which it did, for £450, I had three days worth of graphs.  It was interesting.  But not enough to get over the inconvenience of using the DTron: I visited MIT during that time and the short life of the cartridges was a complete nightmare, jet lagged, tons of paraphernalia and in a hotel suite, it was just annoying when the DTron would have provided all the insulin in a single cartridge.

The deal breaker came after my third sensor.  Remember, one of the reasons I had the sensor was to spot a fast drop.  I spotted the drop one beautiful sunny Sunday morning while the sensor said there were no changes (none, nada, not one) in my blood sugar levels (it maintained that my blood sugar varied a little between 6.4mmol/l and 6.7mmol/l over an hour.  When I tested I was 2.7mmol/l which is a massive drop from the 10.3mmol/l I had been an hour earlier).  I was back on the DTron within the hour.

So, it’s a really bad thing they stopped making the DTron

I feel that.  But injections are such hard work.  In the end, with alarms reminding me to inject, I ended up on six injections a day with highs indicating that that may not have been enough.  After 6 weeks I was ready to accept any pump.

When I got the DTron in 20002, I was choosing between two pumps (really).  Now I had a choice of four: the Roche Spirit pump, Medtronics latest Paradigm, Animas’ Vibe and the Omnipod.

Wireless is the new latest fad which must be great if you have a really young diabetic you are reasonable for as you can  bolus and check the screen while the youngster is off playing 10 feet from you.  As an adult, rushing around much of my time I do not want to be hunting for the user interface of my pump in my bag or round the house.

Cartridge size was the other important consideration, which meant the Animas Vibe was the only choice.  The Vibe has a 2ml cartridge and a similar basal rate delivery as the DTron, so even if the CGMS was not good, it would behave as a better pump for me than the Paradigm had.  (It was also seriously water-proof, up to 3.6m).

The CGMS would be provided for 7 days and had a really good reputation.  So, with the choice between that and injections, I chose the Vibe.

Learning how the vibe works

Basals and setup

The Medtronic was a nightmare from the training on.  I wasn’t told that I needed a vial of insulin to draw up the cartridge – obvious I know, but I didn’t consider it.

So this time, I was really sorted out.  Animas have a really useful orientation course too.  I was promised it would take 90 minutes by the hospital but it was much longer than that, nearer 3 hours.

Chris Sargent, from Animas, helped me set the basal rates and although there wasn’t a straight copy through from the DTron to the Vibe, it was reasonably close (remember that’s the back ground insulin the body needs to function).  The vibe has 12 slots for a day’s basal rates compared to 24 in the DTron but it is programmable in 15 minute segments.  It’s close to perfect by the end of the week.

Bolusing

It is reasonably difficult to place the pump under my clothes and perform a bolus.   There are buttons are all round the pump, so no convenient carriers/bags are available to do this anyway, but even if there were, I have not been able to successfully perform a “fast bolus”, which should be available by pressing a single button.  The idea is obviously to prevent accidental pressing but it is not something I can do easily and requires more presses than using the “normal” bolus menu.

I compensate by a double click of the OK button to get to the simple bolus screen.  This I all miss from the DTron: switching from a simple (a single dose) to a combi (a set of small boluses to cover slowly released carbohydrate) was really simple.  This is a completely separate menu screen, however some thought has gone in to the flexibility of this extended bolus.

One of the nicest features on the Vibe is insulin on board value available from one click of the button on top of the pump.  The CGMS has all its history available from the CGMS sub-menu – this would be great from the bolus screen, it’s not, which is really annoying.  To go from any sub-menu to another takes four button presses!  Though a tip to the wise is to use the fast bolus button: a quick hold on here and a press on the OK menu gets back to the home screen really simply.

There is a lot of data accessible by the pump everything from complete total insulin delivered in a calendar day to total bolused, when the last bolus was to basals and temporary basal rates.

Even now, some of it still doesn’t feel very logical.  It would be great if the insulin on board (that’s how much of the last bolus is still active in my system) was available from the bolus screen not the CGMS screen.  If I don’t think about it that means 6 button presses if I land on the bolus screen and think, I’d better check.

Battery and use

The battery is pretty good and I can swap in a standard AA battery as an emergency measure, which is good.  Unfortunately, to see the screen, I have to press a button, which makes hanging the pump off my belt reasonably pointless, not least because the holder means that I am reading the pump upside down.  I gave up after day one.

What about the CGMS?

It’s really good: the sensor lasts for 7 days minimum and it seems relatively accurate.  I have used four and the data has been really interesting.  It has led me to change some of my behaviour as well as my doses.

I have tried in various locations and have ended up with a site that is both accurate and doesn’t get in the way.  Unfortunately, it means the CGMS is on display, but that’s OK.  People assume it’s feeding in drugs and seem quite disappointed when you say it’s just the transmiter for the sensor and show them the readout.

The colour screen is so easy to use and get that fast reading on what’s happening: whether the readings are static or moving up or down, slowly or quickly.

It seems much more sensitive that the Medtronic had been and responds faster to a recalibration result (I feed it 4 a day: breakfast, lunch, go home/tea and bed).

Ironically, the screen layout makes it much easier to use the CGMS but also to not use it.  There is no wasted space on the home screen if you are not using the CGMS.  It is easily accessed and scrolls between the past hour, 3 hours, 6 hours, 12 hours and 24 hours and a single reading with the insulin on board screen.

The transmitter lasts for around 6 months.  The sensors seem really robust: they don’t need to be chilled while in storage.  The insert devices for the sensor and transmitter are really well designed and can be done single handed with very little hassle.

The alarms can all be configured.  This is really good, giving a welcome break if there’s nothing important going on, but you get that loud warning that things need checking when you’re outside or in the car.

I have had a little trouble with the cloud upload.  There is no way to get the data off the pump with the standard tools without it going to the web site.  That’s appalling.  I appreciate the thought is out there that all mindless morons but actually, there are plenty of us who can work out the numbers if we have the data.

And let’s face it, this is my data.

On the other hand, the sensors do seem to just work.

I still want MY DATA without HAVING to be connected to the internet.  Diasend will not work on a ship without access to the world wide web.

So not only do I have to pay for the sensors but network access if I want to access the data.  This is not cool.

It also is another set of tools that do not work with Linux.

It does seem to be accurate, lasts the distance and is reasonably comfortable and relatively easy to insert.

When in a jam

All of which means when I travel to Africa later this year, I will be taking my DTron and its adapter for my computer.  The night time carrier, the belt carrier, under-clothes holster and a spare injector pen.  Though the fact every one of the new infusion sets will work with my DTron and has its own inserter.

All the data from my testing kits and DTron can be analysed anywhere in the world.  I don’t even need a power supply to do that.  If I really want to use the other pump as a CGMS, I can do that.