Going for the Flatline
Continuous Glucose Monitoring Has Arrived!
But at this early stage, is it all it promises to be?

When I think of one thing that would make diabetes easier to manage – aside from a cure of course - it has to be knowing your blood glucose level in an instant, whether it’s on the way up or down, and what it is right now.

So imagine my delight when the fanfare at the latest Australian Diabetes conference was about a new device which does exactly that. And not just in mice, it’s ready to go for real, live (diabetic) humans! Count me in!

A quick rundown on how it works.

People who use insulin pumps have a big advantage here as the device which is available, RealTime is made by Medtronic, one of the big pump companies, so uses what will be familiar techniques for pumpers.

There are 3 parts to it.

1. The Sensor (C in the photo) is inserted just under the skin using a blue plastic device. There is a needle that you inject quickly, and then you remove the needle immediately and it leaves a small plastic sensor under your skin and a small plastic connector just outside the skin.

2. The Transmitter (D). You then connect the sensor to a plastic device the size of a Kiwi fruit sliced in half, but just 1 cm thick/high. This is the transmitter, which receives and transmits the data from your sensor. It is pretty lightweight – it can be stuck with an adhesive to your skin, or left hanging, or tucked into your pant’s waist.

3. An Insulin pump (A) - Medtronic Paradigm 522 or 722 only must then be worn – though you don’t actually have to hook it up and use it as an insulin pump necessarily. The results are transmitted from the sensor device to the pump. Results over the last 3 hours and also the last 24 hours can be displayed on the screen of your pump at the touch of a button. If you are pumping with the pump, the sensor results are also integrated with your Bolus Wizard function so help when calculating boluses and adjustments. The pump also stores all your data which can be downloaded and analysed.

Matt, Lambo and I have used the RealTime sensor and been comparing notes on this new device, so share our experiences with you.

ACCURACY, NUMBERS & TRENDS

KATE: The word on the street is to use the sensor for trends, not the numbers themselves. On the second day I had a perfect match with my Optium and was very excited, but sadly it did not continue. Did you find the numbers themselves were reliable?

LAMBO: No. Not reliable. Found this out soon enough and then used the trend stuff fairly easily.

MATT: I found that within the range of 5-9mmol the sensor was pretty close to the mark but when my BSL was lower or higher than that range it wasn't close at all. I was sensing hypos long before the sensor was and I even had it set at 4.8mmol - I sense my hypos at about 3.8mmol. And I was feeling the effects of high BSL long before the sensor too. So from that point of view, I was a little disappointed.

KATE: Did you trust it? Should you trust it? I have seriously never done so many finger pricks in my life, checking out every beep, but not unhappily, funnily enough.

LAMBO: I quickly got into the trend analysis mode of using it - so trust wasn't really an issue - I just stopped thinking of it in terms of knowing my BGL accurately all the time.

MATT: In my opinion, the numbers aren't accurate but if you look at the graph for patterns it does give you an idea of what's going on. I too did a lot of finger pricks. It was saying I was around 9mmol but I felt horrible. Did a test to find I was 14 point something. I think that was the first day, so from then on when there was any doubt I'd test to compare.

AND THE POINT OF THE EXERCISE IS ….

KATE: I'm only using it briefly on loan, two sensor's worth, and trying to get the most out of it during that time. My aims are to try to get my basal rates spot on, and maybe learn a bit about variations to the norm, identify what makes sugars rise or drop, but that's about all. What did you get out of it?

MATT: It was useful to see how certain foods effect my bsl. But, more importantly, twice I wore a sensor for the sole reason that I was going out on the piss and wanted to keep track of my levels. I found it very, very helpful. I tried to keep it at around 7-8mmol and if the trend was dropping I'd eat and if it was staying highish I'd give a bolus. I found the sensor most useful for controlling BSL while drinking!!

LAMBO: I used it for 8 weeks. Really useful to help with setting basals. Really good with tricky carb counting foods like rice and pizza.

The 24 hour display screen on Paradigm 522 or 722 pump when a transmitter is sending it BGL data.

GETTING YOUR HEAD AROUND IT

KATE: Did you find it addictive? Did you check incessantly?

LAMBO: Yes, but the novelty wore off really quickly I must say. The first few days I tested more with my meter than I would have. After a week ... not so much.

MATT: The first few days I was looking at the results every 30 seconds!!! It did become less and less over time.

KATE: I started using it in a crazy week at work which included through conducting interviews for hours on end which might have influenced me not getting too obsessed with checking all the time.

MATT: Yeah, if I was busy, I forgot it was even there.

BEING HOOKED UP – DOUBLE-TIME

KATE: Did you go taped or untaped with the transmitter? I was extremely surprised how unobtrusive it has been. I just let it hang and tucked it into the waist of my undies, and often forgot it was there.

LAMBO: I'm the opposite - I found it really, really intrusive. Part of my issue was that the adhesive for the transmitter hated me - as well as the cannula hating me.

MATT: The transmitter was stuck on with the double sided tape only and the sensor was covered with (I can't remember the proper name for it now) the super sticky clear stuff about the size of a hand. I'm sure you know what I'm talking about. I found it unobtrusive too. I even forgot it was there most of the time.

KATE: Did you get a chance to experiment with different sites for the sensor to be inserted in you? Any preferences?

MATT: I had the sensor in my belly above my naval towards my side and I found that the best spot. I also had it stuck to my bum/lower back and that got a bit of abuse. Was a bit bruised and there was a bit of blood around when I removed it.

LAMBO: I had real trouble with the sites - and this has led me down the 'when can I stop this' path. I have found the sites always uncomfortable - and sometimes had to relocate them immediately. The sensor has to go in at a 45 degree angle – some pump infusion sets do the same thing but I have never used those and had a real issue with it.

SLEEPING WITH THE DEVI….CE

KATE: How long did it take you guys to get an unbroken night's sleep?

First night I woke up to my old pump screaming no delivery because it was unhooked and in the bedside table, then a couple of “high” (over 10) sugar alarms.

Second night I got a low just on midnight that set off the alarm. Then early in the morning, I rolled over the wrong way and got a "signal too low" alarm. My partner is amazingly kind and patient but when I explained that the screeching alarm was (this time) just because the pump (under my pillow) was having trouble receiving a signal from the sensor (under my belly) - he was a little annoyed it wasn’t something much more dramatic! Are there any other alarms to be discovered?

MATT: Much the same as you Kate - high BSL at 2am, beeping like crazy with the missus shaking me like mad saying "there's something terribly wrong with you - are you ok?"

LAMBO: I had a severe hypo on the very first night - which the alarm warned me of - but alas too late... I was dropping fast. As I have said I found the cannula always uncomfortable so I had some problems getting to sleep - and being woken up when in the wrong position.

I also found it a little annoying that you couldn't locate the pump on the other side. I found they had to be in pretty close proximity - so the ended up on the same side all the time. I have never had an issue with just the pump in terms of being comfortable with the 'look', but did find the whole 2 cannula's and a transmitter looked a little 'unsexy'.

THE VERDICT

KATE: And what would you need from the organisation to become an invaluable member of our team ... sorry, been interviewing all week, but perhaps rather, what would need to change about the Real-Time to make it an invaluable addition to every D’s life/tools/team?

LAMBO: It would be great to have the cannula built into the pump cannula. The transmitter needs to be much smaller, again built into the pump would be great.

One other issue re the CGM not covered was that my wife absolutely hated how it looked (I did too - a bit). She was concerned prior to me going onto the pump about the visual appeal - but absolutely no problems in the end, however this thing was a different kettle of fish. Hated it - totally.

MATT: I think the cost of the sensor is a biggy. Although I didn't have to pay for mine I was told they are around $70 a pop (that’s a lot every 3 days). And then the transmitter battery only lasting 9 months if you use it constantly, then having to buy a whole new thing – owch! They could make the transmitter a little smaller too.

And a few more details to finish up:

The device Matt, Lambo and Kate used is the Medtronic RealTime. This may sound like an ad for it but it’s the only device of its type available in Australia and there’s no others to compare it with at present for balance – as soon as there is we will write about them too!

The device is not experimental; it can be purchased for use in Australia. There is an upfront cost for the transmitter (which has a lifetime of only 9 – 18 months as the battery can’t be replaced) and then costs for each sensor. You must also have the newest Paradigm pump which is compatible with the transmitter for it all to work.

Your best bet for more info is to contact your endocrinologist, or an insulin pump clinic.