Friday, 30 April 2010

Switch it off an on again!

I have now done two full days on the Minimed Paradigm Real Time CGM system, and boy has it been a roller coaster! In my previous post, I talked about how it was an eye opener to have constant access to information about your blood sugars at the touch of a button. It truly has been a 'journey' so far, but one that took me to new realms of obsession, even I thought impossible.

For me, the reason for my interest in CGM is two-fold. Firstly, I want to be able to see what is going on at times when I wouldn't normally test, such as during the night, in a film, or after a meal. They often tell you not to take a BG reading straight after a meal, because your sugars will always spike giving you an incorrect picture of the overall effect of your last decision - but, to have information about how quickly your sugars go up and how long after you inject it rises, can offer extremely useful tools which can aid in making informed decisions about ways to manage this disease in the future. Secondly, I would like the opportunity to do less blood tests. On some days, if an ill-informed onlooker saw how many times a day I test (15 is nothing out of the ordinary), they may conclude that this was a hobby of mine. It isn't.

At the end of the last post, I commented on how there seemed to be a degree of variation in the blood sugar readings and the sensor readings, but that this was likely to be because the sensor needed time to 'bed in' and formulate the correct algorithm. Well, today got a whole lot worse.

I woke up this morning and keenly pulled the pump up to my sleepy, drowsy eyes to see what was happening in this body of mine overnight. To my delight, there was a practically straight line staring back from the graph on the pump screen. very often in life, we like to see graphs which either climb, or descend. The crime line goes down, good work folks! Performance line goes up, perhaps I'll make bonus this year. On the pump, you really want to see the flattest line possible, like an ocean horizon or perfect spirit level. So to my delight, I woke up this morning to find a spirit level even the most respected architect would be proud of!

I calibrated the sensor with my blood sugar readings (which was still about 3mmol out) and went on my way to work, feeling very good indeed. That's when things got a little weird. About an hour after I arrived I checked the graph, which was starting to climb at a pretty speedy rate. The figure on the pump was telling me I was 12.2, and the little upward pointing arrow next to that, told me I was doing it quickly. I tested my sugar because I hadn't eaten and was a bit surprised at the jump and threatening arrow. My blood sugar reading, again surprisingly, told me I was 6mmol, after having been 7 when I woke up! Now I'm am no mathematician, but that tells me it was heading down, and I would imagine it had a little downward facing arrow next to it.

The weirdness and inaccurary continued from here. The distance between sensor and glucose readings got gradually further and further apart, as the blood glucose reading seemed to stay steady, while the sensor reading got as far as 8mmol away from the blood readings, and the arrow cloned itself so I had two threatening upward facing arrows, meaning my sugars are 'catapulting' themselves toward ketone-ville!

Eventually, I got so sick of staring at confusing figures, and having done 31 glucose tests in the 16 hours I was awake yesterday, I switched it off. I literally just turned it off and decided not to care for a bit.

Being the obsessive I am, it lasted abut 2 hours before I decided that some sort of graph was better than none at all. I also contacted my rep in the meantime to ask what I could have done wrong. Although I was confident that I hadn't done anything wrong, due to the nature of my job meaning I have very busy Wednesday's, I had to do my initial calibrations at funny times. For example, after a meal or when the pump wanted me to do one, but actually it looked as though my sugars were changing a little too quickly.

So I turned the sensor on again at around 2.30pm today. I calibrated it even though my sugars were a little high, because they had been a little high most of the day, so I figured that must count as a 'stable' trend.

Well, since then, I could not have asked for more precise, up to date and informative information! My sugar compared to sensor glucose readings for the past 6 hours have looked like this:

The figure on the left is the blood glucose reading, the one on the right is the sensor reading and the readings are around an hour apart

11.8 13.1
9.8 9.5
7.0 7.5
5.7 6.4
7.3 7.8

Bearing in mind that the sensor reading is always around 10-15 minutes behind the glucose reading, because the information is not taken directly from the blood, which is the most up to date information, I call that pretty precise! It is certainly precise enough to base decisions on, and to feel confident that it is at least giving you information based on what is really going on, rather than the lottery system from this morning!

It is still early days and because I don't yet 'trust' the sensor enough to 'go it alone', I am still doing as many (if not more) tests than before, but this afternoon has been the closest I have gotten to seeing why this tool could be so beneficial. I am hoping that by the time I come to the end of my trial, I will have gained enough confidence to go from testing every hour, or every time my 'sixth sense' kicks in to allow me just to do the two calibration tests I need to do every day, rather than the obsessive and in all honestly, tiresome testing I am doing right now.

Maybe the answer was in the age old cliche of 'turn it off and on again', maybe Bill Gates should copy write that phrase, seeing as it seems no matter how small then computer, it still obeys the rules. Maybe I was so keen to get the sensor going that I didn't calibrate at the best times, or didn't realise that my sugars were changing too rapidly for science to understand. I guess we'll see.

For now, I am just glad to see it's working. But nervous that this might mean I have to find the money to fund buying a CGM of my own.

Whatever happens, straight lines are a new hobby of mine. Here's hoping it stays that way.

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