15 April 2012

CGM: Balancing the Pros and Cons

CGM: Balancing the Pros and Cons

I first dipped my toe into the uncertain waters of continous glucose monitoring when I was about 10 (seven-eight years ago) and all I can recall was the insertion seeming at the time like a full-scale operation, and spending 3 days in significant discomfort. When my healthcare team gave me the new veo insulin pump April 2011, so that I could use the Guardian CGM, I was apprehensive to say the least! I knew how helpful it would probably be, but the thought of insertion alone filled me with dread. When I first started the medtronic insulin pump at the age of 11, I was adament I would use the quick-set (90 degree angle - straight-in). From the age of 13-14 I used the silhouette sets that go in at an angle, and just hated it. The CGM sensor reminded me of this, and the first time I inserted it on my own it took 15 minutes and about 10 'back-outs' before it was inserted. First Pro? It was virtually painless! I was quite shocked to be honest. All that worry and it actually hurt less than my normal set change (which I am so used to by now I barely feel it. As for the actual monitoring. I've compiled a summaritive list of all the pros and cons I found, and of course if anyone has any others feel free to share them - this is all personal experience! Hopefully it can help people decide whether or not to try the CGM if they have considered it, or share experiences with other who use it. I decided to write this after reading a similiar post on the Diabetes Forum.  

  1.  Continuous data. Sounds obvious I know! But really, the data is just amazing. No matter if you test 10+ times a day, you can only ever really see snapshots of your BG readings. With the sensor, what I found so helpful was being able to see the swings - how quickly my Blood Sugar was moving up and down. It also allowed me to work out what foods were better than others. For example I am sure many people can relate to breakfast cereal traumas! (Cheerios is off the menu indefinitely I think!) The sensor showed the different sugar spikes that resulted from this. It could also show me how quickly insulin worked. For example if I did a correction, there are arrows on the CGM that indicate if your BG is rising or falling. If the arrows are falling, I know not to give another connection, even if my meter tells me my BG is still quite high. If for example it was 15 and I corrected, and an hour later it was 12.5. Normally I would give another small correction, but when I was on the sensor a similiar thing happened yet it told me my BG was falling - two hours later it was 6, so it was quite good I didn't correct as I could have had a hypo.
  2. Fingers can have a break! Although you do have to test whilst on the CGM (it is very important not to rely too heavily on it, as it certainly isn't perfect... see one of the cons!) You only need to test about 4 times a day. It says to calibrate every 12 hours, but I tend to do every six hours just to make sure. It is nice not to be constantly testing though. Another advantage with this is that there are no errors due to contamination - if you've been eating and your hands have not been cleaned thoroughly, it can result in errors (i've experienced this a lot!) 
  3. Comfortable to Wear: If you're on an insulin pump already, it really is no hassle to wear. Yes, it's a bit more bulky because of the sensor attachment, and the first time I was so paranoid it would fall off! (Best to put some adhesive tape over it, just to make it really secure). It really is tiny though, the sensor. Definitely thinner than the medtronic canulas for the sets. And insertion really isn't as traumatic as I thought it would be! I tend to insert in the top of my thigh, side of my back - used to put it in my stomach but that hurt far more.
  1. It can be irritating! The sensor has loads of alerts available, probably the most common being the predictive alerts. I mentioned earlier about the arrows. The predicitive alerts literally predict a set time before a high or low will occur. My BG is constantly changing at the moment, and so the first night of my most recent sensor I was awoken no less than ten times by my pump beeping with low and high predictions - at no point was it ever really low or high! I eventually disabled the setting at night, but then had another delightful surprise when it went off in an english test! Now I choose for the moment not to have any settings on except the low suspension (that is useful at night), and instead look frequently throughout the day at the graph on the pump screen.
  2. Supply: obviously in some countries it will be expensive as you cannot get the sensors on prescription. In the UK, however, my Diabetes Specialist Nurse told me that there has been a shortage in supply - it took about five months to get a new batch of sensors! Ordered them early December and only just received them 2 weeks ago...! And each batch does only contain about 5-6. This does bring me onto my second con:
  3. Change of Routine: The sensor is amazing, there is no denying that. However, this does have its downsides. The second time I used the sensor it went so well, and about a week later I put in another one and it therefore became routine for me. The trouble is, when I went back to just finger pricks it was really strange, and I did become quite paranoid testing all the time. I suppose to some extent it's comparable almost to going from injections-pump. I couldn't imagine going back to injections now, as the pump is part of me really. I cannot use the sensor all the time simply because of funding, supply etc... but it is hard when you stop using it.
  4. I mentioned above one other thing too: Becoming Paranoid. Although the continuous data is fantastic, it does mean that everything is laid bare - nothing is concealed. I remember at an appointment recently I was telling my consultant how much I hated seeing my BG high about 2 hours after breakfast when I test. Although since I was diagnosed ten years ago it's been drilled into me "test every two hours!" she said to me "just don't test then! Then the reading won't be high!" Logical... anyway, the whole point is that the sensor is always testing, and shows everything in all its glory - good and sadly often bad. The last sensor I did was a nightmare, literally a yo-yo going crazy! It can be a bit demoralising, and you can't just ask the sensor to please not record after breakfast becuase 'I know I go high then...' This links to the first point about the predictive alerts
  5. This brings me onto the final point. The sensor is not always perfect! I don't know where my last sensor was getting data from, but it certainly was on a different planet to my BG meter! Normally the sensor takes about 1 day to 'sync' and then the final day (5) goes a bit off kilter. However, the first night that I mentioned earlier - it told me my BG was 20 when it was actually 8! And then the whole of the next day it went really low when I wasn't low. May just have been a bad sensor, but this is why it is so important to keep testing.

On balance, the CGM is such an amazing development in diabetes treatment; one step closer to closing the 'loop', in that it finally connects Blood Sugar to a certain extent with insulin delivery - the low supension etc.. I hope that in the future it will become more widely available, as for me a definitely found that 5 days wasn't quite enough to get sufficient data, although of course it has been so helpful in seeing patterns etc... When uploaded onto the computer, I can easily see - ok, I'm going low every morning at about 5am, so let's knock back the basal from 3am to stop this. It is fantastic. Yes there are cons, but with time I think those can be eliminated.
So yes! I hope this is helpful for anyone not sure about continuous glucose monitoring, and of course if anyone else has any pros, cons, do reply to the post - the more information the better!

Sophie :)

1 comment

  1. I want to do the continues glucose meter and I am only 15 years old and had diabetes for 2 years


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