Saturday 23 November 2013

Mastering the temporary basal rate

Temporary basals (TBR) have never been my strong point: it's what you'd call my 'development area'. I gained a little confidence in tweeking them for my needs at the Animas Sports weekend, which went a long way in helping me grasp the TBR reigns, but I am still clumsy, at best.

I now regularly use them for exercise and when I am ill and need an increased amount of insulin to keep me in range.  I sometimes do this successfully and sometimes blindingly badly, but I give it a shot. But there is another time that I have found them to be particularly useful; when warding off an unwelcome overnight blood glucose level drop. 

There are times when I go to bed and my continuous glucose monitor (CGM) trace shows that I am dropping, or that I have been dropping and am now teetering above 'low', but a little too close to it for comfort. At times like these in the past I would feed to raise my BGs just a little. A biscuit, a piece of toast or an apple would often suffice, but in all honesty 11pm isn't a time of night I particularly want to be snacking. That's not also considering how much weight might creep on in a year from several biscuits a week to curb a low blood sugar at night. So in recent weeks when I have seen a drop or a number I'm not too confident about leaving as it is, I've been experimenting with TBRs to restrict the amount of insulin going in, on a temporarily basis, therefore allowing my numbers to level out, or bump up just a touch. 

Last night was a great example of this. At just after midnight Jamie and I crawled into bed. I'd seen a spike after my badly calculated dinner and was all too aware of the insulin I had stacked one bolus on top of another trying to get it down. Finally it was coming down, but at this time of night? C'mon! 

I was 9.1mmol (164mg/do) and showing a downward arrow. Great.  I don't want to eat because 9.1mmol is a little on the high side anyway and I don't particularly want to go up overnight. But I'm also fairly sure the downward trend is going to continue, with just a little insulin on board still burning a hole in my CGM picture. I could ignore, which would no doubt end in a 2am hypo, or I could eat, which I don't really want to do. So I opted for secret option C: reducing my basal rate to 0% for 1.5 hours. It seems a long time to be getting no insulin for, but something seemed instinctively right about it. That's something I believe us PWDs (people with diabetes) have a lot of, instinct.

I awoke two hours later all of a sudden. I don't know why, but after accidentally punching my husband in the back of the head after a bad dream, I figured I must have been low. I turned over, clawed around for my Dexcom receiver and with bleary eyes, squinted at the screen. 

Well I'll be damned. I had nailed it, spot on. The downward trend had continued. It had continued for around two hours, having briefly danced with a 3.9 mmol around 30 minutes ago and was now heading back up, nice and safely within the very respectable 5mmol (90mg/dl) range. And back to sleep I went.

Basal rates are funny things. Something which can take days to fully adjust when you make any strategical changes can also impact your blood glucose within a matter of hours. In this case I hadn't needed to eat and was able to nod off to sleep with the use of a carefully timed basal reduction. 

Game. Set. Match. 


  1. Hi Anna. I have now been on the pump for a week and I've used the TBR twice, both times it's been really effective. The first time was for when I went for a four mile run, so following advice of my DSN I cut my insulin delivery down to 70% for the hour before, during and after the run and hey presto, before the run I was 8.2 and thirty five mins later after the run I was 4.6. What with then unconnecting myself from the pump for fifteen minutes for a shower, I avoided an otherwise expected hypo and even better, I didn't experience a hypo during the night which I can honestly say I did practically every practically night following a run on MDI. Its early days I know and I'm bound to be tripped up along the way but it's a good start. The one thing I have noticed however is that despite excellent readings throughout the day and evening, I'm waking up with rising sugars, in the 10-12 range (possible dawn phenomenon?) and I know I've not experienced a hypo during the evening as I've been checking my sugar at 2am and they're within one point of what they were when I went to bed, so that's a conversation I'll be having tomorrow with my DSN. It does seem to be more prevalent on the morning I'm due to change my cannula so maybe it's just that I can't go to the third day before changing it? As to wearing the pump, I have to say I've hardly noticed it, even at night. And as for the remote, absolutely brilliant, it's so good to be able to blue tooth the pump, have I missed injecting, no I have not! Thanks for your updates, brill to read. Jonathan

    1. Also, I have Dexcom on order too! Can't wait to get it!

    2. Hey Jonathan, so wonderful to hear how successful it has been for you so far. It could well be dawn phenomenonm, you are probably spot on. My insulin gets bumped up at 6am for my wake up and back down again later in the morning. That's the beauty of the pump; hour-by-hour adjustment!

      So, has your Dex arrived yet ?!? :)

  2. Sorry for the long delay in replying! I get my Dexcom G4 tomorrow, have literally just put the order in. I can't wait as despite some good improvements thanks to the pump I am still getting daily hypos, often two or three a day. As you know, the finger stick test just gives you the blood sugar level there and then, which is only adding to the anxiety when going to bed, etc., as I'm just wondering whether the level is going to stay the same, go up or worse go down, and low and behold, it usually goes down! Think I've been overcompensating with the odd highs. Anyway, took the plunge and Dexcom on its way as I just need to know what my sugars are doing rather than feeling I've got to test every five or so minutes! I know it's early days with the pump but I'm sure with the Dexcom as well as, things will soon improve! Happy New Year to you too. Jonathan H