Interesting night with a CGMS

[phoenix]

I've been able to borrow a Guardian Cgms from the hospital. I started on Monday but by the earrly hours of Wed morning, it had stopped working, Went back to the hospital to find in spite of being taped over,the sensor had come out, perhaps I'd better stop doing abs exercises but that would defeat the purpose!
So started sensor number 2 and last night was very interesting :wink:
For some time I haven't been certain what was happening at night. On several nights I've been waking up covered in sweat at about 3am, but my glucose reading was always OK. I didn't know if it was a hypo or 'just' the menopause causing the sweats.
Last night, I woke up soaked in sweat. The cgm said my glucose level was 70 (3.9), but my monitor said it was 5.6mmol. As I lay there the CGM reading dropped rapidly to 58(3.2) As it uses interstitial fluid it is behind glucose levels in time, so this drop had already happened. I tested my blood again and by this time it was 7 mmol. If this is what happens regularly my glucose levels do fall and my liver pretty quickly kicks in.
What I hadn't suspected before was the rise was followed by a second fall. I woke up at 7am to find the monitor had been alarming for 50 minutes (medtronic alarms are too quiet). This time the monitor said glucose had fallen to 60(3.3)and had again risen, not so much this time but to my normal morning level of around 98(5.4mmol). The blood glucose level confirmed this.

So I went to bed with a glucose level of 5.8mmol and woke up with one of 5.4mmol ; on the surface perfect control...but I had 2 hypos!
Now to see if that is typical before I work out what to do with my basal rates.

 

[ebony321]

Hi,

That is very interesting! i'd love to have cgm for a week to see what happens 24/7!!

Sounds to me though your going to bed to low?

I follow DAFNE guidelines which reccommend going to bed 6.5-8.0

Which means if you were just 1mmol higher then you wouldnt have gone low if that makes sense?

i may be really wrong just my idea/opinion/theory

 

[Clorinda]

I have had a similar experience with the same equipment on my son.

The time lag of the sensor reading being 20 mins behind blood levels defeats the object of the sensor - ie by the time the alarm goes it can be too late.

I've also had problems when my son's reading go very high (above 22mmol) the sensor can't cope and needs recallibrating when BG is lover. This tends to happen in the morning when he is more insulin resistent (we are still sorting his insulin requirements).

Anyway, Medtronic say you need more stable BG for the sensor to work properly, which IMO defeats the object of the the sensor!

When his levels are stable (night), the sensor works well.....

 

[phoenix]

Sounds to me though your going to bed to low?

I follow DAFNE guidelines which reccommend going to bed 6.5-8.0

Which means if you were just 1mmol higher then you wouldnt have gone low if that makes sense

Yes, it does make sense, but I think that I'm looking at reducing my basal a bit, I'd prefer to get a flat profile and not have to raise my after dinner levels.

Clorinda,
For me it didn't really matter that I wan't warned of the hypo, my liver kicked in very quickly so there wasn't really any damage done.... other than needing clean sheets! It's a different matter though for the parent of a child, it must be so frustrating. Even in an adult the counter regulation system doesn't always work well. At the moment though it looks as if its going to be very useful for me and certainly better than not knowing whats going on.

I found some very useful posts about calibration on the childrenwithdiabetes forum