Medtronic 780G after a month - algorithm questions/issues

[stevejones1983]

Hi all - have had the Medtronic 780G now for 4 weeks, and overall I've been super impressed with it. However, there are a couple of issues with it which I'm struggling with. I don't know if they are due to something I need to tweak, or whether the pump is still learning about me and I just need to give it time. But hoping some of you might be able to shed some light on them .

1. When I am slightly out of range, the micro boluses it gives to correct don't seem to have much effect. For example, my target is 5.1, but last night I was 9 at bed. I left the pump's SmartGuard to it to correct assuming by morning it would be on target, but it wasn't. It just remained at 9. I could see from the pump/app that it had given numerous micro corrections, but it's like they didn't do anything. Have attached a screenshot. On a more conventional pump, I would maybe adjust my insulin sensitivity value, but I can't in this case (at least what's I've read online is that SmartGuard doesn't use the value set in the settings?)

2. I've noticed immediately after having insulin for food, the pump sometimes temporarily stops my basal. I assume it's because it thinks I will run low, but it's at the point where I know it won't. Because it stops the basal for an hour or 2, it I end up getting a delayed high a couple of hours later which wouldn't have happened if it hadn't suspended the basal. But I've not idea why it does this. Is this to be expected?

To be clear, these are regular issues. Not one offs, so I don't believe it's an issue with the cannula, etc.

Any help or advice appreciated .

 

[mamarvazq1]

Hola Steve:

Puede y debe modificar la sensibilidad a la insulina con SmartGuard en uso.

Espero que esto le pueda ayudar.

 

[mamarvazq1]

Hi Steve:

You can, and must, modify the insulin sensivity, with SmartGuard in use.

Hope this can help you.

 

[Nicola M]

Your first point - it is possible that you were rising overnight and the corrections were working but also with you rising at the same time it couldn’t keep up and so it looks like you just stayed the same. To combat this you can try lowering your Active Insulin Time. This will give you more insulin over a shorter period to combat the high. Most people start on 4 hours and it is recommended if you change it to only change it by 15 minutes at a time, wait a few days see how it goes then change it again. My Active Insulin Time is 2 hours and Medtronic actually recommends that but it does not work for everyone.

Second point - How long before eating are you giving insulin? If at all? If you have insulin on board but your food hasn’t “caught up” yet your blood sugar will start dropping so out of safety the pump will stop your insulin which can result in highs later on. If you are certain your carb ratios are correct I would experiment with giving your insulin at different times, what works for one person may not work for another and a lot of it is trial and error with getting timings right.

 

[Gordontoo]

Hi stevejones1983.
I have exactly the same issue and the shorthand way to fix this, for me at least, is to try to stabilise my sugar levels before I go to sleep. Not necessarily as easy as it sounds, I think I will have to explore Nicola M's solution.
I also find that my 780 has issues with a single meal which contains around 80gms of carbs, or higher, it seems to freak out a tad.

I have given myself zero lead time with my insulin, so I bolus immediately before eating. That did stop a problem I was having with low levels in spite of a full meal being consumed, immediately being followed by a high..
I'd be interested to hear how you get on.

 

[Prancy]

I’m sort of having the opposite problem. I got my 780g set up last Wednesday with my CDE. We set my basal rates, carb ratio, etc. The problem is that in manual mode (initial wait period) , I seem to go low each time I bolus. I’m thinking my insulin/carb ratio needs to be raised. I’ve lost a lot weight and that’s why. I can go into Smart Guard anytime today….just want to increase insulin/carb ratio first. Has that happened to anyone?

 

[Gordontoo]

Hi Prancy. I can relate to your problem. I consistently had lows at about 11Am and 4PM. I adjusted both my carb ratio slightly Prancy and I also dropped the amount of insulin I was getting as a basal load from about 8 in the morning, through to 6 in the evening. I have had no lows at those times since.
That being said Prancy, I would suggest that you run it (any changes) by your pump people first. Once you get your 780 in auto and it starts working as it should Prancy, you will be a very happy camper me thinks.
Good luck.

 

[Prancy]

Hi Prancy. I can relate to your problem. I consistently had lows at about 11Am and 4PM. I adjusted both my carb ratio slightly Prancy and I also dropped the amount of insulin I was getting as a basal load from about 8 in the morning, through to 6 in the evening. I have had no lows at those times since.
That being said Prancy, I would suggest that you run it (any changes) by your pump people first. Once you get your 780 in auto and it starts working as it should Prancy, you will be a very happy camper me thinks.
Good luck.

I’ll do that. I made some reductions in Basal on Temp Basal and that seemed to work ok. When Temp Basal expired, I would go back to Suspend Before Low. That happened most of the night and I checked my meter to ensure numbers were accurate.

Then, this morning I discovered my cgm and meter had gone over 100 points off. Man, I hate it when that happens. It hadn’t happened to me with my 670g in a long time. I was getting ready to go to the gym when it happened. So, I’ve been trying to get it down, bolusing, drinking water, so I can calibrate. Not a happy camper yet. Still in manual mode until I get things a little more acclimated.

 

[Gordontoo]

It does take a little getting used to. Don't you hate it when things get out of whack? If I suspect my sensor is out of sync Prancy I do a BG, then another about 30mins later, just to make sure the pump has adjusted to the new BG previously inputted. I do find that high carb loads seem to throw my pump out of kilter somewhat, to the point that it's quite a job to have it bring BGL's down to within target range. From my perspective this usually means I cheat and add a few ghost carbs, usually about 3 hours after the high carb meal. Someone once told me Prancy, joking I think, that this pump was designed by medical engineers, but the software was written by lawyers. I will cross my fingers and toes for an uneventful transition Prancy. Please take care.

 

[Prancy]

Update on status: I’m keeping an optimistic attitude, but will say this has not gone well. I’m considering hooking my 670 and G3 back up. So, I contined to have huge differences in my cgm BG and meter BG to the point I couldn’t insert my meter BG numbers that often they were so off. By yesterday afternoon, it was still over 50 points off and Medtronic rep instructed me to change the sensor early, which I did. I’ve monitored it carefully and it’s pretty bad. Still over 50 points off. I’ll give the sensor 24 hrs to adjust….then….idk. I can’t go into Smart Guard when my BG numbers are so off. Staying in manual is very frustrating. It may be better just to turn off the cgm and use the pump without one. At least it won’t keep suspending me before low, when I’m not really low. I wish I could get a Libre or another cgm.

Oh, I have a very regimented diet. I only eat 10 carbs at breakfast and 35-40 at dinner. No lunch. So, I know I’m not overloading on carbs. Everything was going quite well with my 670g….I must say, this has been a terrible experience. I suppose I’m blaming the G4 sensors.

 

[Gordontoo]

Hi Prancy.
It certainly sounds like you are in the wars and I feel for you. I don't think anyone who isn't attached to one of these little suckers can ever understand the stress and anxiety that goes with them.
Firstly Prancy please allow me to preface what I am about to say, by stating that I am not in any way a trained doctor, nurse, or nurse practitioner. I am just another pump user, and these are simply my opinions, so I would urge you to contact your pump specialist people to see what they say. Doesn't hurt to work you way up the Medtronic's food chain either, until you find someone who will both listen and provide the assistance you require.

I.M.O. and from my perspective Prancy and as I understand things, the 780G is able to "think" and adjust how it delivers any insulin, based on how it views the disparity between skin glucose readings and blood glucose readings. For instance Prancy, if your skin glucose taken by your G4 sensor is reading 108mg/dl and a BG reading is taken and it reads 80mg/dl, then your 780 will say to itself that your sensor is reading high and it will adjust the amount of insulin it decides to give you , to accommodate that disparity. In full auto there is a pretty pink graph on the phone software, that shows this happening.

I.M.O. Prancy, the real problem starts at warm up. If your sugar levels are on the way up, or down and are changing quite steeply, then you get a much larger disparity, at that time, between SG and BG and the 780 then decides that that is the difference and adjusts itself to suit, so that Prancy, even after your sugar levels stabilise and are more in syc., the pump is still making adjustments based of those previously "learnt" figures, which in turn causes a see saw effect as the pump continues to chase itself up and down.

The only advice I can give you, is as I wrote earlier and to first contact your pump people, then get on to Medtronics and become a "squeaky wheel", until you are happy.
With respect to BG Prancy, what I usually do if this occurs, is to try to stabilise my sugar levels, then take and enter into the pump another BG reading 30mins after the last and another 30 mins after that. Then Prancy, I cross my fingers that the pump manages to "learn" what is happening.

When this system works as it is supposed to Prancy, it is a dream and IMO is the nearest thing to an artificial pancreas that is available today, which is really cool, though it is quite a slog to get there.
I will cross all my fingers and toes for you Prancy, please let me know how you are travelling.

 

[Gordontoo]

P.S.
Sorry Prancy, but I forgot something important. Mia culpa.
Always trust your Blood Glucose readings over Skin Glucose readings.

 

[Prancy]

Hi Prancy.
It certainly sounds like you are in the wars and I feel for you. I don't think anyone who isn't attached to one of these little suckers can ever understand the stress and anxiety that goes with them.
Firstly Prancy please allow me to preface what I am about to say, by stating that I am not in any way a trained doctor, nurse, or nurse practitioner. I am just another pump user, and these are simply my opinions, so I would urge you to contact your pump specialist people to see what they say. Doesn't hurt to work you way up the Medtronic's food chain either, until you find someone who will both listen and provide the assistance you require.

I.M.O. and from my perspective Prancy and as I understand things, the 780G is able to "think" and adjust how it delivers any insulin, based on how it views the disparity between skin glucose readings and blood glucose readings. For instance Prancy, if your skin glucose taken by your G4 sensor is reading 108mg/dl and a BG reading is taken and it reads 80mg/dl, then your 780 will say to itself that your sensor is reading high and it will adjust the amount of insulin it decides to give you , to accommodate that disparity. In full auto there is a pretty pink graph on the phone software, that shows this happening.

I.M.O. Prancy, the real problem starts at warm up. If your sugar levels are on the way up, or down and are changing quite steeply, then you get a much larger disparity, at that time, between SG and BG and the 780 then decides that that is the difference and adjusts itself to suit, so that Prancy, even after your sugar levels stabilise and are more in syc., the pump is still making adjustments based of those previously "learnt" figures, which in turn causes a see saw effect as the pump continues to chase itself up and down.

The only advice I can give you, is as I wrote earlier and to first contact your pump people, then get on to Medtronics and become a "squeaky wheel", until you are happy.
With respect to BG Prancy, what I usually do if this occurs, is to try to stabilise my sugar levels, then take and enter into the pump another BG reading 30mins after the last and another 30 mins after that. Then Prancy, I cross my fingers that the pump manages to "learn" what is happening.

When this system works as it is supposed to Prancy, it is a dream and IMO is the nearest thing to an artificial pancreas that is available today, which is really cool, though it is quite a slog to get there.
I will cross all my fingers and toes for you Prancy, please let me know how you are travelling.

Great response. Makes sense and I was not aware of this info. It helps. Which brings me to a question that I also may have already answered. When I finger stick, the number is automatically sent to my pump from my meter….I can accept or decline that number on the pump. I had been declining, if it was off too much, due to fear it would reject it due to large discrepancy and tell me to start warm up over, change sensor or something else that is terrible. However, earlier today I did accept a number that was over 30 points from the cgm number and it accepted it to my surprise. So, maybe “I” was the problem. Wish my pump trainer had told me that.

Since this afternoon, it was working pretty well. It’s still only a few points from fingerstick. I have renewed enthusiasm. It feels nice. I do intend on entering Smart Guard by Friday if this continues.

Thanks again!

 

[Gordontoo]

Hi Prancy, it is my understanding, that provided you haven't done a fingerstick with dirty hands, or anything else that may skew the results, Prancy, that you should always accept the BG result. This gives your pump and up to date reading on the differential as to how the sensor is tracking against real time B.G.L's and it can adjust itself accordingly. The 780, particularly in auto is a very clever piece of kit and if the sensor is behaving itself, then it is very easy to forget that you are attached to a machine.
Enjoy.
P.S. There is enough stress that goes with T1 and more stress in dealing with insulin pumps and even more stress in working with the various peoples and organisations, that at times seem to treat you like some kind of alien life form, so please Prancy, never, ever even jokingly suggest that you may be the problem. Be a little kinder to yourself.

 

[Prancy]

Hi Prancy, it is my understanding, that provided you haven't done a fingerstick with dirty hands, or anything else that may skew the results, Prancy, that you should always accept the BG result. This gives your pump and up to date reading on the differential as to how the sensor is tracking against real time B.G.L's and it can adjust itself accordingly. The 780, particularly in auto is a very clever piece of kit and if the sensor is behaving itself, then it is very easy to forget that you are attached to a machine.
Enjoy.
P.S. There is enough stress that goes with T1 and more stress in dealing with insulin pumps and even more stress in working with the various peoples and organisations, that at times seem to treat you like some kind of alien life form, so please Prancy, never, ever even jokingly suggest that you may be the problem. Be a little kinder to yourself.

Point taken. Things are continuing to go well. I have renewed enthusiasm. I have high hopes for my next A1c.

 

[Prancy]

I’ve been in Smart Guard mode all day. Things are going very well. Around 120 most of the day.

 

[Gordontoo]

I wish you all good things Prancy.
I look forward to hearing how you are traveling .
Enjoy

 

[Prancy]

Yesterday, when I checked my TIR for the previous 24 hours, my TIR was 95%! I’m so excited. It’s also letting me sleep through the night, so that’s a great benefit.

 

[Gordontoo]

The change in TIR is absolutely mind blowing isn't it Prancy, I know exactly how you are feeling. Also getting a full nights sleep is very humanising.
Enjoy, enjoy, enjoy.