Medtronic 670G Auto-mode and carb-ratios

(Nadia) #21

I could probably do a Kalman filter by hand, but I can’t test myself every 5 minutes. What a headache. I’ll have to wait for insurance to cover replacing it to switch to Dexcom.

(Tracy) #22

My 17-year old son is new to the 670 and automode. He loves the pump but can’t stand the sensors. He finally took the sensor out and is back to manual mode. He says he can feel the sensors because of the adhesive tape that’s required and it’s just uncomfortable. He misses his dexcom.

(Guy) #23

Hi Tracy,

I am also using the 670g pump but had to switch to the Dexcom 5 for my sensors because Medicare only pays for the Dexcom 5 sensors. While I did not have any problems with the Guardian 3 sensors, I had very mixed experiences with the MT auto mode feature and now actually prefer the Dexcom 5 system which includes a really cool and simple receiver.

(Sal) #24

It would appear that people here have skipped the personal training offered by Medtronic. Auto mode requires a certain discipline, and if you don’t abide by its rules then you are not a candidate for it.

The first rule of bolusing in auto mode is that you are supposed to wait 15 minutes between bolusing and eating. It shuts off your basal insulin during this time because having both is redundant. Once your glucose starts moving in one direction or another, auto-mode will then make a decision whether to turn your basal back on keep it suspended.

The second rule is that you must know your insulin to carb ratio. Guessing it won’t fare well with auto mode.

If something has gone very wrong, such as a high BG due to a bad infusion site, you will need to exit auto mode, fix the problem, then go back into auto mode. If at any time it feels like something is not right it will kick you out of auto mode.

Overall, I find that auto mode works wonders for preventing lows. Basal insulin plays a much bigger role in our lows than we think.

(Kenny) #25

Been on 670 for almost a year it takes time for it to learn how each individual reacts mine experience continues to improve

(Kirsten) #26

I have been on the 670G for about 9 weeks. My experience in Auto mode has been mixed. At first I liked it & my A1c dropped from 9.3 to 8.8 in the space of a month. But 2 weeks ago I started crashing in Auto mode. In fact I had to stop using Auto mode because it got so bad. I finally determined that one problem is that the correction bolus that calculates in Auto mode is higher than the one that calculates in regular mode. Why in the world does it do this? I read thru the thread but didn’t see anything specifically about this. Even without a correction bolus I often crash in Auto mode & I have no idea why. No, I didn’t take advantage of the Medtronic training. Should I just go view the training videos and look for answers there?

I appreciate any tips, hints, advice anyone can provide. I’m starting to hate this thing but I’m stuck with it so I need to figure it out

(Sal) #27

When you switched to manual mode, did this problem go away?

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(Kirsten) #28

It diminished but hasn’t disappeared. I still am crashing frequently. I know my correction factors are off but I haven’t figured out how to fix them. I know I need to call my educator & get this straightened out.

(Jess) #29

If your carb ratios are off, or you are entering more carbs than you are actually eating you can get post-meal crashes. Auto-mode can’t do anything about bolus insulin that is already in your system. I would look at your carb ratios and carb counting. Frozen TV dinners are good for getting an accurate carb-count for dialing-in your carb ratios.

Automode will cut-off the micro-bolus (backgound) insulin for about an hour or so, after a large meal bolus. I had to adjust my carb ratios (more agressive) to attempt to compensate for this effect in automode. I consider this problem to be a major system design flaw. Users shouldn’t be forced into adjusting their carb ratios to correct for a flaw in Automode’s micro-bolusing system. And, your pump can only store 1 set of carb ratios. You can’t have two carb-ratio sets at the same time (one for manual mode, one for automode). I actually filed an FDA complaint about this issue. If I had known about this issue before-hand, I would have never purchased the 670G.

Remember carb ratios are (carbs/unit insulin) and a more agressive carb-ratio is a lower numerical value, Good Luck!

(Vicky) #30

This particular problem is not addressed in training. This is a problem that doesn’t go away. At least that’s been my experience.

(Vicky) #31

I agree with all you have said about the 670g but there are a couple of things to be addressed. First off, in automode, the background Basal should not turn off. Fasting is fasting and eating is eating.

Insulin sensitivity is important and shouldn’t be ignored in one mode and included in another.

Insulin carb ratios are important but shouldn’t be used as a basis for your auto mode calculations. Carb ratios are for eating. Basal rates are fasting. Just thoughts from a 42 year pump user.

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(Dwayne) #32

It’s like they did whatever they had to to be first with the closed loop. Surprised they are still in business

(Vicky) #33

You can actually have more than 1 insulin sensitivity set as it is controlled just like carb ratios.

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(Ryan) #34

Insulin sensitivity only applies to manual mode. Auto mode computes its own settings.