CGM—the graduate course

The battered folding chairs are arranged in a circle in the church basement. One by one, the men and women in the room stand, introduce them selves, and then confess to their shared weakness. Then, all too suddenly, it is my turn. I stand and look at my feet while I gather my courage. I lift my head and look each person briefly in the eye, and then I say it:

Hello, my name is Wil, and I’m an information addict.

Yes, it’s true. I love to know everything about anything. Journalistic habit. So more of a occupational hazard, you understand, rather than a personality defect. Just want to make it clear I’m not a snoop, I just like to be well informed.

And the thing I most love to be well informed about is my diabetes, particularly the moment-to-moment status of my blood sugar. Thank God for Guardian.

At any moment of the day I can slip her out of her sturdy belt case with a satisfying KaClick, glance an my diabetes cockpit’s instrument panel, know everything I need to know, and return her to my belt with an equally satisfying KaThunk.

And should I have my head up my ass and not be paying attention when I should be, she’ll give me a head’s up. Assuming I can hear her. Well, it’s not a perfect world.

Since I’ve started CGM, back when dinosaurs ruled the earth, I’ve had a couple of times when finances forced me to be CGM free. It was miserable. With this newer Guardian it would be inconvincibly awful.

Despite the above mentioned VOLUME problems (I’m going to keep harping on this until Medtronic HEARS the problem and FIXES it… and I’ll be really pissed off if they don’t send me the very first ear-shattering upgrade…); this new Guardian is so far above and beyond my original that I’m convinced that withdrawal would be fatal. And given my new-found quest for tight control and my hypo unawareness, it could quite literally be fatal to be without it.

Being pump-free has had an unexpected consequence for me. I’m starting to explore features of this new Guardian that I had not paid attention to before. Overall, it is an amazingly well thought-out device. As always, however, I do have a few nits to pick.

The first set of features I want to tell you about is the “Capture Event” menu. It’s as easy to get to as anything on a MedT product (read that any way you want to). Press ACT once from just about anywhere, down arrow once and ACT again. Here you can choose to enter a variety of information into Guardian’s memory. Choose between, Enter BG, Insulin Marker, Meal Marker, Exercise Marker, and Other.

OK, so why on earth would you want to? Because if you enter this data Guardian will link it up with the real-time sensor data when it chats with CareLink. That puts an awful lot of interesting information in one place for you. When I was on the pump, it was impossible and un-necessary. Or so I thought. But now when I sit down on Sunday morning with my coffee for my weekly “post game” I have some pretty powerful info at my finger tips. All I need is CareLink and my food log to see how my therapy is doing and what adjustments might be in order.

Oh yeah, you should go get a cup of coffee too. This is likely to be a long post.

So I’ve discovered you don’t even need to take your Guardian off your belt to download her to CareLink. Just drop the ComLink into your lap, get some distance from your computer and let her rip.

As a side note, you can print a “Device Settings” report that shows how you’ve personalized the unit. Handy to keep a printout incase you get stuck by lightning or whatever and lose your settings.

First things first. The Enter BG screen lets you enter a fingerstick into the system that IS NOT a calibration stick. This is a great feature, and one of the things on my wish list back when I was bitching about the original crappy Solutions software. Everyone stand and applaud MedT for having the courage to include this. Why? You can now print out a report that shows, among other things, the difference between SG trace and random fingersticks. Anyone who reads this column knows that there are a number of times when a CGM unit will not agree with a BG fingerstick. Most times they are pretty close or trending in the same direction. Still, it is kinda cool to see it. I think most folks will be surprised at how good the system really is.

That said, while were are all standing, we should now “Boo” MedT for wimping out at the last second. On printed reports BG fingersticks are huge black squares that take up about 25 points of space on the graph. The intent, obviously, is to make BGs that are a bit off look more like they are close to the SG plot line. Sigh. You guys were sooooooo close to doing the right thing. Just give us a dot. Have faith. You have a good product. OK, everyone together now: “Booooooooooooooooooooooooo!”

You could also use this menu to calibrate if you want to, rather than entering a calibration stick into the sensor menu. I haven’t yet fooled around with the BD Paradigm BG meter that comes with Guardian. I had assumed that any finger stick would go to calibrate the sensor, a huge defect in the ParaPump system that beyond a shadow of a doubt is the cause of countless calibration problems and subsequently the wide spread belief that the sensor system doesn’t work very well. Now that I see you can opt out of using a BG capture for a calibration, at least on this menu, I’m wondering if the BD meter can be used and let you choose. I’ll have to fool around with it and let you know.

Next up, the insulin marker. Now here is a classic case of hiring a programmer who is not a diabetic and has never worn the device. When you open the menu you are given the choice of entering Fast Acting, Short Acting (even I’m not clear on the difference between those two), Intermediate Acting, Long Acting, Mixed 70/30, or Mixed 50/50. Looks like we got all the bases covered there. Now, when I enter, say my Levemir basal shot of 20u in the evening I go to Long Acting, dial up 20 units. Guardian then asks me if I’d like to store that dose. Delighted at a time saving step the next time around (as basal shots are almost always the same dose every time) I tell her “yes.”

A bit later I take a hit of fast acting. When I open the screen it has defaulted to 20 units. I dial in my 3 unit hit and save. Later, back at the Long Acting screen my 20 units is gone and replaced by 3 units. That’s right. Even though the menu has six types of insulin, the Guardian has only one memory. That’s (insert favorite expletive) nuts. As basal’s are almost always the same, the device should be able to remember a different number for long-versus-fast insulin. Likewise, the meal menu has Breakfast, Lunch, Dinner, and Snack. Again, some D-folk ways have the same size breakfasts or snacks; but Guardian will only remember the most recent meal, regardless of meal type selected. Groan. This pisses me off more and more each night when I have to scroll up to 20 to enter my basal shot. Also worth mentioning, the insulin units are in tenths. Only pumpers get tenths. The rest of us deal in either whole or half units. Somewhere on the preferences menus we should be able to select moving by full units.

So why bother? Why not just enter 2 units of basal and forget about it? Because CareLink can provide us with some handy stats if I give it the right information. Both the “Quick View Summary” and the “Trends Summary” give insulin stats including average daily totals and breakdowns of the percentages of fast vs. long, an important bench mark for determining if you ratios are set right. Generally speaking about half of your total daily insulin should be basal and half fast. If your percentages are way the hell off, odds are you are using one type of insulin to do the job of another type; like taking corrections of fast-acting to compensate for inadequate basal.

Quick View is a 14-day report that shows you the general trend of your glucose. It uses a set of vertical blue bars hovering over each day. The bar shows the peak and low of the day, and a white circle somewhere along the bar shows the day’s average. Little black hash marks on the left of each bar show fingersticks. It is supposed to be a way to quickly see trends. To me it just looks like the thingy that Doctor McCoy had above the beds of the sickbay on Enterprise on the original Star Trek. Not having McCoy’s advanced education I can’t make much sense out of either one. Damn it, Jim, I’m a Un-certified Diabetes Educator, not a Doctor. Quick View also has an Insulin Injection Log, in the form of a table. The bottom of each column is white, showing basal. The top dark for the fast acting. Height of the column lets you compare one day’s insulin to the next. I prefer the Trends Summary, which has much of the same information plus some other useful features.

Trends is also 14 days, and also has a slightly smaller version of Dr. McCoy’s bio-function monitor, but without the BG hash marks. That’s the top panel of four. Next is our Insulin Injection Log, and below that a graph of the Carb intake for the day. At the bottom is a table that summaries key data like average glucose, carb and insulin totals etc. But what is really cool about this report is that the data line up. You can scan your eye up and down the page to see the relationship between glucose, insulin, and carbs. You can scan your eyes left to right to left again and see the relations ship of the data from day to day. On the right side are some min-summary tables that average glucose for the period, average insulin use by total and type for the period, and average, max, and min daily carbs. A nice snap shot.

A cousin to this report is the Modal Day BG report. Don’t run this one. It only tracks fingersticks. Why would you want to look at data based on 3-6 fingersticks when you can look at data based on 288 readings? Into the shredder with that puppy.

Now the really pretty report is the Sensor Daily Overlay. As you might guess from the title, it takes the sensor “trace” from seven days (or fewer if you want) and lays them on top of each other. Each day is a different color, so the chart is quite lively. There is also a dotted line that shows the average of all seven days. I love looking at this chart, it is one of the most visual. It is soooooo cool to look at the swerving, snaky, river-like lines that show the travels of our blood sugar throughout the day. The value here is that if you see all your lines are jumping or dipping around the same time each day, you know you have some adjustments to make.

The Overlay also includes stats on Excursions, which emerging research seems to indicate may be the biggest villain in terms of diabetes complications. That’s the one bummer about being on CGM; you’ll realize that your world is more full of storm-tossed seas than you ever imagined in your worst nightmares.

I love the Daily Summary report, but I’m frustrated by it at the same time. There are three graphic frames. The top one shows glucose and has the SG trace for the day with the BIG black boxes we talked about earlier showing finger sticks. It also has a little horn that shows alarms, but doesn’t show which kind of alarm. High? Rate of change? Sorry, they all look the same. Middle block is insulin injections and the bottom is carbs and exercise (which I’m allergic to). With a food log on your knee this report could really help you fine tune your carb counting and blousing. My gripe here is that it takes foreeeeever to generate reports in CareLink. You can look at one day, but to go to the next takes forever. Want to go back. Oooops! You need to create it again.

I’d love to have CareLink on my hard drive, rather than Online. I’m not sure why this isn’t an option. It may be a monster program that would eat up too much space. Maybe no one thought of it. Maybe they are secretly mining our data. To print out all the days would devastate a small forest. Maybe they cold create a flip feature that would allow you to load a weeks’ worth and flip back and forth on screen (hint, hint, hint…if you folks are reading).

OK, I saved the best and most innovative for last. This report is so innovate I didn’t “get it” at first. This graphic chart pulls sensor data out of time and associates it with a meal bolus. You need to set some preferences at CareLink as to the time ranges in which you eat breakfast, lunch or dinner. But it seems, from looking at my first chart of this kind, that the software then “moves” sensor overlays to show the effect of time-after-eating on the trace post-meal; rather than clock time. To be clear: other reports lay out sensor data based on the clock built into the device. This report associates data to a count-down timer that starts when you eat. It is the difference in using a stop watch or a clock for timing a relay race.

Take breakfast, for example. The chart starts at one hour before, then shows the meal, then up to four hours after the meal.

What’s intriguing about this is that, separated from the flow of clock-time, you can really see the effect of various meals on your SG. I was surprised to see that on the three days that I remembered to enter meals in the Guardian (hey, I was just starting off with this feature) that the breakfast curves were nearly identical. I hadn’t noticed that on the Sensor Overlay, as the meal times were a bit off.

CareLink is not Co-Pilot (the Abbott meter and pump software by which all others must be judged) but it’s not too shabby and used right can be hugely helpful in interpreting results. After all, paying attention in real time is only half the usefulness of CGM. The other half is all that information you can study and use to adjust your therapy; to understand cause and effect in ways impossible when just taking fingersticks, unless you took 288 per day.

I’m quite confident that if they gave all us D-folk CGM units and a half-day off (with pay) per week there would be no looming health care crisis from our tribe.

Well, my poor little fingers are cramping. I’m gonna take the weekend off. I’ll see you all on Monday.

Oh, yeah. And if you made it all the way through this post; you need to join me in the church basement next meeting. You’re an information addict too.