The answer to the question on everyone’s lips: did he or didn’t he?

So on day twelve of my seven day monotherapy trial the Dexcom sensor started acting a little whacky. Not that I’m complaining, it had exceeded its useful life by seventy one percent. Not too shabby.

Failure came in the form of a progressive number of false low alarms as the sensor spooled down. I put in a fresh Med-T sensor and wore both systems together for another thirty hours or so. During the rocky start up phase of the Medtronic sensor, the ailing Dex actually did a better job for a time, then it petered out completely and I was back to just my old girl.

Looking ahead more than a week ago, I had wondered how quickly I’d fall back into my accustomed comfort zone. Would I be glad to be rid of the Dex; or would I miss it? Would I switch or not?

As you might imagine, this was no easy call to make. Let’s review. The Dex is a better sensor. Period. Unless you are a Tylenol addict (acetaminophen apparently can effect sensor accuracy). It is much closer, most of the time, to my Presto fingersticks. It also gets to the scene of the crash, literally, faster than the Guardian. And Dex is quicker to report on excursions. Don’t get me wrong, the Med-T sensor is very good. The Dex is just better. At least in my body.

This point was driven home to me very vividly when I was “back” on the Guardian. You shouldn’t, but you could dose insulin based on Dex readings. That wouldn’t really be safe with the Guardian. I had gotten used to fingersticks and Dex readings being neck n’ neck. When I went back on the Guardian it was a bit of a slap in the face every time I compared fingersticks to the read-out on the monitor. Before Dex I was just happy to have a reading in the same general ball park, and the good trend data. Am I going up or down? Is my blood sugar changing slowly, quickly, or terrifyingly fast?

But now, having lived with something better, going from Dex back to Guardian is proving to be sort of like trading-in a car with cruise control and power windows for a car that has neither. Yeah, you can live with it, but…

But I should point out that my current car, SweetRide, has neither cruise control or power windows. It is also missing the turbo charger, 5-CD changer, moon roof, power mirrors and remote locks that my previous Mean Green Machine had. So it is possible to adjust and be happy.

But back to CGMs, it is crucial to remember that the sensor doesn’t exist in a vacuum. It is only one part of an overall system.

In my book (figuratively), here is how the two systems stack up to each other. First, I prefer the Med-T transmitter. I’ve been wearing the same re-chargeable one since it was introduced, I think about two years, maybe a little more. The Dex is one of those sealed we’ll-guarantee-it-for-a-year-then-you-are-screwed models. I think a replacement runs a couple hundred bucks give or take.

And speaking of re-charging, the Guardian monitor takes AAA batteries. Easy to get and cheap. Small to carry spares. The Dex recharges “like a phone” according to my Dex rep. You know what? My damn phone is always running out of juice when I need it most. He points out that rechargeable devices are more environmentally friendly. Like I care. Most of us T-1s have our own personal landfills for all the trash we generate anyway.

I was particularly irked that the Dex monitor’s charge wouldn’t even last the seven days of the seven day sensor. All of that said, in practice, it really hasn’t been all that bad. The battery life indicator gives you plenty of advanced warning. I kicked around giving the monitor a daily ten minute charge when I’m in the shower, but was unsure how that would affect the life of the rechargeable battery. In the end, I waited until it was low, then plugged it in at bedtime and threw the tethered monitor into bed with me overnight. Seemed to work fine.

So speaking of the monitor, the Dex is big and ugly. But it does have a big screen, which turns out to be not so ugly. In fact, I got quite fond of it. It is very easy to read. One thing I didn’t like was I couldn’t “scroll” back through the display to check out past readings, which you can do with the Med-T device. The range of features and options are much wider with the Med-T device. For instance, you can find out the strength of the signal coming off of the sensor. You can see when your next calibration is due. You can set your rise and fall rate alarms to whatever you want instead of choosing between two factory defaults. Guardian also lets you have different threshold alarms for different times of the day.

And of course, one of the glaring deficiencies of the Dex is that, unlike both Guardian and Navigator, the Dexcom does NOT have predicative alarms. WTF??

But on the very much plus side is the Dex’s aggressive nature of alerting you to alarms, long my biggest beef with the Guardian. Dex has a teeth-rattling vibration and a slap-you-across-the-face audio alarm that can actually wake you up.

Also in the mix is the superior range of the Dex. And by range I mean the distance between your body with the sensor inserted, and the monitor. With Guardian, you’d better not let the monitor get separated from your body. In fact, you literally need to wear it on the same side of your body that the sensor is in. Yeah, it is technically wireless, but in reality you just have an invisible infusion set hose connecting you to your sensor.

Dex seems much more robust in this sense, but not enough to communicate from your night stand through a pile of winter blankets and comforters. Just as well, the hyperactive vibration would probably cause it to migrate right off of the night stand and on the to the floor, likely hitting a cat on the head at the end of its fall.

Now it is only fair to point out that if the Guardian sensor and monitor get separated, the sensor will store data until it communicates with the mother ship again. This is a great feature unless you happen to experience a low blood sugar during the separation period.

Another big difference between the systems is sensor size. This is one area of human endeavor where bigger is definitely not better. The Dex sensor, the wire that ruptures your epidermis and stays parked in your interstitial fluid for the better part of a week or more, is a fraction of the size of the Guardian. Well, that may be an exaggeration, but it is very much significantly smaller.

On top of that, the method of insertion is quite a bit different. The Med-T Guardian has such a bad insertion device that on more than one occasion people who work for Med-T have apologized to me for it. It is so bad I’ve kicked it to the curb and just stick them in by hand, a process that is frequently painful. I had written the pain off as one of the many costs of staying alive with diabetes, and just dealt with it.

Before inserting a Med-T sensor, I’ll often mentally chant the refrain about fear from Frank Herbert’s epic sci-fi novel Dune:

I must not fear. Fear is the mind-killer. Fear is the little-death that brings total obliteration. I will face my fear. I will permit it to pass over me and through me. And when it has gone past I will turn the inner eye to see its path. Where the fear has gone there will be nothing. Only I will remain.

Yeah, it sometimes hurt. Once I bleed so much I stained Debbie’s Berber carpet. But I viewed it as the cost of healthy diabetes. I once told one of my Guardian-enabled T-1 patients, who is more a wuss than I am if you can believe that, to just buck up and be man.

That said, I’m no glutton for pain and Dex sensors don’t hurt on insertion. With the inserter you could even get creative about breaking new ground on your body, sensor location wise. If you are traveling, the Med-T sensors are quite a bit more portable. The Dex sensor, with its elegantly designed one-shot inserter is on the large size.

And speaking of traveling, originally, Med-T sensors needed to be kept cold. They were even shipped Red Label UPS in styrofoam sarcophagus with ice packs to survive the trip from Northridge where they were made, to wherever their D-folk users were located.

One of my early road trips, ending in a hotel room with no mini-fridge, was a nightmare of bucks of ice. Nowadays, neither sensor needs to be kept cold.

As to software, one of the best out there is the doctor office version of CareLink (not the consumer one you can use online). Oddly, however, it is not compatible with the Guardian, which is Med-Ts flagship stand-alone CGM device. Double oddly is the fact the Guardian pre-dates CareLink Pro by quite a bit. Guardian users are relegated to downloading their data to the limited functionality web-based CareLink where all they get is a hand full of PDFs.

The Dex software has come a long way from after-thought to top-of-the-line. I’m irritated that the display is a series of data points reflecting monitor readings rather than solid “trace lines.” While this is at least consistent with the style used in the monitor, I find it highly distracting when studying a large number of days at one time. The graphic resembles a collision between two trucks carrying decorated Christmas trees.

That said, the Dex software has some pretty sophisticated filtering options. Let’s assume you’ve been wearing it for three months. Want to just look at three months of Sundays? You can do that. Want to just look at hyperglycemia? You can do that. What to just look at… well, you get the idea.

The Med-T device, being built into the housing of a Med-T pump, has the full range of pump clips, cases, and holsters. Too bad Med-T didn’t use all that empty space inside the case where the insulin would go if it were a pump to install a louder alarm. The Dexcom has a case that is truly pathetic. Navigator has both a very clever belt holster and a i-Phone style silicone skin to choose from. I for one, would love to see this kind of skin for the Dex, as I had given up on the belt case and was just carrying it in my pocket anyway.

The Dex case is soooooo bad that third-party vendor Nutshell in New Zealand, of all places, has stepped in to sell cases for the device. (But they are expensive, “square,” and have no window for buttons or the screen. Probably just a PDA case some d-folk who works there realized was big enough for the monitor to squeeze into.) BTW, Gina a.k.a. Mommy of Three over at tudiabetes reports that the Verizon “Pouch with Swivel Clip and Wristlet” for the LG Chocolate line of phones also works great and runs less than three bucks per case.

While the Dex transmitter is about half the size of Med-Ts, the skin landscape required is more due to the size of the sensor frame and sticky-pad. The Med-T realistically has to be covered by an IV3000 bandage or the transmitter will “flap” and get pulled out. I, out of habit, covered the Dex an IV3000. Well, two IV3000s, as one was not big enough and I had to overlap them. Based on the sensor tape’s resistance to being removed, even after 13 days, it probably wasn’t necessary.

In several nutshells. Those are the differences. I had a choice to make. Was it clear? No.

So… let’s see… should I make you all suffer by waiting until next time to tell you what I decided?

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Nah. That would be cruel. I did it.

I switched.

The tipping points for me were the combination of the sensor accuracy and the louder alarm. For me those two things out-weighed all else. For me, sensor accuracy and noisy alarms are the essence of Continuous Glucose Monitoring. In the end the choice was simple because there simply was no choice. No array of features can outweigh accuracy and noise together. Had the Guardian been louder I would have stuck with her. The rest of the feature set were strong enough, that had her alarms been loud, she would have even outweighed the Dex’s superior accuracy.

After a minor squabble with my insurance company, this morning got a call from Edgepark, my DME supplier. I’m approved for Dexcom. Would I like FedEx to ship my new CGM and three month’s worth of sensors to my home or work address?

If there weren’t a blizzard outside right now I’d be sitting on my porch, smoking a pipe, and watching for a white truck.

Dexcom Monotherapy Report

As I turned off the Guardian I felt a mix of fear, longing, and separation anxiety—tinged with stomach butterfly excitement and a little bit of guilt.

This machine, and her predecessor, have kept me alive since 2005. Oooooo, I like that. Alive since 2005, what nice rhythm and rhyme. I should get a T-shirt made.

And now I’m contemplating kicking her to the curb? On one hand it just doesn’t seem right. On the other hand, what kind of idiot doesn’t use the very best equipment possible when it comes to keeping alive?

Would you like our top of the line parachute, or this discontinued closeout model we have on final clearance sale?

But on day one I left the Med-T sensor in my body and carried the sleeping Guardian monitor in my Go-Bag to work. Training wheels to fall back on during the first few hours, just for in case, as my in-laws like to say. I inserted a brand-new Dex sensor and started my Monotherapy Week.

The Dex inserter, while looking like the dental tool from hell, is actually very elegantly designed, and sticking a Dex sensor into your body is easy with only the slightest of stings. Med-T sensors are ginormous by comparison. If you are putting a kid on a CGM, this alone might be reason enough to choose the Dex over the Med-T.

Sensor in, I drop the Dex monitor into my cargo pants pocket and head off to work. FYI, don’t do this with the Med-T Guardian, you’ll lose telemetry. The Dexcom has a much more robust communication range between the sensor/transmitter and the receiver/monitor; and damn lucky thing too, given that the Dex belt case is sooooooooo poorly designed.

During our morning medical team meeting two hours later, my pants begin to vibrate vigorously. The nurse next to me raises one eyebrow and gives me a funny look. You always have this effect on me, I whisper to her, which nets me a well-deserved punch in the shoulder.

I enter one fingerstick. And then the second one. I love this concept of dual sticks for initial calibration as most meters on the market are pieces of crap, accuracy wise, and most D-Folk are being robbed of the ability to choose their meter brand by their insurance companies. The Dexcom spooled up and so for the rest of the day things went fine.

But that was about to change.

Oh, and before I forget to tell you, the Dex does talk after all. It’s amazing what you can learn if you read the manual (who would have thought?). When you choose the “Vibe then Beep” mode for alarms in the setup menu, the device vibrates and squawks in your hand. So I naturally assumed it would do the same thing in a real-world emergency. Not so. As it turns out, Dex is a polite little girl with a bad temper. First she tugs on your sleeve for attention. If you ignore her, she stands up on her tippy-toes and shouts in your ear. You see, Dex alarms have two phases.

What happens during a real alarm is this: first the monitor vibrates. Vigorously, as mentioned before. Comparing the vibe of the Med-T to the vibe of the Dex would be like comparing a Prius to a Hummer. Not only can you feel the Dex vibe to your bones, you can actually hear it.

Which is why, on my first week+ using the Dex, I thought my borrowed monitor was broken or mute, I caught every alarm in the first phase. If you do not respond to the vibe, in five minutes all hell breaks loose. And she has a gloriously loud voice. Once I got around to reading the manual and learned that this is how she works, I ignored a vibe and was rewarded by hearing her high-decibel voice. More on that later.

I’m mildly annoyed by this approach. If you miss the vibe, and you are low, it is another five minutes before you are alerted. A lot can happen in five minutes. But on the other hand, if you are in a medical team meeting, maybe it is better that only the nurse next to you knows you’ve been into the Christmas cookies on the carb table; rather than the whole room.

My original Guardian was not only loud, but had a great personality. Low and high alarms were very different from each other and my coworkers learned to speak her language, knew whether to tease me or come running with sugar.

Sigh… I actually miss that machine.

When I got home at the end of the first day, I placed the sleeping Guardian monitor in my medicine cabinet and pulled off the Med-T sensor. No life boats. Time to sink or swim with Dex.

Not fifteen minutes later we hit the ice berg.

Instead of the constant flow of quality blood sugar data I had been getting all day I was suddenly confronted with “???” on the face of my Dex monitor. The manual helpfully tells me that this means “the sensor is sending glucose readings that the receiver does not understand.” Oh, that’s just fucking great.

It is now too late at night to put in a new Med-T sensor to replace the one I just yanked out. I feed the Dex a few fingersticks hoping to wake her up, but with no luck.

I throw the stupid monitor into bed with me, and figure my odds of dying in one night of no-CGM coverage are on the low side. Pissed-off, I pull the covers up to my chin and vow to put a new Med-T sensor in first thing in the morning…

A fog horn wakes me at three in the morning. What the f….???

I fumble among the covers to find the source of the racket. A glowing blue light catches my eye. LOW says the Dex. I groan. Yeah. Right. Suuuuuuuuuuure I am. I’m thinking that this piece of junk that crapped out on me earlier has only come back to life with a false low reading. I turn on my bed-side light, and squinting, reach for my Presto.

Click. Snap. Slurp. 69 mg/dl.

Well, I’ll be…

So not only was I actually low, and not only did I sleep through a vigorous vibe, but the Dex’s fog horn actually woke me up. I wonder, would the Med-T’s delicate vibe and pipsqueak back-up voice have woken me up on this particular night?

Since her nocturnal re-wakening, following a full six hours of no data, the sensor has performed flawlessly. It ran the remainder of the full seven days with frightening accuracy. And then I lied to the monitor and told it that it had a new sensor, and two hours later it booted up just fine. We are now two days into a second week. There has been no drop in accuracy. Being poor, I routinely use a Med-T three-day sensor twice for a total of six days, but I find the accuracy is falling off towards the end, especially on the high and low ends. That the Dex sensor can run strong for more than ten days just blows my mind.

Normally, I would not want something in my body more than a week, but I only have this one Dex sensor, and I want to extend the trail as long as possible. I don’t for even a second recommend going beyond seven days to anyone unless it is an emergency. Do what I say, not what I do. See? I’ve always maintained that I’m a better tour guide than a role model.

The body doesn’t like stuff that doesn’t belong there inside of it. It also isn’t so great for your skin to have something stuck on it, suffocating it, for that great a period of time. Leaving a piece of tape of any sort on your skin for too long is a great way to develop an allergy to it, and if that happens you won’t be able to wear a sensor anywhere on your skin for any length of time. OK, end of lecture. Don’t say you weren’t warned.

But on to the week’s highlights. On Thanksgiving, as all of you saw, too much pumpkin pie taxes the ability of the machine. Like the Med-T, the makers of the Dex assume you have no business being in DKA territory, and both devices simply do not work above 400 mg/dl and will only tell you that you are high. I’m actually fine with that. If you are routinely above 400, you don’t really need a CGM. You need a referral to the dialysis center in your area.

Again, like on my first Dex sensor, I was impressed by how responsive the Dex is to changes in my blood sugar. I got used to carrying it in my right cargo pocket (the sensor is implanted on my right stomach). When alarms shook my pants it was fast and easy to fish out the monitor. Also, if I just wanted to know what was happening, it really wasn’t that big of a deal to reach in and grab the monitor. Carrying it in the right-side pocket forced me to use it right handed, and I found it a simple one-handed operation to check in on my diabetes.

I find the Dex’s size big, and the shape ugly, but it is oddly ergonomic and I never had any fears of dropping the device; especially important as this one does not belong to me.

The Dex works just fine 850 feet underground, although the same can’t be said for my diabetic body. What was I doing 850 feet underground? Oh, the day after Thanksgiving we all piled into SweetRide and drove down to Carlsbad to do the Pecos River Light thing and visited the famous caverns. It’s a lot of walking, and of course I had a hypo. Dex alerted me as I crossed my low threshold and tracked my several doses of glucose as I tried to crawl my way back out of it.

Once again, I tried to trip up the system by giving it calibration sticks under circumstances that would give a Med-T sensor a nervous breakdown, and once again the Dex stayed steady and true to my BGL. I’ve been preaching for years that learning to calibrate under the right circumstances is just part of having a CGM, just like more fingersticks is part of wearing a pump (no basal insulin!). But that said, I found it… liberating… to just calibrate whenever I wanted to, rather than only in still water.

I did find it annoying that there was no way to check when the next calibration is due. I also had no way of checking the signal strength coming off of the sensor, what is called ISIG in the Med-T universe. Nor could I scroll back to check specific readings at specific times. You can only look at the crude graphs for a rough idea of your recent history.

I think a good comparison is to look back at where computers were about 15 years ago. At that time the Microsoft operating system was very paternal. It wouldn’t let you in to the depths of the machine. It protected the user. Macs, at that time anyway, gave you wider access to explore, and if you were careless, to do damage.

Dex is a very much more simple platform. You aren’t allowed to do or know much, but you can’t really cause any harm either. I would think that the learning curve would be much shorter for new users.

After some fooling around, I settled on a low threshold of 90 mg/dl with a 30 minute “snooze.” I don’t like having a snooze that long. If you are still “low” after 15 minutes, you better be stuffing more carbs into your face. But 30 minutes is the shortest snooze period after a low that the Dex offers as an option. I choose 90 mg/dl as it was the highest low-setting I could personally use without being pestered constantly with nuisance alarms.

Sadly, I’m rarely below 90, so if I do clock a 90, I’m probably on my way to trouble. With a system that includes a predictive alarm I usually select either 75 or 80 for the low threshold.

On the high end, I was more troubled. On my Med-T Guardian, with its basal-rate style alarm thresholds that allow me to choose my alarms at different levels every hour, I used a 170 during the day and a much higher number at night so my sleep was not disturbed unless the shit had really hit the fan.

In the end, I set the Dex for 220, and that has worked pretty well as a day and night compromise. I could, in theory, re-set it every morning, but the truth is that I’ll either forget to or won’t be bothered too, so it is better to just choose a number and stick with it.

On the high end, I choose a three-hour snooze for highs. This means if I have a high, the system won’t alarm again for another three hours if I stay high. One of the things about the Navigator that drove me crazy was that it was alarming all the time for highs. The fact is, if you are high, it is going to take a while to fix.

During my one week with only the Dex as a crutch, I got very comfortable with it. If I were wearing an OmniPod I could have my diabetes literally in my pockets with nothing on my belt for the world to see. Huh. That almost sounds weird, I’m so used to having a storm-trooper’s worth of gear on my belt.

I was really worried about the lack of predictive alarms, one of the greatest weakness of the Dex system. I still think they should add a predictive alarm on the next gen monitor, but it was less of a big deal in reality than I had made it to be in my head. The sensor is so responsive to change, it almost doesn’t need the predictive alarms. On drops it reminds me of the one-minute-sampling Navigator system.

And the Dex trumps the Med-T when it comes to my biggest bitch about the otherwise fine Med-T system: the complete lack of volume in the alarms. Simply put, you can’t hear the alarms on the Guardian. This is no small problem as any alarm is a potential life-threatening situation.

So I started my monotherapy week feeling apprehensive, insecure, and a little guilty. How did it end?

I am alive and well. And that includes surviving a carb-filled holiday, a traveling mini-vacation with all the diabetes damage that comes with a change of pace, and several life-threatening hypos that I, of course, did not feel.

The system was accurate, easy to use, and friendly. Other than the rocky start up, which also happens in Med-T sensors fairly often, the sensor performed like a champ. I’ve come to like the big, bright, easy to read screen. I’ve gotten used to having to press the frickin’ button to see my blood sugar. And the re-charging is less of a hassle than I thought it would be.

In short, the week went well. Very well. You, or I, could absolutely live a long and happy life with the Dexcom as our diabetes buddy and watch dog.

But will I switch?

Hmmm…..