Fancy New Toys: Abbott FreeStyle Libre Flash Sensor

Last week I was the happy recipient of one of the new "flash" glucose sensors manufactured by Abbott. Having read some of the reviews for it (an especially good one can be found here), and after my prior experiences with the Medtronic Enlite sensor, I was looking forward to trying out something more low-profile and "dumb."

A bit of background before I get going:

As you have probably figured out by now, I live a pretty active life. Running, hiking, climbing, etc. are a big part of my life. In order to do this, I have developed very good control over the past 20-something years (my A1C's have been between 5.9 and 6.2 for quite a while). In other words, I'm not the target demographic for continuous glucose monitors (CGMs) or sensors, which are generally marketed to people with poor control or who are trying to become (or are currently) pregnant. My  motivation for a sensor is simple: I want to be able to track my blood sugars when I'm exercising in order to improve my performance and push my limits. It's difficult to do this using only finger sticks, since you don't get trends.

So shortly after Medtronic released their Enlite sensor in the US, I got my hands on one. Unfortunately, while it has some very nice features like the threshold suspend and continuous glucose feedback, it proved to be extremely pressure sensitive and the adhesive wasn't up to par for my regularly sweaty skin. The pressure sensitivity proved to be a deal breaker. The Enlite is approved for use on the abdomen, which means it is prone to pressure from pants, underpants, bending, waist belts, etc. This wouldn't be a big deal, except when exposed to external pressure the sensor loses its calibration and gives false readings. Then you get alarms, have to re-calibrate it, and, often in my case, the sensor only lasts a couple of days rather than the 7 it's supposed to.

In short, the Enlite CGM isn't designed with athletes in mind. Which is fine, but it means that I stopped using it because it was getting very, very annoying.

The Flash sensor is different from the available CGM's because it's, well, not a CGM. You get a hand-held reader that you scan the sensor with to get a "flash" reading. So basically, it's a substitute for finger sticks and doesn't constantly transmit data to an insulin pump or reader that can alert you to low or high blood sugar levels and cause alarm fatigue.

The sensor starter kit arrived in a surprisingly small box containing the reader and two sensors, approved for 14 days each.

The reader is smaller than an iPhone 4s and weighs nothing, which is always a good thing. It has one button and a touch screen. Pretty idiot proof.

Because I live in the Netherlands, I got the Dutch edition of the sensor. I attempted to change the language, but I get Dutch, Norwegian, and what appears to be some variety of Slovik (don't even ask, I don't know). Luckily the instruction manual had lots of pretty pretty pictures for those of us who can't read Dutch, and once again Abbott wins major points for an idiot-proof product.

The sensors come in boxes containing everything you need to insert it, up to and including an alcohol swab. Assembly is easy: the grey thing contains the external transmitter bit, and the single-serving coffee creamer thing has the needle and actual sensor. You unscrew the clear lid, peel back the plastic cover, and push the sensor into the adhesive.

Abbott claims insertion is painless. I'm kind of a wuss when it comes to big needles (and regularly have problems when inserting my insulin pump sets as they end up in muscle. Insulin delivery into muscle burns, by the way). Medtronic claims the Enlite insertion is mostly painless, but my personal experience disagrees with that. From what I've heard from Dexcom 4 users, there is some discomfort with insertion with that, too. So I was pleasantly surprised when the sensor inserted and I didn't feel a thing.

Chalk one up for Abbott.

The transmitter is bigger than I thought it was. The reviews pretty uniformly said it was about the size of a 2 euro piece. As you can see below, it's a bit bigger than advertised, but still the lowest profile I've seen on a sensor.

The other big difference between the Flash sensor and the other sensors currently available is that it doesn't require any user calibration. Theoretically, after the initial 60 minute period (where I assume it does it's thing as far as calibration, etc) it's good to go.

Because the Flash sensor is only available in Europe, the units are mmol/L, rather than the mg/dL I've been using for the past 20 years. The conversion is fairly easy (multiply the mmol/L by 18 to get to mg/dL), but I've obviously got some adjustment that needs to happen. While the sensor appears to be pretty close to my finger stick readings (generally within 15%), I'm not taking corrections off it yet, simply because I need to become more comfortable with the units and develop more confidence in the sensor before taking insulin. This is not a criticism of the sensor, since it seems to be quite consistent and indicates trends (always a plus), but rather my well-developed sense of paranoia. I suspect over the next week or so I'll develop more trust in it.

Besides accuracy, the most important feature of sensors (in my mind) is the adhesive. In the past, I've resorted to super-gluing them on in order to get more than 2 days worth of readings. Furthermore, I tend to develop a rash from the adhesives, sweat them off (lame), or (unfortunately regularly) rip them off on stuff. The Enlite was better than some of the sensors I've used for doctor visits (not the insta-feedback ones, but the ones you put on and then download a week later so your doctor can look at them) as far as resisting a bit of pull when caught on stuff, but the adhesive could not handle sweat. Once again, the Flash sensor has impressed. Probably because of its lower profile, it is less prone to catching on things and when it does, seems to stay attached. In fact, the resilience of the adhesive is more in line with my insulin pump infusion sets, which can take a lot of abuse. Over four days I put the adhesive to the test during several runs, the usual (aka huge) amount of biking, and climbing.

Unfortunately, the adhesive wasn't strong enough to resist a rope raking across it when I took a pretty impressive fall at the top of an overhanging route and slammed into the rope. The sensor flew off, barely missed Ev, bounced over a railing to the landing, bounced over that railing, and hit the ground right next to an unsuspecting belayer. Amazingly, I didn't realize I'd lost the sensor until I finished the route and was being lowered, an impressive feat given the unsurprising amount of damage traumatically removing needles can do.

This did, however, provide an opportunity to check out the size of the sensor itself. Once again, I'm impressed with how small it is (and how painlessly it goes in and comes out).

All in all, even after being traumatically removed after 4 days, the Flash sensor managed to be the longest I've ever had a sensor stay in and calibrated. I suspect it had at least 5 more days of solid adhesive before starting to peel up around the edges (based on my experience with infusion sets and various other things that are supposed to stay in for a long time and never do).

I should note that, like all CGM's and sensors, the Flash sensor has a lag between the reported reading and actual blood sugar. This means that it is a useful tool for indicating upwards or downwards trends, but shouldn't be relied upon when you're low. If you're dropping fast check your blood so you can correct. I know I'm beating a dead horse (this is glucose sensor 101), but because the Flash sensor is more of a meter replacement, it can be easy to treat it with the same level of trust as your actual meter. Additionally, I strongly suggest doing a finger stick or two a day to make sure it's holding its calibration.

As of right now, the only downside to the Flash sensor (as far as I'm concerned) is the price. Each sensor costs 60 euros and (theoretically) lasts for 14 days, assuming it holds its calibration. While advocacy groups in the EU are working to get it covered by insurance, right now it's a hefty investment. My hope is I can continue to afford them, but if I keep ripping them out I suspect I can't.

And thus concludes my (probably unexpected and a bit uninteresting for my regular readers) review of my shiny new toy. I'm pretty excited about the potential of this sensor for athletes and hopefully it will be approved by the FDA soon.

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UPDATE

Amazingly, the sensor stayed on for the entire 14 days. The adhesive around the edges started peeling up a bit around day 9, but never got to the point where I was worried it might fall out. I did, however, notice that the calibration appeared to become a little off around day 10 (I had a couple false lows and it sometimes seemed to think I was running around 180 mg/dL when I tested at 120 (for example)).

Week of firsts

It's been a week with a couple firsts in it.

For starters, I wore a hole in a (new-ish) pair of jeans from biking so much. Discovered that during class yesterday when I looked down and saw, well, not pants. Maybe I should give up on pants and get some jodhpurs like you ride horses in. A reinforced crotch/inner thigh is probably a good idea.

Secondly, I officially failed my first class ever. Luckily, exams are offered twice a year and you can retake them until you pass. The (hopefully) passing grades overwrite the failing one, so there's no official record on your transcript that you suck at test taking. I'm not super happy about this, especially since I thought I did ok on this exam. I went and talked to the professor, who sat down with me for half an hour and went through the exam with me, so I know what I did wrong. Actually, I feel a lot better having done that, since it was mostly stupid little things and a massive misinterpretation of a question that screwed me. Hopefully I pass the retake at the end of June.


There's a lot of homework, coding, and report writing this quarter. Plus this little gem that showed up in my inbox yesterday after a lecture riddled with math errors (that are present in the notes and study material provided by the prof):

So confidence inspiring.



Anyways, we're off to Paris in a couple hours to meet Colin and do stuff and things. The bucket list currently includes the catacombs, Louvre, Eiffel Tour (duh), and a run along the Seine. Plus whatever else we run across that looks like a good time.

You know what that means! The next blog update will have a little more content. Probably.

Quarter of the Holiday Weekends

Up until last weekend, we have had a grand total of 0 holiday weekends.

I'm starting to think the Netherlands is trying to compensate for that hell-ish-ness. 

So far we've had Kings Day (the weekend of the last blog post, 3 days), Liberation Day (this weekend, 4 days. This one celebrates the defeat of Germany during WWII, or so I've been told. Once again, I haven't bothered to follow up on it), and finally Ascension Day and Whit Monday (next weekend (aka birthday weekend), 5 days).

So in other words, I basically don't have classes on Mondays.

Which is cute, because if I'm not off traveling, I'm doing school. Actually, that's pretty much true regardless of the day of the week. This quarter involves a lot of time-intensive classes. And Matlab.

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Upon discovery of this new long weekend, Ev and I decided to get out of town and go somewhere new. For a change of pace, we opted to take a train to a cheap destination. So we ended up in Köln (aka Cologne), Germany. 

Köln is about 4 hours by train from Rotterdam and famous for a massive, ornate cathedral that dominates the center of town. My mind was blown by the details of the cathedral, and even more so by the elaborate lattice-work that makes up the towers. I've never seen anything like it. It's pretty incredible seeing sunlight streaming through the church towers.

The details of the stonework are mind blowing. Every surface of the cathedral has ornate, stunning carvings. It's hard to believe that this was constructed in the 1200's (well, I think it was finished in the 1700's, but that's because it kept being added to).

The stained glass is amazing. And, unsurprisingly, hard to get a good picture of.

After a very brief discussion, Ev and I decided that the Inca's have nothing on the stonework in Europe during the same time period. Although this is probably due to the availability of tools and a more developed, centralized economy (plus, you know, large sums of money or its equivalent). 

Saturday was spent walking along the Rhine. There is a lovely trail along the river that made us wish we had our running shoes. We meandered upstream for about 4 hours, marveling at the speed of the current and the sweet little stream barbs installed as erosion control measures.

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Engineering aside

Stream barbs are pretty cool.

Essentially, stream barbs are trapezoidal protrusions into a river channel at an upstream angle, usually constructed of big rock (rip rap) or some other hard material not prone to erosion. This introduces flow interruption and a hydraulic jump that causes eddies and sediment deposition on the leeward side of the barb. This results in slower flow along the section of bank and thus reduces erosion.

This is a major over-simplification, but works for the basic concept.

As I said, stream barbs are cool.

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And then we heard about the chocolate museum. And because we are basically children had have no self control, we went there.

In my defense, it was actually a museum (a much better call than the Nemo Science Center we went to in Amsterdam which was targeted at people 20 years younger), and had exhibits on the growing and exportation of cocoa beans, how they are processed, the steps for actually making chocolate, and packaging/marketing over the years. I have to give them props for placing a big emphasis on the conditions of the people who farm cocoa and the discussion and explanation of the various 'free trade' labels. My conclusion is, in short, buy free trade chocolate because it decreases the human-exploitation in chocolate production. 

They had a greenhouse simulating the ecosystem where cocoa trees grow. It was insanely hot and humid. Which is, I suppose, pretty accurate. 

And what chocolate museum would be complete without a chocolate fountain? That's right, NONE OF THEM! Just fyi, it was delicious. 

There was also some very cool exhibits about the evolution of the chocolate molds and how they are used.

Unsurprisingly, we walked out of the museum really wanting chocolate. Luckily, there is a chocolate cafe right next to the exit. It's almost like they know about people like me.

Again, and I really must emphasize this, I have the self control of a small child.

chocolate raspberry cake. It. Was. Awesome.

And then we went into the museum gift shop and proceeded to buy chocolate. 

As someone who really enjoys delicious chocolatey goodness, I've noticed a few things while living in Europe. Namely, each country seems to have a preferred type of chocolate. The easiest examples are the truffles. The chocolates we got in Lyon (France) were very rich, dark, and sometimes slightly creamy. Fruit flavors were infused or mixed in to the filling, which was primarily chocolate rather than a cream or fruit gel-y thing. The truffles from Köln were much more intensely fruity, with the predominant flavor often the fruit rather than the chocolate. Which was still pretty amazing. The German chocolate also seems to have a smoother texture, but I'll need to do more taste-tests to verify this. 

I like chocolate. Obviously.

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I should probably get back to work/school. This quarter's classes are all pretty interesting. In fact, they're the classes I've been looking forward to all year. Coupled Processes in the Subsurface (apparently the hardest class in the program), Soil Dynamics, Soil Structure Interaction, and Embankments and Geosynthetics.

Have I mentioned I have a grand total of no actual free time? The holiday weekend trips are probably not a good idea. 

Not like that's going to stop me.

Next weekend we go to Paris and I become another year older. Maybe we'll do something romantic. Or, more likely, slightly inappropriate. 

El Chorro Smells Like Rosemary

I've been putting off writing a blog post because it means I'm back in the real world.

I don't wanna be in the real world.

Mostly because El Chorro is beautiful and has mountains and smells like rosemary. This is because there are wild rosemary bushes all over the hills. It's kind of amazing.

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Last week Ev, Jesse and I went to Spain. We flew in to Malaga (about as south as you can get without being in Africa), then took the train to El Chorro. For those who aren't in the know, El Chorro is famous for two things: the Caminito del Ray, and the rock climbing. We went for the climbing.

And it was awesome.

Looking through the climbing guidebook before leaving Rotterdam, we (well, mostly Ev) picked out a multi-pitch that looked pretty good and is a top 50 route for El Chorro (always a sure sign of a good time). Upon some additional research, it came to our attention that this 4 pitch, easy grade (4+ to 5) climb was extended another, oh, 130m and is now a 10 pitch climb with a 6a+ crux at pitch 10, followed by an 11th "pitch" that is, and I quote a review of the route, a "superb scramble to the summit, really worth while." To each their own, I guess.

Escalada Arabia: Rogilio is kind of in the middle of the wall between the two small peaks

So we had an objective: climb a 250m route with the hardest pitches at the very top (5, 5+, and 6a+. Fun times.). We ended up with a half day of beautiful weather and, more surprisingly, time on Wednesday when we arrived, so we checked out a crag near the place we were staying, a mere 10 minute walk away. To be clear, that's the dream.

The crag we ended up on is pretty new (as in the last couple years) and not in the guidebooks. So we did what Ev and I end up doing a lot of the time anyway: eyeball the bolt lines and pick out something that looks fun and doable.

After a couple hours of climbing, we scoped out the big objective, were told it was an hour hike away, got some dinner and sacked out.

The plan was to get an alpine-ish start and hike out to Rogilio at 7am. We were up and ready to go, but the weather wasn't being decisive about what it was doing. It was a) dark, and b) lightly raining when we woke up, so we crawled back under the covers and checked the weather every 15 minutes or so in the hope that it would stop it.

Around 8:30 we decided to risk it and headed out. The rain gods were with us, and the skies started clearing as we approached the wall.

250m is kind of intimidating when you're standing at the bottom looking up.

We drew straws (well, blades of grass) to decide who got the first lead, then proceeded to have Jesse link the first three pitches since they were super short and easy. Ev lead the next two, then it was my turn. After my lead we started leading one pitch at a time, since they got more technical moving up the wall. To my chagrin, there were several hanging belays. Fyi, hanging belays are not a great time for prolonged periods of time.

there are a shocking number of pictures of me in this hanging belay (I was sitting there for almost an hour). This is, amazingly, the most flattering by far.

I got the second to last pitch (5c-ish), which was a fun little corner. And then came the crux.

Climbs are graded based on the hardest move on the route, so theoretically a climb can be 4a 99.9% of the route, but the 6a move means it gets a 6a grade. In the case of pitch 10, the crux move was the first move off the belay. Jesse worked it for a bit but couldn't pull it, so Ev took a shot.

He made it look easy.

I kind of hate him sometimes.

But the view of the valley from the belay was beautiful.

There was a bit of an adventure hauling the backpacks up the pitch before I climbed it, since we had decided it was too hard to climb the pitch with a pack on. Apparently the boys had a pretty elaborate setup at the top, but they weren't able to document it. Something about having Jesse on belay.

I was pretty excited to pull the crux my second try and top out. I was almost as excited to go pee after spending 6 hours on the wall.

As is often the case when you're at the top of something tall, the view was worth it.

The walk off was pretty fun, too. We saw an ibex! Actually, we saw 3 ibex. They might have been a family of some sort.

The next day we checked out another crag that happened to be full of Brits. I love listening to British climbing slang. The best was "it's a right proper jug fest central*, mate!" The American equivalent is "it's a jug haul!"

We climbed a couple routes, but it was getting hot and the crag was crowded, so we decided to hike out towards the Caminito del Rey to get a closer look. Plus, our feet were not thrilled about being stuffed back into climbing shoes the day after a big climb.

So we hiked, and it was beautiful.

The big bridge of the Caminito del Rey. Quite impressive. We actually looked into hiking it, since it reopened at the end of March after being closed for repairs for 5 years or so, but it's booked until July. JULY. That's a lot of planning ahead.

Objective of the hike: check out the big cave. We almost made it. There were bees. Lots of bees.

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Saturday we did another half day of climbing and took lots of pictures, since there weren't many taken during the multi-pitch. So, without more ado, have some climbing porn.

And now I present..... my favorite picture of the trip:

Ev does crazy eyes in a way that's, well, crazy.

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This Monday is King's Day (literally the monarch's birthday. Until recently, it was Queen's Day, and when they got a new King who's birthday is in winter it was decided to keep the date of the holiday the same since holidays with good weather are better. Or so I've been told. I didn't actually bother to do research on this), which means no school for me.

Of course, that's meaningless, since I already have lots of homework and not enough hours to do it.

Shocking, I know.

But we have a long weekend in Paris with Colin coming up, then my kid sister will be here for a few days, then Tae, and then we get to go back to Alaska for a month-ish.

YAY PEOPLE!

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* Jesse has corrected me. It was "jug central," not "jug fest." My bad.

Spring Time!

I think it's spring here. Flowers are blooming, stuff is green, and it keeps thinking about getting warm. Well, warm-ish.

Today I wrapped up my third round of finals. Only one more round to go before summer.

Tomorrow morning we head over Spain for some climbing in El Chorro before classes start again on Monday. I am excited.



To add some volume to this blog post (sorry, I'm not feeling the whole "remember what I've been doing besides study for exams" thing right now), here's another picture of Ev on stuff he probably shouldn't be. It really is a trend in his life.

Also, here's the only store you ever need if you're anniversary or birthday present shopping:

Maybe there will be a real update next week after returning for this most excellent vacation. Until then, happy spring. Or something.