Severed lifeline

[Note to readers: this little miss-adventure happened, was written up, and scheduled before the BIG event I posted about on Monday. In keeping with my New Year’s Resolution to post every Wednesday, I’ve decided to go ahead and let it run, but just know it is out of sequence and happened before the killer low.]

I was freezing my ass off. Literally. And my hands. And my nose. And my toes. I could see my breath, cigarette smoke-like, hanging in the frigid air.

No, I wasn’t out on some Artic adventure, I was in my frickin’ office. The janitor had unplugged the heater. The outside temp was 1° Fahrenheit. The inside temp was 1° Fahrenheit. It was so cold my computers didn’t want to start. The faux leather of my chair stung my skin through my jeans. The frozen keyboard burned my fingertips. My aluminum clipboard was a knife.

It was time to abandon ship. Today, I’d have to find a spot to work in the main clinic. I grabbed my stethoscope and discovered that it was, like the carcass of a snake that had been run over on the highway the night before, stiff as a board.

So the day was off to a great start even before it all went to hell on me. The really crappy part of the day started when the rise rate alarm went off on my CGM.

Groan….

So I fished Mr. Pump out of my pocket to take a correction, and that’s when I discovered:

Massive life support failure. My tubing had snapped. My pump was pumping insulin into my pocket, rather than into my body. I’m sure an astronaut would have the same sort of emotion if he (or she) noticed his (or her) air hose drifting by his (or her) helmet.

We really need a gender-neutral pronoun in the English language.

But back to the story, because I haven’t even gotten to the interesting part yet. In lieu of the traditional syringe-style insulin reservoir, the t:slim has a bag-in-a-box, like cheap wine. Connected to this box is a short length of tubing, about an inch-and-a-half long. At the end of this run of tubing is a female Luer lock hub. It’s actually one of the more bizarre design elements of the t:slim. Every other pump has you hook your infusion set right to the reservoir on the pump.

Tandem and their assorted reps are a bit vague about this design oddity. I’ve heard that they did it to keep the pump slim, but I don’t think it’s so slim you couldn’t have come up with something else. The male side of the Luer lock is not something a porn star would be proud of. Frankly, it’s pretty thin and a bit short.

I’ve also heard that female dFolks with babies asked for this feature so they could more easily carry their papooses on their hips without worrying about delicate baby skin getting scratched by a pump-mounted hub. While I acknowledge that this might be a (rare) side benefit, I have a hard time believing this was really considered in the design phase. To me, it sounds more like the marketing department trying to make lemonade from lemons, after the fact.

Actually, before buying the pump, I worried a bit about this oddball tube-and-hub; but like many t:slim things, in practice, most pre-purchase worries evaporated for me. The oddball location of the hub hasn’t been an issue for me. At least in the winter. But I’m still worried about the summer.

For you to understand why I’m proactively seasonally concerned, I have to detour and talk about my wardrobe. And to do that, I have to talk about my environment, because that dictates my wardrobe. I live a mile above sea level in a dry desert. Summer temps at my house are often in excess of 100 degrees. In the shade. But in the winter it’s freezing. Literally. Like in damn-fucking-cold freezing. So in the winter I favor heavy jeans. Wrangler brand, if you must know. But in the summer Wranglers are too frickin’ hot. In fact, at home, where keeping inside temps below 85 in the summer is a challenge, I generally wear shorts. But at work, shorts are verboten. And as I have a lot of crap to carry, being diabetic and all, I’ve taken to wearing cargo pants in the warm months. They are thin, and they have a lot of pockets to carry said crap. So it’s win-win.

My point here is, so far, I’ve only worn the pump with jeans. We are still months from the cargo pants season. And as I’ve already got a CGM on my belt, and a pouch for my meter, I really don’t feel like adding one more thing to my waist. Although the various t:slim cases and clips look highly serviceable, I’ve yet to test-drive any of them. I’ve just been carrying Mr. Pump in my front pocket, on the right-hand side, and all is well. Oh, and my pocket is deep enough so the stupid hub is hidden from view, inside my pocket.

But cargo pants have a whole different pocket design. The front pockets tend to be deeper, and the tops of the pockets are farther from the waistline. I suspect the pocket-carry won’t work well for me with cargos—the pump will be too hard to fish out—so I’ll need to go the belt route. Of course, with cargos, I have a bunch of pockets on the legs for the meter and such, so there is more real estate on the waist at that point. But come summer, my hub will show, and I’m not sure how I feel about that.

Now, why did that sound vaguely pornographic?

Anyways, now that I’ve bored you to tears with fashion and climate, let me tell you what really sucked about this broken tube. Now, I gotta say, despite being hung up on countless door knobs over the years, I’ve never actually broken a hose. I had one spring a leak in my sleep once, nearly killing me via DKA, but I think a cat was to blame for that.

But look again at the photo. The tube has pulled out of the pump side of the hub. The infusion set itself, and its tubing, is intact. The severed line is between the reservoir cartridge and the female Luer lock hub.

In other words: no quick fix. Actually, no fix at all. The reservoir (brand new and filled to the brim with 300 units of 0.14¢ per unit NovoLog, of course) was shot to hell. There was no way to salvage it. I had to do a reservoir change… and you remember how long that takes, right? Plus, for whatever reason, once my umbilical cord was cut, the infusion line filled with air bubbles, so I had to do the whole kit-and-kaboodle. Luckily, even though I only lasted two days as a Boy Scout (a story for another day), as a proper D-Scout I’m always prepared and had everything I needed for a site change.

Well, everything but time.



Next time: Fat Finger Fuck-ups, a.k.a. F to the Third Power; and why you shouldn’t re-program your basal rate when you are hypo.

Adverse pump event, or the ultimate in bad fucking luck?

Extra! Extra! Breaking news! Man survives killer low in the night! Read all about it!

You know that built-in fixed alarm on the Dexcom G4? The one the manual talks about? The one that you can’t turn off? The one that goes off at 55 mg/dL? I got to hear it last night.

Many times.

It goes Bzzt! Bzzt! Bzzt! Rapid. Staccato. Three times in a row. Bam-Bam-Bam. Un-comfortingly like machine gun fire.

I know this because last night, well… technically this morning, I had my worst hypo ever. Not the lowest; but the longest. I spent an increasingly terrifying total of 1 hour and 25 minutes in the hypo range—below 75—and a whopping 40 minutes sub-50. And nothing I did, nothing, would reverse the trend. It was like being glued to the train tracks with industrial-strength epoxy while watching the express barreling towards you.

My Dex4 fast-acting glucose was like water. My glucose tablets were no more than celery sticks. And shortly before the ice broke, my addled brain entertained a horrifying thought: Maybe my new pump is malfunctioning. Maybe, even though I suspended it almost an hour and a half ago—maybe—even though every indication on its control panel is that it’s dormant—maybe—it’s still throwing fuel on the fire. Maybe it’s pumping away like mad, feeding the never-ending low.

Here’s how it all went down:

12:13 a.m.—A low threshold alarm on my Dex G4, set at the factory default of 80mg/dL, goes off. I groan, swear, and mutter under my breath. After cancelling the alarm, I feel for Mr. Pump’s infusion set tubing in the dark, and finding it, reel the pump in. It’s hiding somewhere in the covers. I wake up the pump and enter a Temp Rate of Zero for 15 minutes, and drink about half the bottle of Lemon Lime Liquid Blast glucose fluid from the just-for-in-case bottle that lives on my night stand.

I use Temp Rates to suspend the pump when I’m low, so I won’t have to worry about un-suspending later, or being pestered by the “Hey, did you know I’m turned off???” alarms that Mr. Pump gives me if I use the Suspend feature instead.

This is my default approach to nocturnal lows. I’m not overly concerned. There was no drop-rate alarm, so this is a slow-moving emergency. Dinner was hours ago and I didn’t need to take a correction at bedtime. There’s nothing but basal on board. Perhaps I’ll need to tweak it in a day or two. Or not, I was a bit more physically active yesterday, I could be paying the price for it now.

12:26 a.m.—Two minutes before my temp rate expires, and 13 minutes after drinking the glucose, my blood sugar has dropped to 67. Not good. I cancel the Temp Rate and enter a longer one: an hour and a half. I drink the rest of the glucose liquid.

12:43 a.m.—The fixed alarm goes off. I’m now at a sensor glucose of 55 mg/dL. Things are very quickly spiraling out of control. Dropping that much? That quickly? After drinking glucose fluid? Could the CGM be freaking out? A fingerstick confirms the damn sensor is right on the money. Dexcom weren’t lying when they said the new G4 sensors have stellar performance in the low range. I start munching glucose tabs.

12:48 a.m.—Sensor glucose dips into the 40s. This is crazy. I haven’t seen a real 40 since… since… since I don’t know when. My CGMs have never let me get this low.

01:03 a.m.—Sensor glucose bottoms out at 44 mg/dL.

01:08 a.m.—Sensor glucose is still at 44 mg/dL. A fingerstick confirms this is the real deal. Seeing the face of my Dexcom receiver glowing blood-red in the dark of the night is un-nerving. A long row of bright red dots march across the screen. Bzzt! Bzzt! Bzzt! My G4 receiver looks like the bullet-riddled body of a Mob hit.

01:13 a.m.—Sensor glucose is still at 44 mg/dL.

01:18 a.m.—Sensor glucose rises to 49 mg/dL. Relief sets in.

01:23 a.m.—Sensor glucose drops again to 48 mg/dL. Panic sets in.

But then, as the “maybes” about the pump fill my brain, and just as I was fixing to rip the infusion set from my body and toss the fucking pump out the window, the ice broke. My blood sugar rose from 48 to 56. Then five minutes later from 56 to 67. Then to 80. Then to 91.

It was over. I set a final Temp Rate for another hour and a half and succumbed to restless sleep, full of fitful dreams dominated by machine gun fire, equipment failure, crashing planes, runaway trains, glowing pools of deep red blood, and big-busted Angels of Death in black lacy lingerie (always male to the last).

This morning I woke unsure who to call: Tandem? The FDA? Bernard? (Seriously, he’s the closest thing we have to the Ghost Busters when it comes to D-Tech.)

But, in the pale morning light of a new day, like a NTSB crash investigator, the fact that the airliner went down is incidental to me. I just want to know why the fucker crashed. Because this was no ordinary crash. It acted like a serious insulin overdose. I needed to know if I had just suffered a genuine adverse pump event.

After all, t:Slim is still new to the market. What if it had some sort of glitch? What if some other type 1 out there had the same thing happen? What if that person didn’t have CGM? A low that long, that deep, that persistent—even with a boatload of sugar thrown at it… What would have happened to a sleeping beauty with no alerts, no chance to throw glucose tablets into the gaping maw of the low? I have no doubt whatsoever that the answer would have been: Seizure. Coma. Angel of Death. No lacy lingerie included: Just paramedics and tears by dawn’s early light. Dead in Bed.

For this crash investigation, we have the plane’s three black boxes. Black box number one is the Dexcom, G4. The hero of today’s story. Sadly, the device itself has no alarm history. More sadly, the Dexcom studio software, for all its lights bells, and whistles, doesn’t have an alarm history either. But with the software, a pen, some paper, a calculator, and with one hell of a lot of work, we can learn quite a bit.

Black box number two, the possible villain in our story, is the Tandem t:slim. Sadly, again, black box number two has no software (yet) so we can only look at the delivery logs on the device itself.

Black box number three, is my meter, which can only serve to confirm that black box number one was reporting the flight data correctly, which is was. By the way, you do know that real “black boxes” are orange, right?

Oh, plus for our investigation, we have the testimony of the sole survivor (thankfully). But this is our least reliable source of information, as my brain is probably damaged by the hour-and-25-minute-long low. Plus my brain wasn’t that great in the first place. Plus my brain has no written logs nor software that allows me to download it. A mixed blessing, surely.

In the bright light of day in my library, on my computer screen, the low didn’t look so bad as it did last night when the receiver bathed me in red light. The low coasted onto the scene. A slow steady drop from my after dinner peak of 158 mg/dL at 8:03 p.m. It doesn’t look dangerous. But, damn, once it got low, it stayed low for a loooooooooooong time despite all waking efforts to reverse it.

The pump didn’t shed much light on the crash, other than confirm, at least according to the history logs, that I didn’t do something stupid like bolus rather than suspend in the middle of the night. But it did give me the first clues as to what might have caused the crash of Flight 44, at least by ruling out some possibilities. Dinner was at 6:50 p.m. That means, as I thought in the night, the insulin from dinner was long gone by the time the shit first hit the fan at 12:13 in the morning. The dinner bolus would have run its course by 9:50 p.m., fully two hours and twenty-three minutes before the plane hit the first mountain peak on its flaming decent. And it wasn’t even an overly large bolus in the first place. 1.59 units to cover a 22 gram meal with a correction for a pre-meal BGL of 160 mg/dL. And it was a “perfect” bolus, 4 hours after the meal, the blood sugar was 120, only 10 points above target. The meal was covered, the blood sugar was “fixed.” Damn I’m good.

Or maybe not.

Because the Dex download shows a different story playing out. Starting out about 10:30 p.m. the sensor glucose starts to drift steadily downwards. Too much basal insulin is indicated. But if that’s true, I should have been having lows many nights in a row. I haven’t touched the basal rates in a week or more.

So I looked back, and sure enough, the same steady downward drop shows up on many a night over the last week. Crap! My blood sugars have just been such a mess this week they never got low enough to make an impact. I missed it. Shit!

I had seen some gentle downwards trend on the CGM traces overnight in the wee hours, so I’d been fucking with my post-witching hour basal rates. After midnight it drops to 0.8 units per hour. At three AM, even lower. But I totally missed the possibility that the problem might be coming from earlier in the evening where I’ve been running a stronger 1.0 units per hour. The trees of basal were lost in the forest of dinner and correction boli.

And this is also an example of how our tools screw us. The midnight-to-midnight software for the Dex G4 gives you a poor snap-shot of how we really live our lives. A much more useful graph would be to display my CGM traces on 6 a.m. to 6 a.m. overlay to look for trends. Let me see my 24-hour life the way I live it. Let me see my night for what it is: one night. Not two nights, the back-half on the left side of the screen; the front-half on the right side of the screen.

But still, I’m not 100% satisfied that the low was triggered by too much basal in the hours leading up to midnight. First, I’ve been running that level of basal at that time of day since I started the pump right after Christmas. If I’m running a lot more than I need, I should have had trouble before now. And I’m still befuddled by the sheer tenacity of last night’s low. I think my basal rates are pretty low for my size. The first shot of glucose should have sucked up the extra insulin lickity-split.

And no, Uncle Wil wasn’t drinking too much, either. I actually drank much less last night than I usually do (further proof that no good deed goes unpunished). I had one glass of wine, rather than my normal two, with dinner, as we had just run out. The economy and all. Plus, I’m having a hard time shedding that five pounds from the holidays, and the extra calories in the carb-free wine probably aren’t helping.

I was a little more active than usual, but not by much. Some minor household repair stuff. Not exactly a major work out.

And consider this: according to the pump log I had no insulin between 12:13 a.m. and 2:30 a.m. That’s two hours and 17 minutes with no life support. Plus I consumed a ton of glucose. Considering all of that, I should have had a hell of a rebound excursion. Where do you suppose I woke up when the alarm went off at 5:30? At only 170 mg/dL. I expected it to be much higher. Sure, it’s not exactly on target, but not the 250-300 I probably deserved, or have seen in the past.

So just to be sure Mr. Pump was telling the truth I suspended him via a Temp Rate for half an hour this morning, leaving the tip of the infusion set on top of my iPod Touch’s screen. Nary a drip nor drop nor smear of insulin was seen. It didn’t even fog the mirror-like glass surface. No insulin escaped from Mr. Pump while the Temp Rate ran.

So what was the cause of the crash? Engine failure, or pilot error? I don’t know. But I decided that I had to call Tandem. It might have just been my basal having an unexpectedly powerful effect on my body. Or maybe I got defective glucose. But… well, if something did happen with the pump, the next person it happened to might not be so lucky. I picked up the phone.

I spent about 45 minutes or an hour with their tech people, who frankly had a hard time getting their heads around the problem. I was lectured about leaving my cartridge on beyond the FDA indicated three day wear-time. Guilty as charged. But if that had bit me in the butt, I should have gone high, not low. Same with infusion set issues, although the tech support lady did ask if I put the site on a very different part of my body. I didn’t, but that was good thinking. Some areas absorb better than others.

I thought I was on to something for a minute when I realized that the “fuel gauge” on the pump showed about forty units less insulin than I thought it should given the amount pumped, plus the amount in the tubing, since the last change—but it turned out to be an illusion. An artifact of how the pump detects and reports insulin.

At long last the Tandem lady decreed she couldn’t seem to find anything wrong with the pump over the phone, told me they have no way to get any more info out of it than I can read on the pump itself, and said, “All I can suggest is you continue to monitor it.”

Ya think?

Oh, and if I have any “further incidents,” we “may” consider replacing the pump.

Huh.

I didn’t know how to respond to that. So I didn’t. The silence grew uncomfortable until she finally asked me if I was OK with that. I can’t recall if she said it flat out, or beat around the bush, but I got the impression they’d replace Mr. Pump if I made a big enough stink. But really, even I confess this is a mystery. This isn’t like the Med-T pumps, regurgitating error messages all over the place. The pump gives every sign of working correctly. I can’t really see a reason they should replace it.

It’s a blood sugar mystery more than a pump mystery. Granted, a blood sugar mystery that acts all the world like an insulin overdose, but there’s no evidence beyond one crazy stubborn low that it was.

“Are you comfortable wearing it?” she asked.

Are you diabetic? Was my reply. No. Her family is chock-full of dFolk, even including her cat. But not her. Well, there’s still time to join us, I gently teased her. I could practically hear her crossing herself. It’s hard to explain how scary this is, I told her, I’ve never had a low this bad, this stubborn before.

But in reality, I survived with no seizure. No coma. And the big-busted Angels of Death in black lacy lingerie didn’t drop in for a visit, or even a brief cup of tea. I told her that I really just called to make sure they were aware of the possible problem. Just in case. Just in case I wasn’t the only one. If this had been a pump problem, I told her, and it had happened to someone without CGM, it could have been fatal. This was serious.

“I know,” she told me. “If you had called us where you were last night, we would have called 911.”

Again, I didn’t know how to respond to that. My sugar was so low it never occurred to me to ask for help last night. After another pause she said, “Well, if it happens again, we’ll replace the pump.”

If this happens again, you couldn’t pay me enough to wear your damn pump anymore, I thought to myself. But I thanked her for her time and her kindness.

I guess I’ll never know why the hypo was so wicked, so deep, and so stubborn. I guess it was just one of those things. Still. It’s a scary reminder of what a difficult game we are players in. Diabetes is a dangerous businesses.

So now what? I reduced the evening basal rate. I took a correction for my morning high and Mr. Pump fixed it just fine. Right now, all systems seem to be go. Right now, I’m at 105 mg/dL, level and stable.

Right now, I’ve still got Mr. Pump in my pocket, steering the ship on calm seas. But of course, my wife hasn’t read this post yet, either.

Profiles: A new approach to programming a pump

Most insulin pumps are like a Monopoly game board: You program your insulin-to-carb ratio over there on Kentucky Avenue; your correction factor across town on St. Charles Place; your target blood sugar up on Marvin Gardens; and your basal rates down on the Boardwalk.

And just like Monopoly, if you screw up your programing, you land in jail.

The t:slim tears up the old board and institutes some excellent new city planning, placing all these key metrics of insulin delivery in the same place, called Personal Profiles.

What does this mean for you, should you adopt the sexy new t:slim as your next pump? It means easier, faster programing, and a new level of control not previously available with an insulin pump. Read on.

A profile works kinda like a traditional basal rate, but it’s a basal rate on steroids. You can create up to six different profiles, and each one can have up to 16 time segments—what I call steps or legs. But in addition to just telling the pump how much to adjust your background dip of insulin either up or down, at each step you can also change your other three key metrics of insulin delivery: the correction factor (called insulin sensitivity by some folks); the insulin-to-carb ratio; and the target blood sugar.

The bottom line is that instead of wandering all over the fucking game board to program your pump’s most basic settings, you can program and adjust all of them from one place.

Genius.

How’s it work in the real world? It’s tap-and-go. Suppose you wanted to add a new basal step. All ya’ gotta do is go into the profile, tap “Start Time” add the time you want it to start. A new leg is created, and it automatically copies all four values from the previous leg. This lets you adjust just the basal, if that’s all you wanted the change. The other three values stay the same.

If you need to change your IC ratio for dinner you can just duck into the profile and change that one factor at that one time and everything else stays the same. If you don’t have a time leg that works right you can add a new one in seconds, modify the one metric that’s pestering you, and leave all the others alone.

Hey, suppose you wanted to create a whole separate profile for the weekend. You can copy an entire profile with a few finger strokes and then modify it. There’s no need to enter all the data manually like some other pumps make you do.

Editing anything in an existing profile is a breeze. Tap on what you want to change and the familiar phone-pad style keyboard pops up so you can enter the new value. Of course, the Big Brother personality of Mr. Pump comes through here as well. Be sure tap DONE, then SAVE, then CONFIRM—all on separate screens—or all is lost. Literally.

Like all t:slim operations, this sounds more time consuming on paper than it really is.
The t:slim is to normal pumps what the first Apple Mac was to MS DOS computers. (Any of you old enough to remember that horrible “operating” system?) The bottom line is that the user interface of the t:slim pump makes sense. It’s intuitive. If you just use common sense and do what comes naturally, doing anything on this pump is fast and easy.

What about that new control I teased you with in the lead? On the pumps we have today we can have multiple basal rates, and we can change our IC ratios and the like by time of day; but as far as I know, none of the other pumps us have different IC ratios on different days. With the t:slim profile system you could have a different IC ratio or correction factor at the same time of day, in different profiles.

Why one earth would you want to do that?

Well, instead of talking about living for the weekend, we need to talk about living on the weekend. Most of us are either more active or less active on weekends than we are during the week. Some of us spend our weekends vegging-out in front of the TV, others climb mountains. So it’s common for pumpers to have a different basal pattern for weekends than for week days. And any pump will let us do that.

But there’s really more to it than that, isn’t there? Your activity level makes a difference to your insulin uptake. If you’re seeking the ultimate control, just changing your basal for the weekend isn’t enough. You also need to adjust your insulin sensitivity and your carb ratios. I guess you could do that on a traditional pump, but you’d have to go to Kentucky Avenue and then over to St. Charles Place every Friday night, manually change the numbers via massive scrolling; and then remember to change them back every Monday morning.

Yeah. Right.

However, with the t:slim, a weekend profile could have alternate correction factors and carb ratios built in, as well as changes in the underlying basal rate.

Genius.

Oh. Right. But I need to tell you where the genius stepped on his own dick. This near-perfect system is ruined by the fact it can’t be automated. It wouldn’t have taken a bunch of rocket scientists to have added a simple line of code to tell the pump what days of the week a given profile should be active. I hate the fact that profiles have to be manually turned on and off. I work three jobs and my activity level is very different at each job. I wish Tandem had designed the profiles so they could change automatically by day of the week.

Sure. I could do it manually. But I won’t because I’m tired. I’d likely forget to either turn one on or turn one off. Instead, I’m designing a happy-medium profile. One that balances my varying needs to best (safe) advantage. It’s too bad, though. I could have had much better control with the simplest of features, damn it.

Still, for those of you who have your shit together better than I, you can now have a whole new level of control at your fingertips—just a screen tap or two away.


Next week: No pump is accident-proof

The longest yard

OK. Technically, it isn’t a yard. It’s 43 inches. So it’s a yard-and-a-fifth. That sounds more like something you’d order at an Irish drive-thru package liquor store than something that deals with diabetes, doesn’t it?

But what I’m talking about this morning is the length of my infusion pump tubing. I prefer sets with long tubes and short 90-degree cannulas. When it comes to cannula length, if you’re lean like me, or athletic and muscular (not like me), then you should use a short cannula—or an angled set. It you are normal, fluffy, or King Size, then you should use the longer cannulas. But when it comes to tubing length, the choice has more to do with lifestyle and wardrobe than anything else.

On the plus side, long tubes let you be more creative about where you place your set and where you carry your pump. But on the negative side, all that extra tubing seems to have a magnetic attraction to passing door knobs and the like. To be blunt and crude, frankly, I like the longer tubing simply so I can leave the pump on my belt or in my pocket when I go to the bathroom. I’m tall enough that I need the long tubing to reach from my stomach to my ankles.

But t:slim might cause long tube lovers to re-think their desires. Oh dear… that sounded rather pornographic, didn’t it? Allow me to restate: the t:slim might cause fans of the 43-inch long infusion set tubing to re-evaluate their choice.

Why?

Because it’s the longest yard. The t:slim, despite its racy look, is no thoroughbred when it comes to site changes. Here, I’ll take you through the process, and it starts with a luggage tag.

Well, that’s what it looks like anyway. Actually it’s a Goldilocks-perfect tab that goes in a slot at the bottom of the t:slim cartridge. Remember that unlike every other pump ever, the t:slim has done away with the syringe. Even though other pump companies call the insulin-holding/dispensing disposable part of the pump a “reservoir,” it’s really just a syringe. T:slim has broken the mold, however. They have a jet-black rectangular cartridge that slides onto the pump and locks in the way a battery attaches to a laptop.

What’s in the cartridge, you ask?

I’m glad you asked, because the very first thing Rio and I did after the first site change was some Spanish Inquisition-style mad science on the discarded cartridge. I had read that inside the cartridge was a bag-like reservoir for the insulin, and we wanted to see it. The bag is a real reservoir, not a semantic mind game like other pump makers play. The t:slim bag holds a supply of insulin, 300 units worth, and then the machine uses a tiny micro-pump to out pull a unit or so at a time as needed. This is touted as being a great safety feature for two reasons; it’s supposed to assure bubble-free delivery; and it’s a literal, physical barrier between you and a fatal overdose of insulin.

I don’t know if it’s ever happened, but in theory, a traditional pump could freak out and deliver its entire contents to you all at once. I never lost any sleep over this fact when I wore other pumps, and I’m not sleeping any better now that I’m wearing a “safer” pump. After all, in theory, the t:slim could freak out, too, and deliver its entire contents. I’d be just as dead—it would just take a bit longer.

Anyway, getting the cartridge apart to see the bag inside turned out to be quite a bit more difficult than I expected. We were able to snap the part off, but getting into the main body took a hammer, two knives, a lot of swearing, and finally two pairs of pliers.

Yeah, we had to crack it open like a walnut.

For some reason, I expected the bag to be black, but it’s clear, and looks disconcertingly like a used condom.

But once again, I’ve gotten off track. To do a site change, you just follow the leader. The pump tells you what to do at every stage. You use the luggage tag to pop off the old cartridge, which you can then dissect later. Next, you slide and snap a new EMPTY cartridge onto the pump.

Here’s where t:slim, once again, diverges from the pack. You attach an empty to the pump. It then sucks all the air out of the bag, at which point you fill it up in situ, as they say in archeology. Which leads me to another “surprise” the t:slim had in store for me.

Most pump companies have their own proprietary systems for filling the reservoir, the best designed probably being Med-T’s elegant docking collar that holds the insulin vial on one end and the “reservoir” on the other end. But when I opened up my first pretty black and white box of Tandem reservoirs I found a bunch of garden-variety BD 26 gauge, 3/8 inch needles, and a pile of 3 ml syringes. All of them individually and separately packaged, of course.

Well, I guess there’s no point in re-inventing the wheel, especially when the wheel needs to be FDA approved, but somehow this came as a surprise to me. It struck me as somehow counterfeit, like a sleek sports car that turns out to be a fiberglass kit on a VW chassis. It’s also more packaging to throw away, and more crap to carry around in my Go-Bag.

Anyway, to fill the empty cartridge that’s waiting for you on the pump, you must first unwrap the syringe. Then unwrap the needle. Attach the needle to the syringe. Draw the plunger down to fill it with air. Inject the air into a vial of insulin. Then draw the desired amount of insulin into the syringe. The max is a whopping 300 units, almost a third of a vial.

I gotta tell you, when you draw down 300 units of insulin in a fat two inch-long syringe, it’s an intimidating amount of fluid.

At this point it’s worth mentioning another nice feature of the t:slim. If the screen times out on you, when you wake up the pump up again, it remembers where you were: It doesn’t return you to the home screen.

If there’s a minimum fill volume, I couldn’t find it in the manual that doesn’t exist in the real world—the t:slim manual exists only as array of ones-and-zeros in the digital universe.

Now, at the top of the cartridge, next to the short length of tubing that extends out of it, is a small white dot. That’s the fill port. You just stick the needle into it, and inject the contents of the BD syringe into the port. That fills the baggie inside the cartridge.

Next, you attach your infusion set tubing to the t:slim’s cartridge hub. This part is a bit bizarre. Rather than attaching the tubing to a hub on the pump itself, like everyone else does, the t:slim’s luer lock connection is downstream about two inches. I can’t say for the life of me why this is. Maybe it had something to do with keeping the pump thin, but it makes the line oddly bulbous in a bizarre location, and makes the consumer-gadget-looking pump look like a medical device again. That said, carrying Mr. Pump in my pocket, the hub is hidden. But if I start using one of the belt cases, it will become more obvious.

All of that up to this point is pretty straightforward, but next comes the loooooooooooooooong part. The t:slim is painfully slow to fill the infusion set tubing. And I mean that literally. Why, this entire post was written while I waited for the pump to fill my tubing.

The t:slim primes at a rate of 7 units per minute. A 43-inch tube holds somewhere in the neighborhood of 30 units of insulin, so the prime time (pardon the pun) is six fucking minutes.

Of course, it feels like six fucking hours.

It’s by far the slowest --filling pump I’ve ever encountered. The reason it takes so long is because of the design we discussed earlier. The pump literally has to pump a unit of insulin or so at a time out of the reservoir bag and into the “micro-delivery” chamber, and from there send it on up the line.

It’s tedious. But it’s not like you have to do it every day, either. So how often do you have to do it? Humalog is approved for use in the pump for 48 hours and Novolog for 72; but you know what? You can carry a pen of either at room temp for a month. I have a hard time believing that you couldn’t leave either insulin in the cartridge for as long as it takes to use it up.

As I was getting the blues waiting for the first drops of insulin to come out the business end of my infusion set, I found myself wishing insulin were blue, not clear. My old eyes aren’t good enough to see the clear insulin marching slowly up the transparent tubing. If insulin had color, it would be easier to see it in our tubing. Easier to see bubbles, too.

Anyway, after your latte and manicure, and checking your stocks online, your tubing is finally full and you can attach the set to your bod. It’s a standard luer lock, so you can use anybody’s infusion sets. I started off with the Animas/Unomedical Inset—which has a crafty disposable inserter device that also stores the tubing, all in a portable plastic hockey puck. The set has a smooth, low-profile arrowhead-shaped hub with a fast and easy disconnect.

I haven’t field tested it yet, but I’m pretty sure that if you disconnected for an intimate encounter, you’d be highly unlikely to scratch your partner with it. I must put that on my “to do” list.

Once the set is in place, you need to fill the cannula, and the t:slim can be programed to remember how much your sets need. You also have the option to activate a site change reminder at 1, 2, or 3 days. Not four. Not seven. Why? Probably because we are supposed to change the site every two-to-three days.

But my thinking on this has been shifting recently. After all, we wear Dexcom CGM sensors for a full week (or more). What’s the difference between a CGM site and an infusion site? Both have sticky tape on our skin, probably made by the same company, as there are only a few makers of this kind of tape in the world. Both have something that pierces the skin—either a sensor or a cannula.

At any rate, if you are insulin-sensitive enough that 300 units will last you more than three days, and if your skin is tough enough to hack longer wear, the site change reminder is useless to you.

And that’s all there is to the site change. With a final blue splash, you’re pumping insulin again.


Next week: Profiling isn’t just for the FBI

Pumping with the pump

This will make it sound worse than it is, but taking insulin for a meal with the t:slim requires a minimum of 19 button presses. Don’t freak out on me. Let me walk you through it.

First, it takes four stabs to wake up the pump: You press the only Honest to God button on the pump, and then do the 1-2-3 bull’s-eye target thing to get to the main menu. Then you gotta press the bolus button. Next, you press the carb button, at which point you’re faced with a phone-style number pad—which I love. No more endless scrolling to get to the right number of carbs! You just dial it in. It’s like placing a phone call to your pancreas.

This is a prime example of how touch-technology for an insulin pump really shines. Entering anything with a number—carbs or blood sugar—is faster and more accurate with this pump than on any other pump ever made.

Even better, the phone-style number pad for carbs is really more like a pocket calculator. It lets you add up a meal on the fly. Exhibit B: behold a pair of tacos with classic sides. OK, 13 carbs for the pair of corn tortillas, 2 carbs for the meat and veggies, 12 carbs for the beans, and 15 more for the rice, plus 4 for the sugar-free margarita. Done. The pump does the 13+2+12+15+4 for me, and gets 46 carbs. A running total is displayed at the top as I go along. That’s right, no more writing on napkins!

After dialing in the carbs, one more press of a “done” button takes you back to the screen where you enter both carbs and blood sugar. “Add BG” takes you to another phone-style pad for fixing less-than-perfect blood sugar numbers (this pad doesn’t have a calculator function, as you’d never need to add multiple blood sugars for taking a correction).

Now this was the part I thought I’d hate the most. The Tandem-supplied Verio IQ meter, a fine and highly accurate device we’ll talk about some other day, doesn’t “talk” directly to the pump. So I knew in advance that I’d have to enter the BG manually. Three finger strokes are needed to enter most blood sugar readings, plus a fourth to confirm the entry. But you know what? With the super-fast key pad-style entry of the touch screen, this is not an issue at all. Both Med-T and Animas pumps have meters that directly “talk” to them, but navigating the multiple firewalls of “are you sures” probably takes just as long as just typing the damn blood sugar into the t:slim. Remember, no more archaic scrolling. If you think about it, the word “scroll” comes to us from the days of papyrus and hieroglyphs.

Anyway, the point of entering your blood sugar is so that you can correct it, if it’s not exactly where it belongs, at the same time you’re getting some insulin to cover your chow. Once you enter a BG number, you’ll get an annoyingly helpful popup that telling you your blood sugar is not at target—no shit Sherlock—and would you like a correction? Yes, Mr. Pump. If I didn’t want a correction, why would I be wasting my time and embarrassing myself by telling you my blood sugar?

Oh, and just for fun, I tried to enter a blood sugar of 1,001, but the pump wouldn’t let me get away with that. Nor does it recognize 10 mg/dL. But I did succeed in entering a 20 mg/dL, at which point the pump helpfully advised me to go the fuck out and eat some carbs. And it said it in red text, just to be sure I knew it meant businesses.

But if you were, say, at 65 mg/dL, the pump would reduce the insulin it’s giving you for a meal to compensate. This is called a reverse correction. But one thing I don’t like about the t:slim is that reverse corrections only works below 70 mg/dL. I have no idea why. If I’m at 90 and my target BG is 110, why shouldn’t the pump shave a little off my meal bolus so that I coast in at 110, in a perfect world, four hours later, rather than at 90 again?

Anyway, unless your BG happens to be exactly perfect before a meal (yeah, right) you should take the extra few seconds to enter a blood sugar if you’re above target, so you get little bit more insulin. If you’re below target, don’t waste your time unless you’re below 70.

Now, with the pump safely awakened, your carbs added and entered, your blood sugar on the menu—you’re ready to deliver some insulin, right? Whoa. Not so fast, cowboy.

Most of those button presses are quick, I don’t mind them, and I don’t see any realistic way they could be reduced. But what I do find annoying and tedious, however, are the four “are you sure,” “are you sure you’re sure,” “are you really sure you’re sure,” and “are you absolutely positively really sure you’re sure” screens that stand between the last of my data and the first of my insulin.

This is one of the few things I don’t like about the Tandem t:slim, a plethora of alert, warning, and “are you sure” screens. All pumps have them, and I haven’t added up all the various ones on the market to compare, but the t:slim strikes me as overly safety-conscious. I wish there were a way experienced users could shut some of them off. Anyway, like all pumpers everywhere, I’ve learned to just quickly skip over these without looking at them. Which, now that I think about it, is the whole problem with this sort of Big Brother approach. If you build in too much safety, we dFolks will just ignore it. I think if I had only one final screen, rather than four, I would probably take the time to look at it. But the overabundant safety features encourage me to blindly press the buttons to just get on with it.

When you are finally done with your 19 or more button pushes, you’re rewarded with the splash logo:

Which I think is very cool and beautiful. I just wish it were animated like the testing-blood sugar video on the iBG Star, where a chemical lightning bolt dives through the blood stream dodging red blood cells. If you haven’t seen this graphic masterpiece yet, I’m sure someone has put it on YouTube by now. It’s so cool I used to look forward to testing my blood sugar so I could watch it. It never got old.

The t:slim Splash! is a frozen image, but it’s still a fun way to be told that insulin from your pump is on its way to your body. Thank you kindly, Mr. Pump.

And even with all the button pushing and warning screens, the t:slim is a hell of a lot faster than filling a syringe and taking a shot; and a lot more accurate than dialing up a dose of insulin in a pen.

I’d forgotten how much pumping rocks, and the Tandem t:slim makes it easy. And fun. It’s going to be a great year.


Next week: Inside insulin delivery. Literally.

t:slim—out of the box and on to the bod

Dare I say it? Using this insulin pump is FUN! Now, some folks will probably regard that statement as heresy, or maybe even a sin. But my diabetes isn’t going anywhere soon, so I don’t think there’s anything wrong with having a good time with it.

And really, if you think about it, diabetes is more of a hobby than a disease. It’s time-consuming, expensive, and frustrating. Everything a good hobby is. Oh, and just like a hobby, when everything works out right, it’s very satisfying to stand back and admire your handiwork.

Exhibit A:

So why not have a good time pumping insulin?

Now, I know that what you’re really interested in are all the nitty-gritty details of the t:slim pump, so I’ll get right to it. I’m sure you’re dying to know if it’s as sexy in person as it looks online. Yes, yes it is. Is the touch screen as responsive as an Apple device? Yep, you bet your boots it is. Does it really fit in the front pocket of your blue jeans like Tandem shows on their website? Damn straight.

But first things first. And I think the first thing most people worried about when it came to a touch-screen insulin pump was an accidental bolus. It’s one thing to butt-dial the LAPD, or some poor citizen in Pakistan; it’s a whole ’nother thing altogether to butt-bolus 120 units of insulin.

Not to worry. Tandem’s got a built-in safety feature that makes Ft. Knox look lightly guarded by comparison. But more than that—the safety feature is actually one of the more endearing features of the pump.

Here’s how it works: To turn on the pump, you must first press the one and only “real” button on the machine. It’s an elongated chrome oval on the top of the pump. This wakes up the touch screen and lets you check the pump’s status without having to do anything else. From here you can see your battery level, date and time, the amount of insulin in your pump—right now I’ve got 110 units still in the cartridge—and your IOB status.

What the fuck is IOB? It’s your Insulin On Board. On board, in this case, means on your body. Well, in your body. It’s the total amount of insulin in play in your bloodstream that can still lower your blood sugar.

I love, L-O-V-E, love this feature. I think IOB is the single most useful pump feature there is, and I can’t believe how long it has taken the rest of the pump market to catch up to where the Deltec CoZmo was back in 2002.

And, unlike some… ahem… other pumps, t:slim tracks all insulin. Every drop. Med-T pumps for years would only count correction insulin when considering the effects of insulin in the blood. Med-T’s assumption was that if you took insulin for food, the food and the insulin cancelled each other out. True. But only in a perfect world. A world in which our insulin-to-carb ratios are exactly correct 24-7, and our carb counting skills are exemplary at every meal, snack, and drink.

That’s not the world I live in. You?

Also, I was spoiled, as my first pump was a CoZmo. I got used to considering IOB when making treatment decisions. Example: It’s bedtime. I’m running sweet, 269 mg/dL, should I correct? If there’s not much IOB, absolutely, I should. But if I just came back from a banana cream pie eating contest (hey, it could happen) and I have 14.8 units in my system with a three-hour run, taking a correction would end badly. A traditional Med-T style pump wouldn’t count all that pie insulin and let me take a correction that would probably kill me.

Of course, the t:slim pump would know I had too much IOB, and would discourage me from taking a bolus, but having the data out where I can see it and think about it is still huge to me. The t:slim gives me both the number of units in play and the amount of time left in its action curve. (Note: the New OmniPod is supposed to have IOB and Med-T has made some changes in this area, too. Apparently the pendulum is swinging my way again.)

Ohmygosh. Sorry. I got waaaaaaaaaaaaay off track there. Back to the anti-butt-bolus feature. So I press the chrome button, and I’m at that home screen I was telling you about. The battery status is at the top left, the date and time top center, the insulin volume is over to the right. The IOB stuff is at the bottom. Across the middle is an archery range: three bull’s-eye targets in a row. The one on the left is glowing bright green and has a “1” in the center.

Faint grey, you can see targets two and three. To activate any of the pump’s features you must first unlock the pump by tapping on these three targets rapidly in sequential order. When you tap “1” it goes grey and the second target lights up:

When you tap “2” number three lights up. When you tap “3” you’re in!

One-Two-Three. Simple. Fast. Fun. I actually love this part, and have yet to tire of it. Each time I unlock the pump, I feel like I’m unlocking the country’s missile defense system. I get a weird testosterone rush out of it.

But for safety, if you touch the screen anywhere outside the lighted target area, the pump shuts off again. Even Jennifer Lopez’s butt couldn’t accidently butt-dial a bolus with this system.


Next week: Pumping with the pump, covering carbs, correcting blood sugar, and other fun with insulin.

The Mayans were wrong

So as the world did not end after all, LifeAfterDx enters its ninth year. Same time, same channel as they used to say on TV. Oh. Wait. I never post at the same time. Never mind. Well, I’ll try to stick with the Wednesday’s with Wil as my New Year’s resolution.

© 2013