Tuesday, November 15, 2011


When first diagnosed, I was given three hard, numeric references for insulin. Not fluffy relative terms but absolute. rules. I like those. There's no room for interpretation. They just are what they are.

The first was a carb ratio. I would take 1U for every carb exchange. And one carb exchange = 15 carbs. That ratio quickly proved to be a little off, but it was a hard number I could work with.

The second was correcting. I would take 1U for every 50 points above 100 I was. That number, too, was fairly quickly changed in the real world but there it was.

The third I still struggle with. It was an explanation of how long after correcting I should wait to eat. From memory, it was something like:

BGnow Dose Delay
100 0 + Meal Now
120 0 + Meal 5 minutes
150 1 + Meal 10 Minutes
200 2 + Meal 15 Minutes
250 3 + Meal 20 Minutes
And so on

The source of confusion, especially now, is my blood sugar doesn't change that fast. 20 Minutes after correcting with a blood sugar of 250 isn't going to put me anywhere near normal territory!

Logically, I can reckon that:

  1. The extra insulin from the meal will lead to a quicker fall than the correction dose by itself.
  2. A meal with fewer carbs will have less of a rebound than a meal with more, so you may be able to fudge and eat a little sooner that way.
  3. And last, you don't want to be #bgnow 100 with 12U active (and active without lag)

But Novalog, for me, tends to take 15-20 minutes before anything appreciable happens to my blood sugar. And with a hypothetical 250, an hour is unlikely to put me anywhere near 100.

So instead of dealing with a reasonable 10 minute pause, I tend to follow one of three (including lows) algorithms.

For a blood sugar < 140ish

I dose whatever fractional correction the pump spits out at me and eat.

For higher blood sugars

I rage bolus the high, check sugar every 20 minutes or so and once it's fallen by about half eat bolus the difference between active and what I'm meant to take for the food.

And for low blood sugars

I tend to take a 30 or 60 minute square wave depending how complex the carbs are and eat now - because remembering to bolus at some indeterminate point in the future is not one of my strengths.

Over the years, I've been able to adapt the first two rules from the initial diagnosis rather easily but just haven't ever figured out how to incorporate the delays/lags/etc defined in the third into my regiment. I may have a system but it too often leads to a low or high a couple hours in the future. I'd love to one day figure out a math function to give me an optimal time differential for correcting & eating.

Thursday, November 3, 2011

Approaching 24 hours with the Dexcom

The Dexcom was waiting outside the door when I got home last night, a day early. So I opened it up, reviewed the getting start process, plugged the receiver in to charge, and went about dinner and #DSMA. After #DSMA, it was time.

I'd worn a Dexcom for about 10 days a month earlier, in a trial through my CDE. (Note, sometimes I call her an Endo, sometimes a doctor, sometimes CDE. I don't really know. I don't really care. She does everything I need and is generally awesome.) I read the process of sensor insertion about half a dozen times and started. It must have taken 15 or 20 minutes to get it in OK. Getting the needle in went ok. Removing the insertion mechanism took some work. Getting that collar up as high as can be HURT. The entire sensor lifted up towards the middle and there was some blood clearly visible. But I did manage to remove the mechanism, and settle the sensor down closer to my skin. The pain was much more severe than when my doctor did it. I suspect that's just the learning curve, because she also did it much faster than I was able.

It was nearly time for bed once calibration was complete. But around 4AM, my wife woke me up because the Dexcom woke her up. (It had been going off for pushing an hour by then.) It was a 48. Confirmed and it really was low, so grabbed some sugar from the nightstand and went back to sleep. When I woke up for real three hours later, the screen looked like ____/----/`````. It said 140-something, but my meter said 104. But over the course of the morning, I had a stubborn but mild high that just didn't want to go away. In retrospect, I wonder if it really was closer to 140.

And now we're at lunch. I had a slice of pizza and salad. Started a square wave 10 minutes or so before eating, so had a slow descent and was in the high 90s while eating. But an hour later, I was still creaping up, past 150. Small correction and kept climbing. Repeat. Repeat. I managed the arrest it by 175 a half hour agp, so the Dexcom adverted a high. I'm flat or slowly descending at 166.

I can't know how I'll feel in 6 months, but for now, I love seeing this kind of information. Probably check the silly thing every 10 minutes. My immediate goal with the Dexcom is just to tighten the ranges. My A1c is pretty good (Labwork likes to warn me that with an A1c around 5.8, I'm at risk of developing Diabetes: HAH!) but it's only that good because I have far too many lows. If I can go from 60 being an every day occurrence to, say, once a week, and make the corresponding cuts on the high end, I ought to be able to hold an A1c in the high fives or low sixes, but hold that much more safely. It'll be the Dexcom's credit if that happens.