Blockage Detected

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There’s at least one thing about using an insulin pump that, when it happens, makes me lament that I’m not still using pen needles. What is it?

The big bolus.

Allow me to explain, briefly, for any non–pump-users—those of you who may be unfamiliar with the day-to-day of insulin-pump use—how a bolus is delivered via my Deltec Cozmo insulin pump. The pump stores my grams-of-carbohydrate per unit-of-insulin ratio. Thus, when I sit down to a meal, I tell the pump, by dialing it up in one-unit increments, approximately how many grams of carbohydrate I’m about to consume. The pump then wants to know if I would like to issue a correction bolus, because it assumes I’ve just checked my blood glucose level. Then it will ask me if I want to proceed with the delivery of insulin.

If I accept the bolus, the pump proceeds to dole out, via thin surgical tubing into my abdomen (or thereabouts, over the course of one minute), however-many units I need to keep me close to good for the meal I’m about to eat.

Over the past three or four weeks, I’ve wanted my pen needles back at bolus time. See, my ratios have been trending a lot smaller. What used to be a ratio of 1 unit of insulin to 17 or 18 grams of carbohydrate is now 1 unit of insulin to about 9 grams of carb. This decrease has happened gradually over the past few months, but it seems that when I dipped into the single digits for grams-of-carb per unit, blockages became more and more frequent.

I’m not blaming the pump and its supplies just yet. These blockages had not been happening much at all prior to the spring, so I don’t want to jump to the conclusion that the infusion site and tubing are faulty (as in maybe I got a bad batch of infusion sets). Nah. But I hate it when it happens. When I’ve needed to bolus more than 6 or 7 units of insulin (the duration of which is one minute) lately, I’ve been cringing. And 6 or 7 units of insulin when my ratios are in the single digits is not a very large meal. So when I eat a larger meal (and by the way, I’m 6’4″ and weigh about 250), the carbs can add up quickly.

In the past, the larger boluses—depending on where the infusion site was—would burn somewhat. Sometimes it was a discomfort I was only mildly aware of, but at other times it felt as if I was being stung by a bee. Lately, though, the sting is gone—is this a desensitization at certain sites?—but something much more frustrating has taken its place. Twenty or 30 or 40 seconds into the bolus, the pumpbuzzing commences and the screen tells me there’s “No Delivery—Blockage Detected.”

What this means is that I have to postpone eating, get the pump back out of my pocket or belt holder, read the message that indeed there is a blockage detected, and then go through the motions. I detach the infusion set from the cannula, look for the tell-tale drop of insulin on the needle’s tip. If that looks good, I will flick the site that is stuck on my stomach, and maybe pat the site or massage the area around it to move any insulin that’s pooled up just below the skin. Often, not always, this fixes whatever’s causing the blockage.

What I really don’t want to do in those moments is change my site, or the reservoir, or the tubing. It’s always inconvenient because, remember, I’m just getting ready to eat. And, it’s not always possible. For example, this afternoon I was at lunch, by myself, sitting in a booth near the front of a pizza place and getting ready to have my two slices of New York Pizza Depot cheese. As I got ready to take that first bite (having already bolused and returned pump to pocket), I detected the far-off buzz of an insulin pump. My pump.


I got the pump back out, saw there was a blockage, and, as discreetly as possible, went through the motions to remedy the situation. I didn’t have any backup pump materials with me; I didn’t have any extras back at the office (having used them already over the past few weeks for other blockages). So, in the course of the minute or so that I was trying to fix the lunchtime insulin-delivery failure, I wondered what I’d do for the remainder of the day if the detach-and-flick, flick-and-pat-and-massage system I’ve come to rely on didn’t take. It did work, and the remaining 5 units of insulin went in just fine.

The situation, however, could have been entirely avoided if I’d only had to dial in the units on an insulin pen.

Pump veterans no doubt have their insulin-pump tricks. Several smaller boluses, right? I could also use the “extended bolus” feature, though for some reason I often overlook it. Or maybe I should just avoid those higher-carb meals and have a salad for lunch instead of two pieces of pizza.

Yeah, right.

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