Starting To Pump (or How I Became Cognitively Challenged)I had been an insulin-dependent diabetic for eight years, with multiple daily injections (MDI) from the beginning. I had also benefited from improved insulin types, with Humalog replacing Regular and Lantus replacing NPH. But until I changed health care providers, I had never heard of the terms "Insulin to Carbohydrate Ratio" nor "Insulin Correction Factor." When I was first diagnosed, I had quizzed my health care team on whether it was possible to figure out exactly how much insulin is needed to cover different foods. The disappointing response I received was that my question couldn't be answered, because "every patient is different."Like many diabetics, I learned through trial and error how to "guess" how much insulin I needed, based on what I ate. As a result, I only felt confident about my bolus amounts for meals that I had eaten many times before and "discovered" the correct amount of covering insulin. If I ate a meal outside my usual repertoire, I would guess the amount of insulin needed. Much of the time, my highs and lows were unpredictable. Many years later I changed health care providers. The first suggestion my new doctor had was to consider switching from injections to an insulin pump. I was hesitant and a bit skeptical until I was taught about carb counting, insulin to carb ratios, and insulin correction factors. I had an "aha!" moment when I realized that I could better control my glucose levels by carefully measuring grams of carbohydrates in my meals, and factoring in how much each unit of insulin lowered my glucose level. I delayed starting on a pump, but added carb counting to my MDI program. Since it's not very practical to deliver partial units with a syringe, most of my bolus decisions came down to: "should I use 2 or 3 units for breakfast?" Or: "should I use 4 or 5 units for lunch/dinner?" I figured with my basal rate being covered nicely with Lantus (just a minimal dawn phenomenon) and Humalog boluses fairly easy to calculate, what further benefits would I get from an insulin pump? After logging my glucose reading more rigorously, I realized that the thorny issue that I couldn't handle easily with MDI/Humalog/Lantus was how to cover high fat meals. When I reviewed my more detailed logbook, I realized a pattern of extended high glucose readings after high fat meals. I started on an insulin pump to better control these situations (using the extended or square wave bolus feature). After starting on a pump, I realized that with the more precise bolus increments, calculating bolus amounts got a lot harder. Instead of: "should I use 4 or 5 units?", the questions became more like: "should I use 4.0, 4.1, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, or 5.0 units?" I also was taught more about how to adjust boluses based on my insulin correction factor, and unused boluses. That's when I started experiencing cognitive overload. When I started on an insulin pump, I was surprised by the number of factors involved in calculating a precise insulin bolus. I usually have no problems with math, but figuring ratios like 17 grams of carbohydrate per unit to cover a meal, 84 points per unit to correct for the last reading, while figuring out how much remains from a previous bolus at a 30% per hour absorption rate was a real pain! When I considered that I'd need to do these calculations once or twice for each meal, I was really put off. The cognitive load required to figure out a precise bolus was just too much. After thinking about the "cognitive overload" problem some more, I realized that what really bothered me was the division and multiplication steps, which I found too hard to do in my head. If I just had an easy way to figure out the partial bolus for each of the three factors (carbs, glucose reading, time since previous bolus) then I could simply add the three numbers together to come up with the total bolus amount. I felt I could handle adding three numbers in my head, as long as finding out the three numbers was easily accomplished. I created a set of three tables that removes the division and multiplication steps by pre calculating bolus levels. Using a spreadsheet, I customized the format of the tables until they were compact enough to fold up and use as a bookmark in my log book. I found the tables a great tool in helping set precise insulin boluses. In order to share these tables with other insulin pumpers, I created a web page that allows each table to be personalized. |
|