CGMs and driving

I put it to you that you are arguing one side of a tradeoff without acknowledging the other side. A flatliner can coast through the 2-hour CGM startup time with no trouble. A surfer will drift out of range except in the fortuitous circumstance of a (temporarily) stable BG. The tradeoff is in the location and size of the burden of managing the BG.

Here’s my view. For the flatliner, it is important to understand everything in great detail, with a scientific analysis that supports highly-accurate dosing decisions to minimize excursions. The benefits of this approach include smaller excursions and longer periods of coasting without intervention. But this approach requires a mind that is willing and capable to do the analysis. Some minds will simply refuse to do it.

On the other side, the surfing approach requires much less analysis and prediction. Look at a plate of food and take a SWAG bolus [scientific wild-ass guess], then glance at the CGM early and often. As soon as the CGM graph shows a change in the second derivative, make an adjustment. For instance, if the curl of an uptrend starts to tighten, stack on more insulin. Continue stacking insulin and carb corrections of diminishing amplitude to dampen the tendency to oscillation. This approach requires checking the CGM frequently and making numerous small adjustments, which is a different kind of burden from the predictive analytical approach.

I believe both approaches can deliver good results in terms of health outcomes. I believe both approaches have the property that more effort can give improved results in terms of time in range and A1C. And I believe that some minds are more comfortable with the predictive flatlining approach, whereas others find the reactive surfing approach to be much easier.

Anyway, I hope that much of this burden will go away in the next few years, as our pumps become able to surf automatically on our behalf, and simply require us to give instructions like “eating soon, large meal,” or “starting long moderate-intensity workout soon.”

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As long as they are stuck in the rabbit hole of thinking interstitial BG values are useful for making decisions, there will never be a pump or algorithm than can do for me what I can do for myself. It isn’t difficult and doesn’t take any great calculations or formulas, it is just personal experience. The automated pump stuff will always be tailored down to the general population, with things like the 120 BG target the Medtronic 670G has. I won’t go that route.