Sugar Surfing Lesson 14: Dosing on the Deltas
Perhaps the most counterintuitive aspect of Sugar Surfing™ is the act of dosing rapid insulin when blood sugars are still in range. Static diabetes self-care limits us to only inject rapid-acting insulin when blood sugars are well outside of our assigned target range. Dosing insulin between meals when the sugar level is in range is largely forbidden and does not make sense when all you have is a single blood sugar value to base that decision upon. One exception might be when additional carbohydrate containing snacks are being eaten between meals. Static diabetes management means insulin doses are based on predetermined formulas, algorithms or arbitrary sliding scales. Specifically, mealtime insulin doses are based on a single blood sugar measurement and a carbohydrate estimate of the food to be eaten. The timing of the insulin dose and the meal may not be done in any particular order. All that matters are that both are done.
The larger situation under which the blood sugar is measured is also not considered. Static diabetes management poorly addresses changing, real world conditions. Sugar Surfers learn to appreciate that life situations are not easily reduced to mathematical formulas or dosing ratios. In contrast, dynamic diabetes self-care depends on balancing the objective (things which are relatively easy to measure or quantify) and the subjective (intangibles like stress, illness, slowly digested foods, even the intensity of physical activity). Timing also becomes a vital element of self-care and has been discussed in prior lessons. This aspect of Sugar Surfing touches on its true power: personal experience being used to act to prevent anticipated events. In the book Sugar Surfing, the term 'pre-empting' describes how to anticipate and avoid blood sugar spikes or blunt steady trendline drifting. By periodic glancing at the CGM trendline, a delta wave or drop pattern is seen and recognized. This is followed by a quick determination of its relative significance in the moment. Next, deliberate action is taken to prevent (‘pre-empt’) a further upward or downward blood sugar trending. Fast carbs are typically used to preempt potential lows and rapid acting insulin to preempt trending highs. Workshops and the book describe how to apply this approach properly.
This essay focuses on the pre-emption of trending highs based on situational awareness (glancing at the trendline). Application of these principles are essential for maximizing blood sugar time in range, which is to be associated with fewer long-term diabetes complications. A1C values are also improved by pre-empting after-meal and between meal blood sugar spikes. Holiday celebrations often revolve around food. Knowing how to “dose on the deltas” is one way to stay in control and enjoy traditional holiday festivals where frequent and often heavy meals are involved.
Here is an example to illustrate this basic concept.
A dose of insulin is taken for a carb-heavy meal which includes a high fat and protein content. This implies two important concepts. First, the digestion of this meal into sugar will take longer than if carbohydrates were simple or the dominant part of the meal. Second, insulin action often wears off before heavy meals are completely digested into sugar.
Sugar Surfing relies on a working knowledge of when the blood sugar lowering effect of a recent insulin dose is being overtaken or outlasted by a slowly digesting meal or snack. Prior posts, the book and workshops teach how to determine one’s own duration of insulin action.
In this example, the first dose was able to achieve relatively stable blood sugar levels for the next couple hours. Due to the complex carb, fat and protein nature of this meal, there was no significant time between when insulin was taken and when the meal was eaten. As time passes from the first meal dose, a slow steady climb in blood sugars begins to define the onset of a significant ‘delta wave’. The next step is based on the judgment of the Surfer. How far must the delta wave continue to rise (and for how long) is used to decide when to administer another dose of rapid-acting insulin to ‘pre-empt’ the rise.
There is usually a lag time between when the dose is injected, and any visible evidence of action is seen. If the dose is enough, the trend line will either inflect into a steady, straight trend (shelf) or fully inflect into a falling trend (‘pivot’ into a ‘drop’). Follow up doses are typically lower than the first dose.
After a delta dose is taken, there must be a wait time to "see" the effect on the blood sugar trend line. In my case that is 25-35 minutes on average. If I see no significant deflection in the line, then after that period of waiting I will consider another (smaller) dose, and then wait another half hour. If I want to be conservative, I wait a full hour before considering another dose. You could also wait an entire 2-3 hours before considering any further dosing actions. But take what you learn about the doses you do use and the situations in which they are used when you try this again, as your next attempt may be more effective as the "practice" this over time.
Notice the blood sugar levels at the time the follow up insulin doses are taken. None of them are outside a range which would suggest the need for more insulin if all that was considered was the blood sugar level itself and no trending information. To summarize, the secret to obtaining this kind of result is based on the following:
· Knowing that carb, fat and protein meals are often slow to digest into sugar (food often outlasts a single insulin dose).
· Experience to know when to suspect a rapid acting insulin dose is wearing off (delta waves).
· Glancing at the blood sugar trendline often enough to recognize a rising delta wave.
· Experience with dosing follow up insulin doses to deflect delta waves.
Sugar Surfers using insulin pumps often use a dual wave (combo bolus) to accomplish results like this. It is possible to set up a dose upfront which covers the early and late effects of a meal. However, it often takes some practice to get the proper dose, duration and percentage of basal versus extended for the combo bolus. And dosing on top of a combo bolus is still not unusual when trying to tackle a challenging complex carb meal.
The image below shows a superimposed curve which imagines the glucose raising effect of the meal.
The final examples show examples based on hamburgers and pizza. Hopefully you can see how to “dose on the delta” with greater confidence after reading this post. Enjoy your holiday meals! Hopefully they will not only revolve around hamburgers or pizza!
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