Any HCL algorithm allows the user to revert back to manual management on demand.
In fact, users may see better results in manual mode when advanced pump features such as extended boluses or temporary basal rates are needed (these features may not be available when HCL is running).
In addition, any time the system isn’t performing just right, it will dump the user back into manual mode by default.
Therefore, it is important that the manual mode settings be optimized before beginning to use an HCL system.
Fine-tuning basal and bolus settings will be discussed in detail in the chapters that follow.
Overall, HCL systems do a pretty good job of fixing rising and falling blood sugars overnight or any time meals/boluses are spaced many hours apart.
The overnight control, in particular, can be a godsend for those in need of a good night’s sleep.
It reminds me of a large ocean liner that’s put on autopilot so the captain can catch some Zs.
If the ship veers off course slightly, the autopilot system gets the ship back on track so that it reaches its intended destination by morning (see Figure 5.16 ).
Figure 5.16: HCLs are like autopilot on a ship, capable of making subtle adjustments in order to keep things reasonably on course.
However, when a big ship is moving at a high speed, a small rudder will not allow it to change directions quickly enough to avoid things like icebergs (this is what happened to the Titanic ). Everyone who lives with diabetes knows about the hour-to-hour, minute-to-minute challenges we must contend with. These are the icebergs, the things the system must navigate around in order to prevent extreme highs and lows.
Essentially, anything that can cause a rapid, abrupt rise or fall in glucose levels represents an iceberg. Remember, we’re dealing with a huge, fast-moving ship with a small rudder. The pump’s basal adjustment just isn’t powerful or responsive enough to prevent high and low glucose levels when confronted with:
food (particularly rapidly digesting carbohydrates)
physical activity (particularly heavy exercise)
stress (particularly sudden, unexpected crises)
sudden hormone changes (resulting from injuries or trauma, rebounds from lows)
rapid-acting insulin (administered for food or corrections)
Bottom line: even with an HCL system in place, you’ll still need to apply your own self-management skills on a regular basis. Users must still count their carbs, adjust for physical activity and stress, and so on. They must also take precautions to prevent anything that can interfere with normal pump and insulin function, such as absorption issues, air in the tubing, displaced or kinked infusion sets, insulin spoilage, and unintended disconnection.
So who is the ideal candidate for an HCL system? To succeed with an HCL, one must:
have conservative glucose management goals (unless using a DIY system)
put in extra work upfront and be willing to tolerate extra alarms or alerts
possess some technical aptitude
be willing to delegate some decision making to the system
lead a relatively structured life (the fewer “icebergs,” the better HCL performs)
Substitution Is Permitted
When selecting an insulin program, don’t think of it as a lifetime commitment.
Many people switch plans because of changes to their lifestyle or when they come to the realization that their current program is failing to do the job.
Several of my clients have tried an MDI program but were unable to achieve the kind of control they wanted, so they made the move to a pump.
I have also had pump users switch back to injections, either permanently or temporarily, because of image concerns, convenience, or the desire for more structure in their lives.
The one constant in life is change, you are not locked into any particular plan.
And what if your physician doesn’t agree with the program you choose? Ask why. Perhaps they have a good argument that will sway your decision. If not, you might want to look for another health care provider. After all, this is your diabetes, and you deserve the right to choose the management approach that suits you best.
CHAPTER HIGHLIGHTS
• For an insulin program to be successful, it should include both basal and bolus insulin.
• Bolus insulin may be supplied in the form of regular, rapid, ultra-rapid, or inhaled insulin.
• Basal insulin may be supplied in the form of NPH, glargine/detemir/degludec, or insulin pump therapy. Pump therapy usually provides the best basal insulin coverage.
• Hybrid closed-loop systems combine an insulin pump, continuous glucose monitor, and computer program to automatically self-adjust the basal insulin around-the-clock.
• Various combinations of basal/bolus therapy are possible, each with its own pros and cons. Choose the one that will best meet your personal needs.
Think Like a Pancreas
SIX
Basal Insulin Dosing
A kind and steady heart can make a grey sky blue, And a task that seems impossible is quite possible for you.
, Peter Gabriel, “That’ll Do”
O nce you have settled on an insulin program that meets your needs, the next order of business is to determine the right doses. Think of yourself as a giant lump of clay that needs to be molded and sculpted into fine art. (My personal self-sculpture is a cross between Rocky Balboa and Bond, James Bond.) Any artistic creation takes time, so be patient. Make one adjustment at a time, evaluate the results, and then fine-tune before moving on.
Another truism about fine art: beauty is in the eye of the beholder. What works for some may not work for others. When looking at dosing patterns and formulas, use them only as starting points. Individual needs may, no, will , vary.
Let’s start with the fine-tuning of basal insulin. Basal insulin serves as the foundation for your entire insulin program. With a solid foundation, you can build something great. With a cracked or crooked foundation, you will struggle to get anything to work right. In diabetes terms, it is difficult to know what is causing out-of-range blood sugars unless you have already established the proper basal insulin levels. That’s why