The Super Bolus And The Projected BG Alert New Insulin Pump Ideas To Improve Glucose Levels, Avoid Hypoglycemia And Speed Correction Of Hyperglycemia John Walsh, P.A, C.D.E. Click here for online slide presentation

© 2004, John Walsh, P.A., C.D.E. What We Will Cover Current basal and bolus concepts The New Super Bolus The New Predicted BG Alert Using them together Conclusion

© 2004, John Walsh, P.A., C.D.E. Current Basal/Bolus Concepts Basal insulin ~ 50% of daily insulin need Limits hyperglycemia after meals Suppresses glucose production between meals and overnight Bolus insulin (mealtime) Limits hyperglycemia after meals Immediate rise and sharp peak at 1 hour 10% to 20% of total daily insulin requirement at each meal

© 2004, John Walsh, P.A., C.D.E. New Basal/Bolus Thinking Some pumpers use extended boluses to cover meals, but today’s “fast” insulins are slow compared to how quickly most carbs raise the blood glucose High GI foods and large carb meals often create unwanted hyperglycemia 1 to 2 hours later Also, eating when the blood glucose is already high creates even higher glucoses There are ways to offset these problems: Give a bolus earlier (delay eating) Increase the size of the bolus before the meal Build into the pump an alert which predicts when the blood glucose will be low enough to eat Let’s take a look at ways to do this safely

© 2004, John Walsh, P.A., C.D.E. Bolus Insulin Is Slow The kinetic line shows when today’s “fast” insulins appear in the blood The dynamics line shows the time period over which the blood sugar is actually lowered by insulin Fast insulins are slow compared to the time over which carbs raise the blood glucose (~2 hrs max) Better ways are needed to match carb boluses to meals

© 2004, John Walsh, P.A., C.D.E. Concept For A Super Bolus The idea for a Super Bolus came from: Getting away from extended or square wave boluses that slow bolus delivery (though they are occasionally needed) and getting toward what is more often needed: larger bolus delivery The desire to avoid hypoglycemia after a larger bolus has been given And from a practice some pumpers use today: using a temporary basal reduction to offset excess Basal On Board (BOB)

© 2004, John Walsh, P.A., C.D.E. New: Rapid Basal Reduction Some pumpers use a rapid basal reduction to offset excess basal on board (BOB), such as at bedtime.

© 2004, John Walsh, P.A., C.D.E. New: The Super Bolus Here, a Super Bolus helps cover a high GI food to prevent a postmeal high. It could be activated above a user-selected carb quantity, such as when more than 40 or 50 grams of carb will be eaten. Can also help cover large carb intakes. A Super Bolus is a 2 to 4 hour block of basal insulin that is turned into a carb or correction bolus to increase the speed at which that bolus will work.

© 2004, John Walsh, P.A., C.D.E. New: The Super Bolus To ensure safety and success, the Super Bolus will require some clinical testing: How long can basal delivery be stopped or reduced without increasing the risk for clogging of the infusion line How long (3, 4, 5 hours?) can the basal be lowered before a rebound high will occur once the Super Bolus is gone? Is a reduction in basal delivery better than complete stoppage? If a pumper’s basal delivery has been set too low or too high, how will this affect a Super Bolus?

© 2004, John Walsh, P.A., C.D.E. New: High BG Super Bolus If a pumper has a high BG after misjudging the carb content of a meal, a Super Bolus enables a faster, safer correction. The pump must measure accurately the impact of the various insulin doses involved.

© 2004, John Walsh, P.A., C.D.E. New: A Reminder Timer Here, a simple timer alerts the user 25 minutes after a bolus that it is safe to begin eating a high GI meal.

© 2004, John Walsh, P.A., C.D.E. New: Projected BG Alert An intelligent pump alerts the user when their decreasing BG is likely to cross a selected threshold value, such as 120 mg/dl. They can then eat without exposure to extremely high readings.

© 2004, John Walsh, P.A., C.D.E. Less Glucose Exposure This graph shows why waiting to eat when the blood glucose is high results in less glucose exposure. The lower the blood glucose is at the start of a meal, the less exposure to glucose there is.

© 2004, John Walsh, P.A., C.D.E. New: Super Bolus Plus Projected BG Alert An intelligent pump alerts the user when their blood glucose is low enough to begin eating

© 2004, John Walsh, P.A., C.D.E. Conclusion A Super Bolus delivers more bolus insulin more quickly to speed correction of hyperglycemia or to better cover larger carb quantities or high GI carbs A reduction in basal delivery equal to the insulin added to the Super Bolus prevents hypoglycemia A Super Bolus combined with a Projected BG Alert can lead to substantial reductions in day to day glucose exposure These features can be of clinical benefit with lower A1cs when added to today’s insulin pumps Requires accurate insulin estimates, such as for Bolus On Board, and some clinical testing to verify outlying parameters