Bolusing Successfully on Hybrid Closed Loop Therapy
Happy New Year 2021 from all of us here at Medtronic! A new year means a fresh start and an opportunity to brush up on some best practices for bolusing in SmartGuardTM Auto Mode
Food boluses are instrumental to your patient’s success in SmartGuardTM Auto Mode. However, the key to maximizing time in SmartGuardTM Auto Mode and helping patients increase their time spent in range is managing certain bolus behaviors. A best practice is to encourage pre-meal bolusing. When possible, patients should bolus 5-15 minutes before meals unless their glucose value is low. A bolus given after eating may increase the risk of post meal hypoglycemia due to Auto basal attempting to lower the sudden rise in glucose. This may increase the risk of post-meal hypoglycemia or sustained post-meal hyperglycemia.
For example, in the case of a patient who has underestimated the amount of carbohydrates for a meal, the recommendation is that they enter and bolus for the remaining carbohydrates after their meal. However, if more than 1 hour has passed since eating, it is usually best to enter the current blood glucose value and deliver a correction bolus as recommended by the system.
What about the patient that is unsure of how much will be eaten at mealtime? This is especially common with toddlers and young children. The recommendation is that they bolus pre-meal for the grams of carbohydrate they are certain will be eaten – for example, if a child will always eat a slice of bread with their meal. If additional carbohydrates are consumed, they can bolus for any additional grams as they are eaten. The goal is to help match insulin to glucose in the bloodstream and help minimize post-meal excursions.
Perhaps the most common bolus behavior of all is when patients forget to bolus altogether; life happens, right? While Auto Basal can usually accommodate for small mismatches in carbohydrates consumed, it is not designed to accommodate for missed meal boluses. That said, considering timing is critical. If less than one hour has passed since mealtime, patients should be encouraged to enter half of the grams of carbohydrate eaten and recheck the blood glucose in one hour. If the glucose remains high, they should deliver a correction bolus as recommended by the system. If more than one hour has passed since eating, the patient should simply enter the blood glucose and deliver the recommended correction bolus.
For more information about boluses behaviors and the SmartGuardTM Auto Mode algorithm as outlined in the Protocol for Hybrid Closed Loop Therapy – Second Edition book, please contact your local Medtronic Diabetes Territory Manager.