For people on insulin pumps, it is important to know the difference between basal and bolus. A basal is an hourly drip of insulin which replaces long lasting insulin. Here’s more on what a basal rate is.
A bolus is an extra dose that is given for the food eaten and to correct the blood sugar if it is high. On pumps, the pump will determine the dose for the bolus based on the carb ratio and the sensitivity or correction factor.
Pumps use a bolus wizard feature where the pumper enters the amount of carbs eaten along with the blood sugar. The pump will either add insulin for a high blood sugar, or subtract insulin (known as reverse correction) if the blood sugar is low. That dose is added to the amount determined to cover the food based on the carb factor.
Using a bolus wizard feature is preferred over doing manual boluses. A manual bolus is where a set amount, for example, 3 units, is given. I see this mostly in people who have had diabetes a long time and just know “I need 5 units for this amount of food.” The problem with this is that the pump doesn’t know to add or subtract insulin based on the blood sugar and especially on the active insulin or insulin on board. This can result in low blood sugars.
One way to remember basal is it is the baseline or amount of insulin per hour to keep the blood sugar normal without eating. A bolus is an extra dose of insulin for a high blood sugar or food, or some people will remember it as a “bowl” of food.
Knowing whether your pump needs an adjustment in the settings for the bolus is determined by watching your blood sugar 2 hours after a bolus. Is it high because the amount for the food is not enough? Or low because you got too much? That means the carb ratio needs adjusting. If you do a correction only, is it high or low 2 hours after the correction? That means the sensitivity or correction factor needs changing. Always look for patterns over several days rather than adjusting based on a single number. And always discuss changes with your doctor before making changes to your settings!