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Insulin Pump Therapy

3.3 What’s different for bolus insulin

The previous page was about what's similar between insulin pump therapy and injections. Here you'll learn what's different between the 2 systems for bolus insulin.

Amount of injections​

The biggest difference is that with injections, you get a lot more needle pokes. You use pens or syringes to get:

  • meal bolus insulin to cover the carbohydrate you plan to eat at a meal or snack
  • correction insulin when your blood glucose is high

But in insulin pump therapy, you get this insulin through a small cannula under your skin, without a separate needle poke. Instead, you need to push a button on the pump or the handheld device.

Meal bolus

In pump therapy, you need a bolus of rapid-acting insulin for most meals and snacks that have carbohydrate. You can choose to get your meal bolus insulin over a long time or all at once.

With injections, you don't need rapid-acting insulin for some snacks or meals. For example, children often get intermediate-acting insulin in the morning to cover daytime snacks and lunch.

Built-in calculator

An insulin pump has a built-in calculator to help with bolus suggestion. You program the pump to do things like:

  • suggest meal bolus and correction doses
  • know if active insulin is still in your body (this is called insulin on board)
  • suggest lower doses if active insulin is still in your body
  • give partial units of insulin (such as 2.3 or 2.7 units)
  • deliver a bolus in different ways, such as all at once or over a longer time

Remember that the pump can only suggest meal and corrections insulin. You still need to decide if the suggested dose is right for you. Here's an example of how the pump's calculator works:

Before her meal, Selina uses buttons on her pump to open a bolus calculator. She inputs the grams of carbohydrate that she plans to eat, as well as her blood glucose level. (Some pumps wirelessly accept blood glucose readings from certain meters.)

The calculator suggests an insulin bolus dose based on:

  • her blood glucose level
  • grams of carbohydrate she will eat
  • her personal insulin-to-carbohydrate ratio
  • her personal insulin sensitivity factor
  • insulin on board

Selina reviews the suggested dose. Since she plans to be more active after lunch, she lowers the dose. She decides she wants it as a regular bolus — right away and all at once. She pushes the correct buttons to get this dose.​​