
My son Gregory, as a Medtronic 640G Insulin Pump user, can use different types of bolus deliveries, depending his insulin needs during the day. There are also different ways he can deliver a bolus, like a Dual Wave and a Square Wave. Let’s see how can they be used to get a nice flat line on your BG readings.
Table of contents:
What is a Bolus insulin?
A Bolus is the amount of insulin taken in order to cover an expected rise in blood glucose level, typically when you eat a meal or a snack. You can also use a bolus to correct a high blood glucose level.
Bolus delivery types on a Medtronic insulin pump
There are different types of bolus deliveries. Always discuss with your doctor to determine which one is the optimal for you.
Normal (N) Bolus
How does it work
It provides a single and immediate dose of insulin.
When to use it
It is the standard type and used to cover a meal or snack or as a correction of a high BG reading.

Square Wave (S) Bolus
How it works
Square Wave bolus delivers a single bolus evenly over an extended period of time. The time frame to spread the dose is between 30 minutes to 8 hours.
When to use it
You may use a Square Wave Bolus:
- If you have delayed food digestion due to gastroparesis or meals high in fat.
- When snacking over an extended period of time.
- If a Normal bolus drops your blood glucose too rapidly.

“A Bolus is the amount of insulin taken in order to cover an expected rise in blood glucose level, typically when you eat a meal or a snack.”
Dual Wave (D) Bolus
Note: It is also known as Extended Bolus in tslim:X2 insulin pumps.
How it works
Dual Wave (D) bolus delivers a combination of an immediate Normal bolus followed by a Square Wave bolus.
When to use it
You may use a Dual Wave Bolus:
- When you eat meals that are both high in carbs and fat which may delay digestion.
- When your meal bolus is combined with a correction bolus for an elevated blood glucose.

Benefits in case of a small child
The above insulin delivery methods can be very helpful. In our case where Gregory is a still a toddler, we are not sure that he will eat all his meal.
Benefits:
- Spreading the insulin over time will help him avoid a big spike in his BG levels.
- In case he does not eat all his food we can stop the provision of the square wave or dual wave bolus. That way we avoid an insulin overdose which may end in a Hypoglycemia.
A Pre-Bolus is another way that we use mitigate the risk of not eating all his food. We will analyze it on another blog post.
How to manage challenging meals [Bonus Video]
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