Using an Extended Wave Bolus
What is an Extended Wave Bolus?
The extended bolus is a function of most insulin pumps. This allows insulin required at meal times to be delivered over an extended period of time.
There are two types of extended wave boluses; a ‘split’ wave bolus and a ‘continuous’ bolus.
Why use a ‘Split’ Wave Bolus?
Some very high fat and/or very low glycemic index (GI) meals and snacks are digested very slowly. Using a standard insulin bolus with these foods can mean the insulin is delivered before digestion has occurred. This can result in a delayed blood glucose level rise after the meal, even up to 6-8 hours later.
The advantage of using a ‘split’ wave bolus is it can better match the insulin delivered by the pump to the digestion of the meal, resulting in better blood glucose control. Insulin is delivered in 2 waves – one immediate wave and the second wave over a pre determined period of time. The amount of insulin in each wave is split as a percentage of the whole bolus e.g. 50/50 (meaning 50% of the meal insulin is delivered in the immediate wave and 50% in the second wave).
Different Insulin Pumps have different names for the ‘Split’ Wave Bolus ‘Split’ Wave Bolus - Foods
Your Dietitian can give you advice on the foods you eat which would be suitable for a ‘split’ wave bolus. The next page will cover some typical foods which may require a ‘split’ wave bolus. Generally the higher the fat intake, the longer the insulin delivery period.
You can discuss with your Diabetes Educator what split of insulin delivery (e.g. 50/50) over what time (e.g. 4 hours).
These examples are only suggestions. Trialling a ‘split’ wave bolus and blood glucose monitoring will allow you to determine if using a ‘split’ wave bolus will assist with controlling your blood glucose levels after meals.
Very High Fat Foods ( >40g fat per meal)
May need extended wave bolus 2+ hours
High fat foods (20 - 40g fat per meal/snack)
May need extended wave bolus around 2 hours
Moderate fat foods (10 - 20g fat per meal/snack)
May not need an extended wave bolus
What is a ‘Continuous’ Bolus?
A ‘continuous’ bolus is when mealtime insulin is delivered by the insulin pump at a constant rate over a set period of time.
For a ‘continuous’ bolus you enter the carbohydrate you plan to eat and the time period over which you want the insulin to be delivered.
Why use a ‘Continuous’ Bolus?
A ‘continuous’ bolus can be useful for:
· Parties or events where small amounts of food are consumed over a long period
e.g. canapés, banquets etc.
· People who have gastroparesis.
‘Continuous’ Bolus - Foods
Your Dietitian can give you advice on the foods or meals which would be suitable for a ‘continuous’ bolus. Dietitians can also assist you with accurately counting carbohydrates for the foods you may consume.
You can discuss with your Diabetes Educator over what time to program the ‘continuous’ bolus (e.g. 3 hours).
These examples are only suggestions. Trialling a ‘continuous’ bolus and blood glucose monitoring will allow you to determine if using a ‘continuous’ bolus will assist with controlling your blood glucose levels.
Baker IDI Heart and Diabetes Institute
Level 4, The Alfred Centre, 99 Commercial Road, Melbourne, Vic 3004 Australia
T (03) 8532 1800 F (03) 8532 1899 W www.bakeridi.edu.au
© 2012 Baker IDI Heart and Diabetes Institute
Review date: Jan 2014 Literacy Level assessed
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