OmniPod UST400, User Manual

Page: 164 / 202

149
Understanding PDM and Pod Function 12 12 Understanding PDM and Pod Function
Insulin on board (IOB) calculations
Duration of insulin action – time since previous bolus x previous bolus
Duration of insulin action
IOB from a previous correction bolus is called a “correction IOB.”
IOB from a previous meal bolus is called a “meal IOB.”
Correction IOB example
Duration of insulin action: 3 hours
Time since previous correction bolus: 1 hour
Previous correction bolus: 3 U
3 hours – 1 hour x 3 U = 2 U correction IOB
3 hours
In other words, one hour after your previous correction bolus, your body
has used up only 1 unit of the correction bolus. The remaining two units of
insulin are still in your body working to correct your blood glucose level.
Accounting for IOB in bolus calculations prevents the delivery of too much
insulin when correcting a high BG or eating a meal.
Meal IOB example
Duration of insulin action: 3 hours
Time since previous meal bolus: 2 hours
Previous meal bolus: 4.5 U
3 hours – 2 hours x 4.5 U = 1.5 U meal IOB
3 hours
In other words, two hours after your previous meal bolus, your body has used
up 3 units of insulin of the meal bolus. The remaining 1.5 units of insulin are
still in your body working to cover your meal.
Meal IOB is only used to reduce a correction bolus; it is does not reduce a new
meal bolus. The correction bolus is only reduced until it becomes 0 units.
Final suggested bolus calculations
Correction bolus
= (preliminary correction bolus - meal IOB) - correction IOB
Note:
The Correction bolus is never reduced below 0 U. Any correction IOB
that was unused in the above calculation is carried over to use in the following
calculation.
Meal bolus
= preliminary meal bolus - unused correction IOB
Suggested bolus
= correction bolus + meal bolus