Once you and your doctor have agreed that insulin pump therapy is right for you, a number of therapy decisions need to be made. For example, should you use human or analogue insulin?
When using Bolus Advice, a number of values also need to be calculated and used to program your insulin pump. They include things like basal rate, insulin-to-carb ratio, insulin sensitivity factor and others. These will be different for each person and will be determined with the help of your healthcare team.
At the end of this lesson, you will:
This lesson focuses on the types of decisions and calculations that will be made to customize insulin pump therapy to suit your needs. You will learn more about this in the Standard and Advanced Training Modules.
As the insulin pump delivers insulin on a continuous basis, in contrast to Multiple Daily Injection therapy, medium or long-acting insulins are not used (only rapid or short-acting insulin). However, it is recommended to carry such insulins as a backup (via pen / syringe) as you will need to revert back to these in the event of an insulin pump failure or when you take an insulin pump holiday.
Since an insulin pump delivers insulin on an ongoing basis, long-acting insulin is not needed.
The onset and duration of action of these two types of insulin may differ between individuals.
As a rule of thumb, you would see a measurable effect on your BG test result starting between 30 and 45 minutes after the injection of regular human insulin with the peak effect after 2 - 4 hours. The total acting time of regular human insulin is about 5 to 8 hours.
On the other hand, you can expect a measurable effect on your BG test result to start between 10 to 20 minutes after the injection of rapid-acting insulin analog(ue)s, with the peak effect after 1-2 hours. The total acting time of rapid acting analogue insulin is about 3 to 5 hours.
Here’s another thing to keep in mind about the use of only short-acting insulin.
When longer-acting insulin is injected, it creates a pool under the skin.
This pool of insulin is slowly released over time. With an insulin pump, a smaller pool of fast-acting insulin is created.
So, if insulin delivery from the insulin pump stops for any reason, blood glucose can start to rise quickly.
This is one of the reasons why regular blood glucose testing
Most insulin pump users need 10-20% less insulin when switching from MDI to insulin pump therapy. However, if you often had episodes of hypoglycaemia when on MDI, the total amount of insulin may needed to be reduced even more. On the other hand, if your BG tended to be high, the total amount of insulin may stay the same or be reduced by a lesser amount. The total daily insulin needed with insulin pump therapy will vary from person to person.
Your personal insulin requirement will be determined by your doctor.
People without diabetes have a constant, low level of insulin in their body between meals and during the night. When mimicking physiologic insulin secretion with an insulin pump, this steady release of insulin is called basal insulin. Basal insulin levels go up and down depending on a number of factors.
For example, with the dawn phenomenon, a person may need more insulin in the early morning hours than earlier in the night which can be managed with the Accu-Chek Spirit Combo insulin pump. You will learn about dawn phenomenon in the next screen. The Accu-Chek Spirit Combo insulin pump delivers basal insulin every few minutes in small pre-programmed doses throughout the day and night. The flow of insulin is called the basal rate. It can be changed and programmed to match your daily needs.
When determining your basal rate, the Dawn and Dusk phenomena will be taken into account. What are they? At certain times of the day, our bodies release hormones, such as growth hormone, that counteract the effect of insulin. In people with diabetes, this leads to an increase in blood glucose.
The Dawn phenomenon occurs in the early morning hours. The Dusk phenomenon occurs later in the day, usually before dinner. The result is that the body needs more insulin to achieve the same effect at this time of the day compared to other times of the day. The Accu-Chek Spirit Combo insulin pump allows you and your healthcare team to make basal rate adjustments to counteract these phenomena.
As a rule of thumb, 30-50% your total daily insulin dose will be used as the basal dose for insulin pump therapy. The remaining percentage will be administered as bolus doses as needed through the day.
Regular blood glucose testing and the omission of certain meals are used to test how your body responds to a basal rate. The overnight basal rate is usually tested before the daytime one. This is to prevent hypoglycaemia during the night and to allow you to wake up with a normal BG level.
Blood glucose levels are monitored closely during the test periods and the basal rate is adjusted in small steps as required. Testing of basal rates is always done under the supervision of a doctor or healthcare team.
Do not change your basal rate without consulting your doctor or healthcare team.
With CSII therapy, you can adjust your basal rates to match your insulin needs. The basal rate profile consists of 24 hourly basal rates. Each hourly rate can be changed independently to match your insulin patterns throughout the day and night. For example, if your activity level is different on Saturday and Sunday, you can select a different basal rate profile for the weekend.
The best basal rate is one that enables the blood glucose to remain constant over many hours when not influenced by food. Each doctor and healthcare team has a preferred method for calculating basal rate profiles. So, follow their advice.
Getting the basal rate just right may take a few weeks or longer. You will need to check your blood glucose level often and regularly during this time. You may also have to perform tests during the night. It is important that you collect good quality information to allow you and your healthcare team to match your basal rate to your personal needs.
You will need to check your blood glucose level often and regularly during the testing of basal rates.
In intensive insulin therapy, such as CSII therapy, insulin bolus doses are delivered to cover meals or to correct elevated glucose values.
The Meal Bolus is an insulin bolus dose delivered to cover food or beverages containing carbohydrates. It is calculated based on the amount of carbohydrates that you are consuming, using the insulin-to-carbohydrate ratio.
The Correction Bolus is an insulin bolus dose that you deliver to reduce elevated BG levels back into the target range. It is calculated based on your current glucose level and your target glucose range, using the insulin sensitivity factor.
When pre-programmed correctly together with the data based on your input; the Bolus Advisor integrated into your
Legend: 1 meal bolus
Calculating an insulin bolus manually is a complex thing. The Accu-Chek Combo diabetes manager has a built-in bolus advisor (also known as a bolus calculator) that does this math for you. This function is called Bolus Advice. The calculations that drive the Bolus Advice function are based on a number of pre-set values as well as manually entered data at the time of the calculation.
Such as :
In addition to the above, the Bolus Advisor takes into account insulin with remaining glucose-lowering potential from the previous bolus dose(s).
The Accu-Chek Combo diabetes manager has a built-in bolus calculator that does this math for you. This function is called Bolus Advice. All you have to do is test your blood glucose, enter the correct amount of carbohydrates you are planning to eat (if any), add "health event" information if required and Bolus Advice will do the calculation for you.
As you learned, meal boluses are amounts of insulin needed to cover a meal or snack. When programmed correctly, the Bolus Advisor integrated into your Accu-Chek Combo diabetes manager can calculate the required bolus doses for you. You then have the choice to accept the advice or not. If accepted, the bolus will be delivered by the insulin pump.
Food is made up of carbohydrates, protein and fat.
Carbohydrates are the main components that affect blood glucose. Your healthcare team will teach you to count the amount of carbohydrate in food.
They will also help you to tell the difference between slow and fast carbohydrates. The tool that is often used for this is the glycaemic index.
Having good knowledge of carbohydrates and the glycaemic index will help you to determine how much carbohydrate to enter into the
In contrast to MDI therapy, CSII therapy enables you to have greater flexibility when delivering insulin for meals.
The Accu-Chek Combo insulin delivery system offers 3 different bolus types (the standard bolus can also be programmed to be delivered as a "quick bolus"). You can adjust your bolus type and the time the insulin is delivered for example
The Accu-Chek Combo insulin delivery system offers you the option to divide a bolus into two or more doses without additional injections. This is especially helpful for children, whose eating habits can often be unpredictable.
Correction bolus, this is the bolus insulin amount needed to reduce an elevated glucose level back into the target range. BG levels can be high / elevated due to a variety of reasons such as not enough meal insulin meal insulin, stress, medications, illness or decreased activity etc.
As with meal boluses, your Accu-Chek Combo diabetes manager will provide you with correction Bolus Advice through its Bolus Advice function. A correction bolus should always be delivered as a standard bolus. Additionally, if you are eating high carb high fat high carb and high fat foods Then the recommended bolus in these situations when a correction bolus is also needed is a "multiwave bolus". This advice is based on a number of pre-set values. One of these values is insulin sensitivity factor.
As seen earlier, the insulin sensitivity factor is the amount of the insulin needed to lower your blood glucose by a certain amount. The insulin sensitivity factor will be calculated by your doctor and healthcare team and pre-set in the Bolus Advisor program.
There is one more calculation to consider when using insulin therapy and this is a "negative correction" calculation. If your pre-meal BG is below your target range (but is not below your hypo limit) before you eat, you should take less insulin for the carbohydrates you are about to consume. In this situation, the Bolus Advisor in your Accu-Chek Combo diabetes manager will calculate a "negative correction" which will reduce the bolus amount of insulin recommended.
If your BG is at or below your hypo limit, no Bolus Advice will be provided. Instead, you will receive a recommendation to eat fast-acting carbohydrates in order to raise your BG level into your target range.
In order not to over correct your hypo which could result in elevated BG levels later on, record the amount of carbohydrates you will actually consume.
If you have un unexplained elevated BG level, wash your hands with soap and warm water. Dry thoroughly and repeat the test again. If the result is still elevated then follow the instructions in your Accu-Chek Combo insulin delivery system Users Manuals and the advice given to you by your healthcare professional.
As you have seen, there are many factors that can have an effect on blood glucose. The following table provides a quick summary of some of them: §
|Situation||Impact on blood glucose level|
|Exercise||↑ or ↓|
|Illness||↑ or ↓|
|Menstrual||↑ or ↓|
Let’s see how the system accounts for these factors.
Your Accu-Chek Combo insulin delivery system has a function called health events. You can use health events to take into account situations that increase or decrease your bolus insulin needs, such as the ones listed in the table seen earlier. For example, when exercising, your insulin needs will decrease in most situations but can also increase in competitive situations. The health events function allows you to lower your bolus dose by a certain percentage. You and your healthcare team should discuss how to program the Health Events on the Accu-Chek Combo diabetes manager.
You can program your Accu-Chek Spirit Combo insulin pump to temporarily increase or decrease your basal rate by the percentage you entered.
Like health events, this function allows you to match your changing insulin needs due to exercise, illness and other situations. When you set a Temporary Basal Rate, each hourly basal rate included in the basal rate profile is increased or decreased by a percentage. Your healthcare team will help you determine when you should use this function. They will also show you how much you should increase or decrease your basal rate to match certain situations.
You can program your Accu-Chek Spirit Combo insulin pump to temporarily increase or decrease your basal rate!
Many situations can affect your BG level, thus, you may require changes to how your insulin is delivered by your Accu-Chek Combo insulin delivery system:
CSII therapy may allow you to have more freedom when travelling. Changes in time zones, sleeping patterns and eating habits are easier to manage with insulin pump therapy. Your healthcare team will provide tips on how to manage time zone changes and the changes in routine that come with travel.
Alcohol intake needs to be managed carefully. If you drink too much, you can be at serious risk of hypoglycaemia for several hours after drinking. Speak to your healthcare team about how to best manage alcohol intake with insulin pump therapy.
Choose the correct key for the graph on the right:
You have completed the getting started section. You now know the factors considered when getting started on insulin pump therapy. Time to move to the next lesson.
Lesson - 5