The Basics of Insulin Pump Therapy
Problems with intensive insulin therapy
Whenever you think about your diabetes treatment, you should always have primarily one thing in mind: The functioning of your pancreas. It shows us how the body should actually be supplied with insulin: quick insulin secretion at mealtimes, basal insulin secretion between meals and during the night.
Fig 1: Insulin secretion of non-diabetics
Intensive insulin therapy with multiple daily injections (MDI), where you inject yourself with insulin more than three times a day, is an attempt to mimic this "biorhythm of insulin supply ". But there continues to be several problems with this approach as you perhaps know from your own experience.
Nocturnal Hypoglycemia (Night-time low blood glucose levels)
If the insulin level of the long or intermediate-acting insulin in the body between midnight and 3:00 am is higher than the actual insulin requirement, blood glucose drops and it can even result in hypoglycemia.
Early Morning Hyperglycemia (Dawn Phenomenon)
If the insulin requirement increases during the early morning hours (so-called dawn phenomenon) and at the same time the insulin effect of the long or intermediate-acting insulin subsides, hyperglycemia can be the result. The consequence: the blood glucose is already too high when you wake up.
Disadvantages in Daily Life
Your daily routine has to be planned and that leaves little room for spontaneity. An insulin pump can help solve this problem.
Insulin Delivery on Demand
The insulin pump therapy is officially called "continuous subcutaneous insulin infusion" (CSII) and this designation describes exactly what it’s all about: There is no need to inject insulin via a pen, needle and syringe any more, rather a pump continuously supplies the body with the required insulin. In contrast to MDI, only one type of insulin is used for insulin pump therapy: regular insulin or fast-acting insulin analogue.
Fig 2: Insulin delivery with insulin pump therapy
You are already familiar with the basic principle of insulin pump therapy from intensive insulin therapy with MDI: The separation between basal rate and bolus.
Basal Rate
It covers the basic insulin need that your body requires independent of mealtimes. This basic requirement is not constant over a 24-hour period, but is subject to fluctuations during the course of the day. It is the lowest as a rule during the night and during physical activity.
Fig 3: Insulin delivery with insulin pump therapy
The requirement for insulin over a period of 24 hours is somewhat dependent on the individual. At the beginning of insulin pump therapy, the insulin requirement will be determined individually with your health care professional on the basis of blood glucose testing and insulin regime programmed into the pump. The insulin pump will then follow this programming for insulin delivery 24 hours a day. The body’s basic insulin requirement and the insulin supply by the insulin pump essentially coincide. This is an important requirement for stable blood glucose control.
Bolus
Approximately one half of the daily insulin requirement is made up of the basal rate. The other half covers the meal-related insulin requirement. The insulin injected at meal times is called a bolus. You are familiar with the procedure from intensive insulin therapy. Measure your blood glucose before mealtimes, estimate carbohydrate intake and determine the insulin quantity required. Unlike intensive insulin therapy, the bolus is not injected with a pen or syringe, but with the insulin pump at the push of a button. And in between - independent from meals - if the blood glucose level is too high just correct it with a bolus.