Insulin pump

An insulin pump is a medical device for insulin pump therapy (English: CSII continuous subcutaneous insulin infusion, for short). In the pump therapy, the insulin preparation is injected several times not via syringe or insulin pen, a day subcutaneously, but by a small programmable pump via a catheter and a hypodermic needle ( infusion ) into the body. The pump is worn permanently on the body but can also be stored under certain conditions for several hours. For this purpose, can the catheter from the pump disconnect and close. The focus of this form of therapy are type 1 diabetics, in rare cases also get type 2 diabetes or women with gestational diabetes an insulin pump.

In Germany in 2011 carry an estimated 55,000 diabetics an insulin pump, for several years now arises here insulin register. In Switzerland and Austria, 10-20% of type 1 diabetics are treated with insulin pump therapy.

Action principle

The principle is similar to the Intensive Conventional ( insulin ) therapy (ICT ): there is a basal rate that meets the basic needs of insulin and individual boluses, which are responsible for meals and corrections values ​​. The concept is called from dissipative basal-bolus principle.

In the pump there is a reservoir with only one type of insulin, either with a regular insulin or rapid-acting insulin analogue with a. Depending on the pump reservoir model as either a small cylindrical vessel is used, which (like a syringe ) is filled with insulin itself by means of a piston or it is a ready-made insulin vial, much like it is used insulin pens used. A reservoir containing between 1.5 and 3 ml U100 (100 IU) of insulin, which corresponds to 150 to 300 units of insulin.

Pump therapy is an alternative therapy to MDI insulin therapy for type 1 diabetes, since both the basal and the meal-related and correction doses can be controlled as opposed to ICT.

The ICT one NPH insulin or is one to injected twice daily long-acting insulin analogue with an insulin pen one to three times daily. The Basalinsulinbedarf is therefore difficult to calculate, because these insulins reach a peak effect after about 6-8 hours depending on applied amount of insulin, the effect levels off again. The main active time includes about 12 hours, the total duration of action depending on the delay insulin up to 24 hours. An insulin pump on the other hand are in small, equal intervals, the fast-acting insulin from (approximately every 3 minutes) to achieve a uniform effect. You can program the basal rate per hour, and in newer models, per half hour into the pump. Pump therapy is now often become a routine therapy of type 1 diabetes.

The setting and adjusting an insulin pump is stationary in a " pump center " of a hospital or outpatient diabetes care in a specialized medical practice instead. These include the training of the patient to the particular pump model selected by him in the operation and the identification and setting of individual basal rate, the bolus calculation, dealing with technical problems, pump breaks, for example, in sports and other things.

Opportunities and constraints

The insulin pump can not replace the function of a healthy pancreas, since it does not detect the blood glucose level independently. There are models with integrated blood glucose monitoring system, which does not automatically able to determine the amount of insulin to be delivered. Nevertheless, many diabetics can almost like healthy people live with a pump, only that they continue several times a day to control blood sugar levels and also the effect of insulin on many external factors ( such as the movement ) is dependent.

The aim of the research is a closed loop ( engl.Closed - loop system, also called artificial pancreas ) in which a continuously measuring glucose sensor automatically measures the glucose level in the blood and delivers it to the body according to a control algorithm insulin. For a study carried out in 2010 an insulin pump has been developed, which also included a Glucagonampulle next to the insulin vial. By a continuous glucose measurement in a closed-loop system glucagon was delivered by pump at Unterzuckerungsgefahr. This means even less and shorter -lasting hypoglycemia occurred.

There are some indications where pump therapy compared to conventional therapy offers advantages. This includes, for example, the dawn phenomenon in which the liver from about 4 clock at night increased glucose pours into the bloodstream and the diabetic wakes up with high values ​​, which outlast the breakfast phase. Here the basal rate can be raised by means of automatic programming while sleeping; resulting in waking up to significantly better blood glucose reflect.

In Systematic reviews that have compared the conventional insulin therapy with insulin pump therapy by patients with type 1 diabetes, patients reported with pump therapy to a 0.3% statistically significantly better HbA1c. Bzgl. the occurrence of mild hypoglycemia were no significant differences are found, severe hypoglycemia occurred less frequently on. The avoidance of hypoglycemia and better overall blood sugar control has now been confirmed in a study in children with type 1 diabetes.

In a Health Technology Assessment ( HTA ​​technology assessment ) from England, the additional costs of technology and catheter material per year were estimated at 1000 to 1400 pounds ( 1160 to 1640 € ). The studies showed some benefits of insulin pump therapy for both children and adults with a mellitus type 1 diabetes, but not with diabetes mellitus type 2, or when used in pregnancy. Overall, insulin pump therapy was cost-effective.

Pump functions

Today's insulin pumps provide the following functions:

• Multibasalratenprogrammierung: Adjustment of basal insulin to the different physiological needs of the day and night during
• Basal programs: programming of different basal rates in the physiological range, which can be different for regular exercise loads on weekdays and weekends, shift work or long-distance travel, for example,
• Bolusoptionen: various fast delivery of an insulin bolus before or during a meal, taking into account the glycemic index of food
• Bolus: calculated on the basis of the current blood glucose value, the target value, the day-dependent insulin sensitivity and still mathematically effective amount of insulin the individually required insulin dose.

Some insulin pumps offer:

• Interfaces: Interfaces by radio or Bluetooth for communication with a blood glucose meter, remote control or personal computer
• Remote Control: Setting the bolus without having to remove the pump from its mounting
• Sensor -assisted pump therapy ( SuP ): In communication with a continuously measuring sensor ( CGM) the pump stops insulin delivery at too low a value for a certain time. Whether this reduces the incidence of hypoglycaemia, is being reviewed in studies.

Is still in development at:

• Artificial pancreas (closed loop engl.Closed - loop system ): A control algorithm receives a continuously measuring glucose sensor ( CGM) constantly, blood glucose and regulates insulin delivery via the pump automatically.

Patch Pumps

A variant of the conventional pump with infusion pumps are often called patches, in which the actual pump with the infusion set is combined in one housing (known as pod ). This unit is adhered to the skin and completely replaced after two to three days. It is controlled by a separate, by radio with the pod connected unit (so-called Personal Diabetes Manager - PDM). Patch pumps were introduced in the U.S. about 2007 and have been since mid-2010 also available in Europe. The disadvantages of this type of pump are that they are equipped with only a single needle type ( both needle material and needle length are predetermined and can not be varied as necessary ) that the pump unpleasant projects depending on the fit to the body and that in case of problems not only a catheter must be replaced with a needle, but the complete pump.

Infusion

An infusion with insulin pump therapy is a tool for continuous subcutaneous insulin infusion. The bag with its needle must be changed every two to three days or relayed. Insulin catheters are available in different lengths with different needle sizes as soft catheter with a flexible plastic cannula Teflon catheter or with classic steel cannula. Some patients do not tolerate steel cannulas, or find Teflon catheter more comfortable to wear. Furthermore, there are two catheter connection systems to connect the catheter with the reservoir of insulin currently on the market. Most insulin pumps use the standard Luer - Lock connector for connection of the catheter. For other systems, there are now a suitable adapter ( LuerP500S/700S ), so that there is no dependence on the catheter system of the pump manufacturer more.