What is an insulin pump?
An insulin pump is a medical device for insulin pump therapy (continuous subcutaneous insulin infusion engl .: CSII abbreviated). For therapy, the insulin preparation of the pump is not injected several times by 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. To this end, the catheter can disconnect from the pump and seal. 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 produced an insulin pump register here. In Switzerland and Austria 10-20% of type 1 diabetics are treated with insulin pump therapy.
Operating principle
The principle is similar to the intensified conventional (insulin) therapy (ICT): there is a basal rate that meets the basic needs of individual insulin and boluses, which are responsible for meals and corrections values. The concept is called from dissipative basal-bolus principle.
The pump contains a reservoir with only one type of insulin, either with regular insulin or rapid-acting insulin analogue with a. Depending on the pump model as a reservoir 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-insulin vial, like it is used in 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 in contrast to ICT.
When ICT is injected one to three times daily or NPH insulin once or twice daily long-acting insulin analogue with an insulin pen. 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, then the effect levels off. The main active Currently 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 small, evenly spaced from the fast-acting insulin (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 respective pump model selected by him in the operation as well as the determination and adjustment of the individual basal rate, the bolus calculation, dealing with technical problems, pump breaks such. As in sports and other.
Possibilities and limitations
The insulin pump can not replace the function of a healthy pancreas, since it does not determine the blood glucose level independently. There are models with integrated blood glucose monitoring system, but which can not automatically determine the amount of insulin to be delivered. Nevertheless, many diabetics can live almost as healthy people 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 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 in accordance with 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 of diabetics and wakes up with high values, which outlast the breakfast phase. Here the basal rate can be raised by automatic programming during sleep; which leads to significantly better on waking blood glucose mirror.
In systematic reviews that have compared the conventional insulin therapy with insulin pump therapy by patients with type 1 diabetes, the patient reported with pump therapy on a 0.3% statistically significantly better HbA1c. Respect. 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 for technology and catheter material per year were estimated at £ 1000-1400 (1160-1640 €). The studies showed some benefits of insulin pump therapy for both children and adults with mellitus diabetes type 1, but not in diabetes mellitus type 2, or when used in pregnancy. Overall, insulin pump therapy was cost-effective.
Pump functions
Today's insulin pumps offer the following features:
-Multi basal rate programming: Adjustment of basal rate at the different physiological insulin requirements in the course of the day and night
-Programming may be different basal rates to the physiological range, eg in the regular sports burdens on weekdays and weekends, shift work or long distance travel differently: basal programs.
-Bolusoptionen: rapid evolution of a different 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 days dependent insulin sensitivity and the computationally more effective amount of insulin necessary to individually insulin dose.
Some insulin pumps offer:
-Interfaces: Interfaces via 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 under development at:
-Artificial pancreas (closed loop engl.Closed-loop system): A control algorithm receives a continuously measuring glucose sensor (CGM) constantly tissue glucose and regulates insulin delivery via the pump automatically.
Infusion
An infusion with insulin pump therapy is a tool for continuous subcutaneous insulin infusion. The bag with its cannula should be changed every two to three days or relayed. Insulin catheters are available in different lengths with different needle sizes as soft catheter with 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. In addition, there are two catheter-port systems to connect the catheter to the insulin reservoir currently on the market. Most insulin pumps use the standard luer-lock connector for connection of the catheter. For the other systems, there are now suitable adapter (LuerP500S / 700S), so that there is no dependence on the catheter system of the pump manufacturer more.