Insulin pump

From Freepedia

An insulin pump is a device used for administering insulin in the treatment of diabetes mellitus.

The device consists principally of three parts :

• the pump itself including controls, processing module, and batteries
• delivery tube to carry the insulin
• needle or more commonly a catheter inserted into the body subcutaneously

The insulin pump delivers a single type of fast-acting insulin in two ways :

• a basal (small) dose that is delivered constantly
• a bolus dose that is delivered before meals or to correct high blood glucose levels

Because a single type of insulin is used, it is easier to determine the effect of a given dose by looking at the delivery profile of that insulin. Insulin pumps also make it possible to deliver much smaller amounts of insulin than can be injected using a syringe. This provides tighter control over blood sugar and Hemoglobin A1c levels, reducing the chance of long-term complications associated with diabetes.

The amount of insulin delivered for a bolus is determined by the bloodsugar level and the grams of carbohydrates consumed. In all cases, delivery rates are determined by the user in consultation with his endocrinologist. Currently there is no means to automatically control the insulin delivery based on the blood glucose level of the user. However, the two main manufacturers of pumps, Medtronic (Paradigm, Minimed), and Roche Diagnostics (Disetronic H-Tron and D-Tron) are testing the concept of a closed-loop system but even if the concept is as promising as it appears there remains the legal problem of what happens if the system is incorrect. For example, continuous blood glucose monitoring technology can report very wide variances of blood glucose. Using the non-US measuring system of mmol/l a closed-system that detects glucose of say, 15 mmol/l might dispense 10u of fast acting insulin. If the patient has an actual glucose of 6 mmol/l (within the accepted glycaemic range), those 10 units of insulin could very quickly lead to hypoglycaemic coma which if not recognised and treated can kill very quickly. There is a lot more research to do on CBGM technology but the first closed-loop systems may be made available for clinical trials by mid-2006.

Use of insulin pumps is increasing as it provides an easier means to deliver multiple insulin injections for those using intensive insulinotherapy. It's alo interesting to note that because of differences in health insurance and public funding, the US has about 150,000 pump users. In the UK, where public funding is limited, most patients have to self-finance their pumps. Because of this, there are maybe 1100 pump users in the UK by comparison.