What is an insulin pump?
The most recently available advance in insulin delivery is the insulin pump. In the United States, MiniMed and Disetronic market the insulin pump. An insulin pump is composed of a pump reservoir similar to that of an insulin cartridge, a battery-operated pump, and a computer chip that allows the user to control the exact amount of insulin being delivered.
How big is an insulin pump?
Currently, pumps on the market are about the size of a standard communications beeper.
How does an insulin pump work?
The pump is attached to a thin plastic tube (an infusion set) that has a soft cannula (or plastic needle) at the end through which insulin passes. This cannula is inserted under the skin, usually on the abdomen. The cannula is changed every two days. The tubing can be disconnected from the pump while showering or swimming. The pump is used for continuous insulin delivery, 24 hours a day. The amount of insulin is programmed and is administered at a constant rate (basal rate). Often, the amount of insulin needed over the course of 24 hours varies depending on factors like exercise, activity level, and sleep.
The insulin pump allows the user to program many different basal rates to allow for variation in lifestyle. In addition, the user can program the pump to deliver a bolus (large dose of insulin) during meals to cover the excess demands of carbohydrate ingestion.
How common is an insulin pump?
Over 50,000 people worldwide are using an insulin pump. This number is growing dramatically as these devices become smaller and more user-friendly. Insulin pumps allow for tight blood sugar control and lifestyle flexibility while minimizing the effects of low blood sugar (hypoglycemia). At present, the pump is the closest device on the market to an artificial pancreas. More recently, newer models of the pump have been developed that do not require a tubing, in fact - the insulin delivery device is placed directly on the skin and any adjustments needed for insulin delivery are made through a PDA like device that must be kept within a 6 foot range of the insulin delivery device, and can be worn in a pocket, kept in a purse, or on a tabletop when working.
Probably the most exciting innovation in pump technology is the ability to use the pump in tandem with newer glucose sensing technology. Glucose sensors have improved dramatically in the last few years, and are an option for patients to gain further insight into their patterns of glucose response to tailor a more individual treatment regimen. The newest generation of sensors allows for a real time glucose value to be given to the patient. The implantable sensor communicates wirelessly with a pager-sized device that has a screen. The device is kept in proximity to the sensor to allow for transfer of data, however, it can be a few feet away and still receive transmitted information. Depending on the model, the screen displays the blood glucose reading, a thread of readings over time, and a potential rate of change in the glucose values. The sensors can be programmed to produce a "beep" if blood sugars are in a range that is selected as too high or too low. Some can provide a warning beep if the drop in blood sugar is occurring too quickly.
To take things one step further, there is one particular sensor that is new to the market that is designed to communicate directly with the insulin pump. While the pump does not yet respond directly to information from the sensor, it does "request" a response from the patient if there is a need for adjustments according to the patterns it is programmed to detect. The ultimate goal of this technology is to "close the loop" by continuously sensing what the body needs, and then responding by providing the appropriate dose of insulin. While this technology is a few more years in the making, the strides in this direction continue to grow.
