Carolyn Robertson

ARE YOU A CANDIDATE FOR AN INSULIN PUMP?

Maybe. But first you need to know a few facts about the therapy - what it is; what it does; as well as what is does not do. An insulin pump is an electromechanical device which delivers a steady supply of insulin. A pump is small (about the size of pager), lightweight, battery powered and expensive ( ~$5000.00). It is an external device which can be worn on a belt, in a pocket or in a holster like device hidden under clothing. A pumps consist of three distinct parts: a programmable computer; a reservoir which is filled with a short-acting insulin and a tubing. One end of the tubing is attached to the pump; the other end is connected to a needle which the user inserts into an area of fat (usually the stomach). The pump user must change the reservior and the tubing every 48 hours. A pump is manually programmed to deliver a continuous supply of insulin (basal); larger volumes of insulin (boluses) - can be delivered by the user as needed (usually before meals or when blood sugar adjustments are desired).

While this combination of insulin delivery partially mimics the manner in which insulin is released by the nondiabetic beta cell, an insulin pump is not a replacement for a normally functioning beta cell. In the nondiabetic individual, insulin is secreted directly into the liver; a pump does not. It delivers the insulin into the fat. As a result, the pump is much slower than Mother Nature in meeting the individual’s needs. Additionally, the delivery of insulin is not automatically adjusted to the individual’s requirements. It is based on a set of instructions which must be entered into the pump’s computer. In other words, a pump does not measure a person’s blood sugar level nor does it vary the volume of insulin delivered based on the blood sugar of the moment. As with traditional insulin therapy, these tasks must be performed by the pump user. The individual who is using a pump must still monitor his blood sugar levels to decide when insulin is needed and how much of a dose is necessary. The pump user must still decide how to modify that dose dependent on food, activity and stress levels. And then, the pump user must program the pump to make the desired alterations. Additionally, the pump user must care for the pump - changing the reservoir and the needle every 48 hours. In some ways a pump takes more work than traditional insulin therapy.

In spite of these limitations, over 32,000 individuals are using the insulin pump as a therapy to manage their diabetes. A pump can allow the user to mimic the nondiabetic pattern of insulin secretion better than traditional insulin therapy. Yes, current insulin regimes can be designed to provide the insulin user with some flexibility and they can be selected to match the lifestyle of the user. But, they have several limitations. They utilize combinations of short and long acting insulin formulations which must be injected several times a day. For many insulin users, the long acting insulins such as Lente or NPH are not predictable. In other words, even though the insulin is taken at the same time and under the same situations, the actual release of the insulin to the blood stream is not consistent dose to dose. This often creates fluctuating blood sugar levels that have nothing to do with food intake, activity or the individuals lifestyle. The frequency of injections also affect the blood sugar level. The longer the delay between injections, the more likely that the level of available insulin will begin to wan allowing the blood sugar level to rise. Additionally, long acting formulations often cannot provide a sufficient level of insulin to achieve a target blood sugar in the morning without the risk of nighttime hypoglycemia. Also, the duration of the insulins used and the frequency of the injections that are actually taken determines when and how often the individual can eat, exercise and sleep . This forces the individual to make concessions and even with those concessions, it does not guarantee that target blood sugars can be acheived.

On the other hand, pump therapy has several advantages not common to multiple daily injections. Insulin delivered by pump is released predictably. Once the insulin requirement is determined , the pump can be programmed to match that requirement. It will deliver the insulin the same way day after day. The delivery can also be programmed to minimize the risk of nightime low blood sugars and maximize the likelihood of waking with a normal blood sugar in the morning.

A pump is an advantage for those individuals who have no schedule- individuals who change their daily activities daily,and for individuals who have a pronounced elevation in their morning blood sugar levels. However, a pump takes time, patience and work. It requires time to learn the system, to master the new method of insulin delivery. It takes time to adjust to wearing a device, to being open to questions about both the pump and the reason why you need one. It takes a committment from the individual with diabetes and from the diabetes professionals they work with. However, if the promise of being able to sleep late, wake with more normal blood sugar levels and skip meals is attractive, then the pump may be for you. To learn more information regarding pump therapy, ask your diabetes health care team. You can also visit the web sites or call the toll free number of both Disetronics and Minimed.

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