An insulin pump is a device slightly smaller than a computer mouse. It administers rapid-acting insulin to the subcutaneous fat tissue through a thin plastic tube and a plastic cannula attached to the skin. The pump itself can be kept in a pocket, for example, or on a bedside table at night. There are also tubeless pumps, which are controlled with a remote.
The cannula placed under the skin on the abdomen, thigh, upper arm, or upper buttock, or the tubeless pump, is self-changed usually every three days. Individually, a shorter replacement interval may be needed if, for example, there are tissue changes or irritation at the cannula sites. Additionally, there are cannulas that are changed once a week. The insulin reservoir of the pump is refilled and changed by oneself every 3-6 days. Some pump models can be linked to a glucose sensor, allowing the sensor's measurements to transfer directly to the pump. The decision on which pump to start with and which cannulas to use is agreed upon individually in collaboration with the treatment facility.
The insulin pump uses only rapid-acting insulin. The pump is set with an individual insulin delivery rate (i.e., basal). The delivery rate, or insulin dose, can be adjusted hourly - but usually, a few different periods are used throughout the day. This so-called basic supply replaces the long-acting insulin used in MDI therapy. The basic supply can be reduced, for example, during exercise or increased in stress situations. An additional dose (or bolus) of the same rapid-acting insulin is taken separately for meals or for temporary blood sugar correction using the pump's button, a remote, or a separate pump control device.
The insulin pump is the best way to mimic the pancreas's normal insulin secretion. The precision of insulin dosing is significantly greater than with MDI therapy. With the pump, it's possible to flexibly and quickly adjust the basic insulin delivery in various situations according to individual needs.