Inulin pump is a device that delivers insulin to diabetes patient without needing an injection. The insulin delivery system of a pump consists of two parts, first is the continuous delivery or "basal insulin" and the second is the coverage for meals or "bolus insulin". The pump delivers only one type of insulin, rapid-acting insulin. The basal insulin is equivalent to long-acting insulin and the hourly rate at which a pump delivers insulin is called "basal rate". For example, if the basal rate is set at 1 unit per hour throughout the day, the total amount of basal insulin would be 24 units. As for the bolus insulin, The amount depends on the amount of carbohydrate and the blood sugar level before the meal. The calculation method is identical to the multi-dose insulin injection regimen but the pump will automatically calculate the dose based on the programmed carbohydrate ratio and insulin sensitivity factor after the patient enters the amount of carbohydrate and the blood sugar level. The pump settings are usually set by the healthcare provider.
Insulin is usually stored in the reservoir and is delivered through a plastic tube and then enters the body via a plastic catheter. This plastic catheter is inserted under the skin by the patient or the caregiver. The catheter can be left under the skin between 2-3 days.
New insulin pump models
Tubeless insulin pump (Omnipod): This type of insulin pump stores the insulin in the "POD" which connects to the catheter directly. The patient can wear each POD between 2-3 days and it is disposable after each use. The POD is controlled by a Personal Diabetes Manager (PDM). The newest PDM model (DASH) has a touch-screen function which makes it very easy to use.
Tandem t:slim X2: This model has also a touch-screen function and its reservoir can hold up to 300 units of insulin. This system can also link to the Dexcom glucose sensor and the newest technology, Basal IQ, will also suspend the basal insulin if the sensor predicts that blood sugar will drop below 80 mg/dl.
Hybrid closed-loop system: The close-looped system incorporates the data from the glucose sensor and automatically adjust the insulin delivery to keep the blood sugar levels closest to the target range. The currently approved models are Medtronic 670G and 770G. Both models use Medtronic's Guardian glucose sensor.