Researchers and manufacturers are developing three main categories of Artificial Pancreas Delivery Systems . They differ in how the insulin pump acts on readings from the continuous glucose monitoring system.
The goal of a threshold suspend device system is to help reverse a dangerous drop in blood glucose level (hypoglycemia) or reduce its severity by temporarily suspending insulin delivery when the glucose level falls to or approaches a low glucose threshold. These are sometimes referred to as "low glucose suspend systems."
This kind of system serves as a potential back-up when a patient is unable to respond to a low blood sugar (hypoglycemic) event. Patients using this system will still need to be active partners in managing their blood glucose levels by periodically checking their blood glucose levels and by giving themselves insulin or eating.
An insulin-only system achieves a target glucose level by automatically increasing or decreasing the amount of insulin infused based on the CGM values. These systems could be hybrid systems that only automatically adjust basal insulin with the user manually delivering bolus insulin to cover meals, or could be fully closed loop systems, where the system can automatically adjust basal insulin and provide insulin for meals.
A bi-hormonal control system achieves a target glucose level by using two algorithms to instruct an infusion pump to deliver two different hormones – one hormone (insulin) to lower glucose levels and another (such as glucagon) to increase blood glucose levels. The bi-hormonal system mimics the glucose-regulating function of a healthy pancreas more closely than an insulin-only system.