Tandem t:slim pump uses Micro-Delivery Technology to deliver insulin in a “fixed volume chamber” of 1/3 unit per stroke. During the delivery of the 1/3 unit insulin to the infusion line, the syringe also blocks the insulin flowing from the reservoir to the chamber. In the event of syringe failure/stuck, insulin cannot flow from the reservoir to the infusion line, therefore, it is safer. Medtronic MiniMed Pump uses “gear type” pump with complicated safeguarding system, however, not sure whether it fails “safe”, i.e. blocking insulin flow to the infusion line. The information above is obtained from the article below: “How Insulin Pumps Work” by Erika Gebel Berg, Diabetes Forecast, September 2014.
Humalog short acting insulin starts to release 15 minutes after injection and the insulin half-life is 60 to 90 minutes. Insulin dependent T2D has insulin resistance issue, which reduces the efficiency of insulin utilization, i.e. portion of insulin may be degraded before being utilized. Multiple micro-delivery of insulin seems a good idea. Dr. Bernstein suggests limit each pen insulin injection to 7 units for better efficiency. Wish all insulin infusion pump manufacturers disclose their proprietary designs for consideration.
When I am ready to use insulin infusion pump, I will consider a pump with “simplicity” design and more built-in “fail safe” features.
Another interesting article, entitled “Usability and Training Differences Between Two Personal Insulin Pumps” by Noel E. Schaeffer, et al, in Journal of Diabetes Science and Technology, Oct. 14, 2015.