An Experimental Study of Pulsed Micro-Flows Driven by an Insulin Pump

In recent years, there is a surge in the popularity of using insulin pump or continuous subcutaneous insulin infusion (CSII) therapy, as opposed to multiple daily injections (MDI) by insulin syringe or an insulin pen. Some case studies have suggested that insulin delivery failure may be caused by the precipitation of insulin within the infusion set. Speculation also exists that the flow of insulin through an insulin infusion set may be reduced or inhibited by air bubbles entrained into the micro-sized capillary tubing system since there are chances that air be introduced into the insulin reservoir during the filling process. In the present study, an experimental study was conducted to investigate the pulsed microflow inside the micro-sized infusion tubing system driven by an insulin pump. A microscopic Particle Image Velocimtry (micro-PIV) system was used to conduct detailed flow velocity field measurements to characterize the transient behavior of the pulsed micro-flows inside the micro-sized tubing system of an insulin infusion set with an insulin pump operating in basal mode (i.e., pulsed insulin pumping). The effects of the air bubbles entrained into the micro-sized capillary tubing system on the insulin delivery process were also assessed based on the micro-PIV measurements.