Performance of a Continuous Subcutaneous Insulin Infusion (CSII) Pump With Acoustic Volume and Flow Sensing in Simulated High-Consequence Situations

Abstract

Goal: An insulin pump's failure to deliver insulin in the right amount at the right time is a preventable cause of hospitalization. We evaluated key performance metrics of a novel insulin pump that prevents “silent insulin non-delivery” caused by blockage, delivery of air and site leakage. This is accomplished via an acoustic sensor that measures the volume of insulin delivered with each pulse in real-time. Methods: We tested long and short-term flow accuracy, occlusion-detection time and pressure, and air management of the new device (ND) versus 3 U.S. commercial insulin pumps (CIPs) using standardized methods. Results: The ND outperformed CIPs on long-term basal flow rate error. Occlusion detection was 5 to 22.5 times faster depending on the basal rate and resulted in significantly lower (2 to 5x) pressures at time of occlusion. With air included in the drug reservoir, the tested CIPs can infuse air without detection, while the ND prevented air delivery without interruption. Conclusions: Bench tests of the ND versus 3 commercially available pumps showed improved occlusion detection and air management without flow performance tradeoffs. Additionally, the lower delivery pressure measured at time of occlusion suggests a substantially lower potential for site leakage at both basal and bolus rates. These enhancements combine to decrease the likelihood of silent insulin non-delivery.

Keywords

• CSII (continuous subcutaneous insulin infusion)
• DKA (diabetic ketoacidosis)
• insulin pump malfunction
• metrology for drug delivery
• occlusion detection