Kalman Filter-Based Novel Methodology to Assess Insulin Pump Accuracy.

Abstract

Background: Insulin pump or continuous subcutaneous insulin infusion (CSII) system is a widely adopted contemporary treatment for type 1 diabetes and is a major component of an artificial pancreas (AP). CSII accuracy is essential for glycemic control and to-date such metric has not been given sufficient study, especially at the range of the lowest basal rate. The gold-standard assessment method IEC (International Electrotechnical Commission) 60601-2-24 has some limitations. Our study presents a new accurate and reactive method for CSII system evaluation based on direct flow measurement. Materials and Methods: A leading-edge assessment method based on a double measurement approach utilizing a direct mass flow meter and a time-stamped microgravimetric bench test was combined with a Bayesian-based mathematical filter (Kalman). The performance of this new method was evaluated while assessing the delivery precision of an off-the-shelf insulin pump at several basal rates. The proposed methodology offers a double reading-volume and flow rate-which provides direct instantaneous flow rate. CSII dose errors were evaluated using mean absolute relative dispersion (MARD) at different time intervals windows over the whole test. Results: The metrological aspect of the measurements and filtering performance were consistent. CSII precision is shown to be different in terms of the flow rate value: MARD15min (2 UI/h) = 12.7%, MARD15min (0.5 UI/h) = 20.4%, and MARD15min (0.1 UI/h) = 65.0%. MARD240min (2 UI/h) = 8.1%, (0.5 UI/h), MARD240min (0.5 UI/h) = 18.8%, and MARD240min (0.1 UI/h) = 18.4%. Instantaneous flow rate results highlight an irregular stroke-based delivery. Conclusion: This new method to assess insulin pump administration has been validated and highlights the current imprecision in insulin delivery, especially for the lowest basal rate, which is mainly used in pediatric cases and AP system delivery. This leading-edge method should be used to precisely compare several CSII performances in those contexts.