All Insulin Pumps Are Not Equivalent: A Bench Test Assessment for Several Basal Rates.

Background and Aims: Continuous subcutaneous insulin infusion (CSII) is a widely adopted treatment for type 1 diabetes and is a component of an artificial pancreas. CSII accuracy is essential for glycemic control, however, this metric has not been given sufficient study, especially at the range of the lowest basal rates (BRs), which are commonly used in a pediatric population and in closed-loop systems (CLSs). Our study presents accuracy results of four off-the-shelf CSII systems using a new accurate method for CSII system evaluation. Materials and Methods: The accuracy of four off-the-shelf CSII systems was assessed: Medtronic MiniMed 640G®, Ypsomed YpsoPump®, Insulet Omnipod®, and Tandem t:slim X2®. The assessment was performed using a double-measurement approach through a direct mass flow meter and a time-stamped microgravimetric test bench combined with a Kalman mathematical filter. CSII accuracy was evaluated using mean of dose error. Mean absolute relative difference (MARD) of error was calculated at different observation windows over the whole series of tests. Peakwise insulin deliverance was assessed regarding stroke regularity in terms of frequency and volume. Results: Mean error values indicate a general tendency to underdeliver with up to -16%. MARD of error shows very wide results for each pump and each BR from 7.4% (2 UI/h) to 61.3% (0.1 UI/h). Peakwise analysis shows several choices for BR adaptation (frequency for Omnipod, volume for Tandem, both for YpsoPump and MiniMed 640G). Precision in interstroke time appears to be better (standard deviation [SD] at 0.1 UI/h: 4.6%-12.9%) than stroke volume precision (SD at 0.1 UI/h 38.3%-46.4%). Conclusions: The accuracy of four off-the-shelf CSII systems is model and BR dependent. CSII imprecision could be due to a variability in volume and/or frequency of strokes for every pump. Some models appear better adapted for the smallest insulin needs, or for inclusion in a CLS. The clinical implications of these delivery errors on glucose instability must be evaluated.

Infective endocarditis in French Polynesia: Epidemiology, treatments and outcomes.

BACKGROUND: French Polynesia is a French overseas collectivity in the South Pacific Ocean, where data on infective endocarditis (IE) are lacking. AIMS: To investigate the epidemiology and outcomes of IE in French Polynesia. METHODS: All hospital records from consecutive patients hospitalized in Taaone Hospital, Tahiti, from 2015 to 2018, with an International Classification of Diseases, 10th revision, separation diagnosis of IE (I330), were reviewed retrospectively. RESULTS: From 190 hospital charts reviewed, 105 patients with a final diagnosis of IE, confirmed according to the modified Duke criteria, were included. The median duration of follow-up was 71 days (interquartile range 18-163 days). The mean age was 55±17 years, and there were 68 men (65%). Thirty-five patients (33%) had a history of rheumatic carditis and 43 (41%) had a prosthetic valve. There were 40 (38%) cases of staphylococcal IE, 32 (30%) of streptococcal IE and six (6%) of enterococcal IE. Cardiogenic shock, septic shock and clinically relevant cerebral complications were strongly associated with death from any cause (hazard ratio [HR] 16.85, 95% confidence interval [CI] 5.45-52.05 [P<0.001]; HR 2.62, 95% CI 1.23-5.56 [P=0.01]; and HR 4.14, 95% CI 1.92-8.92 [P<0.001], respectively). Seventy-three patients (69%) had a theoretical indication for surgery, which was performed in 38 patients (36%). Lack of surgery when there was a theoretical indication was significantly associated with death (HR 6.93, 95% CI 3.47-13.83; P<0.0001). CONCLUSIONS: The pattern of IE in French Polynesia differs from Western countries in many ways. Postrheumatic valvular disease remains the main underlying disease, and access to emergency heart surgery is still a challenge.

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

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.