Continuous subcutaneous insulin infusion is a common therapy for patients with type 1 diabetes, involving the continuous delivery of fast-acting insulin according to preset basal rates. The standard EN 60601-2-24 describes test settings and procedures for the evaluation of infusion pumps in general; however, no acceptance criteria relating to insulin delivery accuracy are stipulated. Most manufacturers specify a basal rate accuracy of ±5%, at least for larger basal rates.
In this study, the accuracy of different insulin pumps was evaluated in an experimental setting based on EN 60601-2-24. The insulin pumps Accu-Chek® Insight, Accu-Chek® Spirit Combo, Animas® Vibe®, MiniMed® 640G, Paradigm® Veo™ and mylife™ OmniPod® were tested with different infusion sets (IIS). Evaluations were based on the determination of weight increase of a water-filled, oil-covered beaker placed on an electronic balance into which insulin was delivered by the pumps. Pumps were installed outside of the balance with the infusion set or a steel pipe (for the patch pump), respectively, connected to the beaker. After priming, a basal rate of 1.0 U/h was run for 72 h while weight increases were recorded. Each combination of insulin pump and IIS was tested 9 times. The total delivery as well as mean delivery over 1-h windows was calculated.
The total weight increase for all pumps was slightly higher than expected for the programmed basal rate (+0.3% to +2.1%), but within the range specified by the manufacturers. During the first 24h, larger deviations between the measured and expected delivery were recorded. For 8 of 10 systems, more than 95% of 1-h windows were within ±15% of the weight increase expected with the preset basal rate.
Using a basal rate of 1.0 U/h, all tested systems showed minor deviations when analyzing a period of 72 h; however, stability during the run time, i.e., variation from hour to hour, differed considerably between the tested systems. This might be important with regard to the clinical use of insulin pumps.
G. Freckmann: Speaker's Bureau; Self; Ascensia Diabetes Care. Research Support; Self; Ascensia Diabetes Care. Speaker's Bureau; Self; Roche Diabetes Care Health and Digital Solutions. Advisory Panel; Self; Roche Diabetes Care Health and Digital Solutions. Research Support; Self; Roche Diabetes Care Health and Digital Solutions. Advisory Panel; Self; Abbott, Novo Nordisk Inc.. Consultant; Self; Sensile Medical AG. Speaker's Bureau; Self; Ypsomed AG. U. Kamecke: None. D. Waldenmaier: None. C. Haug: None. R. Ziegler: Advisory Panel; Self; Abbott. Speaker's Bureau; Self; Roche Diabetes Care Health and Digital Solutions. Advisory Panel; Self; Novo Nordisk A/S. Other Relationship; Self; Sanofi-Aventis. Speaker's Bureau; Self; Animas Corporation.