Background: Accuracy of continuous subcutaneous insulin infusion (CSII) is essential for glycaemic control. Our study presents results of accuracy assessment of three off-the-shelves CSII under fluctuating temperature at 0,5UI/h.
Methods: CSII systems accuracy was assessed by a double measurement approach utilizing a direct mass flow meter and a time-stamped micro-gravimetric test bench combined with a Kalman mathematical filter. CSII was placed inside a chamber of fluctuating temperature: 8h-tests were composed of successions of 1h at 32°C, 1h at 5°C, and compared to 8-hour tests at a 22°C fixed temperature. Accuracy was evaluated using mean of dose error. Mean absolute relative dispersion (MARD) of error was also computed for 15min time-windows. Stroke regularity was assessed in terms of frequency and volume. Tests were conducted both with insulin and medical water.
Results: Delivery errors follow temperature profile. MARD of error is significantly higher with fluctuating temperature (85.2%, 44.4%, 20.4% according to each of the 3 CSII pump models) vs. fixed temperature (13.3%, 9.5%, 12.7%). No difference was observed between insulin and medical water. Stroke volume is affected by temperature changes rather than stroke frequency.
Conclusion: Temperature and its fluctuations may affect the accuracy and amounts of insulin delivered by CSII. The clinical impact of the difference in insulin intake requires clinical investigations.
S. Girardot: Employee; Self; Air Liquide. Employee; Spouse/Partner; Air Liquide. P. Jacquemier: Employee; Self; Air Liquide. F. Mousin: Employee; Self; Air Liquide. C. Rendekeu: Employee; Self; Air Liquide. S. Hardy: None. J. Riveline: None.