ESPE Abstracts

Background: For a few years now tubeless disposable patch pumps are available for insulin therapy.

Objective and hypotheses: Alarmed by initially non explainable beginning metabolic decompensation of two children with type 1 diabetes during their hospital stay for the initial therapy adjustment with patch pumps and alarmed by patients’ reports of frequent premature pump changes and alarms, we decided to scrutinize the patch pumps under laboratory conditions.

Method: Ten patch pumps with different lot numbers were successively filled with insulin (2 ml) according to instructions, brought into the horizontal, fixed on a reagent vessel and hermetically sealed. Subsequently the pumps were activated via control device and the cannulae ‘inserted’ into the reagent vessel. After the expiration of exactly 72 h under a constant basal rate (0.5 U/h) the volume of the collected insulin of each pump was pipetted. Additional patch pumps delivered boli à 0.5, 5.0, and 15.0 U respectively into reagent vessels and again the volume of the escaped insulin was measured.

Results: One of the ten patch pumps under constant basal rate gave alarm (‘blocked’) before expiry of the 72 h and was taken out of analysis. The mean volume of the remaining nine pumps was 199.5 μl, the median 215.0 μl with a range of 35.0–284.0 μl. This corresponds to a mean deviation of 50.4% (range 21.1–90.3%) referred to the expected 360.0 μl. The boli à 0.5 E (5.0; 15.0 U) showed a mean volume of 3.6 μl (41.3; 138.2 μl), corresponding a deviation of 30.2% (17.4; 7.9%) of the expected volume.

Conclusion: We conclude that the available tubeless patch pumps by far do not show the desired accuracy and reliability neither with respect to basal rate delivery nor to bolus delivery. A recommendation for usage in the paediatric field cannot be made until technical improvement.