Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
Jungklaus, M.
The hydraulic tissue resistance at the site of a continuous subcutaneous insulin infusion - Determination of the relationship between hydraulic tissue resistance, insulin absorption as well as catheter wear-time in humans with type 1 diabetes mellitus
Humanmedizin; [ Diplomarbeit ] Graz Medical University; 2018. pp. 81
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- Autor*innen der Med Uni Graz:
- Betreuer*innen:
- Pieber Thomas
- Regittnig Werner
- Altmetrics:
- Abstract:
- In the therapy of type 1 diabetes mellitus (T1DM) with an insulin pump, manufacturers recommend changing the infusion catheter every 2 to 3 days. Studies have shown that insulin absorption is improving over the first three days of catheter wear. Further studies have shown that in a large group of patients the duration of catheter wear can be safely prolonged far beyond the recommended 2-3-day period. There are only limited results regarding the change of the insulin absorption beyond day three. An easily obtainable indicator of the efficiency of insulin absorption from the infusion site could potentially be the hydraulic tissue resistance (TR; defined as the resistance exerted by the tissue upon the insulin solution entering the tissue). To assess TR and the insulin absorption over a prolonged catheter wear-time, a clinical study has been conducted within the EU project “AP@home”. The aim of this diploma thesis was the statistical analysis of the collected pressure and glucose data as well as the graphical representation and description of the results. To determine the TR during catheter wear, pressure measurements were performed during bolus delivery using a sensor interposed between reservoir and infusion catheter. TR measurements were performed shortly after the insertion of a new catheter (basal TR) and on each consecutive day until TR reached values that exceeded more than ten times the basal value. To assess the relationship between TR and insulin absorption within a subject, oral glucose tolerance tests (OGTT; drinking solution containing 75g glucose) were performed directly after insertion as well as at the end of catheter wear. At the beginning of each OGTT, an insulin bolus of equal size was administered by an insulin pump. The average catheter wear-time observed in 10 patients with T1DM was 10.4 (6 to 13) days. Average pressure values increased during the catheter wear-time from 24 to 59 kPa (p<0.01). Average TR values increased from 123 to 3670 Pa×s/mm (p<0.01). The average increase in plasma glucose concentration above basal values was 113 mg/dl during the OGTT on day one and 155 mg/dl during the OGTT on the last day (p<0.05). The results indicate that an increase in the TR is associated with a reduction in the insulin absorption. If this inverse relationship between TR and extent of insulin absorption is confirmed in further studies, TR could be used as an indicator of the efficiency of insulin absorption and applied in future insulin pumps for the determination of the optimal wear-time of an infusion catheter.