Efficient Thermobonding Process Forming a Polyurethane Based Diagnostic Catheter with Liquid Crystal Polymer

Diagnostic and therapeutic catheters play an inevitable role in minimal invasive medical procedures. Unfortunately, standard catheters show a limited transducer density and high production efforts. We propose a novel catheter design and manufacturing method using a liquid crystal polymer (LCP)-based flexible printed circuit board (FPCB) and a thermoplastic polyurethane (TPU) elastomer tube. Both components are bond together with a low cost, additive free lamination process at a re-flow temperature of 250° C. The lamination process is improved with a laser welding seam and LCPintegrated microholes preventing delamination. Standardized Mechanical tests were conducted to characterize the bonding. A Peel strength of up to 8.5 N in the radial direction and a non plastic elongation in the axial direction of 10% provide evidence that the thermobonding process is suitable for the production of flexible and mechanically durable medical catheters featuring high electrode densities

Modelling of peristaltic pumps with respect to viscoelastic tube material properties and fatigue effects

Peristaltic pump technology is widely used wherever relatively low, highly accurately dosed volumetric flow rates are required and where fluid contamination must be excluded. Thus, typical fields of application include food, pharmaceuticals, medical technology, and analytics. In certain cases, when applied in conjunction with polymer-based tubing material, supplied peristaltic flow rates are reported to be significantly lower than the expected set flow rates. Said flow rate reductions are related to (i) the chosen tube material, (ii) tube material fatigue effects, and (iii) the applied pump frequency. This work presents a fast, dynamic, multiphysics, 1D peristaltic pump solver, which is demonstrated to capture all qualitatively relevant effects in terms of peristaltic flow rate reduction within linear peristaltic pumps. The numerical solver encompasses laminar fluid dynamics, geometric restrictions provided by peristaltic pump operation, as well as viscoelastic tube material properties and tube material fatigue effects. A variety of validation experiments were conducted within this work. The experiments point to the high degree of quantitative accuracy of the novel software and qualify it as the basis for elaborating an a priori drive correction

Esophageal ECG: The challenge of electrode design

Two commercially available electrode catheters are examined for their suitability in esophageal long-term ECG recordings. Both, electrical sensing characteristics as well as clinical acceptance were investigated in a clinical study including inpatients with cardiovascular diseases. In total, 31 esophageal ECG were obtained in 36 patients. Results showed that esophageal electrodes were well tolerated by the patients. Hemispherical electrodes with higher diameter required more insertion attempts and were associated with increased failure rates as compared to cylindrical electrodes. In contrast, the higher surface area of hemispherical electrodes resulted in significantly higher signal-to-noise ratio. Contact impedance was equal for both electrode types, but esophageal electrodes had lower impedance if compared with skin electrodes