dimanche 1 juin 2014

Dialyse portable espoir


Frank Simonis1, Leonidas Lymberopoulos2, Marc Correvon3, Sjoukje Wiegersma4, Jasper Boomker5, Hassan Anis6, Julien Fils7, Jens Hartmann8, Maarten Wester9, Frank Poppen10
Nanodialysis, Oirschot, Netherlands2EXUS SA, Athens, Greece3CSEM, Neuchâtel, Switzerland4TNO, Eindhoven, Netherlands5Nierstichting, Bussum, Netherlands6IMST, Kamp Lintfort, Germany7CEA-LETI, Grenoble, France8Donau University, Krems, Austria9UMCU, Utrecht, Netherlands10Offis, Oldenburg, Germany.

Wearable system for continuous dialysis. A wearable dialysis system enables a slow and continuous 24/7 dialysis treatment resembling the functioning of healthy kidneys. Hereby variations of concentration levels in the blood can be kept to a minimum. Thanks to the prolonged dialysis duration, the blood clearance can be improved. Wearability however requires a small and lightweight system.

METHODS: Dialysis using sorbents: in Nephron+ a new dialysis technology is applied based on sorbents. This eliminates the need of 120 liters of dialysate. Blood from a patient is passed through a dialyzer where toxins are exchanged to a dialysate circuit containing only 150 ml dialysate. This dialysate is circulated through a sorbent unit assisted with electro-oxidation for continuous regeneration/refreshing. Compared to thrice a week in-center hemodialysis the Nephron+ system can dialyze 150 hours per week, a factor 10 slower. Blood tubings and dialyzer filter can therefore be downsized to pediatric size which is prerequisite for a wearable device. Excess water is removed in ultrafiltration mode.
Continuous monitoring and control: a range of inline sensors has been developed in order to control the blood clearance and to secure a safe operation. Examples are electrochemical sensors for K, Ca and pH, bubble detection and sensors for pressure, temperature, conductivity and redox state.
Webportal for remote surveillance and personalization of treatment: the Nephron+ dialysis system is remotely monitored by a medical center. Messages and alarms generated by the operating system and sensor data from the wearable artificial kidney are being sent and logged to a webportal. Both doctor and patient have access to the history and actual status of the device and the running treatment. This includes sensor readings, clearance rate, battery status and operation mode. Patient parameters as blood pressure and weight are also recorded once a day. Together with feedback from the patient about his health condition (activity level, sleep, feeling well or sick) a database is generated that can be analyzed by the doctor. Based hereon the treatment and the settings of the device can be adapted and fine-tuned to the personal needs of the patient.
Prototype versions have become available in 2012 and 2013 which have been submitted to extensive in-vitro efficacy tests using animal blood and used dialysate. Adequate clearance of electrolytes, urea and other organic toxins was proven. The current prototype that is in use for animal trials has a weight of 3.2 kg. It has a display for manual control but the device can also be controlled via the smartphone. A weight reduction to 2 kg, including battery, is feasible.

The Nephron+ concept for continuous wearable dialysis has been proven both by in-vitro and in-vivo tests. In order to prepare the system for clinical trials, research effort is now directed to assess the safety and biocompatibility aspects of the system.

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