RenOx: A Novel Artificial Lung Device with Integrated Kidney Support
Ana Martins Costa is a PhD student in the department Engineering Organ Support Technologies. (Co)Promotors are prof.dr.ing. J. Arens and dr. F.R. Halfwerk from the faculty Engineering Technology, University of Twente.
The main function of the lungs is to provide oxygen to blood and tissues while removing carbon dioxide resulting from metabolic functions. Approximately 15 L of oxygen is exchanged in the body every hour in an adult person with healthy lungs. Acute or chronic severe lung diseases affect millions of people worldwide impairing the lungs’ gas exchange function. Conventionally, patients with severe respiratory failure are treated with medication and mechanical ventilation. However, when conventional approaches are no longer sufficient for critically ill patients, artificial lungs, also known as extracorporeal membrane oxygenation (ECMO), provide a lifesaving alternative. Respiratory support is delivered by pumping blood out of the body (extracorporeally), across numerous gas exchange membranes inside an oxygenator. The membrane capillaries function similarly to the lungs´ alveoli. Oxygen flowing inside gas exchange hollow fibers diffuses into the blood while carbon dioxide diffuses from blood to the gas phase to be eliminated.
ECMO patients suffer from multiple complications, with acute kidney injury being one of the most frequent, affecting up to 70% of ECMO patients. State-of-the-art treatment for ECMO patients with acute kidney injury involves separate circuits for lung support (ECMO) and kidney support (continuous renal replacement therapy – CRRT). The need for separate extracorporeal circuits requires a higher number of blood contacting pumps, tubing, cannulas, and membrane devices (oxygenator and dialyzer), and increasing costs and risks including bleeding, blood cell damage, and blood coagulation.
In this PhD thesis, a novel approach to provide simultaneous lung and kidney support for ECMO patients with acute kidney injury was developed with the aim to reduce current treatment complications. The overarching objective of the dissertation was to develop a novel device that is able to simultaneously provide gas transfer, toxin clearance, and filtration in levels required to support patients with combined lung and kidney disease.
· In Part I of this dissertation, the need for the development of a novel technology combining extracorporeal lung and kidney support is evaluated, exploring current literature to answer the research question: How might we improve extracorporeal lung and kidney support for ECMO patients?
· Part 2 focuses on the development of a hollow fiber membrane-based device. Basic technical questions are answered to allow for a novel device (called RenOx) to combine two different types of hollow fiber membranes, i.e. gas exchange and dialysis membranes, while supporting lungs and kidneys sufficiently.
· Part 3 contributes to the physical prototyping of the first RenOx device. In this section, we designed, and verified a novel device aiming to provide integrated lung and kidney support for critically-ill patients.
Our first proof-of-concept RenOx prototype delivers an initial approach to attend clinical needs of a safer combined artificial lung and kidney device. The RenOx integrated membrane bundles allowing for a compact device with similar surface area and priming volume as a single ECMO oxygenator yet aiming to deliver both lung and kidney support. This single circuit possibly reduces complications of using separate ECMO and CRRT circuits. Future cooperation between engineers and medical professionals is important to evaluate the RenOx’ role in in-vivo (animal) studies and to further develop this technology to benefit critically ill patients.
