Assessment of a Wearable Ultrafiltration Device

Overview

Kidney failure is common. In some people the ability of the kidneys to clean poisons out of the blood gets so low they need to be hooked up to a machine three times a week to do it for them. This is called dialysis. Unfortunately, although this treatment removes those waste products, people who need dialysis die much more often than people who don't need dialysis. Dialysis causes extreme stress on the body and leads to many organs being damaged. Removing fluid from the body quickly causes the equivalent of repeated little heart attacks or little strokes in the brain. Many patients struggle to tolerate having all the fluid that they have drunk since their last dialysis session removed- without unpleasant symptoms of dangerously low blood pressure (which makes the damage worse). Dialysis treatments can be done more slowly or more often, but that means having to spend a lot more time at the hospital and is difficult for the health system to be able to provide the extra treatment time. Could extra fluid be removed in between dialysis sessions? Up to now there has not been a way to effectively do this. Investigators have now designed and built an entirely new, very small and very simplified, device that can do part of what a dialysis machine does. It doesn't clean the blood or replace the need for conventional dialysis sessions, but it can provide additional and gentle removal of fluid which wasn't able to be taken off during a standard treatment session. If this study is successful, it will be the first time that a wearable device has been successfully built and used to take off extra fluid when dialysis patients are not in the hospital. The ability to do this opens up the possibility of, 1) helping to treat patients (both making people feel better and live longer) who can't tolerate getting off all the fluid in the short 3-4 hours they are on the dialysis machine in the hospital, and 2) helping patients who feel OK having the fluid taken off but are silently being subjected to damage to their organs due to the rapid removal, have reduced damage.

The stress of having rapid removal of fluids and waste products condensed into only a 3-4-hour dialysis treatment results in vital organs being repeatedly starved of blood and injured. Our investigators have been at the forefront of demonstrating that the poor outcomes experienced by patients are a direct result from the HD process itself, and these outcomes can be improved by making changes to the dialysis treatment. Our investigators have led the way in showing that taking off too much fluid faster than the body can tolerate causes damage to multiple organ systems; increasing risk of death and symptoms like breathlessness, intense fatigue, long recovery driving cognitive impairment in the brain, and damaging the liver and kidneys (destroying what is left of their own kidney function much faster). Failure to remove the desired amount of fluid during HD is a common occurrence (often due to patient tolerability of treatment time constraints) and is associated with worse QOL, increased HD-induced ischemic injury (heart, brain etc.). Recurrent cardiac injury and loss of contractile function leads to even poorer tolerability of HD and escalating failure to remove accumulated fluid. Patients in this challenging position typically die within 12 months whilst experiencing increased hospitalizations and adversity. Even a modest difference in how much fluid needs to be removed is of great clinical significance. For instance, reducing the amount that is removed during a four-hour dialysis treatment by only 1 liter reduces the risk of severe heart injury (which effects the overwhelming majority of people) during that treatment. Our investigators have completed the essential proof-of-concept phase which has allowed refinement of device design and definition of target focus. The principal focus of this next stage was to build a simplified fluid removal system directed at addressing the challenge of patients being unable to remove all the fluid they need to within the standard dialysis treatment. The proposed study is a feasibility pilot study of both a novel device and therapeutic approach to volume management. Although significant improvement in volume status would be highly impactful, this study will still be deemed a success if initial experience supports that the use of the device is feasible and useable. Investigators intend to study 18 patients in a prospective unblinded fashion, with all recruited patients utilizing the intervention- allowing comparison of primary and secondary end points from baseline assessment and comparison after successful utilization of RUF-D.