Renal Technology Projects
Renal exercise programme
Unmet need: At present haemodialysis patients are treated regularly to remove the build up of fluid and toxins normally lost in the urine. However, dialysis units offer little or no rehabilitation.
The development of devices and protocols for safe and sustainable on-dialysis exercise programmes could help maintain muscle function and prevent patients becoming dependent on wheelchairs or walking aids. Exercise is also a way of introducing an element of self-care for this patient group and can be very rewarding, even helping patients to get fit enough for a transplant.
Solution: D4D have made links with the British Renal Society Renal Rehabilitation Group which has allowed the chance to communicate with teams throughout theUK who are interested in Renal Rehabilitation. A review of published literature has identified a unanimous case for the benefits of exercise programmes in dialysis patients. Current focus is on how best to promote exercise to this patient group and offer programmes which are sustainable and practical on busy dialysis units. We also plan to send questionnaires out to the Renal Rehabilitation Group, asking them about the exercise bikes they use with their patients and the particular specifications needed for an exercise bike used on a renal unit. We hope to facilitate the production of cheap bikes that can be used on dialysis chairs and beds.
Fistula Visualisation Device
Unmet need: During dialysis, patients are connected to the dialysis machine for 4 hours, 3 times a week. During this time, their blood is pumped through the artificial kidney that filters out the waste products at rates of up to half a litre per minute. To achieve these high flows, large needles with a bore of about 1.5mm are required. These needles are too big to insert in a normal peripheral vein so an operation to form an ‘arteriovenous fistula’ is performed. The surgeon connects an artery to a vein, usually in the arm, allowing the pressure from the artery to expand the vein. If the operation is successful, the fistula has the high blood flow needed for dialysis and can accept the large needles.
Fistulae take a few weeks to mature. The earlier the needles can be inserted the better, as this minimises the need to use plastic catheters to access blood from the central veins which are prone to
infection and flow problems. ‘Blows’ and ‘infiltrations’ can occur if the wall of the new fistula is torn or the needle is pushed right through the fistula. This leads to extensive bruising and pain and, not surprisingly, makes the patient anxious about the next attempt to puncture their fistula. Although these problems are most likely to occur in new fistulae, some mature fistulae are more difficult to needle than others, especially for staff who are unfamiliar with the patient.
Ultrasound devices that are intended to help doctors insert plastic catheters into the internal jugular, subclavian or femoral veins are sometimes used to visualise fistulae. However, these devices are not available in many haemodialysis locations, partly because they are too expensive, but also because they are too cumbersome to set up and use in a busy unit.
Dr Mark Wright, a Nephrologist from St. James’ Hospital Leeds who brought this unmet need to the attention of D4D believes that “a small ultrasound device could help staff to locate the fistula and guide the needle into the correct position. This would reduce the frequency of unsuccessful punctures and, in turn, reduce patient anxiety and delays in the dialysis unit. The ideal device will consist of an ultrasound probe and a monitor. It must be very portable and relatively inexpensive if it is to become part of standard practice."
Solution: D4D put a call out for applications from teams for funding and support from D4D to address this unmet need. A grant of £15,000 was awarded to Consultant Nephrologist, Dr Nicholas Fardon and Dr Prashant Verma alongside teams from Sheffield Teaching Hospitals NHS Foundation Trust. They will work on the development of a simple battery powered device for viewing fistulae.
Unmet need: It is recognised that dialysis overnight - or nocturnal dialysis - would be the ideal option for many patients. It not only frees up the daytime, but it also frees the patient from virtually all the food and fluid restrictions normally associated with dialysis.
Demand for nocturnal dialysis is gradually increasing as patients hear of its benefits, but it's currently only offered by a few hospitals. This project aims to identify the barriers that are preventing the wider provision of the service and to provide guidance to overcome these barriers.
Solution: D4D commissioned a survey to attempt to identify the barriers that are impeding the widespread availability of nocturnal haemodialysis as a treatment option for patients with renal failure. It is hoped that this information, alongside other sources, can answer some basic questions potential problems in nocturnal haemodialysis and show how innovative centres and patients have found ways of overcoming these barriers. This work has formed the basis of a series of Frequently Asked Questions about nocturnal haemodialysis. We are also developing a forum which we hope will offer patients and service providers the chance to share concerns and solutions to problems and get feedback from other people involved in nocturnal haemodialysis.
Body Composition Monitoring
Unmet Need: One of the roles of the kidneys that haemodialysis has to take over when the kidneys fail is the control of fluid accumulation in the body. This is achieved by reducing the patient’s weight to a specified target at each dialysis. Getting the target weight right is vital. If set too high, the patient will be constantly overloaded with fluid. Excess fluid in the bloodstream means extra work for the heart, and often leads to high blood pressure. Fluid in the lungs makes the patient short of breath and incapable of normal activity. If the target weight is too low, the patient will be dehydrated which can lead to muscle cramps and low blood pressure, as well as accelerating the loss of remaining kidney function. Target weight is usually based on clinical examination, but this can be misleading. For example, low blood pressure can indicate dehydration, but it could also mean that the patient’s heart is failing. Breathlessness could be due to a chest infection or asthma, rather than overhydration.
Solution: The Fresenius Body Composition Monitor (BCM)uses simple, non-invasive electrical measurements to give an indication of the patient’s ‘normally hydrated’ weight (what the patient would weigh if their kidneys were working properly). This helps staff to adjust the target weight and distinguish between problems during dialysis caused by removing too much fluid and those caused by removing fluid too quickly. The BCM has been validated using measurements made between the hand and foot of healthy individuals. D4D is working with Fresenius to extend the use of this technology to more complex patients. With funding from the , we showed that the BCM can be used in children aged 6 to 14 and that monthly BCM measurements can help guide the treatment of paediatric patients (1). We have also developed the BCM use so it can be used to manage bilateral amputees (2). Currently, we are extending our work to look at patients at the extremes of body mass index, malnourished patients, and patients with abnormal fluid distribution (e.g. lymphoedema) and we have received funding from the Yorkshire Kidney Research Fund to look at the potential for using the device to aid management of patients in intensive care with acute kidney injury. D4D is also working with Fresenius to develop training materials to help ensure the effective adoption of the BCM technology.
The BCM has currently been used in the care of over 700 patients across the 8 dialysis units in Leeds. The test is currently being implemented as part of routine management of patients' target weights. Training is beign rolled out to nurses and healthcare assistants so that all the units can manage their own patients. Based on the success within Leeds the BCM is now being used in the renal units in Bradford and York and being trialled in other units across the UK.
Instant Bedside Potassium Monitor
Unmet need: Potassium (K) is a mineral that controls nerve and muscle (including heart) function. Maintaining K within the normal range is important to maintain a normal heart rhythm and maintain fluid and electrolyte balance in the body. Healthy kidneys remove excess K in the urine to maintain normal levels in the blood. When patients have advanced kidney disease, the kidneys cannot efficiently remove excess K, leading to high potassium levels (hyperkalaemia). The effects of hyperkalaemia include nausea, weakness, irregular heart rate, heart failure and sudden death. In patients who are on dialysis therapy or are approaching the need for dialysis, potassium levels can rise due to high potassium intake in the diet, medications and following surgery. Treatment of hyperkalaemia in these patients is urgent dialysis. Currently electrolytes, including K levels in the blood are measured in the labs and can take up to 24hours to receive the result (within 2 hours if requested urgently in the hospital setting). The ability to monitor K levels of patients in a similar fashion to a glucose meter - i.e a pin-prick test with immediate response - would offer a significant improvement to the current practice and allow immediate treatment.
Solution: Currently, portable monitors are utilised in various settings, including in the community to assess blood gases in patients with respiratory disease and in war zones to monitor measures of kidney function (creatinine). Such a device will provide a simple easy to use potassium monitor that will allow a rapid turnaround of potassium levels to aid patient/clinician discussion. The ultimate goal would be to have a monitor similar to a blood glucose monitor with disposable strips, and tailor made for renal patients that could be used by renal units, local clinics and patients.
The D4D team inLeedslooked at available technology to assess if a currently available product could be adapted to meet the needs of renal patients. This work showed that a hand-held blood analyser, used by a non-specialist, can provide repeatable, accurate results for potassium levels when compared to laboratory tests. However, this device is overly complex and expensive for the needs of renal patients, as it provides measurements for a large range of electrolytes and blood gasses. Work is ongoing to try to develop a smaller, simpler and cheaper device based on the same technology but tailored specifically for the needs of dialysis patients.
A 'Patient-Centred' Haemodialysis Machine
Unmet need: About 50,000 people in the UK are receiving treatment for incurable kidney failure. Of these, about 44% are treated with haemodialysis which is usually provided in hospital or free-standing 'satellite' units. Patients have to attend the dialysis unit three times a week. It takes the dialysis machine about 4 hours to remove the toxins and fluid that has built up in the patient's body. But with the time taken for the staff to connect and disconnect the patient, and for the patient to travel to and from the unit, attending for dialysis can take over 7 hours. Patients who are able to undertake haemodialysis at home not only avoid the travel time and the risk of developing hospital-acquired infections, but also have the opportunity to try alternative dialysis schedules. Home haemodialysis patients are increasingly moving to short treatment sessions 5 or 6 times a week and to dialysis overnight while they sleep. These schedules are associated with improved well-being and survivalcompared to the traditional thrice weekly treatment. Even though patients require their own machine, dialysis at home costs the NHS much less than the labour-intensive centre based treatments. But, despite NICE guidance strongly encouraging renal units to promote home haemodialysis, fewer than 3% of dialysis patients choose this modality.
Solution: In collaboration with D4D, Quanta Fluid Solutions are developing a 'patient-centred' haemodialysis machine, the SelfCare+. This small, user-friendly machine will provide treatment that is just as efficient as a centre-based dialysis. Quanta's first innovative step was to replace the bulky, high maintenance hydraulic systems that prepare the fluid required for dialysis with small plastic components moulded into a disposable cartridge. This means the Selfcare+ can be made light enough to be portable and that it has no internal fluid pathways that require disinfection between treatments. With D4D support, Quanta has obtained an NHS i4i (Invention for Innovation) grant to ensure that the Selfcare+ can meet the needs of potential home haemodialysis patients as fully as possible. Feedback from patients to date is very promising. The SelfCare+ is expected to be approved for sale in Europe in mid-2012. It is hoped that, with more flexible installation requirements, short user training period, rapid set-up and strip-down times and the option of use while travelling, will encourage more haemodialysis patients to opt for, and get the benefits of, self-care in their home.