01 Sep 2010
Four times a day, every day for the past 10 years, 65-year-old Foo Ming Tong hooks himself to a machine via a small tube in his abdomen to flush out body waste, fluids and toxins built up throughout the day – a task his kidneys would do automatically had they not failed.
Healthy kidneys clean the blood continuously by removing excess fluid, minerals and waste. When both kidneys fail in end-stage renal disease, build-up of waste causes symptoms like nausea, swelling and itchiness. A kidney transplant is the best solution, but if the patient is physically unsuitable for surgery or a donor is unavailable, dialysis is the only alternative.
“Dialysis is very inconvenient. I can’t go out for too long and when I’m having dialysis, I can’t really move about,” said Mr Foo, who undergoes a form of dialysis known as continuous ambulatory peritonealn dialysis. The procedure is simple and painless, but Mr Foo needs to be home for the four 20- to 30-minute dialysis or exchange sessions every day.Kidney failure patients in Singapore undergo either haemodialysis or peritoneal dialysis.
In haemodialysis, patients have to go to a centre three times a week for the four- to five-hour sessions.
The dirty blood is circulated through a machine, which removes waste substances and returns the cleaned blood to the body. Peritoneal dialysis can be done at home, with patients using their own peritoneal membrane, a fine membrane that lines the gut and abdomen, as a filter.
The patient has a permanent catheter in the abdomen, which is attached to a bag for waste substances to drain into.
Globally, the number of patients with end-stage renal disease continues to rise every year.
But hope is at hand for dialysis patients like Mr Foo. They may well regain their freedom if a small, portable device in development becomes available commercially.
A clinical trial is under way using a 3kg prototype designed and developed by a team of international doctors, local engineers and researchers. If the trial is successful, AWAK Technologies, the company making the device, will look to develop a second-generation 1kg model.
The device, known as Automatic Wearable Artificial Kidney (AWAK), is strapped around the user’s waist much like a traveller’s money pouch or worn as a backpack, and uses the same principle as peritoneal dialysis to clean the blood.
About 700ml of a solution – the dialysate – is pumped into the body to clean the blood, but unlike conventional peritoneal dialysis, the dialysate and waste are recycled through a cartridge in the device, and reused. The excess water is discarded when the cartridge is changed every 10 to 12 hours.
AWAK Technologies is involving Singapore General Hospital‘s (SGH) Peritoneal Dialysis Centre and a US hospital in the trial. “We were chosen because we are one of the larger and more experienced centres in the Asia-Pacific region for peritoneal dialysis,” said Dr Marjorie Foo, Senior Consultant, Department of Renal Medicine, and Director, Peritoneal Dialysis Programme, SGH.
“This trial aims to give patients highqualityhighquality dialysis, which we hope will improve overall patient survival and quality of life. AWAK will be convenient for patients as the device works like the kidney in giving round-the-clock dialysis.
Exchanges are simplified and can likely be done any time, possibly anywhere, as long as you have the cartridge,” Dr Foo said.
For patients on conventional dialysis, waste removal occurs once every few hours for peritoneal dialysis or every few days with haemodialysis. “But with this device strapped on 24/7, waste is practically removed as soon as it passes into the peritoneum via the bloodstream, with little or no stagnation compared with haemodialysis,” she said.
Dr Gordon Ku, Chairman, AWAK Technologies, said the device could do away with many of the disadvantagesassociated with either type of conventional dialysis, such as disruptions to a normal lifestyle and having to use and store bulky machines and solutions.
Peritoneal dialysis patients have to store bags of solution, a deterrent to overseas travel as arrangements need to be made in advance for these bags to be available at their destination.
By recycling the dialysate, the artificial kidney may help preserve body protein usually lost when dialysate is discarded in conventional dialysis. With AWAK, the risk of infection is significantly reduced because patients stay connected to the dialysis device throughout the day, except when showering. Connecting the dialysis device to the permanent catheter needs to be done only about once a month when the dialysate in AWAK has to be changed, while this procedure is performed several times a day in conventional peritoneal dialysis.
AWAK Technologies will determine the price of the device after the trial, although Dr Ku said the company is looking to lower the costs for dialysis patients.
Peritoneal dialysis costs between half to two-thirds that of haemodialysis, while the latter is priced from about $2,400 to $3,000 per month.
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