The automated wearable artificial kidney (AWAK) is a device that is targeted to improve the lives of end stage renal disease (ESRD) patients. The goal is to mimic the functions of kidneys, providing continuous dialysis and eliminating physiological imbalance in patients. The concept is not new, with the first wearable kidney reported in the 1970s. However, the device was more like portable rather than wearable due to its weight and size.

Current and past clinical investigations on wearable kidneys has involved the technology of hemodialysis or hemofiltration, which requires anticoagulation of the extracorporeal circulation and are encumbered with potential immunologic and non-immunologic complications of continuous blood-artificial membrane interactions. In addition, both internal and external bleeding can occur which can be potentially life threatening. Alternatively, this drives researchers to work on a peritoneal-based device, which accomplishes dialysis through the autologous peritoneal membrane and requires no extracorporeal circulation. Most importantly, continuous ambulatory peritoneal dialysis (CAPD) has an established successful and safe record for long-term wearability and is currently the most promising route towards the development of AWAK.

In traditional dialysis, removing toxins, correcting fluid and electrolyte balance is not conducted on continuous basis. Thus, toxin levels and fluid volume tend to fluctuate, affecting the patient physiologically and psychologically. This is seen in traditional hemodialysis, where patients are attached to a machine for 3 to 4 hours, three times a week and similarly, in standard peritoneal-based dialysis, such as continuous ambulatory peritoneal dialysis (CAPD) and automated peritoneal dialysis (APD).

Hemodialysis requires approximately 120 liters of purified water per treatment for the preparation of dialysate. High quality water is not readily available in many parts of the world. Additionally, the structure and size of traditional hemodialysis machines make adaptability to varying environments difficult. In response to the need for a versatile, portable dialysis machine which could be used in a variety of environments, sorbent systems for regeneration of dialysate were developed (1).

Central to the development of sorbent technology for dialysis was the need to remove nitrogenous waste products from the body. In 1920, experiments proved that activated carbon could remove nitrogenous waste products such as uric acid, creatinine and color from urine(1).

In 1966, the concept of regenerating rather than discarding spent hemodialysate evolved. While engaged in the purification research of agricultural waste water, Mr. A. Johnson, who was an engineer, thought that the same concept could be applied to waste hemodialysate(3). Together with Drs. Arthur Gordon and Morton Maxwell of Cedars-Sinai Medical Center, they believed that the development of the concept could provide information on uremic toxins and lead to a wearable artificial kidney.

In early 1968, a project based on the concept and development of a complete dialysate supply system using sorbent technology (4) was carried out. The project's goal was to develop a new dialysate supply system that would eliminate the need for large volumes of high quality water and plumbing installations through continually regenerating and reusing a few liters of dialysate. An appropriate combination of sorbents would remove all toxins, maintain the essential concentration of electrolytes and control acidosis and other metabolic disorders (4).

After nearly 5 years of research and development and in-vitro, preclinical and clinical studies, the Recirculating Dialysate System (REDY), was placed on the market in 1973(3,4). The REDY system’s components included the REDY machine, a sorbent cartridge and a dialysate storage container.

The major market for the REDY system was home hemodialysis (3). There was no need to modify the home for installation of plumbing and thus the sorbent system was less expensive to install and operate than a single-pass system. By 1975, an estimated 10,000 hemodialysis treatments per month were conducted using the REDY system (6). The usage of the sorbent cartridge in a portable machine has also initiated the concept of its use in a wearable kidney.

However, starting in 1981, a number of reports appeared implicating the REDY system as a cause of aluminium toxicity in patients on maintenance dialysis. Although this cartridge was immediately taken off the market and replaced with cartridges with negligible aluminium, the perception of potential issues with aluminium impeded larger acceptance of the REDY system.(3)

Recently, in 2007, researchers in Italy have developed a semi-automated system called the Vicenza Wearable Artificial Kidney for peritoneal dialysis (ViWAK PD). The system is based on a long overnight dwell exchange with a continuous flow PD during the day, with a REDY similar cartridge. Patients can monitor and control their therapy wirelessly via a handheld remote or a computer. The device is still in its research and development phase. Till date, the researchers have not submitted any patents. The intention was to allow investigators over the world to further improve its design and technology.

In 2008, researchers at UCLA and the Veterans Affairs Greater Los Angeles Healthcare System have developed a design for AWAK and also signed an exclusive licensing agreement with the Singapore-based company AWAK Technologies Pte. Ltd. to develop a commercial wearable kidney. This device is able to function continuously, just as natural kidneys do, thereby, eliminating physiological imbalance in patients. Incorporating the sorbent technology, this device regenerates and reuses fluid and protein components in the spent dialysate, minimizing or eliminating protein loss.

The nearly 40 year history of sorbent dialysis has shown the adaptability of this unique technology.

With the future of AWAK, the lifestyle of dialysis patients would be much improved. They will undergo 24 hours, 7 days a week dialysis, maintaining their physiological status, at the same time providing them freedom, thereby, resulting in a lifestyle like other healthy persons. This is also a cost effective and ecological friendly solution, as no large volumes of spent dialysate will be dumped after each dialysis.

Since patients will lead a life like a healthy normal being, this will improves the economic well-being of the patient, as patients would be able to work full-time while doing his/her dialysis. Patients could then contribute to his/her own medical expenses after rejoining the workforce. Hence, this will lead to a better work population and performance, and contributing to the country’s economy.