Hemodialysis is a method of renal replacement therapy, used to replace the lost kidney function of patients with advanced kidney disease. Hemodialysis devices replace some of the functions of the impaired kidneys, and work in a similar manner. Blood is pumped continuously from the patient into a dialyzer, and then back to the patient. In the dialyzer, it passes over a semi – permeable membrane. On the other side of the membrane, there is a continuous flow of dialysis fluid. Low molecular weight solutes and water diffuse across the membrane by osmosis, and consequently, waste products and excess solutes and fluids are removed from the blood, while concentrations of essential solutes in the blood are brought back to within acceptable ranges.
A Hemodialysis system essentially comprises an extracorporeal blood circuit to which the patient is linked, usually via a surgically created arteriovenous shunt in the arm. Blood is pumped from the patient to a dialyzer and from there, returned to the patient. In the dialyzer, the blood passes over a semi-permeable membrane. On the other side of the membrane, there is a continuous flow of dialysis fluid. Low molecular weight solutes and water diffuse across the membrane by osmosis, so waste products and excess solutes and fluids are removed from the blood, while concentrations of essential solutes in the blood are brought back to within acceptable ranges.
The dialysis fluid system pumps purified water and electrolytes through tubes to the dialyzer. The waste products are carried out by the system and finally removed to the drain. An electronic detector monitors the outflow for potential blood leakage.
The blood circuit includes a blood pump, which enables the blood line to take blood from the patient’s vein to the dialyzer. To reduce the risk of clotting of the blood, an anticoagulant is added. A monitoring system monitors the temperature of the blood at the returning end of the circuit, as well as the pressure at the input and the output of the dialyzer.
In the dialyzer, the patient’s blood is cleaned of waste and access water. The waste products from the patient’s blood pass through a semi- permeable membrane into the dialysis fluid. It is a diffusive process maintained by a constant state of unequal levels of solute concentration, and as a result, waste products are removed from the blood and replenished from the elecrolytes in the dialysis fluid.
The Hemodialysis machine has an internal computer which enables the blood and dialysis fluid delivery systems to deliver the required prescription, and for the treatment to be monitored. Alarms alert the healthcare professional or the patient to check the device. The microprocessor also enables treatment data to be recorded and stored for monitoring purposes.
Hemodialysis machines are designed so that they are protected against excessive temperatures, liquid spillage, leakage into the electric or electronic parts, interruption of the power etc. Also, there should be a means of disinfection for non-disposable dialysis tubing and fluid pathways.
The adequacy of Hemodialysis treatment can be evaluated by calculating the reduction ratio of the urea or calculating the value of Kt/V, where K is the known clearance rate of the dialyzer, t is the dialysis time and V is the patient’s estimated total body water.
Hemodialysis machines are class IIb medical devices. They should comply with the general performance and safety requirements set out in EN 60601- 1:2006 and the requirements for Hemodialysis devices specified in EN 60601-2-16:1998.
Home Hemodialysis is a form of self-care. Self-care involves patients taking responsibility for their own health by being committed to a healthy lifestyle and the prevention of illness. It is generally applicable to the management of long-term or complex conditions. Self-care Hemodialysis does not have to be carried out in the patient’s home. Some renal centers and satellite units enable patients to self-manage their treatment in centers to a greater or lesser extent, and provide clinical support when required. To carry out Hemodialysis at home, the patient, or in some instances a healthcare provider/partner, learns to use the equipment, measure blood pressure, and to replace needles in the vascular access or attach the dialysis lines without clinical support.
It was found that home Hemodialysis offers a number of advantages, including more flexibility to tailor the dialysis regimen by changing timing or length of sessions, making it easier for the patient to lead a normal life. At present, the conventional Hemodialysis prescription is three 4-hour sessions per week.
Also, there is evidence to suggest that home-based Hemodialysis is more cost-effective than hospital treatment and improves the quality-of-life experienced by patients.
A key consideration in the implementation of home Hemodialysis is the suitability of the patients home and home circumstances. The physical assessment of the home determines whether a suitable location within the home can be assigned to house the device and associated equipment. The assessment also helps to determine if any subsequent conversion or installation work may be required, depending on the device chosen.
Ideally, the equipment should be installed close to the main water supply and drainage facilities. Water quality should be tested to find out if the water requires treatment prior to the reverse osmosis procedure (if applicable), and water pressure should be checked to ensure that it is within acceptable limits. The electrical wiring should be checked and may require upgrading. The patient’s home should be free from general health and safety hazards, including inadequate heating, damp and mold growth.
The interaction between the patient and the device is a key consideration. Home Hemodialysis machines have certain features which enable the patient to interact more easily with the machine, including height and positioning adjustment of the device and of the screen.
Patients who have decided to undertake their dialysis treatment at home will require training on how to set-up and use the Hemodialysis device, as well as how to deal with any issues which may arise during their treatment. The patient will also learn to take care of the device and get it ready for the next treatment. Training patients to connect themselves to the device is essential, as is learning an aseptic cannulation technique.
Home Hemodialysis is likely to impact on the patient’s family and healthcare providers. A healthcare provider can be a family member or a friend. It is not essential for patients to have help to carry-out home Hemodialysis, however, it may be necessary in some cases.
The healthcare provider should have the opportunity to make a fully informed and independent decision whether to assist in the Hemodialysis treatment at home.
Increasing Hemodialysis patients’ awareness of the amount of social support available to them has been shown to enhance self-care abilities and result in a positive health outcome.