To ensure the dialysis safety, the Integrated Dialysis Facilities, together with a number of dialysis centres in Hong Kong, formed an ad hoc committee to draft dialysis safety guidelines. The ad hoc committee held a meeting on 29 September 1998 in the Hong Kong Baptist Hospital to discuss the safety guidelines of haemodialysis units as part of the risk management procedure

In the drawing up of the guidelines, we also made reference to the recommendation by the Association for the Advancement of Medical Instrumentation (AAMI) and the Centre for Diseases Control (CDC) in America.

1. Although de-ionisers together with filters can be used to provide water treatment for home haemodialysis, reverse osmosis producces pyrogen free water. All renal units should have a RO system together with the filter, water softener and carbon filter.
2. The water quality has to be monitors to safeguard patient safety. The recommended monitor procedure by ASMI was reproduced below for reference

Limulus amebocyte lysate test is not widely available in Hong Kong and we recommend the following procedure:

a. monitoring of the conductivity (or the resistively) of the product water

b. take monthly culture of the water for bacteria. The Total bacterial count in the product water should be less than 200 cfu/ml.

c. Hong Kong water also contains chlorine used for sterilization. Chlorine can be removed by the charcoal filter. The adsorptive power of the charcoal can exhaust without warning and the chlorine may enter into the patients' blood stream causing haemolysis. Checking of chlorine at regular intervals, depending on the age of the charcoal filter and flow rate is recommended.

1. The RO system should be regularly sterilized according to the manufactures' recommendation and load on the system (ie the water flow rate. The AAMI guidelines further state that it is the responsibility of the RO system manufacturer to recommend a method of disinfection that will meet the standard, and that it is the user's responsibility to monitor and validate the process.

1. The product water should be tested for sterilant residue after sterilization. The use of Clinitest to test for residual formaline is dangerous. The sensitivity of Clinitest is only at 80 ppm range and this is 16 times the recommenced standard of 5.0 ppm AAMI. It is also non-specific (depending on the oxidizing reaction of copper sulphate). Reagent strips are available which depends on the oxidation of the formaldehyde by formaldehyde dehydrogenase. They are specific and sensitive.

Schiff's reagent can also be used for testing residual formaldehyde; it is originally designed as a qualitative test in laboratories. When used to test residue formaldehyde, the test procedure should be set up so that it can detect formaldehyde of 5 ppm.

2. No patient should be put on the dialysis until the test procedure for residual chemical is complete. The result of the test should be entered in a logbook with the date and time of the test, method of tests used and signature of the staff.
3. While it is a common practice to turn off the RO system when not in operation, it should be emphasised that stagnate water grows microbes. If a system is left idle for more than 24-48 hours, it should be stored in disinfectant.
4. All disinfection regimens should be well documented, monitored, and validated on a continuous basis.

1. the dialysis staff should maintain good communication with the maintenance workers. The maintenance team should be informed of the problem before they started the work.
2. It is preferable that the piping in the water treatment system should be labeled.
3. No patient should be put on dialysis when the water treatment system is under maintenance. If there is a backup system in the unit, it is possible for patients to be put on dialysis using the backup system provided that the two systems are completely separated from one another, the dialysis and maintenance staff understand the situation. Another no circumstances can the first system be started while the patients is under dialysis.

2. Infection Control (Dialyser reuse)

a. Only pyrogen free water can be used for rinsing of dialysers

b. Dialysers can be reused. They can be sterilized with formaldehyde or peracetic acid. The dialyser should be tested for residual sterilants before use. Sensitive reagent strips are available for peracetic acid (sensitivity <3 ppm) or formaldehyde. If Clinitest is used for testing residual formaldehyde, the dialyser and blood line system need to be recalculated for 15 minutes before use so that residue formaldehyde can be removed.

c. The reprocessed dialyser should be properly labeled.

3. Infection Control (Machine sterilization)

Dialysis machines should be sterilized according to the recommendation from the manufacturer. The following recommendation from the CDC may provide some useful reference:

1. External surfaces of the machine should be cleaned or disinfected

after each treatment of a patient.

2. Venous pressure isolators or transducer filters should be used to

prevent blood contamination of venous and arterial pressure monitors.

These isolators and filters should not be reused.

3. HBsAg positive patients should be treated in an isolation room on a

dedicated machine. If this is not possible then they can be treated in

the general treatment room area away from the mainstream of traffic

using anti-HBs positive patients as a buffer.

4. There is no data regarding the use of heat to inactivate HBsAg+

with the exception of data published by Bond et al, regarding

inactivation of HBV at 98ķu for one minute. The efficacy of 60ķu for

1o hrs varies with the titre of HBV in the inoculum.

4. If a blood leak occurs, the standard disinfection procedure recommended by the manufacturer to control bacterial contamination is appropriate.