2003/3 EDTNA/ERCA Journal Club Discussion Summary

The October 2003 EDTNA/ERCA Renal Care Journal Club discussed the paper entitled  ' Should dialysis machines be disinfected between patients’ shifts?' by André STRAGIER, Belgium. This paper was published in the EDTNA/ERCA Journal XXIX nr.2, pp. 73-76, ISSN 1019-083x.

The paper was discussed and circulated in a group of 532 JC members within the world. Anyone interested in Renal Care can simply become a JC member by subscribing for free at the Journal Club section at: http://www.edtnaerca.org/

The paper has been actively discussed between André Stragier (Belgium), Ian Morgan (UK), Danilo Concepcion (USA), Luc Vonckx (Belgium), Git Eliasson (Sweden), John Stokx (the Netherlands), Henk Gietman (the Netherlands), Bertrand Bellot (Switzerland), Elisheva Milo

(Israel), Elizabeth Lindley (UK), Ray James (UK), Bob Rady (USA), Narayan Venkataraman (Singapore), John Mahalko (USA), Roelf Smit (the Netherlands), Ruth Hyde (USA), Hans Kamps (the Netherlands), Waltraud Küntzle (Germany), John Wright (Scotland), Dave Wheaterill (Canada), Tony Maes (Belgium), Hans Traeger (Germany), Gareth Murcut (UK), Rolf Nystrand (Sweden), Esteban Siga (Argentina), Anne Murphy (Ireland) and Jean-Yves De Vos (Belgium) 

Thanks to all who contributed and all who followed the discussions! 

MESSAGES FROM THE DISCUSSIONS

 Ø      Each dialysis machine has dead spaces, some more than the other ones. As a result, disinfection, cleaning and decalcification procedures are less efficient than anticipated. Also not only will bacteria proliferate in dead spaces but chemical agents will reside too.

Ø      Several centres do not disinfect between patients with no known cross infection incidents. They do disinfect between patients for those patients with blood born viruses and in case of a blood leak ( however, not all blood leaks are of the magnitude that they will be detected by the machines!).

Ø      Several centres claim to always perform a disinfection between patients. They state that it is better to be safe than sorry.

Ø      It is generally recommended and accepted that patients carrying hepatitis B should have dedicated dialysis machines and be isolated in a separate room.

Ø      General hygienic precautions are important! Such as changing gloves between patients, washing hands often enough, clean the outside of the machine and shared surfaces between shifts, using single use materials as much as possible. It is difficult however to have staff always performing the hygienic precautions!

Ø      Special attention to the disposable pressure isolators that are sometimes leaking should be given. Immediately after an incident, replacement of the isolator and tubing and a manual disinfection of the pressure connection port is necessary to avoid infection between patients.

Ø      In centres performing re-processing of dialyzers there is a greater chance of cross contamination inside the re-use area than from the interior of HD machines.

Ø      Viruses getting from a patient in the hydraulic circuit and vice versa is at a low chance. However, the interface between patients is the outlet connection to the dialyzer.

Ø      Renal Care workers still believe that a high-tech dialysis machine is always safe, clean and disinfected if no alarm got off. This is not always true!

Ø      This discussion assumes there is a problem with the HD machines causing or contributing to nosocomial infections, and that present disinfection recommendations and procedures are inadequate.

Ø      If we disinfect after a known positive patient only, what about those patients we do not know about? We must keep in mind that most episodes of virus diseases are detected 14 to 180 days after infection occurred.

Ø      Bacterial growth in dialysis machines occurs mainly during the periods of stand still. So what should be the disinfection interval for machines that are in store? Different practices are given from once a week up to once ever 24 hours. Suggested is to leave the machines connected to the water distribution loop. Dialysis machines used for the production of substitution fluids in haemodiafiltration and haemofiltration should be disinfected between shifts! Standing times for these machines is recommended by the manufacturer not to exceed 12 hours up to 72 hours depending from the manufacturer…although bugs cannot read and do not know in what system they are!

Ø      What about the use of heat?

In 1865 Louis Pasteur demonstrated that heat conveyed by water kills any bacteria or vegetative cells to a safe level. Heat acts on micro organisms by denaturing and coagulation of protein chains. The rate of destruction is logarithmic and dependent on time of exposure and temperature. Heat offers mostly advantages over chemical agents: surfaces where the bugs are located are heated, slits can be heated where chemicals can not enter due to surface tension of the fluid, no risk of residual chemicals, temperature can easily be recorded so it is easy to verify a certain temperature has been achieved for a certain time, micro organisms must adopt the temperature of their environment, it is easy to perform, bugs are not given time to develop if frequently performed.   Spores of some micro organisms are however not affected by the temperatures and time used in dialysis machines, but when the spores germinates and vegetative cells are formed, these cells are sensitive for heat.                                                                           An increased number of failures in mainly older machines (>15,000 hours runtime ) have been seen when using heat disinfections, implying additional costs and time lost.

It is proposed that before actual HD machines are chemically or heat disinfected multiple times a day, the machines must first be better designed to become capable of being subject to the procedures repeatedly.

Ø      However, do not rely on any one method or any one chemical disinfectant. Do both heat and chemicals and use different chemical agents from time to time. Micro organisms are smart and always on the move to survive and reproduce! 

CLOSING WORDS by André STRAGIER

I fully agree that more research is needed on several of the points we were discussing together; if you can contribute to this, please do. 

Firstly, we discussed the issue of HCV cross infection prevention.

The discussion paper stresses the capital importance of the general precautions in the prevention of HCV cross infections. Evidence is also available that HCV cross infections can by incident occur via breaches in the pressure isolators. Therefore we advise to add inspection and care avoiding this route of cross infection to the general precautions; using for example two pressure isolators in line represents a practical extra prevention. 

Some units dialyse HCV positive patients on dedicated machines and in isolation as an extra security. Though this is normally not necessary. However, it is correct that in some situations, especially in high HCV prevalence units, isolation of HCV patients is wishful to avoid HCV cross infections.

To succeed with the general precautions, a rigorous discipline is necessary, without any gaps, always!   

Dialysate is not a suspected route of HCV cross infection.

Secondly, we discussed the importance of machine disinfection between successive patient shifts.

Dialysis machines must be regularly disinfected, including cleaning and carbonate removal but when this exactly occurs is not the most important issue; though this remains a matter of debate! Machine disinfection between two successive sessions is an optimal option in renal units where only two sessions are performed a day. It is anyway important to avoid long machine stagnation times (especially spare machines!).

Keeping dialysate endotoxin levels low is important to avoid chronic patient inflammation.

Patient infection from the dialysis fluid (theoretically possible) can only be excluded if we would use sterile dialysis fluid. Machine disinfection alone is not sufficient to achieve this goal but an extra filtration cascade would be necessary. This makes dialysis treatments more expensive in a first stage but cost saving in the long-term.

Thirdly, a chain is only as strong as it weakest link! Dialysis fluid consists of nearly 93% of RO water. Maintenance of RO water quality however is still too often a weak link.

When you disinfect your RO water distribution, please always disinfect the complete circuit. This is easily performed putting the machines in rinsing phase whilst the disinfecting agent is circulated through the loop and stopping the machines for a two hours disinfection contact time. The disinfecting agent should of course be compatible with your machines.  

Jean-Yves DE VOS (Belgium)

EDTNA/ERCA JC Manager