In preparation for next Wednesday’s Journal Club in partnership with the Healthcare Infection Society around water hygiene (details and registration here), I’ve reviewed this article in the Journal of Hospital Infection. It’s an excellent narrative review on the use of continuous monitoring of key parameters related to water hygiene (e.g. water temperature and flow). Continuous monitoring seems like part of the future of safe water hygiene!

Why I chose this article:

Preventing waterborne healthcare-associated infections, mainly Legionella, Pseudomonas, and non-tuberculous mycobacteria, is a major challenge and an important priority. The best way to prevent waterborne healthcare-associated infections is by keeping hot water hot, keeping cold water cold, and keeping water moving around the system! We currently rely on regular (but far from continuous) temperature readings and assessment of flow through our (complex!) water systems. We know that these are affected by local outlet usage, and the point in time measurement may not be representative of what’s really going on. This review presents a different approach: placing continuous monitoring devices in our water systems to give us a much better idea of the true picture around water temperature and circulation.

Design and methods:

The authors undertook a narrative review of the literature to provide an overview of the prospects for continuous monitoring of key parameters related to water hygiene in hospitals. A total of 37 papers were included in the review, with approximately equal numbers focussing on water temperature, throughout and frequency of usage, and continuous monitoring systems. Oh, and the authors attempt to coin a new phrase: “HAWIs” (healthcare-associated waterborne infections)! Will it stick? Not sure…

Key findings:

• Maintaining water hygiene is challenging in hospitals for many reasons, including old and aging water systems, poor knowledge of the water systems (which have often been modified over the years and much of the pipework is inaccessible), lack of investment in preventative maintenance of water systems, and an ever-increasing group of very immunocompromised patients.
• Several factors related to practice also present challenges to water hygiene. For example, the move towards alcohol gel for hand hygiene and pre-impregnated wipes for surface hygiene reduce the amount of water used and hence reduce the amount of flow through water systems.
• There is strong evidence that temperature is an effective control to prevent HAWIs.
• There must be flow through the system as a whole and through each individual outlet to prevent stagnation and biofilm formation. Low-use outlets are difficult to identify; at least (!) 1/3 of low use outlets are not identified and dealt with!
• Manual monitoring (usually undertaken monthly or even quarterly) does not provide a representative picture of water temperatures throughout a system. Whilst attempts are made to identify a relatively small number of ‘sentinal outlets’ that should be representative of the water system, changes in the local use of the system and fluctuation in water temperature means that a one-off reading on a given day simply doesn’t give a representative picture.
• Continuous monitoring can provide evidence around water temperatures, flow, and individual outlet usage. This helps to give a much more representative picture of the temperature in the system, to identify and define low-usage outlets, and understand flow throughout the system. Continuous monitoring may be labour-saving, reduce carbon emissions by improving efficacy of energy use in water systems, and make inferences about local biofilm formation in order to direct preventative action.

Strengths and limitations:

• This is a narrative review, so methodological weaker than a systematic review.
• There were sufficient articles exploring the use of continuous monitoring systems to make this a comprehensive assessment (I wasn’t certain that there would be at the outset!).
• The cost and cost-effectiveness of implementing continuous monitoring systems was not covered.
• There was no summary of the different approaches to applying continuous monitoring systems to improve water hygiene.

Points for discussion:

• Will we become overwhelmed with data? Who is going to be in charge of reviewing the data, and taking action when things are out of spec?
• Is the main problem with water hygiene management lack of a complete picture about water temperature or flow (which can be improved by continuous monitoring)? Or is it rather inability to respond or lack of organisations investment or focus (which can’t be helped by continuous monitoring, at least not directly)?
• Can we afford to do it? And is it cost-effective if we do?
• What is the relative role of temperature vs. flow in influencing microbiological risk?
• Do we need to do this for sentinel outlets? All outlets? Across the whole system?

What this means for IPC:

Water safety groups should take a very close look at implementing continuous monitoring of key parameters related to water hygiene.

We hope that you can join us for Journal Club next week to discuss this article in more detail, along with one that Phil will present (and plans to blog about next week – so look out for that!).