Biomedical Engineering Reference
In-Depth Information
ATP bioluminescence assays are performed by swabbing surfaces and using a
hand-held sensor to give a real-time quantitative measurement of ATP from the
surface. Several “quality standards” have been set as relative light unit (RLU)
thresholds, ranging from 100 to 500 [
131
,
133
]. There is no direct correlation
between RLU and microbial contamination, but “hygiene fails” determined by
aerobic colony count and ATP do correlate [
131
,
133
].
Fluorescent material in the form of gel, powder or lotion can be applied to a
surface and its removal assessed by a 'black light' illumination. The percentage of
spots removed is used to evaluate cleaning performance [
129
,
131
] and can be
improved by educational interventions [
129
,
138
]. The removal of marked spots
has been shown to correlate with microbial contamination in some studies
[
131
,
138
]. However, altering the location of fluorescent dye spots reduced the
proportion of objects that were cleaned from 90 % to approximately 60 %, indicat-
ing that staff may “get wise” to the location of the markers and preferentially target
them [
139
]. Furthermore, the sustainability of cleaning improvement by using
fluorescent markers, and probably other assessment methods too, is questionable.
One study showed that cleaning performance measured by the removal of a
fluorescent marker increased from a baseline of 52 to 80-85 % through training
and monthly feedback; [
140
] however, compliance soon returned towards baseline
(57-66 %) when the monthly feedback ceased.
3.8.2 Evaluating and Implementing New Technology
Technological developments to assist with cleaning and disinfection include the
introduction of microfiber cleaning materials, which may be more effective
than standard cloths for removing pathogens from surfaces [
141
]. Designers and
manufacturers of hospital equipment can help by producing hospitals which are
easier to clean [
142
]. For example, the 'Design Bugs Out' initiative in the UK aims
to design hospital furniture and equipment that are easier and quicker to clean
New liquid disinfectants boast improved efficacy and practicability, reducing the
risk for human error during formulation [
77
,
101
,
143
-
145
]. The emergence of
wipes impregnated with bleach [
101
] or hydrogen peroxide [
144
] are promising
developments, which seem to be better tolerated by cleaners and effective for
surface disinfection. Emerging new agents include reformulated hydrogen peroxide
solutions (sometimes called “activated” or “improved” hydrogen peroxide) [
143
,
146
] and electrolyzed water [
145
].
The manual application of liquid detergents and disinfectants is limited by
reliance on the operator to ensure appropriate selection, formulation, distribution
and contact time of the agent. These problems can be reduced by the use of
“no-touch” automated room disinfection (NTD) systems [
83
]. A number of NTD
systems have emerged, which remove or reduce reliance on the operator to ensure
distribution, contact time and process repeatability. These aim to improve the
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