WHO Guidelines on Hand Hygiene in Health Care - Safe Care ...

PART I. REVIEW OF SCIENTIFIC DATA RELATED TO HAND HYGIENE
21.4.1.1 Health care-associated colonization and infection: the
prevention targets
The important concepts of colonization and infection associated
with health-care practices have been discussed in depth in Part
I.7.
In summary, four negative outcomes constitute the prevention
targets for hand hygiene: 1) colonization and exogenous
infection of patients; 2) endogenous and exogenous infection in
patients; 3) infection in HCWs; and 4) colonization of the healthcare
environment and HCWs.
21.4.1.2 The core element of hand transmission
During daily practice, HCWs’ hands typically touch a continuous
sequence of surfaces and substances including inanimate
objects, patients’ intact or non-intact skin, mucous membranes,
food, waste, body fluids, and the HCW’s own body. With
each hand-to-surface exposure, a bidirectional exchange of
microorganisms between hands and the touched object occurs
and the transient hand-carried flora is thus continually changing.
In this manner, microorganisms can spread throughout a healthcare
environment and between patients within a few hours. 126,883
The core elements of hand transmission are stripped down
to their simplest level in Figure I.21.4. Effective hand cleansing
can prevent transmission of microorganisms from surface “A”
to surface “B” if applied at any moment during hand transition
between the two surfaces. Typically, surface “A” could be a door
handle colonized by MRSA and surface “B” the skin of a patient.
Another example would be surface “A” being the patient’s
groin and surface “B” being an open vascular access hub. If
transmission of microorganisms between “A” and “B” would
result in one of the four negative outcomes detailed above, the
corresponding hand transition time between the surfaces is
usually called “hand hygiene opportunity”. It follows clearly that
the necessity for hand hygiene is defined by a core element of
hand transmission consisting in a donor surface, a receptor
surface, and hand transition from the first to the second.
21.4.1.3 Conceptualization of the risk: patient zone and critical
site
To meet the objective of creating a user-centred concept for
hand hygiene, the evidence-based hand transmission model
(see Part I.7) was translated into a practical description of
hand hygiene indications. The terms zone, area, and critical
site were introduced to allow a “geographical” visualization of
key moments for hand hygiene (Figure I.21.4a). Focusing on a
single patient, the health-care setting is divided into two virtual
geographical areas, the patient zone and the health-care area
(Figures I.21.4a and I.21.4b).
The patient zone contains the patient X and his/her immediate
surroundings. This typically includes the intact skin of the patient
and all inanimate surfaces that are touched by or in direct
physical contact with the patient such as the bed rails, bedside
table, bed linen, infusion tubing and other medical equipment.
It further contains surfaces frequently touched by HCWs while
caring for the patient such as monitors, knobs and buttons, and
other “high frequency” touch surfaces. The model assumes
that the patient’s flora rapidly contaminates the entire patient
zone, but that the patient zone is being cleaned between patient
admissions. Importantly, the model is not limited to a bedridden
patient, but applies equally to patients sitting in a chair or being
received by physiotherapists in a common treatment location.
The model also assumes that all objects going in or out of the
patient zone are cleaned. If this is not the case, they might
constitute an alternative transmission route.
The health-care area contains all surfaces in the health-care
setting outside the patient zone of patient X, i.e. other patients
and their patient zones and the health-care facility environment.
Conceptually, the health-care area is contaminated with
microorganisms that might be foreign and potentially harmful to
patient X, either because they are multiresistant or because their
transmission might result in exogenous infection.
Within the patient zone, critical sites are associated with
infectious risks (Figure I.21.4a): critical sites can either
correspond to body sites or medical devices that have to
be protected against microorganisms potentially leading to
HCAI (called critical sites with infectious risk for the patient),
or body sites or medical devices that potentially lead to hand
exposure to body fluids and bloodborne pathogens (called
critical sites with body fluid exposure risk), or both precited risks
simultaneously (called critical sites with combined risk). Drawing
blood for example concerns a critical site with combined risk
that is at the same time associated with an infectious risk for the
patient and a body fluid exposure risk for the HCW.
Critical sites either 1) pre-exist as natural orifices such as the
mouth and eyes, etc.; 2) occur accidentally such as wounds,
pressure ulcers, etc.; 3) are care-associated such as injection
sites, vascular catheter insertion sites, drainage exit sites, etc.;
or 4) are device-associated such as vascular catheter hubs,
drainage bags, bloody linen, etc..
The added value of critical sites lies in their potential use
in visual material and training: risk-prone tasks become
geographically located and hence more palpable. On the
behavioural level, manipulation of critical sites corresponds to
either “a clean/aseptic procedure” or “a body fluid exposure
procedure”, and in the case of simultaneous risk, to “a clean/
aseptic and body fluid exposure procedure”.
21.4.2 The concept and its practical application
“My five moments for hand hygiene” explained
The geographical representation of the zones and the critical
sites (Figure I.21.5a) is useful to introduce “My five moments for
hand hygiene”. The correlation between these moments and the
indications for hand hygiene according to the present guidelines
is given in Table I.21.4. To further facilitate ease of recall and
expand the ergonomic dimension, the five moments for hand
hygiene are numbered according to the habitual care workflow
(Figure I.21.5b).
Moment 1. Before touching a patient
From the two-zone concept, a major moment for hand hygiene
is naturally deduced. It occurs between the last hand-to-surface
101