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MODE OF ACTION
N
egative pressure wound
therapy (NPWT) has made
a significant impact on
the management of wounds. First
described by Morykwas et al (1997)
almost 20 years ago, the therapy uses
a pump device to provide controlled
application of subatmospheric
pressure to a sealed, airtight wound.
The use of a wound filler (usually
a foam or gauze dressing) ensures
delivery of this subatmospheric or
‘negative’pressure to the entire
wound surface, while the resulting
pressure gradient encourages
simultaneous removal of wound
exudate through the dressing
material. NPWT provides a closed
system which not only protects
the wound from external sources
of contamination, but creates the
optimal conditions for complex
wounds in particular to progress
towards healing and closure.
NPWT has become widely
adopted by clinicians for the
treatment of many different wound
types, including chronic wounds such
Elizabeth Huddleston PhD, clinical science director,
Global Medical and Clinical Affairs, Advanced
Wound Management, Smith & Nephew UK
as diabetic foot ulcers, pressure ulcers,
and venous leg ulcers, as well as
acute wounds such as split thickness
skin grafts, burns, orthopaedic or soft
tissue traumatic wounds, and post-
surgical dehiscence.
With its suitability for use in
such a wide variety of wound types,
it is likely that NPWT will provide
different clinical benefits depending
on the individual wound and the
particular treatment goals, i.e. wound
closure, reduced exudate volume, etc.
BENEFITS OF NPWT
The benefits to the wound are often
apparent within days of applying
NPWT and include rapid wound
contraction, removal of sloughy
material, appearance of granulation
tissue and overall reduction in
wound volume. This, in turn,
reassures patients and carers that
wounds have been ‘kick-started’ into
a healing trajectory.
What is the mode of action of
negative pressure wound therapy?
IN BRIEF
NPWT uses a pump device to provide controlled subatmospheric
pressure to a sealed, airtight wound.
Recently, single-use NPWT systems have been introduced which
are more portable and simpler to use and apply.
These systems provide a cost-effective means of treating wounds in
different care settings.
Portable NPWT systems provide good clinical outcomes but with
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KEY WORDS:
NPWT
Community
Cost-effectiveness
Portable systems
Single-use
Elizabeth Huddleston
A key benefit NPWT offers is
the management of wound fluid
in moderate-to-highly exuding
wounds, as well as creating a micro-
environment that supports healing
(
Table 1
).
NPWT provides an effective
method of sealing the wound,
and is particularly beneficial in
managing large complex wounds
where exudate can be contained
and removed, usually via a canister.
Fewer dressing changes may be
needed as a result of NPWT’s ability
to manage exudate, offering greater
convenience to both patients
and clinicians.
Additionally, NPWT’s sealed
environment offers protection of
the periwound skin and reduces the
risk of contamination from wound
fluid as well as reducing the risk
of contamination to and from the
outside environment. Thus, NPWT
minimises many of the concerns
for patients living with chronic
wounds such as leakage of wound
exudate from dressings, soiling of
clothes or bedding, and exposure
to wound odour — all of which can
cause considerable patient distress,
low self-esteem and negatively
impact on quality of life (World
Union of Wound Healing Societies
[WUWHS], 2007; Jones et al, 2008).
6
JCN supplement
2015,Vol 29, No 5
‘... NPWT minimises many of
the concerns for patients living
with chronic wounds such as
leakage of wound exudate
from dressings, soiling of
clothes or bedding, and
exposure to wound odour.’