Medical Chronicle November/December 2013 | Page 50

WOUND CARE
Continued from page 48

3. Topical microbicidal
dressings
• Hydrophobic dressings (such as
Cutimed® Sorbact®): Microbes,
including fungi, are irreversibly
bound through hydrophobic
interaction with the DACC
(dialkylcarbamoylchloride) fatty
acid coating on the dressing surface
and are then disposed of at dressing
change. The risk of bacterial
resistance or sensitisation is avoided
as there are no antibiotic agents
involved. Potentially damaging
endotoxin release in the wound bed
is also prevented as microorganisms
are removed whole rather than

destroyed.
• Miscellaneous silver products:
Alginate, activated charcoal,
carboxymethylcellulose (CMC),
chitosan films, collagen,
hydrocolloids, hydrofibre, hydrogel,
nanocrystalline/nanoparticles and
polyurethane foams. All silvercontaining products (whether in
elemental or ionic form) achieve
their antimicrobial effect via the
release and action of silver cations.
Although the exact mechanism of
action is not yet fully understood,
silver cations (Ag+) are thought
to target and bind with multiple
negatively charged sites on the

bacterial cell:
• Affecting critical functional and
structural proteins in the bacterial
cell membrane and cytoplasm
• Binding with essential enzymes,
inhibiting respiration and preventing
nutrient absorption
• Interacting with the nucleotide
bases in the bacterial DNA,
preventing cell division and
multiplication.

Safety considerations when
using silver products
• Silver should be used with caution
on epithelialising wounds or wounds
with a low bioburden.

• The amount of silver cations
released into the wound
environment is affected by the
production and viscosity of wound
exudate, extracellular matrix
components and the frequency of
dressing changes.
• Currently, there is no standard
method to evaluate the silver
release from dressings.
• Do not use in conjunction with
hydrogen peroxide or Eusol
• Silversulphadiazine and active ionic
Ag+ dressings are contraindicated in
pregnancy, neonates, severe renal or
hepatic impairment and wounds with
a large surface area (e.g. Steven’sJohnson syndrome).
• Silver products should not be used
during magnetic resonance imaging
(MRI) scans or diathermy.

Practice ‘pearls’
• It is important to recognise that
there is a fluctuating continuum in
the wound-microbiology ‘lifecycle’
- bacterial populations in chronic
wounds are polymicrobial, and will
represent regional skin flora and the
care environment.
• All wounds are colonised - the
presence of microorganisms in a
wound does not in itself define an
infection, and treatment based
on culture results alone is not
warranted.
• ‘Stalling’ of the healing process,
an unexplained increase in exudate
production or failure to heal within
the expected time frame, may
suggest critical colonisation or local
infection.
• The cornerstones of wound mx
include debridement, management
of inflammation and/or infection and
exudate management.
• Use a ‘step ladder’ approach to
control bacterial bioburden (trial
topical antiseptics prior to using
ionic silver products, because the
latter should be conserved in the
event they are needed to manage a
drug resistant infection).
• Allow a trial period of at least 10-14
days, before making the decision
to change the type of topical
antimicrobial in use.
• If a wound is not 30% smaller by
week 4, it is unlikely to heal by
week 12 - reassess and consider
interdisciplinary involvement for
comorbidities.
• The care and antiseptic toilet (e.g.
using chlorhexidine liquid soap) of
the peri-wound skin is as important
as the wound itself.
• Undertake a ‘dipstick’ urinalysis to
exclude asymptomatic bacteriuria
in patients with poorly progressing
wounds.
• Treat the ‘whole patient’ and not just
‘the hole’ in the patient.
References available on request.

50 MEDICAL CHRONICLE NOVEMBER/DECEMBER 2013