Treatment
Following the trend to discharge patients earlier, many wound infections
may be missed by surgeons unless they undertake a prolonged and carefully
audited follow-up with family doctors. Suppurative wound infections take 7—10
days to develop, whereas cellulitis around wounds caused by invasive organisms
(such as the beta-haemolytic streptococcus) appears in 3-4 days. Major wound
infections with systemic signs (Fig.
7.10) or evidence of cebbubitis justify the use of appropriate antibiotics. The
choice may be empirical or based on culture
and sensitivities of isolates harvested at surgery. Although the
identification of organisms in wound infections is necessary for audit and wound
surveillance purposes, it is usually 2—3 days before sensitivities are known (Fig
7.11 and Fig 7.12). It is illogical to withhold antibiotics but if clinical
response is poor by the time sensitivities are known then antibiotics can be
changed. This is unusual if the empirical choice of antibiotics is sensible —
change of antibiotics promotes resistance and risks complications, such as Clostridium
difficile enteritis.
When the wound is under tension or there
is clear evidence of suppuration removal of sutures aids evacuation of pus.
There is no evidence that subcuticular continuous skin closure enhances or
worsens the effect of suppuration. In severely contaminated wounds, e.g.
laparotomy for faecal peritonitis, or incisions made for drainage of an abscess,
it is logical to leave the skin layer open. Delayed primary or secondary suture
is undertaken when the wound is clean and granulating (Fig 7.13 and
Fig 7.14).
Leaving wounds open after dirty operations is not practised as widely in the UK
as in the USA or mainland Europe.
When
taking pus from infected wounds, specimens should be sent fresh for
microbiological culture. Swabs should be
placed in transport medium but as barge a volume of pus as possible is
likely to yield more accurate results. Communication with microbiologists is
essential for the most meaningful results. If bacteraemia is suspected, repeat
specimens may be needed to exclude negative results.
Reports
on infective material can be based rapidly on an immediate Gram stain. Aerobic
and anaerobic culture on conventional media allows sensitivities to be assessed
by disc diffusion. The measurements of minimum inhibitory antibiotic
concentrations (M1C9O in mg/litre), together with measurements of endotoxin and
cytokine bevels, are usually only used in research.
Many
dressings are now available for use in wound care. These are listed in Table
7.3. Polymeric films are used as incise drapes and also to cover sutured wounds
but are not indicated for use in wound infections. Agents that can be
used to help débride open infected wounds, others to absorb excessive
exudate or to encourage epitheliabisation and formation of granulation tissue
are also listed (Fig. 7.15).