Biomedical Engineering Reference
In-Depth Information
thickness autograft (AG) is grafted in the same procedure at an adjacent site. To
prevent microbial contamination and provide nutrients to the grafted CSS, the CSS
and AG comparative site are kept in a moist dressing for 5 days post surgery.
Topical antimicrobials in the irrigation solution are used in conjunction with the
dressings and must provide effective coverage of a broad spectrum of gram-
negative and gram-positive bacteria as well as common fungal contaminants. For
use with CSS, topical antimicrobials must also have low cytotoxicity to allow
healing to proceed. Previous studies from this laboratory have determined an
effective and non-cytotoxic formulation consisting of polymyxin B, neomycin,
mupirocin, ciprofloxacin and amphoteracin B.
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In addition, caution is exercised in
order to avoid overlap of topical and parenteral drugs that could possibility lead to
resistance to the topical agents and subsequent sepsis.
12.4.3 Nursing considerations
The mechanical fragility of cultured skin substitute is another important source of
failure from shear or maceration. These losses may be minimized by development
of appropriate handling, securing and dressing of the cultured grafts. For friable
grafts such as CSS, the porous, non-adherent N-terface backing material allows
surgical application with minimal damage to the graft caused by handling and
stapling. This porous dressing allows both the delivery of topical solutions and
drainage of wound exudates from grafts during the period of engraftment. To avoid
mechanical disturbance, the frequency of dressing changes is low (two to four
changes per week) during the first week, and increases to twice daily after a fibro-
vascular issue and epidermal barrier develop. With attention to these surgical and
nursing factors, closure of excised, full-thickness wounds can be accomplished
with reduction of requirements for donor skin autograft.
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12.5
Clinical assessment
After treatment of wounds with CSS, the outcome must be measured to determine
whether the benefits of a prospective therapy justify any risks associated with the
therapy and if risks associated are reduced for the disease being treated. Assess-
ment may range from the level of the individual (e.g. survival),
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to function (e.g.
range of motion, return to work),
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to tissue integrity (epithelial closure, scar
formation),
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to cellular markers (e.g. cell phenotype, synthesis of proteins and
nucleic acids).
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12.5.1
Quantitative assessment
To evaluate the efficacy of CSS, quantitative measurements of engraftment, closed
area to donor area and percent increase in CSS area are collected. A major
advantage of CSS compared to that of split-thickness AG is its ability to close a
