Biomedical Engineering Reference
In-Depth Information
done cautiously. If the need arises, additional devitalized
tissue may be removed during future daily bandage
changes. Wounds that appear fresh, healthy, and void of
visible contamination may be closed primarily, making
sure to eliminate dead space and avoid excessive tension.
Topical antibiotics are useful in assisting in the prevention
of infection if used within 24 hours, but have limited utility
once an infection is established (
Hedlund, 2008
). Because
abscesses form in tissue that is enclosed, often the best
option in contaminated or infected wounds is to leave them
open to drain and heal by second intention. This is often the
situation in animals presenting from outdoor breeding
colonies.
Bandaging wounds provides protection, cleanliness,
reduction of dead space and edema, absorption of exudate,
and a moist environment that is conducive to epithelial-
ization (
Hedlund, 2008
). However, unlike companion
animal medicine, in which many traumatic wounds are
routinely bandaged, the decision to place a bandage on
a wound in nonhuman primates is complicated by their
manual dexterity and tendency to remove bandages as well
as the requirement to anesthetize them to repeatedly change
bandages. Bandages that are wrapped circumferentially
around extremities are generally more difficult for an
animal to remove compared with bandages that are applied
to the abdomen or thorax. An additional consideration
when applying a bandage is that, in their attempt to remove
a bandage, nonhuman primates are at risk of manipulating
the bandage so that it becomes a functional tourniquet. For
these reasons, the decision about whether or not to bandage
a wound should be given careful consideration and be based
on a case-by-case assessment of benefit versus risk. For
example, small wounds demonstrating a healthy bed of
granulation tissue may be left unbandaged while deep,
contaminated wounds on distal extremities would be better
off bandaged in order to prevent further contamination and
allow assessment of the amount and type of discharge.
If the decision is made to bandage a wound, the bandage
should be applied aseptically. The type of bandage applied
depends on the level of exudation and/or debridement
necessary. Wet-to-dry bandages are appropriate for wounds
in which additional passive debridement would be benefi-
cial, whereas dry-to-dry bandages are useful when wounds
are already moist with exudative material. Unpasteurized
honey has been used successfully in laboratory nonhuman
primates as a topical agent to enhance wound healing in
large, purulent wounds, and it is the authors' experience
that it dramatically shortens the time to a healthy bed of
granulation tissue (
Staunton et al., 2005
). Honey acts as an
antibacterial agent through the production of low concen-
trations of hydrogen peroxide and by creating an acidic,
hyperosmolar environment (
Mathews, 2005; Staunton
et al., 2005
). An additional benefit of honey bandages over
traditional wet-to-dry bandages is that the interval between
FIGURE 15.6
Female-induced bite wound trauma
e
subcutaneous
surface. Photograph taken at necropsy of the subcutaneous aspect of the
elbow and antebrachium of a rhesus macaque (Macaca mulatta) with
female pattern bite wounds. The skin surface appeared similar to the case
in
Figure 15.5
. Underlying soft tissue injury is far more extensive than
would be apparent from the skin lesions, and massive release of nephro-
toxic myoglobin from crushed muscle puts the animal at risk for acute
renal failure. (Courtesy of the Division of Comparative Pathology, Tulane
National Primate Research Center.)
the skin surface and the extensive damage to underlying
tissues from female-induced bite wound trauma.
Diagnostics
Fight wound trauma is diagnosed by supporting history in
animals at risk and evidence of wounding on physical
examination. Culture and sensitivity should be performed
on wounds that are contaminated or purulent. Serum
biochemistry may show elevated creatine kinase (CK),
aspartate animotransferase (AST), potassium, phosphorus,
lactate dehydrogenase (LD), and severe azotemia that
worsens over time (
Ford et al., 1998
). CBC may reveal
anemia secondary to blood loss and neutrophilia if bacterial
infections are present.
Treatment/Management/Prognosis
The first step in wound management is to prepare the skin
around the wound site. The application of a sterile, water-
soluble gel to the wound allows clipping/shaving hair
around the edges of the wound without further contami-
nation. The water-soluble gel with clipped hair fragments is
lavaged out of the wound after clipping is complete to allow
further direct cleaning of the wound. The wound is then
lavaged liberally with a balanced electrolyte solution. A
35-ml syringe attached to a 19-gauge needle provides the
appropriate amount of pressure for wound lavage (
Hed-
lund, 2008
). Necrotic tissue should be debrided aseptically
using sharp dissection techniques. In fresh wounds, tissue
that appears devitalized initially may appear viable within
24 hours so initial attempts to debride wounds should be
