Biomedical Engineering Reference
In-Depth Information
7
10 mm from the wound edge. Without tying, the same
motion is replicated starting on the right side. Then the ends
of the suture are cinched up and tied forming a letter X
pattern on the skin. Some wounds, including significant bite
wounds to extremities and repeated repairs of cranial
implants, will require plastic surgical techniques beyond
the scope of this text. The reader is referred to descriptions
of cosmetic closure techniques (
Trout, 2003
). Stocking up
a selection of 2/0, 3/0 4/0 and 5/0 sutures with appropriately
sized swaged-on needles in both absorbable and nonab-
sorbable materials covers most investigative needs.
Stapling devices can be successfully used in select proce-
dures such as pulmonary lobectomy or gastrointestinal
anastomoses.
against Gram-negative bacilli and cocci and some Gram-
positive pathogens. All above listed agents may be helpful
in initial surgeries on research na
ยจ
ve animals. The routine
use of prophylactic antibiotics, however, is a practice
that should be considered based upon the likelihood of
intraoperative or postoperative contamination and the
complexity and duration of the surgery. For other surgeries
such as repairs, especially when an infection is present, it
is critical to request bacterial cultures and antibiotic
sensitivity first and choose antibiotics accordingly. Metro-
nidazole is recommended when there is evidence or
suspicion of anerobic organisms. Antibiotics that cross the
blood
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brain barrier such as the third and fourth generation
cephalosporines and chloramphenicol would be recom-
mended in bacterial encephalitis or meningitis. In the
therapy of methicillin-resistant Staphylococcus aureus
infections, vancomycin is the antibiotic of choice.
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Perioperative Therapies
The section below only highlights select therapeutic
approaches detailed in other chapters in this textbook.
Fluid Therapy
Fluid therapies include crystalloids, colloids, plasma
expanders in cases of hemorrhage, hypovolemia, or shock
(for more details see Chapter 15).
Pain
Commonly used analgesics are: systemic opioids (bupre-
norphine,
fentanyl),
local blocks
(bupivicaine),
and
combinations
opioid/non-steroidal anti-inflammatory
drugs (NSAIDs) (aspirin, ketoprofen), opioid/local block
(for more details see Chapter 17).
Postoperative Sedation/tranquilization
Some nonhuman primates will interfere with implants or
stitches. Systemic opioids are capable of producing
a calming effect at higher doses but are impractical for
prolonged use. Tranquilizers such as acepromazine maleate
at 0.1
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Inflammation
Soft tissue manipulations result in trauma. NSAIDs are
helpful in minor local secondary edema, systemic cortico-
steroids are recommended for life-threatening situations
(e.g. cerebral or laryngeal edema), and diuretics or
mannitol in noninflammatory edemas (brain, lungs) or
circulatory fluid overload (for more details see Chapter 15).
1 mg/kg s.c. or i.m., s.i.d. or b.i.d., may be effec-
tively used.
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Ancillary Considerations
Iatrogenic Complications
Aseptic techniques, gentle tissue handling, and knowledge
of anatomy are critical in avoiding trauma and secondary
swelling/edema, hemorrhage, microbial contamination
(e.g. lanced abscess, nicked intestine), and induced
dysfunction (e.g. severed peripheral nerve).
Infection and Antimicrobials
Indiscriminate use of antimicrobials has resulted in an
increased risk of superinfection, development of resistant
organisms, increased cost of treatment, and increased host
toxicity (
Dunning, 2003
). Major emphasis must be put on
using sterile or sterilized materials and aseptic surgical
techniques. Antibiotics, such as the first generation ceph-
alosporins (e.g. cefazolin, cephalexin) offer a good
coverage for Gram-positive pathogens. The second gener-
ation cephalosporins (e.g. cephoxitin) are effective against
Gram-positive and some Gram-negative pathogens
(e.g. Bacteroides). The third generation cephalosporins
(e.g. ceftriaxone, ceftazidime) have a broad spectrum
activity against Gram-positive and Gram-negative patho-
gens. ceftazidime (third generation) and cefipime (fourth
generation) are effective against Pseudomonas aeruginosa.
Fluoroquinolones (e.g. enrofloxacin) offer effectiveness
Repair and Re-implantation Surgeries
Potential benefits should be weighed carefully against the
experimental and humane endpoints. Desperate attempts
that compromise sound principles of surgery are discour-
aged. Thorough clinical assessment, common sense, and
animal welfare considerations are paramount. Small,
noninfected areas of dehiscence may be allowed to heal by
second intention and large noninfected ones may be
repaired surgically. When infections are apparent, the
therapeutic regimen should include bacterial culture and
sensitivity, initiating broad spectrum antibiotic treatment
24
72 hours prior to repair surgery, thorough irrigation
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