Biomedical Engineering Reference
In-Depth Information
bandage changes is increased from daily to two to three
times weekly, resulting in fewer anesthetic events for the
animal. There are a number of commercially available
hydroactive dressings that accomplish similar functions.
Treatment of fight wound trauma that involves signifi-
cant amounts of bruising is directed at prevention of myo-
globinuric nephropathy, sepsis, gangrene, and tetanus.
Potentially nephrotoxic drugs should be discontinued and
avoided. Crystalloid intravenous fluid administration should
be administered immediately as a delay in fluid therapy is
associated with an increased risk of acute renal failure ( Ron
et al., 1984; Better and Stein, 1990 ). Mannitol (1.65
Etiology/Risk Factors/Transmission/Species
Gastric dilatation occurs in both Old World and NewWorld
monkeys ( Newton et al., 1971; Bennett et al., 1980; Stein
et al., 1981 ). It usually occurs in caged monkeys, and risk
factors are multifactorial and include food restriction fol-
lowed by overeating, excessive water intake, antibiotic
administration, the stress associated with shipping, delayed
gastric emptying, pyloric outflow obstruction, aerophagia,
activity following a meal, malposition of the spleen, pro-
longed recumbency, spinal cord injury, blunt abdominal
trauma, and anesthesia ( Mathews, 2009 ). Often, Clos-
tridium perfringens type A is isolated from stomach
contents and is responsible for the production of large
amounts of gas ( Bennett et al., 1980 ). Individual monkeys
may be particularly prone to gastric dilatation ( Soave,
1978 ), and unlike companion animal medicine, volvulus
does not usually accompany gastric dilatation.
2.2 g/
kg, given i.v. over 20 minutes; California National Primate
Research Center (CaNPRC), 2009) is both a volume
expander and an osmotic diuretic. Once urine production
has been confirmed, mannitol may be considered for the
treatment of hypovolemia and to promote urine production
and tubular washout ( Malinoski et al., 2004 ). Bicarbonate
administration may also be considered to address the
acidosis and hyperkalemia associated with crush syndrome
( Malinoski et al., 2004 ). During treatment, osmolality,
electrolyte, acid-base, and volume status should be moni-
tored on a regular and frequent basis. Broad-spectrum
antibiotics with anaerobic coverage should be administered
empirically, and subsequent changes to initial antibiotic
therapy should be based on culture and sensitivity results
and response to treatment. Analgesic therapy should be
instituted immediately, with consideration also given to
providing nutritional support, as these animals will often
experience inappetance for several days.
Because fight wound trauma often occurs during
periods of changing social group composition or during the
formation of new groups, it is important that informed
decisions are made regarding the age/sex configuration of
animals within social groups. Staff members who are
involved in these decisions should have knowledge of the
natural history of the species. Veterinary, animal care, and
behavioral staff should be aware of new social group
formation in order to prepare for adverse outcomes that
would require emergency care. It is often wise to perform
introductions of new social groups early in the work week
to assure that adequate staff is available.
e
Clinical Signs
Restlessness, abdominal distention, hypersalivation,
anorexia, depression, tachycardia, pale to gray mucous
membranes, increased capillary refill time, petechiation,
tachycardia, tachypnea, and dyspnea may be seen, but often
the first clinical sign is sudden death due to impaired
venous return and shock, which is accompanied by an
enlarged, taut abdomen. Stomach rupture may occur as
well as rectal and/or vaginal prolapse.
Diagnostics
Gastric dilatation is diagnosed by clinical signs and
abdominal radiography, in which an enlarged gas- and
fluid-filled stomach is observed ( Figure 15.7 ). C. per-
fringens may be cultured from stomach contents which are
usually a mixture of food and liquid ( Figures 15.8, 15.9 ).
Treatment/Management/Prognosis
Treatment for gastric dilatation involves prevention of
circulatory collapse via administration of crystalloid fluids,
decompression of the stomach, and treatment of pain and
sepsis ( Mathews, 2009 ). If there is evidence of circulatory
compromise upon presentation, volume resuscitation
should take priority over gastric decompression at an initial
rate of 100 ml/kg/h. A stomach tube should then be passed.
This may be done with the animal in sternal or lateral
recumbency. Placing the animal in dorsal recumbency
should be avoided because the weight of the distended
stomach will compress the vena cava, severely compro-
mising venous return. A large-bore tube should be pre-
measured, lubricated, and passed through a speculum to the
stomach while avoiding the use of excessive force. If
resistance to tube passage is encountered, rotation of the
tube should be attempted. If decompression fails using an
Gastric Dilatation
In nonhuman primates, gastric dilatation is not usually
accompanied by volvulus.
l
The first clinical sign of gastric dilatation is often
sudden death.
l
Gastric dilatation is diagnosed by clinical signs and
abdominal radiography.
l
Treatment should be aimed at prevention of circulatory
collapse, decompression of the stomach, and treatment
of pain and sepsis.
l
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