Biomedical Engineering Reference
In-Depth Information
performed under anesthesia unless the animal is severely
debilitated, obtunded, or unconscious. Because repeated
anesthesia in nonhuman primates causes inappetance and
other negative effects, it is important to obtain as much
diagnostic information as possible during the initial eval-
uation (
Springer and Baker, 2007, 2008
). Following the
initial evaluation, the benefits of obtaining additional
diagnostic information should be carefully weighed in light
of the risks of repeated anesthetic events. Unless unavoid-
able, samples should be obtained if and when the animal is
anesthetized for subsequent therapeutic interventions such
as fluid administration or bandage changes.
Airway and breathing are evaluated via auscultation and
by visual observation for respiratory rate and effort. If
increased respiratory sounds are noted during inspiration,
obstruction in the upper airway should be ruled out,
whereas increased respiratory sounds during expiration
may indicate obstruction in the lower airways. Cyanotic
mucous membranes indicate hypoxia, and supplemental
oxygen should be provided via mask or intubation (if
patency of the airway is in question) if the animal is
dyspneic or tachypneic. The presence of wheezing may
indicate bronchial disease, and shallow or short breaths
accompanied by the absence of breath sounds on thoracic
auscultation are indicators of pleural space disease. If
pulmonary edema is suspected or diagnosed by radio-
graphic studies, furosemide may be administered at a dose
of 2
FIGURE 15.1
Location of saphenous vein in a rhesus monkey. The
caudal aspect of the lower leg of a rhesus monkey (Macaca mulatta)
demonstrating the location of the saphenous vein (arrows), which is
commonly used for the administration of intravenous fluids.
7 mg/kg i.v. (
California National Primate Research
Center, 2009; Kirby, 2009
). Thoracic radiography with
a minimum of a lateral and ventrodorsal view should be
utilized in the diagnostic workup if there is any indication
of pulmonary involvement or pulmonary disease.
If present, external hemorrhage should be immediately
controlled via direct compression, followed by an assess-
ment of the circulatory system. Physical examination
findings that provide information on circulatory status are
heart rate, mucous membrane color, capillary refill time,
pulse quality, temperature of the extremities, and blood
pressure. Bradycardia may be indicative of increased vagal
tone, intracranial disease, or hyperkalemia. Tachycardia
and pale mucous membranes are indicators of functional
hypovolemia and may result from blood loss, loss of fluids
in the form of vomiting or diarrhea, or systemic inflam-
mation. After ruling out heart failure as the cause of low
circulating volume, rapid fluid resuscitation should be
instituted using the largest-bore catheter possible. Periph-
eral vein access in most nonhuman primate species used in
the laboratory is via the saphenous vein located superfi-
cially on the caudal aspect of the lower leg (
Figure 15.1
).
Figure 15.2
shows the placement of an intravenous catheter
in the saphenous vein. For long-term vascular access, the
internal jugular and subclavian veins have been used often
in association with access ports to promote central venous
access.
e
FIGURE 15.2
Catheterized saphenous vein and padded restraint for
intravenous fluid administration. Proper placement of a saphenous vein
catheter and application of restraints to the rear left and right metatarsal
regions of a juvenile rhesus monkey (Macaca mulatta) receiving intravenous
fluid therapy. Restraints are utilized when intravenous fluids are administered
to conscious animals. As seen above, nylon restraints are applied to the
metatarsal region of the rear legs after a thin layer of padding has been
applied. If the layer of padding is too thick the restraints are prone to slipping.
