Biomedical Engineering Reference
In-Depth Information
A mushroom-tipped catheter is used and is placed under
endoscopic visualization through the greater curvature after
insufflation of the stomach with air. The tube is exteriorized
through the left abdominal wall where it is secured to the
skin surrounding the exit site. A bandage can be used to
protect the catheter, but a primate jacket provides a greater
level of comfort for the animal. The exit stoma should be
examined and cleaned at least once a week. When treat-
ment is complete the tube is removed by applying traction
to the exteriorized portion and pulling it through the stoma.
The stoma is then closed in two layers. Complications are
rare, but include peritonitis if gastroabdominal adhesion
does not form. Intestinal obstruction may occur if pieces of
the catheter remain in the intestinal tract after removal of
the tube.
Just as there are risks to the animal associated with
providing insufficient calories during a period of illness,
providing excess calories can also negatively affect
outcome (
Freeman, 2008a
). Both of these issues can be
avoided by calculating the animals' resting energy
requirements in kilocalories/day using the following
equations (
Freeman, 2008a; Chan, 2009
):
composition of milk from several primate species (
National
Research Council, 2003
).
Infants that are too weak to suckle should be fed via oro-
or nasogastric intubation so as to ensure that adequate
caloric intake is achieved and to reduce the risk of aspira-
tion pneumonia. The risk of aspiration pneumonia is lower
for nasogastric than for orogastric intubation, but the
technique is more difficult to master (
Ruppenthal and
Sackett, 2006
). If orogastric intubation is used, a small
amount of sterile saline may be infused after positioning the
tube to check for coughing, which would indicate endo-
tracheal intubation.
Body weight at various stages of development in
nonhuman primate species commonly used in the labora-
tory may be found in table 9-2 of the NRC publication
Nutrient Requirements of Nonhuman Primates (
National
Research Council, 2003
). While a healthy neonate would
be expected to gain weight according to the growth curve
unique to its species, ill neonates may not begin to gain
weight until their primary disease process is under control
(
Freeman, 2008b
). The goal should be to provide sufficient
calories to meet resting energy requirements and to
increase caloric intake gradually as recovery from illness
occurs.
For animals weighing 3
25 kg: 70(weight in kg)
þ
75
e
l
For animals greater than 25 kg: 30(weight in kg)
þ
70
l
Animals that are critically ill should receive one half of the
resting energy requirement on the day of presentation and
the total requirement on the second day and every day
thereafter during which the animal is anorexic (
Freeman,
2008b
).
Compared to adult animals, neonates have fewer
glucose reserves, increased glucose excretion, and
decreased gluconeogenesis. In addition, the neonatal brain
requires a relatively greater amount of glucose to function
properly, and cardiac muscle utilizes glucose preferentially
in neonates (
McMichael, 2003
). For these reasons,
neonates are especially prone to hypoglycemia, and proper
nutrition is paramount to the hospitalized neonate. Ill or
injured neonates should be housed in a nursery setting
where supplemental heat, regular feedings, and intensive
care by experienced staff are provided. They should be fed
as frequently as every 2 hours, depending on the age at
presentation, and feedings should increase in volume and
decrease in frequency over time (
Ruppenthal and Sackett,
2006
).
While many species of laboratory nonhuman primates
are successfully nursery-reared using human infant
formulas, it is important to be familiar with the unique
nutritional requirements of a species. Some species require
higher levels of particular nutrients, and if these require-
ments are not met with human infant formula, then they
must be supplemented. Table 9-4 of the National Research
Council (NRC) publication Nutrient Requirements of
Nonhuman Primates
Behavioral Considerations
The most effective method of maintaining psychological
well-being in nonhuman primate species is through the
provision of social housing with compatible partners.
Treatment plans for critically ill nonhuman primates should
place emphasis on maintaining contact between established
social partners whenever possible. This is important not
only for the behavioral well-being of the animal, but also
the integrity of its immune system (
Capitanio et al., 2006
).
Also, since most nonhuman primate social systems rely on
dominance hierarchies and kinship, changes in group
membership can destabilize social groups and incite
aggression, as a result of either removal due to illness or the
return of an individual after treatment has been completed.
On the other hand, even when critically ill animals are
stabilized, sedation and analgesic therapy may place the
treated animal at risk of aggression from its partner(s). In
addition, bandages, catheters, or other medical devices may
be manipulated and disturbed by full-contact social part-
ners. Group housed, recuperating nonhuman primates may
be housed in visual contact with group-mates if physical
contact is not feasible. The return of animals to the social
group as promptly as possible may facilitate reintegration.
For a pair-housed animal, alternatives to continuous full
contact can avoid the logistical problems associated with
clinical treatment. For example, pairs may be provided
periods of full contact on a regular, but intermittent basis
based on treatment schedules and the need to observe
provides
information
on
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