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252 Section IV: Postoperative Care and Rehabilitation

relatively soon after surgery. However, if anorexia is expected to
persist beyond 3 days from the last meal, then supplementation
should be considered.
In patients that have had prolonged periods of anorexia, such as
those with intracranial disease or when it is unknown whether normal
neurological status will be maintained postoperatively, nutritional
supplementation should be considered as part of the perioperative
management. Enteral nutrition is preferred over parenteral nutrition
as it has been shown to be superior in maintaining enterocyte health
and promoting gastrointestinal motility. Enteral nutrition should be
used any time the intestinal tract is functional. Another consideration
is when to start feeding patients following surgery, particularly when
intracranial surgery has been performed. This depends on the period
of anorexia prior to surgery, the postoperative neurological status, and
method of nutritional supplementation.
Enteral Nutrition
There are several ways of providing enteral nutrition with varying Figure 28.5 Postoperative patient with a nasogastric tube secured in place
degrees of invasiveness. The ability to prehend and swallow without (right nostril). Source: Courtesy of Andrea Steele.
risk of aspiration may be a concern in the immediate postoperative
period in patients that have undergone intracranial surgery. The
presence of megaesophagus or vomiting and regurgitation as well as the tube or the tube is removed prior to a permanent adhesion
having undergone intracranial surgery are risk factors for the devel- forming to the abdominal wall. Complications that can be seen with
opment of aspiration pneumonia [43]. either esophagostomy or gastrostomy tubes is infection around the
The simplest method of providing enteral nutrition is with a stoma. Daily inspection and stoma care should be performed, with
nasogastric tube. Tube placement is minimally invasive and can bandaging of the site recommended.
be performed under sedation. A tube is passed from the nares Whenever possible, bolus feeding (versus continuous‐rate
into the stomach with confirmation of tube placement via a lat- infusion feeding) should be considered for nutritional supple-
eral thoracic radiograph to ensure that the tube is in the stomach. mentation. If the patient is conscious and not vomiting, bolus
An advantage of the nasogastric tube is the ability to aspirate feeding is recommended as it is more physiological and stimu-
stomach contents if there is delayed gastric emptying, which can lates normal gastrointestinal motility. The maximum amount of
otherwise lead to vomiting and regurgitation. A limitation of food that is currently recommended to be fed to critically ill and
nasogastric tube feeding is the type of food that can be placed postoperative patients is based on a patient’s resting energy
down the tube, with only liquid diets such as Clinicare® or requirement (RER). It is not currently recommended to feed
Ensure® being appropriate. This method of feeding is considered more than RER, with increasing evidence to suggest that over‐
temporary and if the patient is conscious the tube can cause some feeding of patients can compound the metabolic alterations of
irritation leading to sneezing (increasing intracranial pressure) the stress response leading to hyperglycemia [44]. Although it is
and pawing at the face, so caution should be exercised for crani- unknown whether this translates to other species or to naturally
otomy patients (Figure 28.5). occurring disease processes, restrictive feeding on an every other
For provision of longer‐term nutritional supplementation or day schedule was shown to be neuroprotective in a rat cervical
when intracranial surgery has been performed, placement of an spinal cord model [45].
esophagostomy tube (E‐tube) should be considered while the The following formula can be used to calculate RER:
patient is under general anesthesia. This is especially important if RER = 70 kcal × body weight in kg
0.75
prolonged anorexia or delayed neurological recovery is expected.
Esophagostomy tubes are easy and quick to insert, are associated Depending on the period of anorexia, begin with feeding one‐third
with few complications, and have the advantage of allowing foods to half the RER. The amount of food to be fed can be initially
with increased consistency, such as Hill’s a/d®, to be fed through divided into six to eight bolus feedings over a 24‐hour period or
them along with any oral medication. The tube is typically placed divided over the 24‐hour period if continuous‐rate feeding is used.
on the left side of the neck and extends down to just past the base Prior to feeding bolus amounts, residual volumes should be
of the heart, which is confirmed by thoracic radiography. An checked by aspirating the feeding tube. Residual volumes that are
E‐tube can remain in place for short or long periods of time, with considered normal in veterinary patients have not been established,
abscessation around the tube stoma being the most frequent com- although 4‐hour residual volumes exceeding 50% of what was
plication. This tube can be converted into an esophagogastric tube administered over the preceding 4 hours (or at last feeding) is
if desired. considered excessive. For nasogastric tubes, if there are large resid-
A gastrostomy tube could be considered to provide longer‐term ual volumes in the stomach, this could indicate poor gastric motil-
nutrition to patients. They can be placed either surgically via a celi- ity and may lead to increased nausea and risk of vomiting and
otomy or percutaneously using endoscopic guidance (PEG tube). regurgitation. If aspirating residual volumes for removal, approxi-
Percutaneously placed gastrostomy tubes should remain in place mately 1–2 mL/kg of the volume should be returned to prevent
for a minimum of 10 days to allow adhesion of the stomach to the development of metabolic alkalosis. If there are large residual
abdominal wall and a stoma to form. A potential complication of volumes or vomiting, addition of gastric motility agents should be
the gastrostomy tube is septic peritonitis if there is leakage around considered (Table 28.4).