CRITICAL CARE
•
nasogastric (NG) feeding largely depends on the
preference of the attending clinician.11 Previously it
was thought that NG feeding tubes were associated with more complications than NE tubes. These
potential complications include regurgitation,
aspiration pneumonia, gastroesophageal reflux
and reflux esophagitis.11 Arguments for NG tube
placement include the fact that gastric decompression can be achieved if the end of the tube is
situated within the stomach lumen and that gastric residual volumes can be measured regularly.11
It was shown in a study that complication rates
with naso-enteric tubes are quite low and complication rates between NG and NE tubes are not
significantly different.11
Disadvantage:
• Small tube diameter, thus food has to be very
liquid. Volume can limit amount of calories
given.
• The tube may also cause discomfort in the nasal passages.
Fig 3: Oesophagostomy tube placed in a puppy. (Photograph Courtesy Dr van Schoor. Onderstepoort Veterinary Academic Hospital)
5. AMOUNT and method
Daily food volumes are calculated and divided into
approximately 6 meals.7. Food is warmed to body
temperature prior to feeding. Feed relatively slowly over a few minutes to avoid oesophageal spasm and
discomfort. Make sure the animal is sitting and not in
lateral recumbency when feeding.
Fig 2: A nasoenteric tube placed in an anaesthetised bull terrier.
Placement of a cuffed ET tube and elevation of the patients
head and thorax while feeding reduces the risk of aspiration.
(Photograph Courtesy Dr van Schoor. Onderstepoort Veterinary Academic Hospital)
Oesophagostomy tubes
In patients where severe facial injuries prohibit the use
of naso-enteric tubes or where tube feeding will be
required for more than a week, an oesophagostomy
tube should be used.9
The tubes are easily inserted although GA is required.
Advantages are a wider tube diameter as well as
placement on the neck - which causes less irritation
and interference with normal function. Even if pulled
out accidentally before the 7- 10 days required for
stomaformation, the incision will close up without
complications.
Gastrostomy tubes
These are placed surgically or endoscopically. Once
again a relatively large diameter catheter can be
placed. The stomach wall must be fixed to the abdominal wall if doing surgical placement as this limits the risk of peritonitis if the tube is accidentally removed before a stoma has developed (<10 days post
op).
The feeding tube is flushed with warm water (5 - 20ml
depending on patient size and tube volume) at each
meal prior to feeding and immediately after feeding
to avoid obstruction of the tube. Maximum tolerable
feeding volumes in debilitated dogs and cats can be
estimated as 5 – 10 ml/kg body weight initially.7. Patients that do not tolerate large volumes can be fed
very small volumes more often and in certain patients
continuous rate infusion (CRI) feeding may be preferred.7
Attempts to unblock a blocked tube with warm water
flushing followed by suctioning are often not successful.8 Sodium bicarbonate added to the water may be
more successful. Unfortunately it may be necessary
to replace a blocked tube.8
Metabolic complications resulting from too much
food too soon are referred to as “refeeding syndrome”.7,8,9 It causes amongst others, hypophosphataemia, hypokalaemia and hypomagnesaemia.8,9
Clinical manifestations of refeeding syndrome include
muscle weakness, cardiac arrhythmias, respiratory
depression, intestinal ileus and haemolysis. Refeeding syndrome can be avoided by initially feeding 25%
-50% of RER and gradually increasing the energy supply over a period of a few days until 100% RER is being
fed.7
References available from www.vet360.vetlink.co.za
Issue 06 | DECEMBER 2015 | 33