1. The special feeding methods depend on the type of disease, the patient's conditions and his tolerance to food. The different modes of feeding patients are 1.Enteral 2. Parenteral
By definition enteral means 'within or by the way of the
gastrointestinal tract.' As for as possible, the patient should be encouraged
to ingest food through the oral route. Supplements may be added whenever
necessary. The foods are administered via a tube and hence enteral feeding in
also called tube feeding.
Tube feeding may be advised where the patient is unable to eat but the
digestive system is functioning normally. Full fluid diets or commercial
formulas may be administered through this route.
The tube may be passed through the nose into the stomach (nasogastric),
duodenum (nasoduodenal) or jejunum (nasojejunal).
When there is an obstruction in the oesphagus, enteral feeding is done
by passing a tube surgically through an incision in the abdominal wall into the
stomach (gastrostomy), duodenum (duodenostomy) or jejunum (jejunostomy).
Indications for tube
Inability to swallow due to paralysis of muscles
of swallowing (diptheria, poliomyelites)
Unwillingness to eat.
Persistent anorexia requiring forced feeding.
Semiconcious or unconscious patients.
Severe malabsorption requiring administration of
Short bowel syndrome.
Babies of very low birth weight.
For enteral feeding for a short period of time locally available thin
bore nasogastric tubes are usually adequate. For prolonged use, specially
prepared thin bore, soft, flexible tubes are desirable.
The preparations to be administered are kept in
bottles marked 'For intragastric use'. They are connected to the tube and
allowed to drip into the stomach by gravity. Feeding is started as a continuous
drip of 50 ml per hour, increased by 20 ml every 24 hours until the required
rate is achieved (usually 100 to 120 ml per hour). There is evidence that giving
intermittent boluses of feeds every two hours improves metabolism, compared to
feeding by continuous drip.
The types of feeds that can be administered though a tube include:
1. Blenderized food
This is prepared for patients who cannot chew
and swallow due to cancer of the oral cavity, larynx or oesophagus.
Ordinary food items which cannot be swallowed
are cooked well and blenderized to make them liquid for feeding through a
2. Polymeric mixtures
Polymeric mixtures contain intact protein, fat
and carbohydrate of high molecular weight and are thus lower in osmolarity and
require normal digestive juices.
3. Elemental diets
Elemental diets are commercially predigested mixtures of amino acids,
dextrins, sugars, electrolytes, vitamins and minerals with small amounts of
fat. They are free of lactose and can be easily administered.
The main indication for elemental diets is short bowel syndrome, till
functional regeneration occurs in the residual bowel. These diets are used as alternatives
to intravenous feeding. The disadvantages of this diet are high cost and
unpleasant taste and sometimes high osmolarity. Therefore, easily digestible
and more palatable preparations of casein and egg albumin are preferred.
To prevent essential fatty acid deficiency enteral feeds should provide
4% of total calories as essential fatty acids.
Commercial enteral mixtures of varying osmolarity, digestibility, energy
supply, lactose content, viscosity and fat content are available Eg: Ensure,
Ensure plus, osmolite, Triosorbon, Isocal.
The three common methods of tube feeding administration are
This is the most common form of administration. The drip rate is
adjusted in increments to prevent cramping, nausea, diarrhoea or distention.
Feedings are started at 30 to 50 ml/hr every 8 or 12 hrs until the final rate
In this 4-6 feeds are given with regular periods of interruption example
: 4 hours on and 4 hours off.
In this method large volumes are given in a short time. For example, 200
ml is administered in a minimum time of ten minutes.
The delivery of nutrients directly into the
circulation through the peripheral or central vein is termed as parenteral
nutrition. This can be total or supplemental.
The total sustenance of increased nutritional
requirements through intravenous feeding has been termed Total Parenteral
Nutrition (TPN). When parenteral nutrition provides 30-50% of the total daily
nutrients it is termed partial parentral nutrition. Intravenous feeding is best
used in conditions when the patient cannot eat, will not eat, should not eat,
cannot eat enough or cannot be fed adequately by tube feeding.
Conditions which necessitate parenteral feeding include
Inflammatory bowel disease
The peripheral vein solution should be of less than 600 mOsm, as higher
osmolarity results in thrombosis and inflammation of the vein. The parenteral
feed solutions contain;
crystalline amino acids
electrolyes - Sodium, chlorine, phosphorus,
potassium, calcium and magnesium
trace elements - zinc, copper, chromium,
manganese and iodine
Advantages of enteral
feeding over intravenous feeding
Convenient to administer.
No sterlization of tubes or nutrient.
Expert supervision not necessary.
Avoids catheter related sepsis and infections.
Avoids metabolic disturbances.
Intestinal mucosa regenerates more rapidly as in case of short bowel syndrome.