Rectal feeding is a method of alimentation of great value in the treatment of some diseases. It is indicated in many disorders of the stomach or other part of the upper alimentary tract, such as gastric ulcer, oesophageal and gastric cancer, and acute gastritis resulting from the action of corrosive and other poisons. It is also useful in cases of prolonged reflex vomiting, such as occurs in some cases of pregnancy, and in other conditions in which the power of absorbing food is temporarily suspended, as in cases of severe cerebral haemorrhage and the like. A vast amount of investigation has been carried out on the subject of the amount of proteins, fats, and carbohydrates that are absorbed from the large bowel, when food is introduced into the system in this way. The results obtained from these investigations are somewhat conflicting, and are not always in accord with the results of clinical experience. This much is certain: sufficient nourishment can be absorbed from rectal alimentation to maintain life and fair nutrition even for some weeks; and as in the great majority of cases it is not necessary to have recourse to this system of feeding for more than eight or ten days at the outset, it is certain that rectal alimentation, when carefully carried out, is of very great value in treatment.
Great care is necessary with regard to certain details in the management In the first place, it is essential to clear out the bowel as a preliminary measure. All mucus and faeces must be removed by an injection of soap and water, preferably followed by an enema of plain water. In the next place, the nutrient encmata must be carefully regulated, both in number and amount, so as to diminish the irritation in the bowel and avoid excessive peristalsis. The nutrient enema should be preferably given by a long flexible tube, which is inserted, in the case of adults, 8 or 10 inches into the bowel. By this method the injection is less likely to be rejected, and the food constituents are absorbed into the inferior mesenteric vein, from whence they pass to the liver via the portal vein, in place of passing direct into the inferior vena cava, as they do when brought into contact with the lowest part of the rectum only. Not more than 4 to 6 ounces should be given at a time, the patient being instructed not to strain during administration. The patient should lie on his left side with his hips raised. Care must be taken not to inject air. The temperature of the food is important, it should range from 95 to 100° F. If too hot or too cold, absorption is interfered with, and undue peristalsis may be induced. As a general rule, the frequency of administration should not exceed one every six hours. The bowel should be thoroughly cleansed out once daily, the tube being connected with a funnel to a height of 2 to 3 feet. The addition of ten to twenty drops of tincture of opium to the nutrient enema once a day, or every second day, is of value in diminishing the irritation in the bowel.
All the various classes of food may be employed in rectal feeding. Proteins are supplied in the form of milk, white of egg, meat juice, peptones, and various concentrated protein foods such as Plasmon, Protene, and Somatose. Carbohydrates are given in the form of lactose in milk, dextrose in its pure form, and grape sugar (glucose). Care has to be exercised not to administer too much sugar, as this may induce pain and diarrhoea. Not more than from 4 to 6 ounces of a 10 per cent, solution of sugar should be given. Starch may also be employed, and appears to be fairly well absorbed, even when given in the raw state. Fats have a more restricted value, and the best form of administration is the yolk of eggs. The recent investigations of Koester have shown that more than 50 per cent, of cream is absorbed when emulsionised with Pancreon.
Reference must be made to the digestion and absorption of nourishment from the bowel. There is little or no power of digestion in the large bowel, hence protein foods should always be administered in a predigested form. Pancreatised preparations are here of the greatest value (see p. 173).
Probably about one-fourth of the nutriment required by the body can be absorbed by the large bowel, and this suffices to tide patients over a critical period, extending it may be over several weeks. Absorption of all the food constituents in the enema is facilitated by the addition of common salt, this probably being due to the action of the saline in inducing reverse peristalsis. From 1/2 to 1 teaspoonful of common salt should therefore be added to each nutrient enema. The recent investigations of Boyd and others appear to show that protein foods are less completely absorbed than has hitherto been supposed, and increasing attention is now being directed to the special value of the sugars when given in pure form. Dextrose and glucose should therefore enter largely into the dietary of a patient who is being fed entirely by the bowel. The chief food constituents of value for rectal alimentation may be tabulated as follows: -
White of eggs.
Concentrated proteins, such as Plasmon, Somatose, and the like.
Carbohydrates. Dextrose. Milk sugar, Fats. Yolks of eggs.
As the addition of common salt facilitates absorption of the nutrient elements of food, a good pinch of salt should be added to each nutrient enema. The addition of alcohol, notably in the form of whisky or brandy, is also of much value in treatment. Some authorities attach more value to the use of the injection of 15 to 20 ounces of normal saline, containing from 1/2 to 1 ounce of pure dextrose, twice or thrice daily, than to the use of ordinary nutrient enemata The following series of recipes will be found of value: -
Pancreatiscd milk . . . . iv to vj.
Common salt .... 3j.
(a) Pancreatised milk . . . . iv to vj.
Whites of 2 eggs Common salt 3j. 3ij of milk suyar may be added.
(b) Pancreatised milk and pancreatised beef juice, each . . . . iij.
(c) Pancreatised milk .... iv.
Brandy or whisky (diluted with equal amount of water) . . . . . j.
Common salt .... 3j.
(d) Pancreatised milk .... iv.
Peptone ..... 3j.
Common salt . . . . 3j.
(e) Pancreatised milk . . . . iv to vi.
Grape sugar ..... ij.
This may be given either in normal saline, or as a constituent of a nutrient enema, as follows: -
(a) Dextrose ..... ss. to j.
Normal saline . . . . x to xx.
(b) Dextrose ..... ss.
Pancreatised milk . . . . iv to vj.
As already stated, the total amount of nourishment absorbed from the judicious use of these enemata is very small. But it amply suffices in the great majority of cases to tide the patient over a critical period in his illness.
There are numerous nutrient suppositories in the market, their chief basis being peptone. These are not as a rule readily absorbed, and their use is rarely advisable.