Nutrient enemata date back to the days of Galen, but it is on the work of Voit and Bauer, of Leube and of Ewald, that most of the modern practice is based. In the early days nutrient enemata were composed of meat broth, milk, eggs, or any other article of food which the physician fancied, and very little trouble was taken to establish the capacity of the intestine for the assimilation of the substances thrust upon it. Now we have more exact metabolic observations on which to base our treatment, and modern pharmacy has given us a number of predigested foods which are more or less easily absorbed.
Voit and Bauer seem to have been the first to carry out observations on the nitrogenous metabolism of rectal feeding. Working with dogs they found that the absorption of albumin by the bowel was greatly aided by the presence of common salt. Eichorst confirmed these results, and it is now generally admitted that common salt forms an essential ingredient of every rectal injection.
Leube in 1872 published a paper on meat and pancreas enemata by which he claimed to get very favourable results. The enemata consisted of 150 to 300 grammes (4 1/2 to 9 oz.) of finely chopped or scraped meat; 50 to 100 grammes (1 1/2 to 3 oz.) pancreas, finely chopped and freed from fat; 150 c.c. (5 oz.) warm water were added, and the whole stirred into a mushy mass. This was injected by means of a pressure syringe. Leube claims to have got good results; in one case the patient was nourished for six months on the enemata. Riegel speaks highly of Leube's meat pancreas enemata. The writer's experience has been that they are difficult to administer, that the pancreatic value of fresh pancreas is very variable, and that the putrefactive decomposition set up in the intestine is marked and is liable to give rise to unpleasant results. On the whole the method is complicated and not to be advised at the present day.
Huber and Ehrstrom obtained relatively good results by the use of milk, grape sugar and protein, a sugar casein preparation. The composition and method of preparation of the nutritive enemata which have been advised vary greatly. Nearly every writer on disease of the stomach has a formula of his own.
Ewald recommends the following : two or three eggs are mixed with a tablespoonful of cold water, a small quantity of flour is boiled in half a cup of 20 per cent solution of dextrose, and to this mixture a wineglassful of red wine is added; the egg solution is then stirred in, care being taken that the mixture is not sufficiently hot to coagulate the albumen. The whole mass should amount to about 1/4 of a litre. The caloric value of such a mixture would amount to 230 to 300 calories.
Boas uses 250 grammes (8 1/2 oz.) milk, 2 egg yolks, a small quantity of salt, a tablespoonful of red wine and a tablespoonful of flour. Riegel employed 250 c.c. (8 1/2 oz.) milk, two or three eggs, a little salt, and one or two spoonfuls of red wine. The use of peptone has been recommended by some writers, but clinical experience seems to show that it is apt to irritate the intestine and cause diarrhoea. The writer has found the following mixture to give good results : the yolks of two eggs, 30 grammes (1 oz.) pure dextrose, .5 grammes (8 grains) common salt, pancreatized milk to 300 c.c (8-10 oz.). The nutrient value of such an enema equals 300 calories, and given every six hours the total nourishment injected would equal 1,200 calories. Absorption under most favourable circumstances might equal 500 calories, but would most probably be much less. The caloric value might be increased by the addition of an artificial protein preparation such as sanatogen, plasmon, or protene, preparations for which rapid absorption is claimed.
In carrying out a course of rectal feeding the preparation and adequate nursing of the patient are very essential factors. Under the conditions where rectal feeding is used, thirst is a prominent feature, and the patient should be allowed a mouth wash, or water to rinse out the mouth, but should be cautioned against swallowing the water. If gastric rest is desired the sucking of ice and the swallowing of water must interfere with gastric rest, for water is not absorbed from the stomach and must be passed on for absorption in the intestine. If thirst be a distressing symptom a normal saline injection should be given. In cases of gastric haemorrhage oral sepsis is common, the patient should therefore be provided with an antiseptic mouth wash, and great care taken in the cleansing of the buccal cavity. The products of decomposition in the mouth if swallowed are apt to interfere seriously with gastric rest, and to prolong gastric irritation. The rectum and lower bowel must be washed out daily with a simple saline injection; indeed some writers advise this should be done before each nutrient enema, but this seems scarcely necessary. If, during the treatment, rectal irritation and diarrhoea should supervene, a drachm or two drachms of laudanum may be added to each injection, or a morphia suppository used. The method of administration and size of the enema are important points. The enema should be given with the patient lying on the left side and the hips elevated, or on the back with the buttocks raised. A syringe should not be used, as a substance rapidly injected into the bowel will be as rapidly returned. The enema should be very slowly syphoned in by means of a soft rubber catheter and a small sized filter funnel. The retention of the nutrient material is not then a matter of difficulty. The patient should be cautioned to remain very still after the nutrient injection has been given. The amount of the nutrient injection commonly used is four to six ounces (112 to 168 c.c), which is possibly too small an amount. If the enema be given slowly 8 to 10 oz. (250 to 300 c.c.) can often be retained, the patient absorbs at least some water, and does not suffer thirst, which is a prominent difficulty when small injections are used. Large injections do not require to be so frequently repeated, a distinct advantage when gastric rest is desired, for it must be remembered that the injection of nutrient material into the lower bowel excites gastric secretion. This gastric secretion, long recognized clinically, has been clearly demonstrated by Umber on a patient on whom gastrostomy had been performed. After a nutrient rectal injection it was found that there was free gastric secretion with a total acidity of 30, free hydrochloric acid equalling 20. Gastric secretion is accountable for the gastric pain and vomiting which are sometimes such prominent features during a course of rectal feeding. Some clinicians have advised that with every rectal injection a small quantity of milk and bicarbonate of soda should be given by the mouth to satisfy the acid secretion and obviate pain.
It is a popular belief that substances injected into the lower bowel are absorbed below the ileo-ccecal valve, but this does not seem invariably to be the case. Insoluble substances injected into the rectum may, under favourable circumstances, reach the stomach. Cannon's observations would support this view. Grutzner has shown that if starch emulsion be injected into the rectum, along with normal saline solution, starch granules can be washed out of the stomach four to six hours afterwards. Church records a case of duodenal fistula where the soap and water of the enema invariably flowed through the fistula. The passage of the nutrient material through the ileo-coecal valve may account for the favourable results in some cases of rectal alimentation, and is an argument in favour of increasing the size of the nutrient enemata when the patient can tolerate the larger injections. That the ileo-ccecal valve will permit the passage of fluid in every case cannot, however, be expected; in fact the writer has frequently failed to find insoluble particles, such as charcoal, in the stomach washings in cases where charcoal was added to the nutrient enemata.