We have seen what immense difficulties are encountered in the regulation of heat and food supply, and this holds especially true when the infant weighs less than 1500 grams, but a still more important consideration is found in the infections. Infections spare none of the infants, the smallest and the largest may succumb. The "graduate" may go as rapidly as the new-born. One of the objects concerned in the rearing of the premature infant is the prevention of infection, but every pediatrist will concur if I state that in any institution where many infants are placed together it is a most difficult problem.
What are the infections that kill premature infants?
They are the same that are encountered in every foundling asylum. One infant or an attendant acquires the disease on the outside and this forms the source of the epidemic. Infants in institutions die in epidemics, the high death-rate is the result of repeated catastrophes.
Inasmuch as any incubator institution taking care of more than one or two infants is practically a similar institution to a foundling asylum, the dangers of the latter are only accentuated in the former. A baby asylum is a success only when human milk can be fed, and the most rigid asepsis is enforced. This holds especially true for the incubator institute. Our experience on the "Pike" only accentuates well-known facts, that asepsis in all things must be rigidly enforced.
There are two portals of entry for the infection which should be especially considered -- the respiratory tube and the alimentary canal. Hence, the food and air form the most common carriers of infection. The other carriers are those things that come in contact with the infant, namely, the nurses' hands, nipples, thermometers, clothing, napkins, etc.
The infants are very subject to influenzal and pneumococcal infections, resulting in inflammation of the respiratory tube. These infections arise from some one who has the disease. Fortunately, we had no respiratory infections, that were recognized clinically. Budin reports an epidemic among his premature babies ("Le Nourrison,", page 105). I am very familiar with these epidemics in the Bethesda Foundling Home. The origin of these are visitors, most commonly the nurses or wet-nurses. Hence, the following rule must be adopted, especially in the colder months: No nurse must care for the premature infant, and no young mother must nurse an infant, who shows any signs of acute infection of the respiratory tract, that is, bad colds, angina, bronchitis, laryngitis, tracheitis. Nurses with a "bad cold" must be excluded until they are better.
The Incubator Institute on the "Pike" had a frightful experience with gastrointestinal infection. During the first part of the season, in charge of my predecessor, for a time mothers' milk was not procurable, and through some error an infected baby, an infant with gastroenteritis was placed in the nursery. Following this, an epidemic of gastroenteritis commenced, and until September 2d, it raged continuously. It was the catastrophe of hospitalism.
One September 1st, when I took general charge, the most rigid rules of asepsis were laid down and carried out and the epidemic subsided.
But how does this epidemic spread? In this epidemic, the data on hand are insufficient, but the epidemics spread mostly by the fingers of the nurse and the nipples. When the nurse cleanses the mouth of an infected infant, and without thoroughly disinfecting her fingers, another mouth is washed, the germs may be carried in this way. The nipples may be insufficiently boiled. Another common method is the thermometer when used in the rectum of the infected baby and, when not sufficiently disinfected, introduced into the rectum of a healthy infant. The diaper may serve as a source of infection, especially when only slightly wet it is dried and placed on another baby. Flies and insects may light on the lips of one baby and carry the infection to the mouth of another.
In must be conceded that part of this epidemic may have been due to the milk, although it was mostly sterilized.
More concerning this epidemic will be related in the next section.
Besides the gastroenteritis, there are several forms of septicemias that occur in the newly-born. The origin of the infection is probably in the food. I refer to the so-called hemorrhagic diseases. Again, occasionally, on the third or fifth day, there may be a sharp rise in the temperature with no hemorrhagic spots, but the infant rapidly succumbs. It has been shown that the mucous membranes of the newly-born are permeable to bacteria, and this probably holds true for the premature infant. Hence, a variety of septic infections, or septicemias, may occur without any local lesions. We had a few examples of this.
Infections of the conjunctiva are common in the newly-born, and even more so in the premature infants. It is a very easy matter to carry the infectious material from one eye to the other. Several cases of purulent conjunctivitis occurred among the babies.
One of the most difficult problems is the question of oral asepsis. As the secretion of the muciparous and salivary glands are scant in the premature baby, the retention of milk-particles somewhere in the mouth is the rule. It is absolutely necessary to cleanse the mouth several times a day with a physiological salt solution or some mild antiseptic, and yet this very cleansing process is dangerous. I saw cases of thrush transferred in this way. It is so easy for the nurse to convey the spores of the saccharomyces from one mouth to the other. Thrush, however, is a comparatively mild disease, when we consider other pathogenic micro-organisms: e.g., the colon or Shiga bacilli, may be carried in the same way, the importance of this mode of infection is obvious. Nurses must be taught to disinfect their hands thoroughly. After washing the mouth of any baby, especially a sick one, the fingers must be dipped in 70 per cent alcohol for a few minutes before washing the mouth of another baby. It is, perhaps, unnecessary to state that the rubber nipples must be thoroughly boiled between each nursing.
The mammilla of the wet-nurses forms a most common conveyor of infections. Let the wet nurse give the breast to one infant with a sore mouth, or with some disease, and very soon nurse another infant, the pathogenic germs may thus be carried one to the other.
This is a most troublesome method to deal with. The thorough disinfection of the mammilla is practically impossible. Boric acid solution, of course, is unreliable, and stronger antiseptics cause the nipple to harden and crack. The rough surface of the mammilla can not be thoroughly cleansed; 70 per cent alcohol is about as safe and effective disinfectant for the nipple as any with which I am familiar. But great pains must be taken that the wet-nurse nurses only perfectly healthy infants. The sick infants should receive their human milk from a bottle, which can be completely sterilized. The real solution of the question is this: Every mother should nurse her own baby and not nurse any other. But when one wet-nurse gives her breast to several infants, you can expect trouble. Altogether, it is safer, in the very young, to have the wet-nurse "milk" herself and feed the milk to the premature infant from a bottle. Of course, the rule does not hold in private practice.
Another source of infection is decomposed milk in the nose or nasopharynx. The infant vomits and the milk passes through the nose, where particles cling and by decomposition causes irritation. After vomiting through the nose, the installation of salt solution through the nostril will be found helpful.
The skin forms another route by which the infant may be infected. The most common lesions are impetigo and furunculosis. When I took charge I found several cases of furunculosis. Again the cases started by having received an infant in the nursery with a few small boils. The disease spread. I discovered that the infants with boils on their body were placed on the same pad, while being dressed, as the healthy babies. The deposition of a drop of pus, however minute, conveyed the infection to the skin of healthy infants. Hence, the pads on which the babies are laid may initiate a severe epidemic. When the order was given that all infants with sores or boils on them should be placed on a special pad, the cover of which was changed frequently, the furunculosis stopped its spread.
The diapers may serve as a source of contagion. For a time the diapers, when only slightly wet, were dried again and placed on a baby, but unfortunately the baby was not always the same. Hence, any gastrointestinal or skin infection could be carried thus. I ordered each diaper to be burned after having been taken off. This was rather an expensive but effective measure.
Each infant should have its own thermometer, otherwise the thermometer should be kept in strong sublimate solution and washed off before using. The umbilicus, of course, may be a source of infection. When properly dressed in the beginning it will rarely be troublesome. The cord drops off much slower in the premature infant, and its decomposition should be prevented by allowing it to dry thoroughly and using antiseptic powder.
The skin and mucous membrane of the premature infant must be considered as a wound from the surgical standpoint, and no septic material must be allowed to enter. It is not remarkable that the high incubator temperature should enhance the activity of bacteria in the mouth, nose and skin, when it is recalled that the pathogenic micro-organisms grow best at high temperatures.
In any institution where premature infants are kept, certain rules of isolation must be maintained and adequate provision must be made for this isolation. Four departments are necessary, these should be in five separate rooms and entirely separate as regards treatment.
It will be seen that the incubator institute should have four departments. Separate nurses for each department are absolutely necessary. Wet-nurses for each department should also be distinct. To repeat, the departments where everything must be separate, are as follows:
In the accompanying sketch (Fig. 11) the general plan of such an incubator institute may be readily seen.
I must admit that the building of the incubators on the "Pike" did not follow this plan, but insofar as it was deficient in carrying these rules of isolation, its results were imperfect.
It need scarcely be mentioned that bottles, clothing, thermometers, etc., should never be taken from one department to the other.
The treatment of acute infectious diseases differ in no way in the premature infant from those at term. Of course, they cannot do anything with gruels, yet, if dextrinized, they can be substituted for a short period for milk. We used liquid takadiastase for dextrinising gruels. This was given to those infants who were sick with gastroenteric infection; a small quantity of human milk was gradually added. But the treatment of infectious diseases in premature infants must be mainly prophylactic.
Fig. 11 -- Diagram illustrating the ground plan of a public institution for Baby Incubators. a, Dressing room for healthy infants. b, Dressing room for infants showing some mild infection. c, Room for incubators. d, Nursery for healthy "graduates." e, Room for visitors, separated from c and d by glass partitions g and h. f, Baby hospital room for contagious diseases.