A rectal temperature below 36° C. (96.8° F.) should be considered an indication for employing warming measures. It is not sufficient to raise the temperature of the incubator only; it is necessary to inquire into the cause of the reduction in temperature. In the first place, there is the post-natal hypothermia which resulted from too great exposure after birth. A fall in temperature will also occur even if the infant is placed at once in the incubator. The observation of Perrett is instructive in this connection:
A premature infant, weight at birth, 950 grams, had a rectal temperature of 36.1° C. It was immediately placed in an incubator at 32° C. The temperature taken every two hours thereafter gave these results -- 35.6, 34.2, 34, 35.2, 35.9, 36.9° C. In other words, the temperature dropped to 34° C. in spite of the incubator; then, after six hours, it gradually rose to normal. Even Lepine, more than forty years ago, asserted that the temperature of the premature infant at the room temperature may drop to 33° C., but, as Budin remarks, the return to normal is not so easy as he indicated.
Evaporation and radiation from the translucent congested skin, causes a rapid loss of heat, and the incubator is designed to prevent this. It is questionable, however, if the incubator should be used to supply heat to the infant. Warm air is a slow method of heating the infant. For the initial drop in temperature the warm bath should be resorted to. When the infant's temperature is normal it must be thoroughly dried and placed at once in the incubator. These warm baths can be frequently repeated.
Repeated attacks of cyanosis usually result in a fall of the rectal temperature. Warm baths and careful attention to diet are necessary.
Very serious is the reduction in temperature following attacks of indigestion. When there are symptoms of colic, green, undigested stools, some of which contain mucus, the question of treatment offers many problems. Blair has been very successful in these cases by heating the incubator up to 96 to 98° and keeping the rectal temperature slightly above normal. In addition he employs bathing. Personally, I feel that the bathing and careful dieting without the incubator being so high will be found equally successful. In private practice it not infrequently happens that after the premature infant is a few days old, and has been overfed, dyspeptic symptoms appear and the infant has hypothermia. The careful treatment of the indigestion and the employment of warm baths are the rational indications and may be absolutely necessary.
Here again I must insist that attention to clothing should be given in just such cases. There is no better way to stop heat loss from a radiating body than to envelop it in non-conducting (woolen) clothing or blankets. Frequently, a reduction in temperature may be checked by enveloping the infant in a soft woolen blanket. Even its head may be thus enveloped and radiation checked.
Our experience shows that infants weighing even less than 1000 grams should be allowed a difference of 4° between their own and the atmospheric temperature. When, even with additional clothing, hypothermia ensues, attention to the food supply and nutrition is necessary.
Finally, a sudden hypothermia may be caused by some infectious process and rapidly end fatally. Altogether, the prompt and careful management of hypothermia is one of the problems of premature infants.
Fever results from an insufficient water supply, an overheated incubator or some infection. Occasionally, constipation seems to be the only cause present. It is remarkable how the temperature of the premature infant fluctuates, being disturbed by slight causes. An elevation of temperature up to 38° C. (100.4° F.) has no significance. A temperature higher than this demands attention. Fever was a very common condition of the infants of the First Series. As I have incomplete data, a report of the cases would be unprofitable. In the Second Series the only two infants having a temperature of more than 102° were infected.
The treatment of fever in the premature infant does not differ from that of older infants. As a rule, it is best to remove the infants from the incubator if the temperature rises above 102°. Often this is all that is necessary, besides the treatment directed to the underlying pathologic condition.
Under this head may be grouped a class of disturbances which are brought about by functional derangement of digestion. It ranks with cyanosis as one of the disorders which causes great anxiety to the attendants. The symptoms do not differ from those in older infants and yet a few symptoms are more pronounced. The most usual cause of indigestion is overfeeding. I have already, in the Sections on Feeding, referred to this cause. If, during the first few days, the milk is given in too large quantities, or later, when the quantity of food given represents more than 130 calories (energy quotient), symptoms of indigestion are liable to appear. In the first week severe indigestion is likely to be fatal; in fact, the impossibility of digesting a sufficient quantity of milk is probably the principal cause of death in infants weighing less than 1000 grams.
Another cause of indigestion is insufficient ventilation. In foundling homes, as Routh, long ago pointed out, bad air gives rise to severe dyspeptic symptoms. Premature infants, also, will lose their appetite, and digest food poorly, when their air is impure. Not only must the most rigid rules for ventilation be enforced as regards the incubator, but the room in which the incubator stands must be thoroughly ventilated. When an infant is fed, the door of the incubator is opened for a short time and the cooler air from the room flows rapidly into the incubator and displaces the warm air (Fig. 9). In a show incubator, therefore, it will not do to have the incubators stand in the same room with the visitors. The incubator room must be tightly separated from the visiting room by glass partitions (Fig. 10).
How far mild infections contribute to indigestion is uncertain as it is often impossible to distinguish digestive disturbances arising from overfeeding or a primary infection.
By what symptoms do we recognize the onset of digestive disturbances? As these infants are usually constipated it will not be sufficient to depend on inspection of the stools except as a corroborative sign. The diagnosis must be tentatively made without seeing the passage.
The symptoms which will direct our attention to the digestion are as follows: Somnolence, anorexia, loss in weight, drop in the rectal temperature, cold extremities and cyanosis. Furthermore, the infant may have repeated attacks of crying and other indications of colic. Vomiting also is very significant, but by no means a very instructive symptom. That form of indigestion which induces colic seems to be less serious, although the colicky attacks may be followed by stupor and death.
Several problems suggest themselves in this connection and it may be instructive to inquire into some of them.
As to the quantity of food sufficient has already been told in the Section on Feeding. Another question that demands consideration is the relation of the incubator and the rectal temperature to the powers of digestion?
I again make two divisions -- First Series and Second Series, the first under the management of my predecessor. For want of space I can give only a few histories.
Case 30. -- Louise, weight 1360 grams, gestation 7 months. Admitted a few hours after birth with a rectal temperature of 101.4°. First day, food 60 calories energy quotient; several stools in the evening, temperature above 101°. Second day, gavage several times, part of the first day, food was given having an energy quotient of about 80 calories, but stools were frequent, several attacks of cyanosis appeared and food was reduced to 20 calories The temperature remained high (Chart 18). Several baths were given. The stools improved when several enemata were employed. The bowel movements remained free and contained undigested food. The third day the food was reduced too much, only about 12 cc. being given in eighteen hours. Death from repeated attacks of cyanosis.
As the quantity of food was too large the first day it is difficult to state whether the indigestion was caused by this or by the high incubator temperature.
The same remarks may apply to Earnest (Case 26), an infant of about the same weight as the preceding, who was given a mixed feeding, was given more than 6 ounces of food in the first eighteen hours and when he would not take it gavage was employed. There was vomiting, great crying with pain and on the third day several attacks of convulsions, and death. As I have not the complete data on hand, the cause of all this is not clear. The temperature was over 101° all the time.
In the case of Warden (Case 14), who soon after admission had a temperature of 104°, the vomiting of mucus suggests that mucus is not always the result of cold, but rather to overfeeding and high temperature of the incubator.
Celeste (Case 15), gestation 7 months, weight 1460 grams, was placed in the incubator at 94°, when the rectal temperature rose to 102°, it was reduced to 90°. On the following four days the rectal temperature was about normal (97 to 99.6°). A few hours after admission with a temperature of 102°, she vomited several times mucus and curds. Otherwise no dyspeptic symptoms appeared. Water was administered freely. Food given was mother's milk diluted 1 in 4 parts -- and the baby did not receive sufficient food. Energy quotient third day 25 calories. She died suddenly on the fifth day. I place this case among the others to illustrate how great care will avoid indigestion, but the infant may die suddenly from exhaustion.
Two more cases of the First Series will be noticed:
Mildred (case 35, see Chart 5), gestation 7 months, had fever (101 to 104.4°) during the first few days of life. Weight at birth 1930 grams. She was fed on mother's milk. Her alimentation daily was as follows: In calories (E.Q.) second day, 20; third day, 30; fourth day, 35; fifth day, 50.
It will be seen that during this time she had fever, probably from the incubator being too high (96°). She received no excess of food, and yet she developed marked indigestion. She had foamy stools, with curds and the stools did not become yellowish, but remained green. The stools also contained mucus.
I will have occasion to refer to this case again under the heading, Inanition. Altogether, the high temperature inhibited the digestion.
In the case of Leonore (Case 21), though a smaller temperature did not go over 100°, and no dyspeptic symptoms appeared during the first week.
Cases from the Second Series need not here be repeated, suffice it to state that a subnormal temperature (below 97°) also inhibits the digestive functions as it appears from the records of several babies. I must conclude, therefore, that maintaining the temperature of the incubator too high or too low predisposes to indigestion.
The treatment of indigestion resolves itself into measures that evacuate the bowels and careful feeding. A dose of castor oil should be given and the quantity of food reduced. As a rule, it is safer to lengthen the intervals and leave the quantity the same when the stomach is not very irritable, while stopping the food altogether for a few hours may be necessary, if there is not much vomiting. Yet, in very small infants the stopping of the feeding is dangerous, as cyanosis may appear.
In all cases of indigestion the food should be reduced to an amount which represents an energy quotient of 70 to 80 calories and should be maintained there until dyspeptic symptoms disappear. In larger infants (more than 1800 grams) it is often advisable to reduce the food to a quantity that represents 60 calories (E.Q.).
I used various methods in order to increase the digestion. Budin has had remarkable results with pepsin, and in a few cases pepsin in the form of Fairchild's essence of pepsin was administered. In these cases I could not find the striking results which Budin obtained, yet in those cases characterized by colic, or evidences of proteid indigestion it should be given.
Further observations on the subject of indigestion will be given under the headings, Loss in Weight, and Inanition.
Not infrequently premature infants become somnolent and show no disposition to nurse; occasionally a repugnance to food is manifested. These are symptoms of overfeeding, hypothermia or infection. A dose of castor oil should be given, less food administered, if too much has been given, and gavage employed. In several cases I used a physiological salt solution, per os. This supplies water and, after a few doses, induces a thirst, which causes the infant to drink its milk eagerly.
In fact, the stimulation of the appetite is very necessary in many cases. Since Pawlow found meat extracts as powerful stimulants of the digestive juices, the employment of meat broths seems rational. In fact, we used small doses of mutton broth in many cases (see Inanition). Wine of cod liver oil (Merck) was also employed as a digestive stimulant.
Several authorities draw attention to the fact that premature infants are subject to constipation. The muscular coat of the bowel either lacks the power, or the mucous membrane is less irritable. At any rate the evacuation of the bowels needs daily attention. As a rule, an emema of salt solution was employed. In several cases olive oil in half teaspoonful doses twice daily was used but not always successfully. Castor oil can be given, but has the well-known disadvantage of constipating afterward. All of our infants suffered from constipation when the diet was not excessive in quantity.
Several disorders may be properly classified under nutritive disturbances. At the onset, it may be profitable to observe normal and abnormal variations in the weight. All infants lose weight immediately after birth, but premature infants in incubators, especially, may lose, relatively, more than the infant at term. Thus, in the Second Series, the loss in weight is represented in Table 23.
This table illustrates the loss in weight of five of our infants who ultimate [sic] did very well. When it is recalled that the initial loss of the infant born at term is about 11 per cent. of its body weight (Holt), simple calculation shows at once that these infants in the first five days lost as follows: John H. 9 per cent, Pearl 11 per cent, Omega 4 per cent, Margaret 14 per cent, St. Louis 12 per cent; the loss, therefore, was not more than the average infant at term, but it must be remembered that these infants are fed regularly after the first few hours, while the infant born at term gets very little until about the third day. Then this does not represent the total initial loss as most of our babies lost for one or two more weeks. The total initial loss was as follows: John H. had the lowest weight on the fifteenth day (Table 16), initial loss 13 per cent; Bernice, lowest weight on the twenty-first day, initial loss 3 per cent; Pearl, lowest weight on the ninth day, initial loss 11 per cent; Omega, lowest weight on the fourteenth day, initial loss 5 per cent; Margaret, lowest weight on the twelfth day, initial loss 12 per cent; St. Louis, lowest weight on the eighteenth day, initial loss 12 per cent.
All of these infants, who lost more than 10 per cent suffered from indigestion, hence their loss should not be compared with those of healthy infants. There should be no extreme loss in weight in premature infants if the feeding and water supply is properly adjusted. No doubt the highly-heated incubator favors loss of weight by evaporation. Unfortunately, the records of the First Series on this point are incomplete. I, therefore, must refer to one little infant treated recently in private practice, who was kept at a warm room-temperature (75 to 78° F.) but clad warmly and a hot water bottle usually applied to the body. The weight at birth was 1820 grams. The infant was put to the breast every two hours soon after birth and in addition pasteurized whey was given in quantities of 4 to 8 cc. every hour and a half. The lowest weight on the third day was 1760 grams. Hence, the initial loss was less than 4 per cent.
It remains to examine a few fatal cases:
C. G., weight on arrival at the incubator 910 grams, second day loss 84 grams, third day loss 30 grams, fourth day loss 58 grams. The initial loss was 19 per cent.
E. K., gestation 7 months, weight on arrival 1930 grams, second day loss 67 grams, third day loss 38 grams, not weighed on day of death.
W. K., gestation 25 weeks, weight 1100 grams, second day loss 31 grams, third day loss 76 grams, total loss about 11 per cent. Slight edema occurred on the second day.
These cases demonstrate that, as a rule, infants who die in a few days lose weight relatively more rapid than those who survive. This again accentuates the importance of prompt and careful alimentation. The prevention of a rapid loss in weight is one of the difficult problems in the care of premature infants.
Persistent loss or stationary weight characterize inanition, malnutrition and marasmus.
In studying the gain in weight, it is obvious from the cases reported (Section IV) that one gram daily is a satisfactory increment of growth. A sudden gain of weight often signifies the appearance of edema. A rapid rise in weight in a very sick baby is often the precursor of death.
Fig. 9. Feeding the Infant, the Doors of the Incubator Being Open.
Fig. 10. The Incubator Room with the Glass Partition which Separated the Incubators from the Visitors.