Although there are many investigations on the etiology, cause of death, and clinicopathology of the premature infant, a few reports are found on the continuously perspective study.
The author observed the etiology and causes of death of 188 premature infants statistically and further studied perspectively the dead infants with particular reference to the relationship between their clinical and autopsy findings. Results obtained were as follows.
a) Statistical observations on the etiology and the cause of death in premature infants.
1) Forty three (22.9 %) were expired within 40 days after admission.
2) Birth and mortality of premature infants observed from the age of parents: The delivery of premature and the rate of death are deeply related with maternal age. Among the younger age group of 15-19 years and older age of 40-44 years the rate of delivery is very small, and the rate of premature infants is 1.1 % respectively, while 41.5 % of delivering rate was seen among the age group of 25-29 years old. The death rate of premature infants is as small as 13.2 % among the maternal age of 30-34 years, but is very high as 36.1 % among the age of 20-24 years. Paternal age is 3 to 4 years higher than those of maternal one. The difference of paternal and maternal ages is corresponded with thier marital age difference.
3) There is no sex difference among the living newborn, although the mortality rate in male premature is 30.8 % and in female premature 16.7 %, indicating the male mortality is significantly higher.
4) Toxicosis and nephritis during the pregnancy were seen among the mother of 29.8% of prematurity. Previous history of miscarriage was observed in 52.1 % of poor hygienic status in 7.1 % of severe working. There were 11.7 % of rupture of the membrane and 10.1 % of Caesarian section among the abnormal deliveries, and 15.4 % of twin pregancy, 3.1 % of syphilis, deformities and blood group incompatibility among the fetal anomalies.
5) Status of growth of premature infants at birth, smaller the body weight, circumferences of head and thorax is, higher the mortality. Particularly, smaller the every months Kaup growth index of intrauterine fetus is poorer the prognosis, and those whose ratio circumference of thorax/that of head are below 0.9 all died.
6) Of the cause of death of premature infants the respiratory insufficiency at admission is of particular important. Apgar Score, Silverman Retraction Score taken at admission, and the graph made by the continuous changes of breathing, pulse rate, body temperature between 3 and 6 houres after admission are very helpful or the judgement of the prognosis.
b) Relationship between the clinical and pathological findings of expired premature infants.
1) Survival time within 18 hours: Clinical main features are nondevelopment of spontaneous respiration, weakness of cardiac output, loss of reflexes, and pathological ones are pulmonary atelectasis, extramedullary hematopoesis in lung, liver, spleen and adrenals. In particular, for short time after birth, those who had shallow respiration and goan, and got improvement of respiration by oxygen inhalation, and fell into shortly apnoea and severe cyanosis, lived as long as 3-11 hours, and showed on dissection hyaline membrane formation of the lung. In other words, pulmonary atelectasis is either associated with hyaline membrane formation or without.
2) Survival time of 37-76 hours: Clinically they showed tachypea, tachycardia, weak weep with normal tendon reflexes and no cyanosis, and worse signs and symptomes in the course of about 24 hours until death. On the other hand, there are found pathologically, as main features, emphysema, a part of pulmonary atelectasis, petechia, and some degree of extramedullary hematopoesis in liver, and prematurity of zona glomerulosa of the adrenal cortex.
3) Survival time of 8 days: Twins of 32 weeks of pregnancy.
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