Forrest H. Adams

Pulmonary arterial pressure changes in human newborn infants from birth to 3 days of age

Pulmonary arterial and systemic pressure measurements were obtained in 51 normal full-term infants ranging from 1 to 54 hours of age by retrograde catheterization of the aorta, ductus arteriosus, pulmonary artery, and right ventricle via the umbilical artery. A left-to-right shunt through the ductus arteriosus was demonstrated in the majority of the infants under 15 hours. Pulmonary arterial pressure does not fall abruptly after the establishment of respiration. The systolic pressure level approximates that in the aorta during the first few hours of life and is accompanied by a drop in diastolic pressure. Mean pulmonary arterial pressure approaches the 50 per cent value of mean systemic pressure by the end of the first day.

The nature and origin of the fluid in the fetal lamb lung

Studies on fetal lambs near term with intact placental circulation have demonstrated a significant chemical gradient for hydrogen ion, total carbon dioxide, chloride, and lactic acid between the tracheal fluid and the fetal blood. It seems clear that the tracheal fluid is formed in the fetal lung either as the result of ultrafiltration with selective reabsorption or ultrafiltration with selective secretion. Since the glottis is probably open at all times except during swallowing, the tracheal fluid must move into the pharynx where it is readily swallowed or passes out through the nose and mouth into the amniotic cavity. A fetal lamb was studied that had no eyes, nose, or mouth and thus no communication between the trachea and amniotic cavity. The tracheal fluid in this lamb was similar to that of normal lambs.

Control of flow of fetal lung fluid at the laryngeal outlet

Abstract Lambs near term with placental circulations intact were delivered by cesarean section. Cineroentgenograms of contrast material injected into the trachea demonstrated the presence of a sphincter mechanism at the laryngeal outlet. The sphincter opened periodically and allowed the lung fluid to be discharged into the nose and pharynx where it was swallowed. The mechanism consists of two large arytenoid cartilages which are held together and up against the back of the epiglottic cartilage by contraction of a muscular sling comprising thyro-arytenoid and inter-arytenoid muscles. Material injected into the nose or mouth did not enter the trachea except following occlusion of the umbilical cord. Sectioning the recurrent laryngeal nerves paralysed the muscle component of the sphincter. The mechanism probably aids in lung growth by maintaining a positive intraluminal pressure, and assists in the retention of lung surfactant. It also acts as a barrier to the ingress of mucus and amniotic fluid in utero into the future airway.

Surface properties and lipids from lungs of infants with hyaline membrane disease

The data presented in this paper indicate that although active phospholipid components are present in lung extracts from very small premature infants and infants dying of hyaline membrane disease, the quantity of these active components is low. This suggests that an inadequate amount of surface-active material is at least one of the major factors contributing to atelectasis in this syndrome.

Absorbed dose in the presence of contrast agents during pediatric cardiac catheterization

Administration of x-ray contrast agents during heart catheterization examination increases the absorbed radiation dose in tissue. To estimate the dose absorbed by the blood of children undergoing diagnostic heart catheterization and angiocardiography, a number of measurements and calculations were conducted. First, entrance and exit exposures to the patient were measured with thermoluminescent dosimeters calibrated for the diagnostic x-ray energy range. Second, a dose enhancement factor was calculated from mass energy absorption coefficients for various concentrations of the contrast media and at selected x-ray energies. Third, the dose enhancement factor was estimated from survival of peripheral blood lymphocytes suspended in varying concentrations of the contrast agent during exposure to graded doses of x-rays. Fourth, a mean absorbed dose to the patients blood was calculated using (a) the dose enhancement factor determined above, (b) an estimate of the mean exposure in the irradiated body volume calculated from the entrance and exit exposure measurements, (c) an effective iodine concentration in the blood during the exposure time, and (d) a ratio correcting for the distribution and circulation of the blood. For eight pediatric patients monitored, absorbed doses to the blood ranged between 3 and 12 rad. These values were two to three times greater than the expected dose without administration of a contrast agent.

Surfactant in fetal lamb tracheal fluid

Studies on fetal lamb tracheal fluid have demonstrated the presence of surfactant, the substance which lines the internal surface of the lungs and helps to stabilize the air spaces. These observations are further evidence indicating that this fetal tracheal fluid has its origin in the fetal lung.

The Growth of the Normal Aorta and of the Anastomotic Site in Infants Following Surgical Resection of Coarctation of the Aorta

Observations were made on the growth of the anastomotic site 2 to 4 years after surgical resection of coaretation of the aorta in 5 infants who were less than 2 years of age at the time of surgery. Aortic measurements were made from biplane angiocardiograms. The physiologic adequacy of the anastomotic site was demonstrated by absence of a gradient in direct pressure measurements between the upper and lower extremities. Additional observations on the normal growth of the descending thoracic aorta were made from studies in 154 subjects with other forms of heart disease. They ranged in age from 2 days to 74 years.

A comparison of the maximal endurance of normal children and patients with congenital cardiac disease

A technique to measure maximal endurance in children is described, and the results of its application to normal children and to those with congenital cardiac lesions are recorded. The children with heart disease were unable to achieve pulse rates as high as could the normal ones, and had considerably less endurance. The maximal endurance score of a child with cardiac disease tended to reflect his functional status as indicated by cardiac catheterization studies.

A Syndrome Featuring Defects of the Heart, Sternum, Diaphragm, and Anterior Abdominal Wall

Three patients featuring a syndrome of defects of the heart, sternum, diaphragm, and anterior abdominal wall are presented. The striking similarity of the anomalies manifested by the 3 cases posed a question whether or not a recognized syndrome previously existed. In order to determine this, a search was made to find other such cases, and an attempt was made to establish a common embryologic pathogenesis. Review of the literature as well as extensive personal communication was carried out. Embryology of the involved organs was considered in order to determine a specific phase of defective development.

The disappearance of fetal lung fluid following birth.

The fetal lung at term contains a large amount of extravascular water which fully expands the future air spaces. This study on full-term newborn rabbits shows that the extravascular fluid disappears slowly over a period of several days, initially more rapidly in those delivered vaginally as compared with those delivered by cesarean section. The mechanisms of removal of the fluid are discussed. To our surprise, lung blood volume did not increase as was anticipated.