George C. Emmanouilides

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.

Patent ductus arteriosus complicating the respiratory distress syndrome in preterm infants

In 46 preterm infants with RDS the patency of the ductus arteriosus was established by single film aortography or by clinical diagnosis and confirmation at surgery. The estimated left-to-right shunt through the PDA by aortogram correlated well with the heart size and the clinical diagnosis of heart failure. In 14 infants massive cardiomegaly and heart failure with a PDA occurred before the appearance of a heart murmur. Twelve infants had severe RDS and 34 had mild or moderate RDS. Massive cardiomegaly occurred significantly earlier in infants with severe RDS. It is suggested that ductal ligation is indicated when an infant with massive cardiomegaly requires IPPV and whose aortagram shows that all of the contrast material is in the pulmonary arteries and none in the aortic arch. A heart murmur may or may not be present.

Late onset complete heart block. Newly recognized sequela of cardiac surgery

Abstract Two children who had undergone definitive repair of tetralogy of Fallot suddenly had sustained complete heart block 3 and 4 years, respectively, after operation. Review of the literature and a nationwide survey revealed similar experiences in additional 18 cases. Ten of the patients had tetralogy of Fallot, 5 had endocardial cushion defects, 4 had isolated ventricular septal defects, and 1 had transposition of the great vessels. The interval between time of operation and documentation of the block ranged from 1 month to 14 years. The data indicate a need for careful evaluation of postoperative conduction disturbances. Delayed onset of complete heart block is a possibility in all patients but particularly in those with evidence of damage to one or both bundle branches.

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.

Fetal responses to maternal exercise in the sheep

Abstract Fetal responses to maternal exercise were studied in twelve long-term sheep preparations. After hysterotomy, a polyvinyl catheter was inserted into the fetal aorta via the femoral artery (11 fetuses) or via a ligated umbilical artery (4 fetuses) and exteriorized. Seven to ten days later, the ewes were exercised on a treadmill (2.0 to 2.5 miles per hour) for 30 to 60 min. Maternal and fetal arterial pressures, heart rates, and blood pH, Po 2 , and Pco 2 were monitored before exercise, at the end of exercise, and after a 30 min. recovery period. The results indicate that fetal responses to maternal exercise generally follow those of the mother. A significant increase in fetal pH and decrease in fetal Pco 2 were observed at the end of exercise, and these were associated with maternal hyperventilation and respiratory alkalosis. Moreover, a significant reduction in fetal Po 2 was noted with maternal exercise. A moderate increase in fetal heart rate was also observed with insignificant change in mean arterial blood pressure. The responses were similar in both fetuses with intact umbilical circulation and those with a ligated umbilical artery. However, the latter fetuses had a lower pre-exercise Po 2 level and had greater decreases of oxygen tension with maternal exercise. The observed changes were reversible after 30 min. of recovery. These observations suggest that moderately severe maternal exercise may be detrimental to fetuses with some compromise of the umbilical circulation but that the normal fetus tolerates maternal exercise well. It is suggested that the decrease in fetal Po 2 is due primarily to reduction in uterine flow during exercise and partially to changes of the oxygen affinities of maternal and fetal hemoglobins consequent to respiratory alkalosis.

Pediatric cardiologyLate onset complete heart block: Newly recognized sequela of cardiac surgery☆

Abstract Two children who had undergone definitive repair of tetralogy of Fallot suddenly had sustained complete heart block 3 and 4 years, respectively, after operation. Review of the literature and a nationwide survey revealed similar experiences in additional 18 cases. Ten of the patients had tetralogy of Fallot, 5 had endocardial cushion defects, 4 had isolated ventricular septal defects, and 1 had transposition of the great vessels. The interval between time of operation and documentation of the block ranged from 1 month to 14 years. The data indicate a need for careful evaluation of postoperative conduction disturbances. Delayed onset of complete heart block is a possibility in all patients but particularly in those with evidence of damage to one or both bundle branches.

The Contractility and Performance of the Preterm Left Ventricle before and after Early Patent Ductus Arteriosus Occlusion in Surfactant- Treated Lambs

ABSTRACT.: The influence of left-right ductal shunting on early hemodynamic responses, namely left ventricular performance, contractility, and systemic perfusion was evaluated in nine preterm lambs (120 days gestational age) treated with surfactant. Blood gases were maintained in the physiological range using mechanical ventilation; hemodynamic and blood flow measurements (radionuclide labeled microspheres) were obtained before and after occlusion of the patent ductus arteriosus with a catheter balloon. The mean left-right ductal shunt before occlusion (1.2 h postnatal age) was 59 ± 11% SD. Left ventricular output was increased in all lambs with PDA (pre: 306 ± 106 verus post: 155 ± 31 ml/min/kg; p < 0.001); effective systemic blood flow and organ blood flows did not change. The left ventricle end-diastolic volume was increased in all and decreased following ductal occlusion (pre: 2.0 ± 0.4 verus post: 1.5 ± 0.2 ml/kg; p < 0.01). Cardiac rate, ejection fraction, and contractility (peak dP/dt) did not change. Right-left ductal shunting was not detected in six similarly treated lambs. Thus, during the 1st h of life the hemodynamic profile of preterm lambs with patent ductus arteriosus was characterized by large magnitude left-right shunt and a “high” cardiac output state sufficient to maintain unchanged systemic perfusion. The increased left ventricle output was accomplished by increasing end-diastolic volume (Frank-Starling mechanism), but left ventricle contractility remained unchanged. We speculate that the preterm left ventricle may be unable to sustain the high level of pump performance and contractility required to compensate for the ductal “steal” of systemic blood flow.

Early versus late treatment of neonatal acidosis in low-birth-weight infants: Relation to respiratory distress syndrome

Neonatal acidosis was detected by analysis of fetal scalp, umbilical cord arterial, or umbilical arterial blood during the immediate perinatal period in 90 preterm low-birth-weight (appropriate-for-date) infants. The acidosis was randomly treated early (at approximately 30 minutes of life) or late (approximately 2 1/2 hours) by rapid intravascular infusion of sodium bicarbonate. Serial analyses revealed that the group treated early had a higher arterial blood pH during the first 24 hours and a higher Pao 2 during the first three hours of life. The incidence of respiratory distress syndrome was similar in the early and late treatment groups; however the severity of the disease was significantly milder in the early treatment group. There was no significant difference in the mortality rates between the early and late treatment groups, whether the infants weighed less than 1,500 Gm. or between 1,501 and 2,250 Gm. However, when infants who weighed 1,001 to 1,500 Gm. were considered separately by retrospective analysis, more of those treated late died (9 of 21) than those treated early (4 of 21). It was concluded that early detection and correction of neonatal acidosis in low-birth-weight infants is helpful in reducing the morbidity rate and may improve the survival rate of infants with respiratory distress syndrome.

Placenta to lamb fetus transfusion in utero during acute hypoxia

Maternal and fetal hemodynamics, placental blood flow, fetal-placental blood volume, placental blood volume, and fetal blood volumes were measured in six chronic sheep prepartions to evaluate their changes during acute fetal hypoxia induced by maternal hypoxia. During fetal hypoxia, the maternal and fetal arterial blood pressure and heart rate were essentially unchanged. The placental blood flow (control equal to 325 ml.per kilogram per minute) was also unchanged during the hypoxia period. However, the placental blood volume decreased significantly from 65 to 60 and 51 ml. per kilogram at 15 and 30 minutes of hypoxia period, respectively. The fetal blood volume increased reciprocally and significantly from 86 to 109 and 102 ml. per kilogram at the same periods of hypoxia since the fetal-placental blood volumes were unchanged. These blood volume changes persisted for 30 to 60 minutes following the stoppage of hypoxia experiments. The placental vascular resistance measured in six experiments showed a significant increment during hypoxia, suggesting placental vasoconstriction as the responsible mechanism for the reduction of placental blood volume and reciprocal increase in fetal blood volume. The data suggest that significant placental transfusion to the lamb fetus may occur in utero during fetal hypoxia resulting in a higher fetal blood volume before birth.

Pulmonary Artery Stenosis Associated with Ductus Arteriosus Following Maternal Rubella

Nine patients with pulmonary artery stenosis associated with patent ductus arteriosus following maternal rubella are described.Five of the patients had bilateral pulmonary artery stenosis and four cases involved only the right pulmonary artery. Mild pulmonary valvular stenosis was present in five and a ventricular septal defect in one.The persistence of a systolic murmur transmitted to the lateral chest wall, after ligation or division of a patent ductus arteriosus, should arouse suspicion of the presence of pulmonary artery stenosis.This report supports the recently described implication of maternal rubella as a cause of pulmonary artery stenosis. Careful auscultation in patients with history of maternal rubella may discover the presence of such an arterial anomaly, but cardiac catheterization and angiocardiography are necessary for substantiation of diagnosis.The natural history of these lesions is not known.