PubMed Health⌕ Search

Biomedical subjects

V Y Yu

Publications and source records attributed to V Y Yu.

At least 145 records · Page 8Linked to original sources

Perinatal asphyxia and outcome of very low birthweight infants.

Seventy-eight very low birthweight (VLBW) infants (whose birthweights were 1500 g or less) were admitted to the Neonatal Special Care Unit in 1977. Seventy-two of them required treatment in the intensive care area; these represented 40% of admissions to that area of the Unit. The mortality rate was 20% for infants weighing 1001 g to 1500 g, and 52% for those weighing 501 g to 1000 g. An Apgar score of 0 to 3 at two minutes and five minutes was reported in 34% and 19% of VLBW infants respectively. Although there was no difference in birthweight between the groups with a high or low Apgar score, the mortality rate of infants with a five-minute Apgar score of 0 to 3 was 79% compared to 22% in those with a score of 4 to 10. Over 50% of the infants developed hyaline membrane disease regardless of Apgar score. However, in the infants with a five-minute Apgar score of 0 to 3, the severity of respiratory insufficiency was increased as indicated by increased requirement for high inspired oxygen, and the need for intermittent positive pressure ventilation. The duration of stay in the neonatal intensive care area, and the total length of hospital stay of the 49 VLBW survivors were shorter in the group with higher two-minute and five-minute Apgar scores. Long-term morbidity cannot yet be ascertained. It is likely that prevention, or prompt detection, and appropriate management of perinatal asphyxia would produce a further decline in mortality as well as morbidity for VLBW infants.

Acute Disease↗

Neonatal necrotizing enterocolitis: 1. Clinical aspects.

Forty-infants were diagnosed as having necrotizing enterocolitis (NEC) during a 33 months' period; these represented 4% of all neonatal admissions. Pathological confirmation was obtained at surgery in 12 cases and at autopsy in 11, In the case of 21 infants who recovered without operation, the diagnosis was based on clinical and radiological criteria inculding the presence of intramural gas. NEC occurred primarily, though not exclusively , in low-birth-weight infants. Two-thirds of the infants developed NEC in the first week of life. Clinical features attributable to gastrointestinal malfunction as well as a systemic illness could be defined. Complications included pneumoperitoneum (34%), localized peritonitis as suggested by the development of an abdominal mass (11%) and intestinal obstruction (25%). Fourteen of the 15 cases of pneumoperitoneum were diagnosed within 24 hours after the onset of NEC. The 5 infants were localized peritonitis, who were managed conservatively initially, developed intestinal obstruction during recovery. Intestinal obstruction presented between 2 and 7 weeks after the onset of NEC. The overally mortality was 25%, infants with intestinal perforation or obstruction having and increased mortality of 38%.

Age Factors↗

Neonatal necrotizing enterocolitis: 2. Perinatal risk factors.

Forty-four infants were diagnosed as having necrotizing enterocolitis (NEC) during a 33 months' period; these represented 4% of all neonatal admissions. An increase in incidence was observed during this period, particularly in low-birth-weight infants weighing under 1,500 g. Perinatal risk factors occurring in infants preceding their onset of NEC are found also to be significantly more common in infants under 1,500 g compared with those between 1,500 and 2,499 g. When the incidence of these clinically associated conditions in infants with NEC are compared with the incidence in infants who did not have NEC in the same birth weight category, a difference can be demonstrated only in 4 out of the 23 analysed: prolonged rupture of membranes with amnionitis; birth asphyxia; hypertonic milk feeds; exchange transfusion. As NEC is possibly a disease of multifactorial aetiology, a multivariant analysis of the data is indicated to define the role of combined perinatal risk factors in the pathogenesis of this disease.

Asphyxia Neonatorum↗

Effect of continuous positive airway pressure breathing on cardiorespiratory function in infants with respiratory distress syndrome.

A method of investigating the cardiorespiratory responses to continuous positive airway presslre (CPAP) in infants with respiratory distress syndrome is described. All measurements were made immediately before and within five minutes of application or any change in level of CPAP. Ventilation was derived from a pneumotachograph and dynamic compliance calculated. We have also measured arterial pH, oxygen and carbon dioxide tensions, arterial blood pressure and central venous pressure. Arterial oxygen tension increased in association with a decrease in the alveolar-arterial oxygen gradient. No consistent changes occurred in pH or carbon dioxide tension. Heart rate and mean arterial blood pressure remained the same but the arterial pulse pressure narrowed and the increase in central venous pressure averaged 17% of the applied airway pressure. There were less variations in both tidal volumes and instantaneous respiratory rates with CPAP compared with spontaneous breathing without CPAP. The respiratory rate decreased, but there were no consistent changes in tidal volume, resulting in a lesser reduction of minute ventilation. Dynamic compliance decreased on CPAP. With correct use of CPAP, and improvement in oxygenation generally occurs without obvious adverse cardiorespiratory effects. CPAP must nevertheless be used cautiously and in conjunction with close monitoring; because when the appropriate pressures are exceeded, it is possible that both circulatory and ventilatory function might be severely compromised.

Blood Pressure↗

Cardiorespiratory response to feeding in newborn infants.

Milk feeds were given through indwelling nasogastric tubes to 14 infants with respiratory distress. Similar cardiorespiratory disturbances were observed when the infants were fed (5 ml/kg per feed) human milk, cow's mild, or distilled water. Pao2 fell after a feed but recovered to the prefeed value at 30 minutes, at which time Paco2 had fallen and the respiratory rate had increased. No changes in pH, heart rate, or blood pressure were observed. Portal sinus pressures rose after feeding in association with an increase in central venous pressure. In contrast, when the ill infants were fed human milk at a volume of 2-5 ml/kg per feed no consistent changes in any of the measurements were found. These studies suggested that the cardiorespiratory effects were related to volume displacement resulting from feeds being introduced into the stomach. The relation of the increase in central venous pressure and the magnitude and direction of shunting in infants with the respiratory distress syndrome is uncertain. Adverse effects may be avoided by giving smaller, and therefore even more frequent, feeds.

Animals↗

Effect of feeding on ventilation and respiratory mechanics in newborn infants.

Measurements of ventilation and respiratory mechanics were made before and after tube feeding in 24 infants. In 12 infants with the respiratory distresssyndrome tidal volume tended to fall after feeding; as the respiratory rate increased after feeding; as the respiratory rate increased after feeding, minute ventilation remained unchanged. Hypoventilation is therefore unlikely to be the cause of hypoxaemia after feeding. Compliance, resistance, and the work of breathing showed no changes after feeding. In 12 healthy infants feeding had no effects on pulmonary function. There was a slight rise in compliance and a tendency for work of breathing to fall after feeding. Respiratory rate, tidal volume, and minute ventilation remained unchanged. There was therefore no evidence of adverse effects of feeding on any of the factors measured. It is suggested that hypoxaemia without hypoventilation after feeding in infants with pre-existing respiratory distress syndrome might be attributable to a reduction in functional residual capacity associated with a greater extent of airways closure than before feeding.

Enteral Nutrition↗

Lymphocyte reactivity in pregnant women and newborn infants.

The mitotic response to phytohaemagglutinin (PHA) was determined in lymphocytes of mothers and their newborn infants obtained at delivery and seven days later by measuring the rate of 125 I-idoxuridine uptake into DNA in lymphocytes cultured in their own plasma and after washing and resuspension in fetal bovine serum. There was no difference in the unstimulated counts of maternal lymphocytes taken at delivery, whether unwashed or washed, compared with those from nonpregnant controls. With PHA stimulation the mitotic response of the maternal lymphocytes cultured in their own plasma was reduced compared with that of the control lymphocytes but washed maternal cells showed a similar response to the controls. These findings suggest that the reduced lymphocyte mitotic response to PHA in pregnancy is due to a plasma inhibitory factor This inhibition was not evident in maternal blood taken seven days after delivery. DNA synthesis in unstimulated cultures from newborn infants at birth and seven days after birth was greater than that in adult control cultures. With PHA stimulation the mitotic response of cord-blood lymphocytes cultured in their own plasma paralleled that of control lymphocytes but washed newborn cells showed a greater response. Thus plasma suppression similar to that observed in the mother seems also to affect infants at birth. This inhibition was not demonstrable in blood taken from infants of 7 days.

Culture Techniques↗

Massive pulmonary haemorrhage in the newborn infant.

Six cases of massive pulmonary haemorrhage in newborn infants are described. 2 term infants suffered severe birth asphyxia and massive pulmonary haemorrhage presented early (mean 5 hours); in 4 preterm infants massive pulmonary haemorrhage presented late (mean 4 days) while receiving assisted ventilation. All the infants were treated with positive pressure ventilation, vigorous correction of pH, anaemia, and hypovolaemia, and 4 survived the acute condition. We suggest that the early elective use of intermittnet positive pressure ventilation may be effective in controlling the pulmonary haemorrhage.

Asphyxia Neonatorum↗

Pneumothorax in the newborn. Changing pattern.

The clinical course of pneumothorax and its allied conditions was studied in 34 newborn infants who presented over a 2 1/2-year period. We found an overall incidence of 3/1000 live births. 11 term infants without obvious pulmonary pathology presented early (9 within minutes of birth); 6 of these had aspirated meconium or blood. The remaining 23 were preterm infants with hyaline membrane disease (HMD) and accounted for 68% of the infants in this series. In contrast, they presented late (mean 45 hours) and 16 were on continuous distending pressure (CDP) or intermittent positive pressure ventilation (IPPV) at the onset of pneumothorax. 15% of all infants with HMD who required CDP/IPPV developed pneumothorax; this increased incidence was most evident in infants who received CDP only. All except 2 of the 11 term infants in the first group were managed conservatively and all survived. Wehn pneumothorax occurred as a complication of HMD in preterm infants, 14 of the 16 infants required intrapleural drainage. Persistence or recurrence of pneumothorax occurred in 9 infants, 7 of whom were receiving CDP/IPPV at the time. Lung expansion was affected only after replacement with a patent chest drain through the same incision or insertion of a second drain on the same side of the chest. All 5 deaths occurred in the group of preterm infants with HMD. 3 resulted directly form respiratory failure due to severe HMD complicated by pneumothorax. We emphasize the increasing importance of pneumothorax as a complication of HMD in preterm infants, particularly in those receiving CDP. Successful management depends on prompt diagnosis and treatment of pneumothorax, which may occur as unexplained sudden deterioration at any time during the course of illness in this group of high risk infants.

Drainage↗