Passive compliance of total respiratory system in preterm newborn infants with respiratory distress syndrome

The passive compliance of the total respiratory system (CRS) was measured by the occlusion technique in 34 preterm newborn infants with respiratory distress syndrome. Gestational age ranged from 27 to 33 weeks. Preterm newborn infants were divided into four groups on the basis of clinical criteria. Group 1 consisted of 10 infants tested during the first postnatal days (1 to 3 days) while acutely ill and requiring ventilation and oxygen therapy. After the acute phase of respiratory distress syndrome, two groups were tested: group 2 consisted of nine infants (5 to 22 days of age) who no longer required ventilation, and group 3 consisted of six infants (7 to 28 days of age) who subsequently had bronchopulmonary dysplasia. Group 4 consisted of nine infants older than 1 month of age with confirmed bronchopulmonary dysplasia. Group 1 had significantly lower CRS and CRS normalized for body weight (CRS/BW) than group 2 had (P less than 0.001). In groups 3 and 4 CRS was significantly lower than in group 2 (P less than 0.001), as was CRS/BW (P less than 0.001). There was no significant difference in CRS and CRS/BW values between groups 3 and 4. This cross-sectional study in preterm infants with respiratory distress syndrome suggests that CRS may have predictive value in regard to development of bronchopulmonary dysplasia after the acute phase of respiratory distress syndrome.     

Behavior of Clostridium perfringens in the intestine of newborn infants born by cesarean section

Colonization of the digestive tract by C. perfringens was studied in infants born by cesarean section. Correlations between the level of colonization and the environment, type of feeding, and presence of other anaerobic bacteria were looked for. Colonization by C. perfringens was found as early as the second day of life in one of the maternity wards studied, suggesting presence of the microorganism in the environment. By the 14th day of life, colonization with C. perfringens was demonstrated in all the bottle-fed or breast and bottle-fed infants. In strictly breast-fed infants, findings suggested antagonism between Bifidobacterium and C. perfringens. Bactero?des and Clostridium species other than C. perfringens were not found prior to colonization by C. perfringens.     

Difference in TcB readings between full term newborn infants born vaginally and by cesarean section

We studied the influence of method of delivery on TcB readings at the forehead and sternum in full term neonates in the first week of life. Our present study demonstrated that TcB readings at the forehead and sternum of the infants delivered by cesarean section were significantly lower than readings from infants delivered vaginally without complications, from day 1 to day 7 of life (p less than 0.05). This is probably due to the decreased placental transfusion at cesarean section. The present study suggests that the degree of placental transfusion or time of cord clamping may be more influential than meconium passage or weight loss on serum bilirubin levels in the first week of life.     

Levels of total and free tryptophan in maternal and in umbilical blood of infants born by vaginal delivery and by elective cesarean section

The variations of total and free tryptophan levels in samples of maternal and umbilical blood obtained on the occasion of elective cesarean section have been compared with similar samples taken from vaginal deliveries. In the neonates studied the umbilical blood levels of total and free tryptophan have been found to be higher than in the blood of the respective mothers, while the percentage of free tryptophan is comparable. In addition, the umbilical blood levels of both fractions of tryptophan appeared to be higher in newborn infants after spontaneous delivery than in those after elective cesarean section. These data show an active transport of tryptophan through the placental barrier that seems to be favored by spontaneous delivery.     

Effect of preoperative stabilization on respiratory system compliance and outcome in newborn infants with congenital diaphragmatic hernia

To determine whether preoperative stabilization and delay of operative repair of congenital diaphragmatic hernia (CDH) may decrease operative risk, we performed serial pulmonary function tests on 22 newborn infants with CDH and on four infants without pulmonary hypoplasia (two with ileal atresia and two with tracheoesophageal anomalies) who served as control subjects. We used 2 passive respiratory mechanics technique to measure respiratory system compliance. All patients with CDH had respiratory distress immediately after birth, and required mechanical ventilation. Thirteen babies underwent emergency repair (six survived, seven died); nine of them received extracorporeal membrane oxygenation (ECMO) after the operation (two survived, seven died). Operative repair was delayed deliberately for 2 to 11 days in nine infants with severe hypoxemia. Six immediately received ECMO for 4 to 10 days; one died of intraventricular hemorrhage, and five survived and later underwent surgical repair. The seventh patient did not receive ECMO but appeared to have respiratory distress syndrome of infancy and improved after administration of synthetic surfactant. Improvement was seen in two additional infants who received conventional assisted ventilation during a 48-hour delay before surgery, and survived. In all, eight of nine infants who underwent preoperative stabilization survived (p less than 0.05 compared with survival after emergency surgery). Following surgical repair immediately after birth, respiratory system compliance improved only slightly during the first week of life, a time when control infants had a rapid increase in respiratory system compliance (p less than 0.001). In contrast, respiratory system compliance increased nearly twofold in the nine patients undergoing preoperative stabilization (p less than 0.02). Preoperative ECMO was associated with an increase in respiratory system compliance of more than 60% for 1 week, a significant difference from respiratory system compliance among patients undergoing emergency CDH repair (p less than 0.05). These observations provide physiologic evidence of possible benefits of preoperative stabilization before repair of CDH.     

Chlamydia trachomatis infection in infants delivered by cesarean section

This report describes a well documented case of Chlamydia trachomatis pneumonia in a child delivered by cesarean section. The case indicates that infants delivered by cesarean section are still at risk of developing chlamydial infection. Various routes of infection are discussed, with a review of chlamydial disease in infants born by cesarean section.     

Effect of exogenous surfactant on total respiratory system compliance

We measured total respiratory system compliance (Crs) before and after instilling 25 mg artificial surfactant in 1 ml saline down the endotracheal tube of preterm babies requiring resuscitation at birth, and compared results with data from 6 similar babies receiving saline only. Surfactant did not produce a significant improvement in Crs.     

Adenosine concentration in umbilical cord blood of newborn infants after vaginal delivery and cesarean section

Umbilical blood was collected immediately at birth (less than 30 s) in full-term infants after vaginal deliveries (n = 33) and elective cesarean sections (n = 11). Blood gases, plasma adenosine, hypoxanthine, and catecholamine concentrations were determined. In vaginally born infants the median arterial adenosine concentration was found to be 0.46 microM (range 0.13-2.06) and the venous 0.48 microM (0.09-1.62). These levels were significantly higher (p less than 0.01) than in infants delivered by elective cesarean section; 0.16 microM (0.04-0.42) in the artery and 0.17 microM (0.02-0.56) in the vein. Vaginally born infants showed about a 4-fold higher level of umbilical arterial catecholamines than infants born by elective cesarean section. There was a strong inverse correlation between arterial hypoxanthine concentration and pH (r = -0.81, p less than 0.01). It is suggested that increased adenosine release at vaginal delivery modulates the stress response elicited by the strong catecholamine surge and may furthermore exert protective effects in perinatal asphyxia.     

Effect of exogenous surfactant on total respiratory system compliance.

We measured total respiratory system compliance (Crs) before and after instilling 25 mg artificial surfactant in 1 ml saline down the endotracheal tube of preterm babies requiring resuscitation at birth, and compared results with data from 6 similar babies receiving saline only. Surfactant did not produce a significant improvement in Crs.     

Automated respiratory support in newborn infants

A considerable proportion of premature infants requires mechanical ventilatory support and supplemental oxygen. Due to their immaturity, exposure to these forms of respiratory support contributes to the development of lung injury, oxidative stress and abnormal retinal development. These conditions are associated with poor long-term respiratory and neurological outcome. Mechanically ventilated preterm infants present with frequent fluctuations in ventilation and gas exchange. Currently available ventilatory modes and manual adjustment to the ventilator or supplemental oxygen cannot effectively adapt to these recurrent fluctuations. Moreover, the respiratory support often exceeds the infant's real needs. Techniques that adapt the mechanical ventilatory support and supplemental oxygen to the changing needs of preterm infants are being developed in order to improve stability of gas exchange, to minimise respiratory support and to reduce personnel workload. This article describes the preliminary evidence on the application of these new techniques in preterm infants and animal models.     

Non-invasive respiratory support in newborn infants

Respiratory failure is the most common morbidity in newborn infants, often requiring respiratory support. Traditionally, invasive mechanical ventilation was the preferred method of neonatologists. Over the last two decades, various forms of non-invasive ventilation have become popular as modes of respiratory support in newborn infants, especially if they are born preterm. These modes differ from mechanical ventilation in not needing an endo-tracheal tube, and are commonly delivered by bi-nasal prongs. We review the common modes of non-invasive respiratory support in newborn infants, including their proposed mechanisms of action and the evidence supporting their use.