Respiratory distress syndrome of the newborn is a lung dysfunction in infants. Premature infants are particularly affected.
What is respiratory distress syndrome of the newborn?
Respiratory distress syndrome of the newborn (ANS) also goes by the names respiratory distress syndrome of the premature infant, surfactant deficiency syndrome, hyaline membrane syndrome, or infant respiratory distress syndrome (IRDS). This refers to a pulmonary dysfunction in newborn infants that not infrequently leads to death. The pulmonary disorder manifests itself after birth and is due to immaturity of the lungs. Overall, one percent of all newborn infants are affected by respiratory distress syndrome. The proportion of babies born prematurely is particularly high, at around 60 percent. Due to lung maturation induction, it was possible to reduce the death rate in ANS. However, if respiratory distress syndrome occurs before 28 weeks of gestation, the death rate is still very high.
Causes
The cause of neonatal respiratory distress syndrome was discovered by the American pediatrician Mary Ellen Avery (1927-2011) in 1959, which enabled targeted treatment procedures. The physician discovered that a surfactant deficiency in the lungs is responsible for the severe functional disorder. The English artificial word surfactant means “surface-active substance” in German translation. This substance is usually produced from the 35th week of pregnancy. However, in about 60 percent of all affected infants, respiratory distress syndrome manifests itself before the 30th week of pregnancy. Up to this point, the type 2 pneumocytes within the lungs have not yet been able to produce sufficient surfactant, which is a surface film. With each breath, this surface film supports the unfolding of the alveoli (pulmonary alveoli). Because premature infants are not yet equipped with sufficient lung maturity due to their early birth, neonatal respiratory distress syndrome is particularly common in them. However, if the risk of preterm birth is known, ANS can be counteracted during pregnancy by administering glucocorticoids. The drugs administered have the property of accelerating the baby’s lung maturity.
Symptoms, complaints, and signs
Typical symptoms occur with respiratory distress syndrome in the newborn. These include accelerated breathing by the baby, who has a respiratory rate of more than 60 breaths per minute. The newborn’s breathing activity is difficult, which can be perceived as moaning when exhaling. In addition, breathing cessations occur repeatedly. Other features of ANS that appear immediately after birth include pale skin, bluish skin discoloration (cyanosis), nostril breathing, retraction of the intercostal spaces, the area below the larynx, and the upper abdomen on inhalation, and decreased muscle tone. Possible acute complications of respiratory distress syndrome in the newborn may include accumulation of air in the body cavities and the development of interstitial emphysema.
Diagnosis and course of the disease
Respiratory distress syndrome of the newborn is usually diagnosed during the first early infant examination. Imaging procedures such as an X-ray examination are also used to provide further information. In this way, typical changes can be identified on the X-ray images. In medicine, respiratory distress syndrome in newborns is divided into four stages. Stage I is described as a fine granular reduction in transparency. In stage II, there is a positive aerobronchogram that extends beyond the cardiac contour. In stage III, further reduction in transparency sets in, accompanied by blurring at the cardiac and diaphragmatic contours. In the fourth and final stage, the lungs turn white. No difference can be seen between the heart contours and the lung parenchyma. As the ANS progresses, additional diseases may occur. These include primarily bronchopulmonary dysplasia or retinopathy of prematurity, which causes damage to the eyes. Furthermore, bronchial malformations, bronchial asthma, emphysema and cerebral hemorrhage are within the realm of possibility. In the worst case, respiratory distress syndrome ends with the death of the child.
Treatment and therapy
Treatment of respiratory distress syndrome ideally takes place in a perinatal center that is optimally equipped.It is particularly important not to place unnecessary stress on the child. One therapeutic option is the application of recombinant surfactant via a tube. In this way, it is possible to improve gas exchange and reduce the risk of complications. In the case of severe prematurity, respiratory distress syndrome must always be expected. For this reason, unborn children receive surfactant prophylactically before the 28th week of pregnancy. If it is only a mild respiratory distress syndrome of the newborn, it is treated by CPAP ventilation through the nose. In this procedure, positive pressure is applied during the inspiratory phase. If, on the other hand, the case is severe, machine ventilation is usually required. Basically, the therapy of respiratory distress syndrome in neonates is divided into causal as well as symptomatic treatment. Symptomatic therapy consists of blood gas analysis, careful observation of the infant, and regular monitoring of body temperature. In addition, the administration of oxygen, artificial respiration, a thorough fluid balance, laboratory controls, and the administration of antibiotics have proven effective. In contrast, surfactant substitution is used as part of causal therapy, which can reduce mortality in affected children.
Prevention
If premature birth is expected, effective prevention of respiratory distress syndrome is possible. For this purpose, the infant receives betamethasone, which is one of the synthetic glucocorticoids and accelerates lung maturation. Under tocolysis, prematurity can be delayed for some time to allow more time for lung maturation. It is important that preventive therapy begin 48 hours before delivery.
