Infant respiratory distress syndrome

When respiratory distress syndrome (ANS ) (also hyaline membrane disease, surfactant deficiency syndrome, Eng. Infant respiratory distress syndrome ( IRDS ) ) is a lung disorder in the neonatal period. The dysfunction is one of the leading causes of death in newborns. Previously, it was still referred to as idiopathic respiratory distress syndrome, but this name is now obsolete. The cause was discovered in 1959 by Mary Ellen Avery. Therapy by administration of surfactant were developed from the 1970s by Tetsuro Fujiwara in Japan and Bengt Robertson in Sweden.

Frequency

Approximately 60% of preterm infants below 30 weeks of pregnancy develop respiratory distress syndrome. Overall, 1 % of newborns develop respiratory distress syndrome. In preterm infants the respiratory distress syndrome is the most common cause of death. By lung maturity induction before birth, the incidence of respiratory distress syndrome could be reduced. In preterm infants before 28 weeks of gestation but the respiratory distress syndrome is still the main cause of death.

Pathophysiology

In premature births usually the adrenal cortex is not fully developed ( only happens in the 35th week of pregnancy ). Therefore, the fetus is not yet able to produce cortisol there, but what is absolutely necessary for the development of type II pneumocytes, as these form surfactant. Is a surfactant produced by the pulmonary surfactant, which, reduces the surface tension of the liquid film, which bears the air sacs (alveoli ) and thus reduce the pressure which is necessary for their development ( → lung maturation ).

At Surfactantmangel the alveoli collapse already during normal intrathoracic pressures, it must be spent high ventilation pressures, the development (and the lung ventilation ) ensure (see Section therapy). High airway pressures may cause lung damage (further). Surfactant deficiency in the lungs leads to the formation of hyaline membranes ( mucopolysaccharides and glycoproteins from the blood plasma), the lungs behave little elastic to rigid.

Many authors such as Mayatepek or Muntau define the term ANS relatively narrow as:

  • Primary surfactant formation disorder of preterm infants. In this case, the lung tissue is simply not yet mature enough to form sufficient surfactant.

In addition, however, there are other scenarios of Surfactantmangels with hyaline membrane formation and shortness of breath:

  • Excessive inactivation of already formed surfactant, such as meconium aspiration syndrome (inhalation of mekoniumhaltigem amniotic fluid, in this case, however, other aspects such as chemical pneumonia, fibrosis and super-infections play a role ).
  • Secondary surfactant formation disorder: hypoxia, circulatory disturbance, changes in lung metabolism or structure lead to reduced surfactant production. This phenomenon plays eg bronchopulmonary dysplasia / lung hypoplasia, pulmonary hypertension and persistent fetal circulation a role.

Exist between surfactant deficiency, many of the above disease phenomena and their complex interactions therapies so that they can reinforce each other and to the Surfactantmangel also in terms.

Clinical picture

A respiratory distress syndrome occurs immediately after birth or a few hours after birth. Symptoms suggestive are increasing respiratory distress of the newborn with cyanosis, retractions in the spaces between the ribs or above the sternum when breathing, moaning while exhaling, moving the nostrils when breathing ( nostrils ) and a rapid breathing ( tachypnea ).

Potential acute complications of respiratory distress syndrome is the formation of emphysema and air accumulation in the body cavities (pneumothorax, pneumomediastinum, pneumoperitoneum ).

Radiologic Staging

On chest X-ray characteristic changes can be seen. It comes gradually shadowed areas to full screen the "white lung".

  • I. fine granular lung pattern
  • I II on the heart contours also reaching Aerobronchogramm
  • III. II blur or partial obliteration of the cardiac and diaphragmatic contours
  • IV "white lung"

Prophylaxis

Lung maturation: In preterm labor with manifestation of a primary ANS trying 2malige by administration of betamethasone at 24 h to the mother to put the child's lungs in a more mature state, as it would correspond to the gestational age. This makes it possible to achieve a significant increase in available Surfactants for days. In addition, this treatment results in a stabilization of the blood-air barrier and the reduced inactivation of already synthesized surfactants.

Parallel were tempted by the administration of blow -inflammatory agents ( tocolytics ), herauszuzögern birth to at least a few days to give the lung maturation therapy, the time to "attachment ".

Therapy of the manifest ANS

A slight respiratory distress syndrome can be stabilized by a CPAP. For more severe gradients endotracheal intubation and controlled ventilation with increased inspiratory pressure and positive end-expiratory pressure ( PEEP) is required. A respiratory distress syndrome often requires a long-term ventilation with partial high oxygen partial pressures. This can result in the clinical picture of bronchopulmonary dysplasia. Another feared complication of the forced administration of oxygen is the retinopathy of prematurity.

In the therapy of the manifest ANS is in principle different symptomatic and causal therapy. Symptomatic therapy include:

  • Minimal handling: Avoid loads at maintenance and diagnostics
  • Careful observation
  • Regular temperature checks ( child, incubator, breathing gas )
  • Blood gas analysis (the best transcutaneous measurement)
  • Oxygen supply via nasal CPAP or respirator
  • Nasal CPAP in oxygen demand
  • Artificial respiration
  • Antibiotic treatment
  • Careful fluid balance
  • Ductus arteriosus: attention to the increased risk for a Reopening
  • Laboratory tests (blood gases, blood glucose, hematocrit, electrolytes, total protein, blood count, platelets, signs of infection )

The causal treatment of respiratory distress syndrome is made by the Surfactantsubstitution. This is generally applied on the tube directly into the trachea. This reduces the mortality and complications are reduced.

The combination of small-meshed perinatal care ( lung maturation, postpartum Surfactantgabe, ventilation) and gentler induction of labor a respiratory distress syndrome may be mitigated and the incidence of complications can be reduced. The treatment of respiratory distress syndrome of newborns occurs in perinatal centers.

Mechanical ventilation
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