Tuesday, January 25, 2011

Respiratory distress syndrome of the newborn

Respiratory distress syndrome of the newborn Respiratory distress syndrome of the newborn is a respiratory problem that occurs after birth due to lung function disturbance.
Etiology
Risk factors for respiratory distress syndrome, asphyxia and premature birth are correlated with impaired lung development. A less common cause is the Kartagener syndrome. Approximately 60% of premature infants (less than 30 weeks gestation) develop respiratory distress syndrome, which is the most common cause of death among newborns.
Pathogenesis
Respiratory distress syndrome of the newborn is based, most times, the inability of lung expansion and to ensure sufficient gas exchange due to lack of surfactant. In the case of perinatal asphyxia, hypoxia induces (by acidosis) constriction of pulmonary arterioles. Cause pulmonary hypertension as a cardiac shunt which further complicate the initial hypertension. Additionally, there may be a meconium aspiration. Premature birth is associated with an absolute lack of surfactant, because it is produced by type II pneumocitele in recent weeks, along with lung maturation and reaches maximum functionality in week 35. In the absence of surfactant, surface tension which limits the alveoli, the lungs colabeaza after expiratory phase (microatelectazii) and can not sufficiently expanded. Lack of surfactant may be complicated by the passage of capillary plasma proteins in the alveoli, which are covered by hyaline membranes. Hypoxia ensues causes similar asphyxia, a chain of reactions with acidosis, pulmonary hypertension and hypoxia initial aggravation.
Clinical
Respiratory distress syndrome occurs immediately after birth or several hours later. Characteristic signs are: - Nasal wing beats; - Sternal region skin retraction and intercostal spaces; - Tachypnea (respiratory rate greater than 60 beats per minute); - Exhalation is accompanied by groans; - Respiratory noise reduction; - Gray-blue discoloration of the skin; Respiratory distress syndrome may be complicated by an interstitial emphysema or accumulation of air in the cavity (pneumothorax, pneumomediastinum, pneumoperitoneum).
Diagnosis
In addition to clinical examination can detect specific symptoms, chest radiography arara changes that may culminate in the image characteristic "white lung".
Treatment
Treatment of respiratory distress syndrome of the newborn is in an obstetric center with specialized equipment and highly competent staff. In mild forms to apply a positive pressure expiratory phase of breathing (CPAP), but severe cases require endotracheal intubation and artificial respiration. In terms of continuous monitoring are the following interventions: - Pulse oximetry; - Monitoring of transcutaneous or intra-arterial partial pressure of oxygen and carbon dioxide; - Blood gas analysis at regular intervals; - Measuring blood pressure; However, in obstetrics is trying to limit the maximum application of medical techniques in order not to overburden the infant through these diagnostic interventions. Lack of physiological surfactant can be filled by applying through a tube, a combination of surfactant improves gas exchange and reduce the appearance of complications and mortality.
Prophylaxis
If required a premature birth can significantly influence the evolution of respiratory distress syndrome by administration of glucocorticoid (betamethasone) before birth, in order to accelerate the maturation of lung function. Under the action of tocolysis delivery is delayed and more time for lung maturation. Despite treatment complications may occur. Respiratory distress syndrome often require artificial respiration for a long period of time with a partial pressure of oxygen sometimes quite high, which favors the occurrence of bronchopulmonary dysplasia. Another feared complication is retinopathy of prematurity.

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