Overview of Respiratory Failure
Respiratory failure is caused by inadequate gas exchange by respiratory system. Neonatal respiratory failure occurs in premature infants due to developmental insufficiency of pulmonary surfactant production and structural immaturity in the lungs. Pulmonary surfactant is a mixture of phospholipids and lipoproteins secreted by pulmonary cells. It reduces the surface tension of the water film lining alveoli and decreases the tendency of alveoli to collapse. With surfactant deficiency, alveoli have to exert greater pressure to expand causing lungs to become atelectatic which leads to inflammation and pulmonary edema. The inadequate oxygenation of blood makes neonates hypoxemic. Neonatal respiratory failure affects 1% of newborn infants and is the leading cause of death in preterm births. This disorder is more frequent in babies of diabetic mothers.
Causes and Risk Factors of Respiratory Failure
Various causes of neonatal respiratory failure include developmental and structural immaturity, neonatal infections and genetic mutations. Deficiency of surfactant occurs most commonly in premature babies as adequate surfactant is not produced until relatively late in gestation (34 to 36 weeks). Other risk factors include maternal diabetes, cesarean delivery, asphyxia and multifetal pregnancies. The genetic causes of surfactant deficiency include mutations in surfactant protein genes (SP-B and SP-C) and ATP-binding cassette gene (ABCA3) which are critical for surfactant formation and function.
Signs and Symptoms of Respiratory Failure
Neonatal respiratory failure is manifested by a faster heart rate, recession (chest wall retractions), expiratory grunting, cyanosis (blue discoloration of skin during breathing), nasal flaring and expiratory grunting. With progression of disease, baby may develop ventilator failure (due to high CO2 concentration in blood) and apnea (prolonged cessation of breathing). The clinical course of disease can last up to 3 days weather treated or non-treated. Complications can also occur in the form of metabolic acidosis, low blood sugar, patent ductus arteriosus, low blood pressure, chronic lung changes intraventricular haemorrhage and brain haemorrhage (due to hypotension and low cerebral perfusion).