Neonatal respiratory distress syndrome: Clinical sciences

Neonatal respiratory distress syndrome, also called neonatal RDS or hyaline membrane disease, is a life-threatening condition characterized by lung immaturity and alveolar surfactant deficiency. Now, surfactant is a complex of phospholipids and proteins that reduces alveolar surface tension and prevents collapse of the alveoli. Alveolar cells called type 2 pneumocytes produce surfactant beginning around 24 to 26 weeks of gestation, and it doesn’t reach mature levels until 34 to 36 weeks of gestation, so the incidence of neonatal RDS is inversely related to gestational age at birth.

Surfactant deficiency causes decreased lung compliance, atelectasis, low lung volumes, inflammation, pulmonary edema, and pulmonary arterial vasoconstriction; all of which result in hypoxia, hypercapnia, and acidemia.

Now, if a pediatric patient presents with a chief concern suggesting neonatal RDS, perform an ABCDE assessment to determine if they are stable or unstable. These patients are typically unstable, so begin acute management immediately. First, stabilize their airway, breathing, and circulation; and then provide noninvasive respiratory support, such as nasal continuous positive airway pressure, or nasal CPAP. If your patient is apneic or has a poor respiratory effort, you may need to perform endotracheal intubation and begin mechanical ventilation. Next, obtain intravenous or intraosseous access, or consider placing an umbilical venous catheter.

Then, start IV fluids; begin continuous vital sign monitoring, including heart rate, blood pressure, pulse oximetry, and respiratory rate; and provide supplemental oxygen to maintain oxygen saturations between 90 and 95 percent.

Once you stabilize your patient, perform a focused history and physical examination and obtain pulse oximetry measurements. History will reveal the onset of respiratory distress within minutes or hours of birth. These patients are typically premature, with the majority being between 23 and 29 weeks of gestational age at birth; or are very low birth weight, which is defined as under 1500 grams. The prenatal ultrasound is usually normal, but in some cases, the obstetrical history might identify risk factors, such as multiple gestation, biological male, maternal diabetes, fetal distress or asphyxia, C-section delivery without labor, or a family history of neonatal RDS. The history may also reveal preterm labor without antenatal corticosteroid administration.

Here’s a clinical pearl to keep in mind! Betamethasone is a corticosteroid that’s usually given when labor begins before 34 weeks of gestation to stimulate alveolar surfactant production and reduce the risk of neonatal RDS. Antenatal corticosteroid administration can also decrease the incidence of intraventricular hemorrhage and necrotizing enterocolitis, and reduce mortality in premature infants.

As for the physical exam, these infants classically demonstrate tachypnea, with a respiratory rate above 60 breaths per minute; as well as signs of labored breathing, such as grunting, nasal flaring, and intercostal and suprasternal retractions. Lung auscultation often demonstrates poor air movement, and occasionally, audible crackles. Your patient might also appear cyanotic. In addition, pulse oximetry usually reveals an oxygen saturation below 90%.

These findings should lead you to suspect neonatal respiratory distress syndrome, which can often be diagnosed clinically. Still, in most cases, you’ll want to obtain a chest X-ray to confirm the diagnosis.