Approach to respiratory distress (newborn): Clinical sciences

Newborn respiratory distress refers to an increased work of breathing beginning in the first days of life. If not recognized and treated promptly, respiratory distress can lead to respiratory failure.

Some important risk factors that can lead to respiratory distress in newborns include prematurity; conditions such as congenital diaphragmatic hernia and congenital heart disease; meconium aspiration syndrome; infections such as pneumonia and sepsis; pneumothorax; and transitory tachypnea of the newborn.

When a newborn presents with respiratory distress, first perform an ABCDE assessment to determine if they are unstable or stable. If unstable, stabilize their airway, breathing, and circulation. In severe cases, you might need to intubate your patient and start mechanical ventilation. Next, obtain IV access and put your patient on continuous vital sign monitoring, including respiratory rate and pulse oximetry. Finally, if needed, don’t forget to provide supplemental oxygen.

Now, let’s return to the ABCDE assessment and take a look at stable patients. In this case, obtain a focused history and physical exam and check pulse oximetry. History reveals the beginning of respiratory distress in the newborn period. The physical exam reveals signs of respiratory distress, such as grunting, nasal flaring, and suprasternal, intercostal, or subcostal retractions.

Tachypnea, or a respiratory rate above 60 per minute, will also be present. Depending on the underlying cause, you may also hear wheezing or crackles on auscultation. Finally, pulse oximetry might show oxygen saturation below 90 percent.

These findings are suggestive of respiratory distress, so your next step is to look for an underlying cause. Start by assessing prenatal ultrasound findings. If you detect an abnormal prenatal ultrasound finding that increases the risk of respiratory distress, you should consider congenital defects. Then order a chest X-ray, as well as an echocardiogram, if needed.

First, let’s start with congenital heart defects. In this case, your patient’s history usually reveals prenatal identification of a congenital heart defect, and there might even be a family history of congenital heart defects. The physical examination could reveal a cyanotic newborn, with or without a heart murmur, loud S2, or hepatomegaly. Chest X-ray commonly shows cardiomegaly and increased pulmonary vascularity. Finally, the echocardiogram will confirm the presence of structural heart abnormalities or defects with pulmonary overcirculation. With these findings, you can confirm the diagnosis of a congenital heart defect.

Now here’s a clinical pearl to keep in mind! If an echocardiogram is not available, you could use the hyperoxia test to distinguish congenital heart conditions from lung conditions. The test is based on the premise that supplemental oxygen will not increase the PaO2 in the presence of congenital heart disease to the same degree it would with isolated pulmonary disease.

To perform a hyperoxia test, provide the newborn with 100% oxygen for several minutes and check their oxygen saturation. In newborns with cyanotic heart defects with an intracardiac shunt that bypasses the lungs, pulse oximetry will show little to no improvement in oxygenation. On the other hand, when the disease is primarily a pulmonary condition, such as pneumonia or respiratory distress syndrome, the oxygen saturation will improve and rise beyond 90%.

Next, up is the tracheoesophageal fistula. These patients might have a prenatal ultrasound finding of polyhydramnios, with features of VACTERL association, which includes Vertebral, Anal, Cardiac, Tracheo-Esophageal, Renal, or Limb abnormalities.

Physical examination usually reveals mucus and saliva bubbling from the nose and mouth. You might even notice a single artery in the umbilical cord, as well as various findings consistent with VACTERL, such as anal atresia or absent thumbs.

Before you order a chest X-ray, place an orogastric tube. In these patients, the radiograph will likely demonstrate a coiled tube within the esophagus, suggesting the presence of a tracheoesophageal fistula with esophageal atresia.

Finally, let’s go over the congenital diaphragmatic hernia, or CDH for short. In this case, prenatal ultrasound will mention a congenital diaphragmatic hernia. The physical exam will reveal a scaphoid abdomen and the presence of bowel sounds in the chest. These findings are indicative of congenital diaphragmatic hernia, but if the diagnosis is still unclear, order a chest X-ray.

X-ray findings suggestive of CDH include bowel loops and gas visible in the left hemithorax, with displacement of the cardiac silhouette to the right. Keep in mind that CDH most often occurs on the left side since the liver usually blocks the intestines from migrating into the chest cavity. At this point, you can confirm the diagnosis of a congenital diaphragmatic hernia.

Now here’s a clinical pearl to keep in mind! Some craniofacial malformations can cause upper airway obstruction shortly after birth. One example is bilateral choanal atresia, which blocks the posterior nares. Since neonates are obligate nose breathers, when feeding, they experience respiratory distress. While crying, however, respiratory distress is relieved when they breathe with an open mouth.

Now, let’s switch gears and discuss newborns with normal prenatal ultrasound findings. In this case assess perinatal risk factors. First, let’s focus on meconium-stained amniotic fluid. In this case, you should consider meconium aspiration syndrome as a cause of respiratory distress, so make sure to order a chest X-ray!

Affected infants are typically born at term or post-term, and intrapartum fetal distress may have been noted. The physical exam will likely demonstrate a barrel-shaped chest with increased work of breathing, nasal flaring, grunting, or retractions, as well as diffuse crackles, rhonchi, or wheezing. If the chest X-ray reveals bilateral fluffy densities and lung hyperinflation, you can diagnose meconium aspiration syndrome.

Alright, next, let’s consider the next risk factor of prematurity. Prematurity should prompt you to consider complications, such as respiratory distress syndrome and patent ductus arteriosus. In this case, order a chest X-ray or lung ultrasound.

With respiratory distress syndrome, your physical exam will reveal poor air movement, tachypnea, and retractions; and crackles might be heard upon auscultation. If the X-ray reveals a ground glass appearance with air bronchograms and hypoexpansion, or if the ultrasound shows compact B lines with an echographic white lung appearance, diagnose respiratory distress syndrome.