Respiratory Distress Syndrome

Question 1

What is respiratory distress syndrome?

Answer 1

Respiratory distress syndrome affects premature neonates, born before the lungs start producing adequate surfactant.

Question 2

At what age does respiratory distress syndrome occur?

Answer 2

Respiratory distress syndrome commonly occurs below 32 weeks.

Question 3

At what age in the neonate is surfactant produced?

Answer 3

Surfactant is made from around 26 weeks gestation, although adequate levels are not achieved until about 35 weeks. This means that premature babies do not have enough surfactant.

Question 4

Briefly describe the pathophysiology of respiratory distress syndrome

Answer 4

Inadequate surfactant leads to high surface tension within alveoli. This leads to atelectasis (lung collapse), as it is more difficult for the alveoli and the lungs to expand. This leads to inadequate gaseous exchange, resulting in hypoxia, hypercapnia (high CO2) and respiratory distress.

Question 5

What cells produce surfactant?

Answer 5

Type 2 pneumocytes.

Question 6

How is respiratory distress syndrome diagnosed?

Answer 6

Diagnosis of neonatal respiratory distress syndrome is through clinical evaluation and a ‘ground glass’ appearance on chest x-ray.

Question 7

How does respiratory distress syndrome present on a chest x-ray?

Answer 7

Ground glass appearance.

Question 8

What are the clinical features of respiratory distress syndrome?

Answer 8

Symptoms and signs of RDS include rapid, labored, grunting respirations appearing immediately or within a few hours after delivery, with suprasternal and substernal retractions and flaring of the nasal alae. As atelectasis and respiratory failure progress, symptoms worsen, with cyanosis, lethargy, irregular breathing, and apnea, and may ultimately lead to cardiac failure if adequate lung expansion, ventilation, and oxygenation are not established.

On examination, breath sounds are decreased, and crackles may be heard.

Question 9

Briefly describe the maternal treatment for respiratory distress syndrome

Answer 9

Antenatal steroids (i.e. dexamethasone) given to mothers with suspected or confirmed preterm labour increases the production of surfactant and reduces the incidence and severity of respiratory distress syndrome in the baby.

Question 10

Briefly describe the neonatal treatment for respiratory distress syndrome

Answer 10

Premature neonates may need:

• Intubation and ventilation to fully assist breathing if the respiratory distress is severe
• Endotracheal surfactant, which is artificial surfactant delivered into the lungs via an endotracheal tube
• Continuous positive airway pressure (CPAP) via a nasal mask to help keep the lungs inflated whilst breathing
• Supplementary oxygen to maintain oxygen saturations between 91 and 95% in preterm neonates

Support with breathing is gradually stepped down as the baby develops and is able to maintain their breathing, until they can support themselves in air.

Question 11

What are the short term complications of respiratory distress syndrome?

Answer 11

• Pneumothorax
• Infection
• Apnoea
• Intraventricular haemorrhage
• Pulmonary haemorrhage
• Necrotising enterocolitis

Question 12

What are the long term complications of respiratory distress syndrome?

Answer 12

• Chronic lung disease of prematurity
• Retinopathy of prematurity occurs more often and more severely in neonates with RDS
• Neurological, hearing and visual impairment