Neonatal Respiratory Distress Syndrome: Surfactant Replacement Update
Neonatal respiratory distress syndrome (RDS) remains one of the most important causes of respiratory failure in premature babies. It develops when immature lungs produce too little pulmonary surfactant, increasing surface tension in the alveoli and making each breath harder. The resulting pattern can include tachypnoea, grunting, chest recession, oxygen requirement and progressive respiratory fatigue.
Surfactant therapy has changed from routine intubation and prolonged ventilation to a more carefully timed strategy that combines antenatal corticosteroids, early non-invasive respiratory support, selective surfactant administration and lung-protective care. For Australian clinicians, treatment decisions also need to account for retrieval distances, state-based formularies, tertiary neonatal capacity and the practical realities of caring for families travelling from regional areas.
| Clinical area | Current direction | Practical relevance in Australia |
|---|---|---|
| Initial respiratory support | Early nasal CPAP or non-invasive ventilation for spontaneously breathing preterm infants | Supports stabilisation before transfer or escalation |
| Surfactant timing | Early rescue treatment when oxygen needs and clinical signs indicate worsening RDS | Avoids waiting for severe respiratory failure |
| Administration | LISA or MIST where staff are trained; INSURE or intubation when necessary | Depends on local expertise, equipment and retrieval pathways |
| Product selection | Poractant alfa and other approved preparations according to hospital policy | Availability, cost and state procurement influence choice |
| Ongoing care | Caffeine, oxygen targeting, temperature control and repeat assessment | Reduces exposure to invasive ventilation and related complications |
Why Surfactant Still Matters
Pulmonary surfactant is a mixture of phospholipids and proteins produced by type II alveolar cells. It lowers alveolar surface tension, improves compliance and reduces the work of breathing. In a very preterm infant, surfactant deficiency can lead to widespread alveolar collapse, uneven ventilation and increasing oxygen requirements.
The clinical picture often evolves over the first hours after birth. A baby may initially maintain acceptable oxygenation on CPAP, then develop rising FiO₂ needs, more pronounced recession and respiratory acidosis. Chest radiography can support the diagnosis, but treatment should be guided by the overall clinical pattern rather than imaging alone. Lung ultrasound is increasingly used in some Australian units to assist early diagnosis and predict the need for surfactant, although local expertise varies.
Prevention remains essential. Antenatal corticosteroids, delayed cord clamping where appropriate, careful delivery-room stabilisation and avoidance of hypothermia all influence respiratory outcomes. A coordinated plan between obstetric, neonatal and retrieval teams is especially important when birth occurs in a regional hospital and transfer to Sydney, Melbourne, Brisbane, Perth or another tertiary centre may be required.
Choosing The Right Moment
Current practice favours early rescue surfactant rather than either automatic prophylaxis for every extremely premature infant or delayed treatment after severe deterioration. A common guideline-based trigger is increasing oxygen need while the infant is supported on CPAP or another non-invasive mode, often around an FiO₂ of 0.30, although thresholds must be adapted to gestational age, blood gases, work of breathing and local protocols.
The decision is more nuanced in extremely preterm infants. Some babies under 28 or 29 weeks’ gestation may benefit from very early treatment if they show signs of RDS, even when their initial oxygen requirement is modest. Others stabilise well on CPAP and can avoid an invasive procedure. The aim is to treat surfactant deficiency before lung injury and fatigue become established, while avoiding unnecessary laryngoscopy and ventilation.
A rising oxygen requirement should prompt a structured review. Clinicians should check mask or prong fit, CPAP pressure, pneumothorax, blood glucose, temperature, haemoglobin and the possibility of infection or pulmonary hypertension. A diagnosis of RDS should not obscure other causes of neonatal respiratory distress, including transient tachypnoea, congenital diaphragmatic hernia, pneumonia, pulmonary haemorrhage or critical congenital heart disease.
Less Invasive Administration
Less invasive surfactant administration, commonly called LISA, and minimally invasive surfactant therapy, or MIST, deliver surfactant through a thin catheter while the infant continues spontaneous breathing on CPAP. The approach is intended to reduce exposure to endotracheal intubation and mechanical ventilation. Evidence supports its use in appropriately selected preterm infants when an experienced team can maintain oxygenation and manage possible deterioration.
Technique matters. The infant needs effective non-invasive support, a prepared airway plan and close monitoring of heart rate, oxygen saturation and respiratory effort. Brief desaturation or bradycardia can occur, and some babies still require intubation. Training, simulation and consistent procedural roles help make LISA safer, particularly in busy units where staff may have different levels of experience.
INSURE—intubation, surfactant administration and early extubation—remains useful when LISA is unsuitable or unsuccessful. Immediate intubation may be the safest option for apnoea, severe hypoxaemia, poor respiratory drive, shock or the need for sustained ventilation. The technique should serve the infant’s physiology, rather than becoming a target in itself.
Surfactant should be warmed and administered according to the product instructions and neonatal unit policy. A relatively large volume can cause transient airway obstruction or uneven distribution, so careful catheter positioning and gentle ventilation are important. In Australia, access to LISA equipment and local competency can differ between metropolitan NICUs and smaller units, making regional protocols and retrieval advice valuable.
Products, Doses And Repeat Treatment
Animal-derived surfactants remain the mainstay of replacement therapy because they contain surface-active lipids and, in many products, important surfactant proteins. Poractant alfa is widely used internationally and in Australian neonatal practice. Other preparations may be available depending on Therapeutic Goods Administration approval, hospital procurement and state or territory formulary arrangements. Product concentration and recommended dose vary, so staff should follow the current Australian product information rather than relying on memory.
An initial dose of poractant alfa is commonly 200 mg/kg, with a lower repeat dose used when indicated, although exact regimens depend on the formulation and institutional policy. A second dose may be considered when significant RDS persists or returns, after checking for problems such as malpositioned airway support, air leak, pulmonary haemorrhage or infection. Repeated dosing should reflect ongoing surfactant deficiency and clinical need, not a fixed schedule.
Clinical response is often seen within minutes, with improved compliance and falling oxygen requirements. This creates a risk of excessive oxygen exposure or excessive delivered pressure if ventilator settings are not promptly reduced. Continuous reassessment is therefore essential after administration. Blood gases, oxygen saturation trends, chest movement and ventilator pressures should guide adjustment.
The Australian market also includes practical cost and supply considerations. Public hospitals purchase medicines through formal procurement systems, and a product familiar to a tertiary unit may not be stocked in every rural service. Clear transfer packs, dose calculations based on current weight and communication with the receiving NICU can prevent delays when a baby is stabilised outside a metropolitan centre.
Protecting The Infant Beyond Surfactant
Surfactant replacement works best as part of a bundle of lung-protective care. CPAP or non-invasive positive-pressure ventilation should be delivered with the lowest effective pressures, while invasive ventilation, when needed, should use gentle tidal-volume strategies and allow adequate exhalation. Caffeine supports respiratory drive and reduces apnoea in very preterm infants, particularly around extubation.
Oxygen should be titrated carefully. Both hypoxaemia and excessive oxygen exposure are associated with harm, including retinopathy of prematurity and oxidative lung injury. Target ranges are set by local policy and gestational age, with continuous pulse oximetry interpreted alongside perfusion, blood gases and the infant’s overall condition.
Temperature control, glucose management, nutrition and infection assessment are equally relevant. A preterm infant who is cold, hypoglycaemic or developing sepsis may appear to have worsening RDS even when the primary problem is broader physiological instability. Australian neonatal services also need practical plans for transport incubators, ambulance or aircraft transfer and continuity of respiratory support over long distances.
Comfort should be part of every procedure. Containment, facilitated tucking, non-nutritive sucking and carefully considered sucrose may reduce procedural distress when clinically appropriate. Teams reviewing respiratory pathways can also draw on guidance about neonatal pain assessment to incorporate comfort measures during CPAP placement, catheter insertion and intubation.
Monitoring Outcomes And Family Communication
After surfactant, clinicians should monitor oxygen requirement, respiratory rate, work of breathing, blood gases and the need for escalating support. A sudden deterioration warrants urgent assessment for pneumothorax, pulmonary haemorrhage, tube or catheter complications, sepsis and haemodynamic instability. Improvement may be rapid, so ventilator pressures and oxygen concentration should be reduced without delay when the infant’s lungs become more compliant.
Longer-term outcomes depend on gestational age, infection, ventilation exposure, nutrition and other complications of prematurity. Surfactant reduces the severity of RDS, but it does not eliminate the risk of bronchopulmonary dysplasia or later respiratory vulnerability. Follow-up should therefore include growth, feeding, neurodevelopment and respiratory health rather than focusing only on survival to discharge.
Families need plain, consistent explanations. Parents may hear that surfactant is a medicine placed directly into the lungs, while also being told that their baby is receiving CPAP rather than “a ventilator”; these terms should be clarified carefully. Families from regional or remote communities may face accommodation, employment and travel pressures, particularly when treatment takes place far from home in Melbourne, Sydney or Perth.
Communication should also distinguish respiratory illness from other common neonatal conditions. For example, families seeking information about yellow skin colour may benefit from a clear explanation of when jaundice needs treatment, including the role of gestational age, bilirubin measurement and treatment thresholds. Reliable written resources can reduce confusion after a stressful delivery.
Translating Evidence Into Australian Practice
The strongest current approach is selective, early and technically competent surfactant therapy combined with non-invasive support. Units should define who can perform LISA or MIST, what monitoring is required, when intubation is preferred and how infants will be retrieved if respiratory failure progresses. Regular audit of oxygen exposure, intubation rates, repeat dosing, pneumothorax and bronchopulmonary dysplasia can show whether a local pathway is achieving its aims.
Policies should be reviewed against current national and international evidence, TGA product information, state or territory medication governance and the capabilities of the individual service. Australian practice is shaped by substantial distances, uneven access to neonatal specialists and the need to coordinate obstetric, neonatal and aeromedical teams. A pathway that works in a large Brisbane or Adelaide NICU may need adaptation before it is applied in a small regional hospital.
The scientific focus of the FAOPS 2020 congress included perinatal and neonatal medicine, reflecting the international collaboration needed to improve care for premature infants. Although the Tokyo meeting was cancelled during the COVID-19 pandemic, its broader field remains active: better surfactant delivery, improved non-invasive ventilation, lung ultrasound, precision oxygen targeting and family-centred care continue to shape neonatal respiratory practice.
For Australian clinicians, the next step is practical: review the local RDS guideline, confirm available surfactant products and doses, rehearse the LISA or INSURE pathway, and ensure families receive clear information before and after treatment. Consistent preparation can help more premature babies receive timely lung support while limiting avoidable ventilation and transport-related risk.
