Introduction
Respiratory distress is the leading cause of NICU admissions. Rapid diagnosis and appropriate treatment are vital for improving outcomes. Mechanical ventilation (MV) is a key therapy but carries risks such as barotrauma, ventilator-associated pneumonia, and bronchopulmonary dysplasia. Noninvasive support is preferred when possible, but MV remains necessary for severe cases.
Point-of-care lung ultrasound (LUS) has emerged as a valuable tool for diagnosing and monitoring neonatal lung disease. It provides immediate, accurate, and radiation-free assessments, often outperforming chest X-rays. LUS can guide respiratory management, assess MV efficacy, determine extubation readiness, and identify candidates for surfactant therapy. It enables real-time evaluation of lung pathology and treatment response, potentially improving outcomes.
Despite growing evidence, standardized guidelines for LUS use in the NICU are lacking. This study aims to establish expert consensus on its role in managing respiratory diseases, including MV and surfactant administration.
Method
A three-step Delphi process was conducted via e-mail to develop expert consensus. Neonatologists and radiologists with at least five years of thoracic ultrasound experience were invited, selected based on publications and active NICU involvement. Experts were recruited internationally through professional associations and snowball sampling to ensure diversity of opinions. The guideline was registered with PREPARE (registration no. PREPARE-2025CN011), and about 30 panellists were targeted.
In round one, panellists completed an open-ended questionnaire to refine statements proposed by the core group. In subsequent rounds, they rated statements on a four-point Likert scale (essential to irrelevant), with no neutral option. Statements reaching consensus were retained or modified based on feedback, while those without consensus were revised or excluded.
Data collection was managed through Microsoft Forms and analysed in Excel. Responses were summarised using medians, modes, and interquartile ranges (IQR) to assess consensus, as IQR is more robust for ordinal data. Agreement levels were graded from unanimous (100%) to C-level consensus (67–77%).
Results
Twenty-eight panellists from 12 countries, with over a decade of experience in lung ultrasound, reached consensus on 18 statements for its use in neonatal respiratory distress. Across three rounds, statements were refined for precision and applicability, with ‘essential’ responses rising from 58.7% to 74.5%. The agreed practices provide evidence-based guidance for integrating LUS into neonatal respiratory care and decision-making.
Discussion
Lung ultrasound (LUS) plays an important role in the differential diagnosis of neonatal respiratory failure. Traditional methods such as chest X-ray often lack accuracy, whereas LUS demonstrates high sensitivity and specificity in identifying conditions like RDS, TTN, pneumonia, MAS, atelectasis, and pneumothorax. Evidence shows that LUS can outperform CXR in diagnosing RDS and TTN, and its scoring system further improves differentiation of disease severity.
Beyond diagnosis, LUS is also effective in guiding mechanical ventilation (MV). A severity score based on lung regions can indicate whether invasive or noninvasive ventilation is more appropriate. A threshold score of ≥8 strongly suggests invasive MV, while lower scores support noninvasive strategies. This approach helps clinicians monitor lung aeration, predict treatment response, and adjust ventilation settings accordingly.
Consensus guidelines recommend invasive MV for moderate to severe RDS on LUS, while mild RDS or partial resolution of consolidation after bronchoalveolar lavage (BAL) may only require noninvasive support. Similarly, TTN and mild PTX usually do not need invasive MV unless symptoms worsen. These findings highlight the value of LUS in tailoring respiratory management in the NICU.
Using LUS to guide MV therapy in newborns with dyspnoea
LUS is highly valuable for guiding mechanical ventilation (MV) decisions, outperforming conventional radiology in predicting intubation and monitoring lung aeration. A consensus was reached that LUS severity scoring can distinguish between invasive and noninvasive MV needs. Each lung is divided into three regions, scored 0–3 (total 0–18). A score ≥8 suggests invasive MV, while lower scores support noninvasive approaches.
Guidelines recommend invasive MV for moderate–severe RDS, while mild RDS can be managed noninvasively. In cases of severe MAS, pneumonia, or atelectasis, bronchoalveolar lavage (BAL) may resolve consolidations, avoiding MV if effective. In TTN, invasive MV is rarely needed unless disease progresses to RDS; noninvasive support may suffice for severe dyspnoea. For pneumothorax, mild cases typically require no MV, while moderate–severe PTX warrants invasive high-frequency oscillatory ventilation. Thus, LUS provides a precise, dynamic tool to tailor respiratory support in critically ill neonates.
For lavage, the steps include placing the patient in the right position, connecting ECG and oxygen monitoring, and ensuring optimal ventilator settings. A saline solution (0.9% NaCl, 1–2 ml/kg) is instilled through the endotracheal tube, followed by positive pressure ventilation for 20–30 minutes.
The lung area is tapped for 3–5 minutes, then secretions are suctioned for less than 10 seconds each time. LUS should be repeated immediately after to assess lung re-expansion and decide if further lavage is required. Continuous lavage should not exceed three cycles. If no improvement is seen after 2–3 attempts, diluted pulmonary surfactant can be used during or after lavage.
LUS also helps monitor lung changes during mechanical ventilation in respiratory failure. In RDS patients on invasive MV, LUS should be done every 2–4 hours. It effectively detects overexpansion, atelectrauma, and other lung injuries, making it highly useful for safe and targeted treatment.
Using LUS to guide the adjustment of MV settings and weaning from MV
Maintaining normal oxygenation in infants with minimal ventilator settings is not enough when using LUS monitoring. The key principle is to adjust ventilator parameters so the lungs can fully expand under ultrasound guidance.
LUS-guided recruitment manoeuvres (RMs) in preterm neonates with RDS showed better outcomes than non-LUS-guided RMs. They achieved earlier oxygenation with lower FiO₂ needs, shorter oxygen dependency, reduced ventilation duration, and faster NICU discharge. LUS guidance also reduced lung inflammation, likely due to minimised atelectrauma and optimised lung recruitment.
LUS further aids in weaning from MV, a critical step since prolonged ventilation increases risks of BPD, infections, neurodevelopmental impairment, or death. Studies show LUS can predict weaning success, but clinicians recommend interpreting it alongside the overall clinical picture. Since extubation failure is common and linked to severe complications, tools like LUS hold significant value in improving outcomes.
Using LUS to assess the lung water content
LUS can be used to estimate lung water content in neonates. While its role in measuring EVLWI at lower thresholds is debated, higher thresholds (>20 ml/kg) show good sensitivity and specificity in children. In very-low-birth-weight infants, B-line patterns provide an accurate, noninvasive way to assess lung oedema and predict fluid overload, especially in septic shock.
Based on expert consensus, LUS helps stratify the need for respiratory support in pulmonary oedema. Noninvasive support may be considered if lung water content is >10–15 ml/kg, while invasive MV should be reserved for >15–20 ml/kg. However, further studies are needed to confirm these thresholds in neonates.
LUS is also valuable for guiding surfactant (PS) therapy in infants with severe dyspnoea. Experts recommend PS if RDS is confirmed on LUS, while BAL-related resolution of consolidation or a TTN diagnosis usually rules out PS use. Studies show LUS improves both accuracy and timing of PS administration, often allowing for lower doses than guideline recommendations. In mild RDS, noninvasive ventilation with LISA is preferred, whereas invasive MV plus PS is advised for more severe RDS cases.
Conclusion
This study highlights the important role of lung ultrasound (LUS) in managing neonatal respiratory diseases. With high sensitivity and specificity, LUS effectively supports decisions for PS treatment or MV in infants with RDS. Being repeatable and bedside-based, it enables continuous monitoring, early detection of worsening conditions, and individualized therapy.
LUS is simple to learn, shows strong interobserver agreement, and requires only a few minutes in skilled hands. It also provides regional lung function assessment, giving clinicians greater precision in tailoring treatment.
However, possible risks like pulmonary capillary haemorrhage, suggested by animal models, need further study. This paper serves as a foundation for international discussion on evidence, safety, and future use of LUS in neonatal respiratory care.
