Innovative Lung Ultrasonography may Revolutionize Surfactant Therapy for Late Preterm and full-term neonates: JAMA

The multicenter diagnostic study of 157 late preterm through full-term neonates with respiratory failure early after birth, published in JAMA Network Open, suggests that the lung ultrasonography score (LUS) can accurately guide surfactant administration.

"LUS accuracy in these neonates was comparable to that in early preterm neonates," the researchers reported.

An LUS greater than 8 and 4 or less had the highest global accuracy (replacement test) and highest sensitivity (triage test), respectively.

Surfactant therapy, the administration of a natural substance that helps keep the lungs open, is crucial for the respiratory health of preterm infants. However, determining the optimal timing for surfactant therapy in late preterm and neonatal babies can be challenging, as traditional methods rely on clinical assessment and subjective criteria.

Enter quantitative lung ultrasonography, a non-invasive imaging technique that provides real-time information about lung aeration and function. By using ultrasound to assess lung aeration and the response to mechanical ventilation, clinicians can make more informed decisions about when to initiate surfactant therapy and how to optimize ventilator settings.

The lung ultrasonography score is accurate in guiding surfactant replacement in early preterm neonates, but it has not been studied yet in the late preterm through full-term neonatal population. Considering this, Daniele De Luca, AP-HP–Paris Saclay University, Paris, France, and colleagues aimed to assess whether LUS is equally accurate in predicting surfactant need in late preterm through full-term neonates as in early preterm neonates.

For this purpose, the researchers performed a prospective, international, multicenter diagnostic study between 2022 and 2023 in tertiary academic neonatal intensive care units in Italy, France, the US, and Spain. It enrolled late preterm through full-term neonates (≥34 weeks gestation) with respiratory failure early after birth.

Point-of-care lung ultrasonography to calculate the neonatal LUS (range, 0-18, with higher scores signaling worse aeration), registered in dedicated research databases and unavailable for clinical decision-making.

The outcome was the area under the curve (AUC) in receiver operating characteristic analysis and derived accuracy variables, considering LUS as a replacement for other tests (i.e., highest global accuracy) and as a triage test (i.e., highest sensitivity).

The sample size was calculated to evaluate LUS noninferiority to predict surfactant need in the study population compared with neonates born prematurely. The research team assessed correlations of LUS with the ratio of hemoglobin oxygen saturation as measured by pulse oximetry (SpO2) to fraction of inspired oxygen (FiO2) and with the oxygen saturation index (OSI).

The following were the key findings of the study:

• One hundred fifty-seven neonates (61.1% male) were enrolled and underwent lung ultrasonography at a median of 3 hours of life; 20.4% needed surfactant administration (pretest probability, 20%).
• The AUC was 0.87. The highest global accuracy and sensitivity were reached for LUS values higher than 8 or 4, or lower, respectively.
• Subgroup analysis gave similar diagnostic accuracy in neonates born late preterm (AUC, 0.89; n = 111) and early term and later (AUC, 0.84; n = 46).
• After adjusting for gestational age, LUS significantly correlated with SpO2:FiO2 (adjusted β, −10.4) and OSI (adjusted β, 0.2).

LUS accuracy to predict surfactant need was not inferior to that observed in earlier preterm neonates in the diagnostic study of late preterm through full-term neonates with respiratory failure early after birth.

"An LUS greater than eight is associated with the highest global accuracy (replacement test), suggesting that it's usefulness to guide surfactant administration," the researchers wrote. "An LUS value of 4 or lower was linked with the highest sensitivity (triage test), indicating it is unlikely for this population to need surfactant."

Reference:

De Luca D, Bonadies L, Alonso-Ojembarrena A, et al. Quantitative Lung Ultrasonography to Guide Surfactant Therapy in Neonates Born Late Preterm and Later. JAMA Netw Open. 2024;7(5):e2413446. doi:10.1001/jamanetworkopen.2024.13446