Measurement of lung oxygenation by near-infrared spectroscopy in preterm infants with respiratory distress syndrome: A proof-of-concept study

Introduction: Noninvasive markers more accurate than FiO2 would be useful to assess the severity of RDS and guide its treatment. Our aim was to assess for the first time the possibility of continuously monitoring lung oxygenation (rSO2L) by near-infrared spectroscopy (NIRS) and to evaluate whether rSO2L correlates with other oxygenation indices and RDS severity. Methods: We carried out this proof-of-concept study on 20 preterm infants with RDS requiring noninvasive respiratory support. Patients were continuously studied for 24 h by NIRS and rSO2L was correlated with SpO2/FiO2 ratio, a/APO2, and O.I. Results: The overall value of rSO2L was 80.1 ± 6.2%, without significant differences between the right and left hemithorax (80.2 ± 6.7 vs. 80.0 ± 5.7%; p = 0.869). Mean values of total, right, and left rSO2L did not significantly change during the 24-h study period. Linear regression analysis demonstrated a significant positive relationship between total rSO2L and SpO2/FiO2 ratio (p < 0.001) and a/APO2 (p = 0.040), and a negative relationship between total rSO2L and O.I. (r = −0.309; p = 0.022). Conclusions: Continuous monitoring of rSO2L by NIRS in preterm infants with RDS is feasible and safe. The correlation of rSO2L with other indices of oxygenation and RDS severity supports the accuracy and reliability of this measurement.