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

Abstract

Introduction: Noninvasive markers more accurate than FiO 2 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 (rSO 2 L) by near-infrared spectroscopy (NIRS) and to evaluate whether rSO 2 L 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 rSO 2 L was correlated with SpO 2 /FiO 2 ratio, a/APO 2 , and O.I. Results:The overall value of rSO 2 L 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 rSO 2 L did not significantly change during the 24-h study period. Linear regression analysis demonstrated a significant positive relationship between total rSO 2 L and SpO 2 /FiO 2 ratio (p < 0.001) and a/APO 2 (p = 0.040), and a negative relationship between total rSO 2 L and O.I. (r = −0.309; p = 0.022).Conclusions: Continuous monitoring of rSO 2 L by NIRS in preterm infants with RDS is feasible and safe. The correlation of rSO 2 L with other indices of oxygenation and RDS severity supports the accuracy and reliability of this measurement.

Regional pulmonary oxygen saturations in late preterm and term infants with respiratory distress at birth

“…A recent study evaluated postnatal pulmonary oxygenation in 20 preterm infants within the first 24 h of life and demonstrated that regional pulmonary oxygenation was correlated with other oxygenation indices such as SpO 2 /FiO 2 , arterial/alveolar oxygen tension ratio (a/AO 2 ) and oxygenation index (O.I). The authors concluded that continuous monitoring of rSO 2 of lung in preterm infants was feasible and correlated with other reliable indices of oxygenation and RDS severity 11 . Apart from this study, there exists no data about the early pulmonary oxygenation in late preterm and term newborn infants with respiratory distress.…”

“…Although the penetration depth of 1.0-1.5 cm of NIRS light is appropriate to assess the oxygenation of lung parenchyma, there is a concern about whether NIRS can measure oxygenation of a non-solid air filled tissue accurately. 11 The first study that reveals the oxygenation of lung parenchyma showed that NIRS is technically able to assess quantitatively tissue oxygenation of lung tissue both in vivo and in vitro medium. 20 One of the pioneer clinical study evaluating the regional oxygenation of lung areas was performed by Yang et al They evaluated regional pulmonary oxygenation in 26 preterm infants and reported that NIRS objectively reflected the changes in oxygenation in the lung tissue.…”

“…Even most of the studies up to date assessed the somatic oxygenation at splanchnic, renal or skeletal muscle areas, the oxygenation of lung tissue is still obscure. Although the penetration depth of 1.0–1.5 cm of NIRS light is appropriate to assess the oxygenation of lung parenchyma, there is a concern about whether NIRS can measure oxygenation of a non‐solid air filled tissue accurately 11 . The first study that reveals the oxygenation of lung parenchyma showed that NIRS is technically able to assess quantitatively tissue oxygenation of lung tissue both in vivo and in vitro medium 20 .…”

“…However, pulmonary NIRS is a novel method and there is very limited data about the use of pulmonary NIRS in neonates. [9][10][11] Although cerebral oxygenation changes in the transitional period has been well defined, only one study reported reference pulmonary NIRS values during transition period in neonates. 10 There exists scarce data about the use of pulmonary NIRS monitorization in neonates with respiratory distress.…”

“…Cerebral and mesenteric NIRS have been increasingly and more widely used for monitorization of critically ill neonates. However, pulmonary NIRS is a novel method and there is very limited data about the use of pulmonary NIRS in neonates 9–11 . Although cerebral oxygenation changes in the transitional period has been well defined, only one study reported reference pulmonary NIRS values during transition period in neonates 10 .…”