Global longitudinal strain is an informative index of left ventricular performance in neonates receiving intensive care.

Echocardiographic assessment of left ventricular function is crucial in NICU. The study aimed to compare the accuracy and agreement of global longitudinal strain (GLS) with conventional measurements. Real-life echocardiograms of neonates receiving intensive care were retrospectively reviewed. Shortening fraction (SF), ejection fraction (EF) and S' measurements were retrieved from health records. GLS was calculated offline from stored images. The association with stroke volume indexed for body weight (iSV) was evaluated by regression analysis. The diagnostic ability to identify uncompensated shock was assessed by ROC curve analysis. Cohen's κ was run to assess agreement. 334 echocardiograms of 155 neonates were evaluated. Mean ± SD gestational age and birth weight were 34.5 ± 4.1 weeks and 2264 ± 914 g, respectively. SF, EF, S' and GLS were associated with iSV with R2 of 0.133, 0.332, 0.252 and 0.633, (all p < .001). Including all variables in a regression model, iSV prediction showed an adjusted R2 of 0.667, (p < .001). GLS explained 73% of the model variance. GLS showed a better ability to diagnose uncompensated shock (AUC 0.956) compared to EF, S' and SF (AUC 0.757, 0.737 and 0.606, respectively). GLS showed a moderate agreement with EF (κ = .500, p < .001) and a limited agreement with S' and SF (κ = .260, p < .001, κ = .242, p < .001). GLS was a more informative index of left ventricular performance, providing the rationale for a more extensive use of GLS at the cotside.

A structured programme to promote breastfeeding improved the rates in very preterm infants at discharge.

AIM: We developed the Promotion of Breastfeeding (PROBREAST) programme and evaluated what effect it had on the breastfeeding rate in infants born at less than 32 weeks of gestation or weighing ≤1500 grams. METHODS: We compared the breastfeeding rate in two cohorts of patients who were born before (n = 72; January 2017 to June 2018) and after (n = 80; July 2018 to December 2019) the application of the programme. Moreover, we compared the correlation between type of feeding at discharge and post-discharge breastfeeding rate, between exclusive breastfeeding, postnatal growth and neurodevelopment. RESULTS: Infants in the PROBREAST group had an exclusive breastfeeding rate at discharge higher (42 vs. 16%, p < 0.001) than that in the historical control group. Exclusive breastfeeding was negatively correlated with weight z-score at discharge, but not at 12 and 24 months corrected age, and was positively correlated with cognitive score at 24 months corrected age. CONCLUSION: The application of a structured programme for the promotion of breastfeeding improved the breastfeeding rate in very preterm infants. We demonstrated that exclusive breastfeeding at discharge improved their neurodevelopment without impairing growth.

Nasal intermittent positive pressure ventilation during less invasive surfactant administration in preterm infants: An open-label randomized controlled study.

INTRODUCTION: Approximately half of very preterm infants with respiratory distress syndrome (RDS) fail treatment with nasal continuous positive airway pressure (NCPAP) and need mechanical ventilation (MV). OBJECTIVES: Our aim with this study was to evaluate if nasal intermittent positive pressure ventilation (NIPPV) during less invasive surfactant treatment (LISA) can improve respiratory outcome compared with NCPAP. MATERIALS AND METHODS: We carried out an open-label randomized controlled trial at tertiary neonatal intensive care units in which infants with RDS born at 25+0-31+6 weeks of gestation between December 1, 2020 and October 31, 2022 were supported with NCPAP before and after surfactant administration and received NIPPV or NCPAP during LISA. The primary endpoint was the need for a second dose of surfactant or MV in the first 72 h of life. Other endpoints were need and duration of invasive and noninvasive respiratory supports, changes in SpO2/FiO2 ratio after LISA, and adverse effect rate. RESULTS: We enrolled 101 infants in the NIPPV group and 99 in the NCPAP group. The unadjusted odds ratio for the composite primary outcome was 0.873 (95% confidence interval: 0.456-1.671; p = .681). We found that the SpO2/FiO2 ratio was transiently higher in the LISA plus NIPPV than in the LISA plus NCPAP group, while adverse effects of LISA had similar occurrence in the two arms. CONCLUSIONS: The application of NIPPV or NCPAP during LISA in very preterm infants supported with NCPAP before and after surfactant administration had similar effects on the short-term respiratory outcome and are both safe. Our study does not support the use of NIPPV during LISA.

Tissue-Tracking Mitral Annular Displacement in Neonates: A Novel Index of Left Ventricular Systolic Function.

OBJECTIVES: To assess the feasibility, accuracy, and reproducibility of tissue-tracking mitral annular displacement (TMAD) compared with other measures of left ventricular systolic function in healthy preterm and term neonates in the transitional period. METHODS: This was a prospective observational study. Two echocardiograms were performed at 24 and 48 hours of life. TMAD, shortening fraction (SF), ejection fraction (EF), s', and global longitudinal strain (GLS) were measured offline. Accuracy to detect impaired GLS was tested by ROC curve analysis. DeLong test was used to compare AUCs. Intra and interobserver reproducibility of the off-line analysis was calculated. RESULTS: Mean ± SD gestational age and weight were 34.2 ± 3.8 weeks and 2162 ± 833 g, respectively. TMAD was feasible in 168/180 scans (93%). At 24 hours the AUC (95% CI) of SF, EF, s', and TMAD (%) was 0.51 (0.36-0.67), 0.68 (0.54-0.82), 0.63 (0.49-0.77), and 0.89 (0.79-0.99) respectively. At 48 hours the AUC (95% CI) of SF, EF, s', and TMAD (%) was 0.64 (0.51-0.77), 0.59 (0.37-0.80), 0.70 (0.54-0.86), and 0.96 (0.91-1.00), respectively. The AUC of TMAD was superior to the AUC of SF, EF, s', at both timepoints (P < .02). Intraclass correlation coefficients (95% CI) of intra and interobserver reproducibility of TMAD were 0.97 (0.95-0.99) and 0.94 (0.88-0.97), respectively. CONCLUSION: TMAD showed improved accuracy and optimal reproducibility in neonates in the first 48 hours of life.

Lung UltrasouNd Guided surfactant therapy in preterm infants: an international multicenter randomized control trial (LUNG study).

BACKGROUND: The management of respiratory distress syndrome (RDS) in premature newborns is based on different types of non-invasive respiratory support and on surfactant replacement therapy (SRT) to avoid mechanical ventilation as it may eventually result in lung damage. European guidelines currently recommend SRT only when the fraction of inspired oxygen (FiO2) exceeds 0.30. The literature describes that early SRT decreases the risk of bronchopulmonary dysplasia (BPD) and mortality. Lung ultrasound score (LUS) in preterm infants affected by RDS has proven to be able to predict the need for SRT and different single-center studies have shown that LUS may increase the proportion of infants that received early SRT. Therefore, the aim of this study is to determine if the use of LUS as a decision tool for SRT in preterm infants affected by RDS allows for the reduction of the incidence of BPD or death in the study group. METHODS/DESIGN: In this study, 668 spontaneously-breathing preterm infants, born at 25+0 to 29+6 weeks' gestation, in nasal continuous positive airway pressure (nCPAP) will be randomized to receive SRT only when the FiO2 cut-off exceeds 0.3 (control group) or if the LUS score is higher than 8 or the FiO2 requirements exceed 0.3 (study group) (334 infants per arm). The primary outcome will be the difference in proportion of infants with BPD or death in the study group managed compared to the control group. DISCUSSION: Based on previous published studies, it seems that LUS may decrease the time to administer surfactant therapy. It is known that early surfactant administration decreases BPD and mortality. Therefore, there is rationale for hypothesizing a reduction in BPD or death in the group of patients in which the decision to administer exogenous surfactant is based on lung ultrasound scores. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT05198375 . Registered on 20 January 2022.

Comparison among three lung ultrasound scores used to predict the need for surfactant replacement therapy: a retrospective diagnostic accuracy study in a cohort of preterm infants.

Lung ultrasound (LU) has emerged as the imaging technique of choice for the assessment of neonates with respiratory distress syndrome (RDS) at the bedside. Scoring systems were developed to quantify RDS severity and to predict the need for surfactant administration. There is no data on the comparison of the three main LU scores (LUS) proposed by Brat, Raimondi and Rodriguez-Fanjul. Moreover, there is not enough evidence to recommend which score and which cut-off has the best ability to predict surfactant need. The three LUS were compared in terms of ability to predict the need for surfactant and reproducibility in a cohort of very preterm infants. This was an observational, retrospective, multicenter study. Neonates below 32 weeks of gestational age with RDS, on non-invasive ventilation with a LU performed prior to surfactant administration (1-3 h of life) were included. Brat, Raimondi, and Rodriguez-Fanjul's scores were calculated for each patient. Receiver-operating characteristic (ROC) curve analysis was used to assess the ability to predict surfactant administration. K-Cohen test, Bland-Altman, and intraclass correlation coefficients were used to assess the intra and interobserver variability. Fifty-four preterm infants were enrolled. Brat, Raimondi, and Rodriguez-Fanjul scores showed a strong ability to predict the need for surfactant: the AUCs were 0.85 (95% CI 0.74-0.96), 0.85 (95% CI 0.75-0.96), and 0.79 (95% CI 0.67-0.92), respectively. No significant differences have been found between the AUCs using the DeLong test. Brat and Raimondi's scores had an optimal cut-off value > 8, while the Rodriguez-Fanjul's score > 10. The k-Cohen values of intraobserver agreement for Brat, Raimondi, and Rodriguez-Fanjul's scores were 0.896 (0.698-1.000), 1.000 (1.000-1.000), and 0.922 (0.767-1.000), respectively. The k-Cohen values of interobserver agreement were 0.896 (0.698-1.000), 0.911 (0.741-1.000), and 0.833 (0.612-1.000), respectively.Conclusions: The three LUS had an excellent ability to predict the need for surfactant and an optimal intra and interobserver agreement. The differences found between the three scores are minimal with negligible clinical implications. Since the optimal cut-off value differed, the same score should be used consistently within the same center. What is Known: • Lung ultrasound is a useful bedside imaging tool that should be used in the assessment of neonates with RDS • Scoring systems or lung ultrasound scores allow to quantify the severity of the pulmonary disease and to predict the need for surfactant replacement therapy What is New: • The three lung ultrasound scores by Brat, Raimondi and Rodriguez-Fanjul have an excellent ability to predict the need for surfactant replacement therapy, although with different cut-off values • All three lung ultrasound scores had an excellent intra and interobserver reproducibility.

Prognostic accuracy of Neonatal SOFA score versus SIRS criteria in preterm infants with late-onset sepsis.

Neonatal SOFA score was reported as an accurate predictor of mortality while the prognostic accuracy of SIRS criteria is unknown. The aim was to compare neonatal SOFA and SIRS criteria for the prediction of late onset sepsis-related mortality in preterm newborns. Newborns ≤ 32 weeks with late onset sepsis were retrospectively studied. Neonatal SOFA and SIRS criteria were calculated at onset of sepsis (T0), and after 6 ± 1 (T1), 12 ± 3 (T2) and 24 ± 3 h (T3). Outcome was death during antibiotic treatment for late onset sepsis. We studied 112 newborns with gestational age 26.9 ± 2.3 weeks; 11% met the study outcome. Neonatal SOFA was significantly higher in non-survivors vs. survivors at all time intervals; SIRS criteria were significantly higher in non-survivors vs. survivors at T1, T2 and T3. Neonatal SOFA increased over time in non-survivors (p = 0.003). At T0, the area under receiver operating characteristics curve was significantly higher for neonatal SOFA score than SIRS criteria (0.950 vs. 0.569; p = 0.0002), and the best calculated cut-off for T0 neonatal SOFA score was 4. In multivariate analysis T0 and T1 neonatal SOFA were predictors of late onset sepsis-related mortality (p = 0.048 and p < 0.001).  Conclusion: Neonatal SOFA score showed greater discriminatory capacity for mortality than SIRS criteria and might be helpful to plan management for patients at higher risk of death. What is Known: • Neonatal SOFA score may be an accurate prognostic tool. • No prognostic score has been fully standardized for septic newborns in NICU. What is New: • Neonatal SOFA score outperformed SIRS criteria for the prediction of prognosis in preterm infants with late onset sepsis. • Neonatal SOFA score assessed at onset of sepsis and 6 hrs later is a predictor of mortality.

Effect of fortification on the osmolality of human milk.

BACKGROUND: It is known that human milk fortifiers (HMF) increases osmolality of human milk (HM) but some aspects of fortification have not been deeply investigated. Our aim was to evaluate the effect of fortification on the osmolality of donor human milk (DHM) and mother's own milk (MOM) over 72 h of storage using two commercial fortifiers and medium-chain triglycerides (MCT) supplementation. METHODS: Pasteurized DHM and unpasteurized preterm MOM were fortified with 4% PreNAN FM85, 4% PreNAN FM85 plus 2% MCT, or 4% Aptamil BMF. Osmolality was measured in unfortified DHM and MOM and, moreover, just after fortification (T0), and after 6 (T6), 24 (T24) and 72 h (T72) to determine the effect of mixing and storage. RESULTS: Unfortified DHM and MOM did not show changes of osmolality. Fortification increased osmolality of DHM and MOM without changes during the study period, except for Aptamil BMF which increased osmolality of MOM. The addition of MCT to fortified human milk (FHM) did not affect its osmolality. CONCLUSIONS: Changes of osmolality in the 72 h following fortification of both DHM and MOM did not exceed the safety values supporting the theoretically possibility of preparing 72 h volumes of FHM. Supplementation with MCT of FHM does not change osmolality suggesting that increasing energy intake in preterm infants via this approach is safe.

Effects of caffeine on diaphragmatic activity in preterm infants.

BACKGROUND: Caffeine is the first-choice drug for the treatment for apnea of prematurity (AOP) in preterm infants and it has been reported that it improves the diaphragm activity. The aim of this study was to evaluate by ultrasound possible changes in diaphragm contractility and motility induced by caffeine. METHODS: We studied 26 preterm infants with gestational age ≤34 weeks treated with caffeine for the prevention or treatment of AOP. Diaphragmatic ultrasound was performed 15 min (T0 ) before and 60 min (T60 ) after the loading (20 mg/kg) or maintenance (5 mg/kg) dose of caffeine. RESULTS: Diaphragmatic excursion (DE) and thickness at the end of inspiration (DT-in) and expiration (DT-ex), as well as peak velocity of the excursion at the end of inspiration (DT-in) and expiration (DT-ex) increased after administration of both loading and maintenance dose of caffeine. CONCLUSIONS: Ultrasounds confirmed that caffeine improves the activity of diaphragm in preterm infants improving its thickness, amplitude of excursions, and contraction velocity. These results are consistent with the effectiveness of caffeine in treating AOP and decreasing the risk of failure of noninvasive respiratory support in preterm infants with respiratory distress syndrome (RDS).

Neonatal Outcomes of Term Infants Born with Meconium-Stained Amniotic Fluid.

Background Meconium-stained amniotic fluid (MSAF) is considered an alarming sign of possible fetal compromise and it has recently been reported that neonatal outcome correlates with the degree of meconium thickness. Methods We retrospectively studied 400 term infants allocated in clear amniotic fluid and grade 1, 2, and 3 MSAF groups on the basis of color and thickness of AF. Multivariable logistic regression analysis was performed to evaluate the potential independent effect of delivery with MSAF of different severity on the risk of a composite adverse neonatal outcome. Results We found that delivery with grade 2 (OR 16.82, 95% Cl 2.12-33.52; p = 0.008) and 3 (OR 33.79, 95% Cl 4.24-69.33; p < 0.001) MSAF is independently correlated with the risk of adverse neonatal outcome, such as the occurrence of at least one of the following: need of resuscitation in the delivery room, blood cord pH < 7.100, occurrence of meconium aspiration syndrome (MAS), persistent pulmonary hypertension (PPH), transient tachypnea of the newborn (TTN), acute respiratory distress syndrome (ARDS), hypoxic-ischemic encephalopathy (HIE), and sepsis. Conclusions There is a positive correlation between the severity of amniotic fluid meconium staining and thickness and the outcomes of term infants. Therefore, the evaluation and grading of MSAF during labor is useful in order to plan for the presence of a neonatologist at delivery for immediate and proper neonatal care.

Enteral and Parenteral Treatment with Caffeine for Preterm Infants in the Delivery Room: A Randomised Trial.

BACKGROUND: Early treatment with caffeine in the delivery room (DR) has been proposed to decrease the need for mechanical ventilation (MV) by limiting episodes of apnoea and improving respiratory mechanics in preterm infants. Our aim was to verify the hypothesis that intravenous or enteral administration of caffeine can be performed in the preterm infant in the DR. METHODS: Infants with 25±0-29±6 weeks of gestational age were enrolled and randomised to receive 20 mg/kg of caffeine citrate intravenously, via the umbilical vein, or enterally, through an orogastric tube, within 10 min of birth. Caffeine blood level was measured at 60 ± 15 min after administration and 60 ± 15 min before the next dose (5 mg/kg). The primary endpoint was evaluation of the success rate of intravenous and enteral administration of caffeine in the DR. RESULTS: Nineteen patients were treated with intravenous caffeine and 19 with enteral caffeine. In all patients the procedure was successfully performed. Peak blood level of caffeine 60 ± 15 min after administration in the DR was found to be below the therapeutic range (5 µg/mL) in 25 % of samples and above the therapeutic range in 3%. Blood level of caffeine 60 ± 15 min before administration of the second dose was found to be below the therapeutic range in 18% of samples. CONCLUSIONS: Intravenous and enteral administration of caffeine can be performed in the DR without interfering with infants' postnatal assistance. Some patients did not reach the therapeutic range, raising the question of which dose is the most effective to prevent MV. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT04044976; EudraCT number 2018-003626-91.

Splanchnic oxygenation during phototherapy in preterm infants with hyperbilirubinemia.

BACKGROUND: It has been reported that preterm infants can develop feeding intolerance during phototherapy (PT) and that PT can affect mesenteric perfusion in these patients. AIMS: Our aim was to assess if PT can decrease regional splanchnic oxygenation (rSO2S) measured by near infrared spectroscopy (NIRS). STUDY DESIGN: We prospectively studied infants with gestational age of 25-34 weeks with hyperbilirubinemia requiring PT. Splanchnic regional oxygenation (rSO2S), oxygen extraction fraction (FOES), and cerebrosplanchnic oxygenation ratio (CSOR) were recorded before, during, and after PT discontinuation. RESULTS: During PT rSO2S and CSOR significantly decreased and this effect lasted for some hours after its interruption. FOES contemporary increased, although this effect was not statistically significant. CONCLUSIONS: PT treatment decreases splanchnic oxygenation in preterm infants likely due to peripheral vasodilation which triggers a redistribution of blood flow. These results can help explain the association between PT and the development of feeding intolerance in preterm infants.

Lung ultrasound in Italian neonatal intensive care units: A national survey.

INTRODUCTION: Lung ultrasound (LU) is a noninvasive, bedside imaging technique that is attracting growing interest in the evaluation of neonatal respiratory diseases. We conducted a nationwide survey of LU usage in Italian neonatal intensive care units (NICUs). METHODS: A structured questionnaire was developed and sent online to 114 Italian NICUs from June to September 2021. RESULTS: The response rate was 79%. In the past 4 years (range: 2-6), LU has been adopted in 82% of Italian NICUs. It is the first-choice diagnostic test in 23% of the centers surveyed. The main LU diagnostic applications reported were: pneumothorax (95%), respiratory distress syndrome (89%), transient tachypnea of the newborn (89%), plural effusion (88%), atelectasis (66%), pneumonia (64%), bronchopulmonary dysplasia (43%), congenital pulmonary airway malformation (41%), and congenital diaphragmatic hernia (34%). Thirty percent of participating centers calculated LU score routinely, but only seven units used it to predict the need for surfactant replacement. Sixty-six percent of respondents learned the LU technique via a self-training process, while 34% of them visited an expert in the field for one-to-one tuition. CONCLUSIONS: LU has a widespread use in Italian NICUs. However, the use of LU is extremely heterogeneous among centers. There is an urgent need to ensure standardization of clinical practice guidelines and to design and implement a formalized and accredited training program.

Lung ultrasound scores in neonatal clinical practice: A narrative review of the literature.

Lung ultrasound (LU) has in recent years increasingly been used as a point-of-care method. Initially, LU was used as a so-called descriptive diagnostic method for neonatal respiratory diseases. Instead, this review article focuses on the use of LU as a "functional" tool using classification of findings in patterns or using semiquantitative scores. We review and describe the evidence that led to the implementation of LU in predicting the need for surfactant replacement therapy in preterm infants and in the identification of newborns at risk of developing bronchopulmonary dysplasia. LU appears to be a very promising method for the future of clinical management of newborns in both acute and chronic phases of pulmonary pathologies related to prematurity. However, further studies are needed to define its role before full implementation.

Effect of selective gastric residual monitoring on enteral intake in preterm infants.

OBJECTIVE: Prefeed gastric residuals (GRs) monitoring has been correlated with an increased time to reach full feeds and longer parenteral nutrition without beneficial effect on necrotizing enterocolitis (NEC) occurrence. We aimed to assess effects of a new local protocol to provide for the selective evaluation of GRs excluding their routine monitoring. METHODS: We carried out a retrospective study based on a "before and after" design in a cohort of infants born at 23+0-31+6 weeks of gestation. The primary outcome was the age at full enteral feeding (150 mL/kg/d). Secondary outcomes included age at regaining of birth weight, and evaluation of Z-scores of weight, length, and head circumference at discharge. RESULTS: We studied 49 infants in the selective GR group and 59 in the routine GR group. Age at full (150 mL/kg) enteral feeding (17.8 ± 10.1 vs. 22.9 ± 10.5 days, P = 0.017) and regaining of birth weight (11.1 ± 3.0 vs. 12.5 ± 3.5 days, P = 0.039) were lower while the Z-scores of weight at discharge (-1.10 ± 0.83 vs. -1.60 ± 1.45, P = 0.040) were higher in infants in the selective GR group in comparison with infants in the routine GR group. CONCLUSIONS: Selective monitoring of GRs decreased age at full enteral feeding and at regaining of birth weight and induced better Z-scores of weight at discharge in comparison with routine GR monitoring in a cohort of extremely preterm infants without increasing the incidence of NEC. Omitting prefeed GRs monitoring in clinical practice seems reasonable.

The management of late preterm infants: effects of rooming-in assistance versus direct admission to neonatal care units.

Late preterm infants (LPIs) represent a significant percentage of all neonates (6-8%), but there are limited published data on their postnatal management. Our aim was to compare the frequency of neonatal intensive care unit (NICU) admission and the breastfeeding rate of LPIs born at 35+0-36+6 weeks of gestation who were cared for by initial rooming in strategy rather than directly admitted to the special care unit (SCU) and, eventually, to the NICU. We carried out a retrospective study in the perinatal centers of Careggi University Hospital (CUH) and San Giovanni di Dio Hospital in Florence, Italy, where the first and second strategies were applied, respectively. Main outcomes were LPIs admission rate at SCU/NICU and breastfeeding rate at discharge. We studied 190 LPIs born at SGDH and 240 born at CUH. The admission rate in SCU (81 vs. 43%; P < 0.001) and NICU (20 vs. 10%; P = 0.008) was higher in SGDH than in CUH, as was the exclusive breastfeeding rate (36 vs. 22%; P < 0.001). However, infants who were assisted in rooming-in at CUH and infants with similar clinical characteristics at SGDH had similar mixed (60 vs. 69%) and exclusive (35 vs. 31%) breastfeeding rates.  Conclusion: Postnatal assistance of LPIs in rooming-in, eventually followed by admission in SCU/NICU based on their clinical conditions, allowed to safely halve their hospitalization. The assistance of infants in rooming-in did not negatively affect their breastfeeding rate. These results support the possibility of assisting LPIs in rooming-in. What is Known: • Late preterm infants represent a significant percentage of all neonates. • Early rooming-in and breastfeeding is recommended for late preterm infants. What is New: • Postnatal assistance of late preterm infants in rooming-in, followed when necessary by admission in neonatal units based on clinical conditions, allowed to safely avoid about half the number of hospitalizations in comparison with direct admission in neonatal units. • This strategy did not affect breastfeeding rate. Infants who were admitted to SCU/NICU after initial rooming-in had worst breastfeeding rate.

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 (rSO2 L) by near-infrared spectroscopy (NIRS) and to evaluate whether rSO2 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 rSO2 L was correlated with SpO2 /FiO2 ratio, a/APO2 , and O.I. RESULTS: The overall value of rSO2 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 rSO2 L did not significantly change during the 24-h study period. Linear regression analysis demonstrated a significant positive relationship between total rSO2 L and SpO2 /FiO2 ratio (p < 0.001) and a/APO2 (p = 0.040), and a negative relationship between total rSO2 L and O.I. (r = -0.309; p = 0.022). CONCLUSIONS: Continuous monitoring of rSO2 L by NIRS in preterm infants with RDS is feasible and safe. The correlation of rSO2 L with other indices of oxygenation and RDS severity supports the accuracy and reliability of this measurement.