The Montreux definition of neonatal ARDS: biological and clinical background behind the description of a new entity

Reflections on the introduction of surfactant therapy for neonates with respiratory distress

When pulmonary surfactant was first detected in the 1950s by Pattle and Clements, many thousands of infants perished each year due to a respiratory illness termed hyaline membrane disease. Hyaline membranes are formed by plasma leaking through damaged endothelial barriers into the terminal bronchiolar: alveolar spaces. Since the leaking plasma lacks erythrocytes, these clots are opaque. Insightful research by Avery and Mead soon led to the suggestion that the neonatal respiratory distress syndrome (RDS) did not arise because of the presence of hyaline membranes, but rather was related to the lack of sufficient pulmonary surfactant, mainly as a result of immaturity. Unfortunately, initial attempts at treating RDS with aerosolized dipalmitoyl-phosphatidylcholine, the major single molecular component, proved unsuccessful. Almost 20 years later, it was demonstrated by Enhorning and Robertson that treating prematurely delivered rabbit pups with natural surfactant prevents respiratory failure. Initially, it appeared unlikely that animal surfactants could be used for therapy with human infants. However, in 1980, Fujiwara demonstrated that a modified bovine surfactant extract promoted gaseous exchange with infants suffering from RDS. Soon a number of bovine and porcine-modified surfactants and two wholly synthetic formulations were shown to alleviate RDS. The present review relates some of the key scientific findings and significant clinical contributions responsible for reducing the neonatal morbidity and mortality associated with RDS. It further describes some of the more recent findings on the biological, biophysical, and physiological significance of pulmonary surfactant in health and disease.

Characteristics, triggers, treatments, and experimental models of neonatal acute respiratory distress syndrome

Neonatal acute respiratory distress syndrome (NARDS) is a severe and potentially life-threatening form of lung injury recently defined by the International Neonatal ARDS Consensus. It is marked by extensive lung inflammation and damage to the alveolar epithelium and vascular endothelium. NARDS can be triggered by direct inflammatory exposures, such as pneumonia and aspiration, and indirect exposures, including sepsis, necrotizing enterocolitis, and chorioamnionitis. This review provides clinicians and researchers with the latest insights on NARDS. We adopt a cross-disciplinary approach to discuss the diagnostic criteria, pathobiology, triggers, epidemiology, and treatments of NARDS. In addition, we summarize existing clinical studies and advanced preclinical models that help address current knowledge gaps. Future research should focus on standardizing the Montreux consensus definition of NARDS in preclinical and clinical studies, identifying biomarkers, developing prediction models, and exploring novel therapies for affected infants.

Clinical Diagnostic Value of miR-193a-5p in Neonatal Acute Respiratory Distress Syndrome and Analysis of Its Effect on Human Lung Epithelial Cells

Aim: To explore the clinical value of miR-193a-5p in neonatal acute respiratory distress syndrome (ARDS) and its role in ARDS cell model in vitro. Methods: RT-qPCR was utilized to detect miR-193a-5p level. Correlation analysis was implemented to assess the correlation between miR-193a-5p and clinical indicators (IL-6, IL-1β, TNF-α, LUS). Human lung epithelial cells induced by LPS were used to construct ARDS cell model. The effects of miR-193a-5p on cell viability, apoptosis and inflammation were evaluated by CCK-8, flow cytometry and ELISA. The target gene of miR-193a-5p was predicted and verified by StarBaseV2.0 and luciferase reporter gene, respectively. Results: MiR-193a-5p level in the ARDS group was down-regulated. MiR-193a-5p levels were negatively correlated with clinical indicators. In vitro studies revealed that up-regulation of miR-193a-5p significantly improved LPS-induced apoptosis, inflammation and viability inhibition. Conclusion: The expression of miR-193a-5p was decreased in neonatal ARDS, it is negatively correlated with the pro-inflammatory factors levels.

Associations of maternal age with outcomes in very low birth weight singleton infants: a retrospective study

Background

With advances in perinatal medicine, there has been a rise in the preterm birth rate, especially the rate of very low birth weight (VLBW) and extremely low birth weight infants. Studies have shown that maternal age during pregnancy and at the time of delivery is associated with pregnancy complications and poor neonatal outcomes. Little is known about the effect of maternal age on the outcome of very low birth weight infants.

Objectives

To investigate the effects of maternal age on the adverse outcomes of singleton very low birth weight neonates.

Methods

We used data of VLBW infants from the neonatal database of our hospital. Maternal age was categorized as 20-24, 25-34 (reference group), 35-39 and ≥40 years. Statistical analyses included univariate and multivariate logistic regression analysis.

Results

The study ultimately included 603 singleton, very low birth weight infants. After adjustment, neonatal outcomes in the group of older mothers were similar to those of the reference group for bronchopulmonary dysplasia, necrotizing enterocolitis, respiratory distress syndrome, severe asphyxia, retinopathy of prematurity and intraventricular hemorrhage grades 3-4. In the 20-24 year age group higher odds were present for sepsis [Odds ratio (OR) = 6.021; 95% confidence interval (CI), 1.741-20.818, p < 0.05] and for mortality (OR = 7.784; 95% CI, 2.198-27.568, p < 0.05). Higher odds for asphyxia (OR = 1.891; 95% CI, 1.238-2.890, p < 0.05) and death (OR = 2.101, 95% CI, 1.004-4.395, p < 0.05) were observed in infants of mothers in the 35-39 year age group. The incidence of sepsis was significantly higher in the age group of ≥40 years (OR = 2.873; 95% CI, 1.186-6.958, p < 0.05).

Conclusions

In singleton very low birth weight neonates, neonatal outcomes were associated with maternal age, and adverse outcomes were more pronounced in infants of advanced maternal age (AMA) mothers.

Thoracic electrical bioimpedance in preterm newborns with and without respiratory distress syndrome: an exploratory observational study

To test the hypothesis that thoracic fluid content (TFC) by thoracic electrical bioimpedance would be higher in preterm infants with respiratory distress syndrome (RDS) both at birth and in the first 48 h of life than in those without RDS and that TFC measured at birth would be associated with RDS diagnosis and need for surfactant. Cross-sectional exploratory observational study including infants ≤ 34 weeks of gestation admitted to two level three NICUs. TFC, clinical, and respiratory data were recorded at 5 timepoints: within the first 2 h of life, before surfactant therapy, and at 4, 12, 24, and 48 h of life. TFC was compared between infants with and without RDS. A ROC curve was calculated to assess the association between TFC at birth and the need for surfactant. TFC was higher in infants with RDS than in infants without RDS at all timepoints. The ROC AUC of TFC measured at birth for the need for surfactant was 0.817 (95% CI 0.64-0.93, p < 0.001); a TFC cut-off of 20.4 1/KOhm/Kg yielded a sensitivity of 83% and specificity of 80% for the need for surfactant. Conclusion: TFC in the first 48 h of life was higher in preterm infants with RDS than in infants without RDS. TFC measured within the first 2 h of life had a good association with the need for surfactant. What is known: • Thoracic electrical bioimpedance can be used to measure thoracic fluid content (TFC) non invasively in newborns What is new: • TFC was higher in premature newborns with respiratory distress syndrome (RDS) that in those without RDS in the first 48 h of life. A high TFC in the first 2 h was associated with the need for surfactant.

EIT guided evaluation of regional ventilation distributions in neonatal and pediatric ARDS: a prospective feasibility study

BACKGROUND

Despite international guidelines for lung protective ventilation in neonatal or pediatric acute respiratory distress syndrome (nARDS/ pARDS), prospective data on bedside monitoring tools for regional ventilation distribution and lung mechanics are still rare. As a bedside and radiation-free procedure, electrical impedance tomography (EIT) offers a practical and safe approach for analyzing regional ventilation distributions. Recent trials in adults have shown the efficacy of an individualized EIT guided strategy for the improvement of ventilator induced lung injury (VILI).

METHODS

We performed a single-center prospective feasibility study from November/2021 to December/2023 in the department of neonatal and pediatric intensive care medicine at the University Children´s Hospital in Bonn. All patients with diagnosis of nARDS (or history of perinatal lung disease-PLD)/ pARDS were screened for study inclusion. In all patients a decremental PEEP (positive end-expiratory pressure) trial was performed with a continuous EIT monitoring for an individual analysis of the EIT guided pixel compliance (CEIT) and PEEP finding (EIT-PEEP). In the offline analysis, further EIT derived indices, such as global inhomogeneity index (GI), and center of ventilation (CoV), were calculated.

RESULTS

Overall, 40 EIT measurements were performed in 26 neonatal and pediatric patients (nARDS/PLD, n = 6; and pARDS, n = 20) within a predefined decremental PEEP trial. Thirteen patients were classified as having severe nARDS (PLD)/ pARDS with an Oxygen Saturation Index (OSI) > 12 or Oxygenation Index (OI) > 16. In-hospital mortality rate was 27% in the overall cohort. The median EIT-PEEP (11mbar) was calculated as lowest, as compared to the clinically set PEEP (11.5mbar, p < 0.001), and the ARDSnetwork PEEP table recommendation (ARDSnet-PEEP, 14mbar, p = 0.018). In patients with nARDS/PLD, the EIT-PEEP was calculated 3mbar below the clinically set PEEP (p = 0.058) and 11 mbar below the ARDSnet-PEEP (p = 0.01). In the linear regression analysis, EIT-PEEP and the dynamic compliance (CDYN) at -2mbar presented a significant correlation with a Cohen´s R2 of 0.265 (β: 0.886, p = 0.005).

CONCLUSION

EIT is feasible and can be performed safely in patients with diagnosis of nARDS/PLD and pARDS, even during ongoing extracorporeal membrane oxygenation (ECMO) support. An individualized PEEP finding strategy according to the EIT compliance might optimize regional ventilation distribution in these patients and can potentially decrease VILI.

CLINICAL TRIAL REGISTRATION

The study was registered at the German Clinical Trials Register (GCT; trial number: DRKS 00034905, Registration Date 15.08.2024). The registration was performed retrospectively after inclusion of the last patient.

Response to Inhaled Nitric Oxide and Mortality Among Very Preterm Neonates With Pulmonary Hypertension

Importance

Clinical observations of immediate improvement in fraction of inspired oxygen (FiO2) in a proportion of cases is often cited as the rationale for using inhaled nitric oxide (iNO) in the management of acute pulmonary hypertension among very preterm neonates (gestational age, <32 weeks). However, the clinical effectiveness of such a response pattern remains underinvestigated.

Objective

To identify factors associated with predischarge mortality among very preterm neonates receiving iNO for acute pulmonary hypertension, with specific a priori emphasis on iNO responsiveness.

Design, Setting, and Participants

This prospective observational cohort study was conducted from January 1, 2018, to December 31, 2022, at 12 Canadian tertiary neonatal intensive care units. Consecutive very preterm neonates who received iNO for a diagnosis of acute pulmonary hypertension and pretreatment FiO2 of 0.50 or more were included. Neonates with congenital anomalies or those who were treated for chronic pulmonary hypertension with iNO were excluded. Early acute pulmonary hypertension (≤72 hours of age) and late acute pulmonary hypertension (>72 hours of age) cohorts were analyzed separately. Statistical analysis was performed from January 2023 to January 2024.

Exposure

Treatment with iNO for acute pulmonary hypertension.

Main Outcomes and Measures

The study cohorts were divided for comparison based on the primary outcome of predischarge mortality. Logistic regression analyses were used with predefined variables, including iNO responsiveness, to identify factors associated with mortality. A positive response to iNO was defined as a pre-iNO minus 4-hour post-iNO FiO2 of 0.20 or more.

Results

The early acute pulmonary hypertension group (mean [SD] birth gestational age, 26.3 [2.4] weeks; median treatment age, 1 day [IQR, 1-2 days]; 147 boys [56%]) included 262 neonates; 179 (68%) had a pre-iNO FiO2 of 1.0. The late acute pulmonary hypertension group (mean [SD] birth gestational age, 24.9 [1.7] weeks; median treatment age, 13 days [IQR, 9-20 days]; 72 boys [66%]) included 109 neonates; 51 (47%) had a pre-iNO FiO2 of 1.0. Neonates with early acute pulmonary hypertension more frequently had a positive iNO response (71% [186 of 262] vs 41% [45 of 109]) and lower mortality (34% [90 of 262] vs 49% [53 of 109]) than those with late acute pulmonary hypertension. Accounting for pretreatment illness factors, greater reduction in FiO2 with iNO remained associated with lower mortality for neonates with early acute pulmonary hypertension (adjusted odds ratio per FiO2 reduction of 0.10, 0.74 [95% CI, 0.65-0.84]). For those with late acute pulmonary hypertension, however, only pretreatment illness severity (lower pre-iNO FiO2 and higher pre-iNO pH), and not positive response to iNO (adjusted odds ratio, 0.47 [95% CI, 0.17-1.30]), was associated with mortality.

Conclusions and Relevance

In this cohort study of very preterm neonates with acute pulmonary hypertension treated with iNO, responsiveness to iNO was associated with improved outcomes during the first 72 hours of age. The prognostic role of iNO response in acute pulmonary hypertension presenting after 72 hours of age remains unclear. Future studies should investigate the distinct pathophysiological mechanisms associated with late acute pulmonary hypertension in this population.

The diagnostic and prognostic value of serum angiopoietin-like 4 level in neonatal respiratory distress syndrome

OBJECTIVES

Neonatal respiratory distress syndrome (NRDS) is the most common respiratory disease in preterm infants (PIs). The implication of Angiopoietin-like 4 (ANGPTL4) was reported in lung diseases. We delved into the role of serum ANGPTL4 in NRDS diagnosis/prognosis.

METHODS

Totally 256 PIs were prospectively selected, including 128 NRDS infants and 128 non-NRDS PIs. NRDS infants were assigned into Survival and Death groups. ANGPTL4 level in PIs and its diagnostic and prognostic value for NRDS were separately assessed by ELISA and receiver operating characteristic curve. The independent risk factors (IRFs) for death in NRDS infants were analysed by multivariate logistic regression.

RESULTS

NRDS infants exhibited reduced gestational age, birth weight, and 5 min Apgar score. ANGPTL4 level rose in NRDS infants, and increased with NRDS severity. Serum ANGPTL4 level was negatively correlated with 5 min Apgar score in NRDS infants. The area under the curve of serum ANGPTL4 for the diagnosis of NRDS was 0.902, with 88.28% sensitivity, 86.72% specificity, and 255.98 ng/mL cut-off value; the AUC for the diagnosis of severe NRDS was 0.741, with 66.67% sensitivity, 79.52% specificity, and 625.5 ng/mL cut-off value. Low gestational age, birth weight and 5 min Apgar score, severe NRDS, and elevated serum ANGPTL4 levels were IRFs for death in NRDS infants. NRDS infants with increased serum ANGPTL4 level displayed decreased survival rate and short survival time.

CONCLUSIONS

ANGPTL4 exhibited high diagnostic value and predictive value for death in NRDS, and it served as a biomarker for the diagnosis and prognosis of NRDS.

A nomogram for predicting neonatal acute respiratory distress syndrome in patients with neonatal pneumonia after 34 weeks of gestation

Objective

To establish a prediction nomogram for early prediction of neonatal acute respiratory distress syndrome (NARDS).

Methods

This is a retrospective cross-sectional study conducted between January 2021 and December 2023. Clinical characteristics and laboratory results of cases with neonatal pneumonia were compared in terms of presence of NARDS diagnosis based on the Montreux Definition. The NARDS group and non-NARDS group were then compared to establish a prediction nomogram for early prediction of NARDS. The predictive accuracy and compliance of the model were evaluated using subject operating characteristic curves, area under the ROC curve, and calibration curves, and the model performance was estimated by self-lifting weight sampling. The Hosmer-Lemeshow test was used to assess the goodness of fit of the model.

Findings

NARDS group consisted of 104, non-NARDS group consisted of 238 newborns in our study. Gestational age, triple concave sign, blood glucose measurement after birth (Glu), Apgar score at the 5th minute (Apgar5), neutrophil count (ANC) and platelet count (PLT) are independent predictors of NARDS in late preterm and term newborns who present with progressive respiratory distress and require varying degrees of respiratory support within the first 24 h of life to minimize work of breathing and restore organismal oxygenation. The area under the ROC curve was 0.829 (95% CI = 0.785-0.873), indicating the model's strong predictive power. In addition, decision curve analysis showed that the model had significantly better net benefits.

Conclusion

In this study, a predictive column-line plot was constructed based on six clinically accessible conventional variables. Early application of this model has a better predictive effect on the early diagnosis of NARDS, thus facilitating more timely and effective interventions.

Two risk assessment models for predicting white matter injury in extremely preterm infants

BACKGROUND

Extremely preterm infants (EPIs) are at high-risk of white matter injury (WMI), leading to long-term neurodevelopmental impairments. We aimed to develop nomograms for WMI.

METHODS

The study included patients from 31 provinces, spanning ten years. 6074 patients before 2018 were randomly divided into a training and internal validation group (7:3). The external validation group comprised 1492 patients from 2019. Predictors were identified using the least absolute shrinkage and selection operator (LASSO) and multivariable logistic regression and nomograms were constructed. Models' performance was evaluated using receiver operating characteristic (ROC), decision curve analysis (DCA) and calibration curves.

RESULTS

The prenatal nomogram included multiple gestation, premature rupture of membranes (PROM), chorioamnionitis, prenatal glucocorticoids, hypertensive disorder complicating pregnancy (HDCP) and Apgar 1 min, with area under the curve (AUC) of 0.805, 0.816 and 0.799 in the training, internal validation and external validation group, respectively. Days of mechanical ventilation (MV), shock, patent ductus arteriosus (PDA) ligation, intraventricular hemorrhage (IVH) grade III-IV, septicemia, hypothermia and necrotizing enterocolitis (NEC) stage II-III were identified as postpartum predictors. The AUCs were 0.791, 0.813 and 0.823 in the three groups, respectively. DCA and calibration curves showed good clinical utility and consistency.

CONCLUSION

The two nomograms provide clinicians with precise and efficient tools for prediction of WMI.

IMPACT

This study is a large-sample multicenter study, spanning 10 years. The two nomograms are convenient for identifying high-risk infants early, allowing for reducing poor prognosis.

Establishing a nomogram for predicting necrotizing enterocolitis in premature infants: A retrospective multicenter cohort study

BACKGROUND

To construct a nomogram for predicting necrotizing enterocolitis (NEC) in preterm infants.

METHODS

A total of 4,724 preterm infants who were admitted into 8 hospitals between April 2019 and September 2020 were initially enrolled this retrospective multicenter cohort study. Finally, 1,092 eligible cases were divided into training set and test set based on a 7:3 ratio. A univariate logistic regression analysis was performed to compare the variables between the two groups. Stepwise backward regression, LASSO regression, and Boruta feature selection were utilized in the multivariate analysis to identify independent risk factors. Then a nomogram model was constructed based on the identified risk factors.

RESULTS

Risk factors for NEC included gestational diabetes mellitus, gestational age, small for gestational age, patent ductus arteriosus, septicemia, red blood cell transfusion, intravenous immunoglobulin, severe feeding intolerance, and absence of breastfeeding. The nomogram model developed based on these factors showed well discriminative ability. Calibration and decision curve analysis curves confirmed the good consistency and clinical utility of the model.

CONCLUSIONS

We developed a nomogram model with strong discriminative ability, consistency, and clinical utility for predicting NEC. This model could be valuable for the early prediction of preterm infants at risk of developing NEC.

Transient tachypnoea: new concepts on the commonest neonatal respiratory disorder

Transient tachypnoea of the neonate (TTN) is the commonest neonatal respiratory disorder, but it is quite mild and so has been the subject of relatively little academic and educational work. Recent animal studies and the introduction of new bedside monitoring techniques (e.g. quantitative lung ultrasound and electrical cardiometry) have clarified its pathogenesis. Given its high incidence, TTN is a relevant public health issue and its clinical management should be considered in an era of resource constraints. This review focuses on the latest data on TTN in terms of its pathophysiology, biology, diagnosis, imaging, therapy and cost-effectiveness, so as to optimise clinical care at the bedside. The need for a new pathophysiology-based definition of TTN is also highlighted and the available therapeutics are analysed considering the associated public health issues. This updated knowledge can help to improve the management of TTN and impact positively on its relevant public health consequences. This is particularly important since the mortality of TTN is virtually nil and so cannot be used to evaluate any clinical innovation. We also aim to give some practical guidance for the real-world clinical management of TTN and contribute to the training of neonatologists who care for TTN patients.

Elective high frequency oscillatory ventilation versus conventional mechanical ventilation on the chronic lung disease or death in preterm infants administered surfactant: a systematic review and meta-analysis

BACKGROUND

Use of elective high frequency oscillatory ventilation (HFOV) compared with conventional mechanical ventilation (CMV) results in a small reduction in the risk of chronic lung disease (CLD) or death, but the evidence is weak. Our objective was to explore whether elective HFOV was associated with less CLD or death as compared with CMV in preterm infants administered surfactant.

METHODS

We conducted a systematic review and meta-analysis, including 1835 ventilated participants from 11 randomized controlled trials comparing elective HFOV with CMV between February 1993 and February 2014. The primary outcome was the incidence of CLD or death.

RESULTS

Compared with CMV, elective HFOV was associated with less CLD or death (relative risk (RR) 0.76, 95% confidence interval (CI) 0.61-0.94, p = 0.01) (p = 0.01, I2 = 55%), CLD (RR 0.71, 95%CI 0.53-0.93, p = 0.01) (p = 0.03, I2 = 50%), and ≥2nd stages of retinopathy of prematurity (RR 0.77, 95%CI 0.62-0.94, p = 0.01) (p = 0.42, I2 = 0%). In the subgroup of > 1 dose of surfactant, compared with CMV, elective HFOV was also related to less CLD or death (RR 0.87, 95%CI 0.77-0.98, p = 0.02) (p = 0.10, I2 = 42%). No differences were found in the incidences of death, grade 3 or 4 of intraventricular hemorrhage, periventricular leukomalacia, airleak and necrotizing enterocolitis between the two groups.

CONCLUSION

Elective HFOV is superior to CMV in reducing the incidence of CLD or death in ventilated preterm infants administered surfactant, especially in the subgroup of >1 dose of surfactant.

TRIAL REGISTRY

International Prospective Register of Systematic Reviews: No.: CRD42022301033; URL: https://www.crd.york.ac.uk/PROSPERO/ .

Establishment and evaluation of nomogram for predicting acute respiratory distress syndrome in meconium-stained amniotic fluid neonates

OBJECTIVE

To delineate risk factors and develop a predictive nomogram for acute respiratory distress syndrome (ARDS) in neonates exposed to meconium-stained amniotic fluid (MSAF).

METHODS

We conducted a comprehensive retrospective analysis of neonates with MSAF, classifying them into ARDS and non-ARDS groups based on the onset of ARDS within the first week after birth. Clinical and laboratory data are collected to screen the risk factors for ARDS in MSAF neonates, multivariate logistic regression was performed to identify independent predictors and establish a nomogram to predict the occurrence of neonatal ARDS.

RESULTS

We recognized five variables as independent risk factors for ARDS with MSAF neonates via logistic regression analysis, consisting of 1-min Apgar score (Apgar 1 min), white blood cell (WBC), platelet (PLT), red cell distribution width (RDW) and serum calcium (Ca). These predictors were integrated into a nomogram designed to estimate the individual risk of ARDS development in neonates. The predictive model achieved a C-index of 0.942 (95% CI: 0.915-0.970), indicating high predictive accuracy. Additionally, the nomogram was internally validated, demonstrating excellent calibration and practical utility for clinical decision-making.

CONCLUSIONS

The validated nomogram, based on five pivotal factors, provides clinicians with a reliable tool for early identification and management of ARDS in MSAF neonates, potentially improving outcomes by facilitating timely and appropriate therapeutic interventions.

OPtimal TIming of antenatal COrticosteroid administration in pregnancies complicated by early-onset fetal growth REstriction: results of a large multicenter cohort study (the OPTICORE study)

BACKGROUND

Early-onset fetal growth restriction as consequence of placental insufficiency frequently requires iatrogenic preterm birth. Administration of antenatal corticosteroids reduces risks of neonatal morbidity and mortality following preterm birth and is most beneficial if the neonate is delivered within 2 weeks following treatment. International guidelines on fetal growth restriction pregnancies do not provide directives regarding the timing of antenatal corticosteroids, resulting in practice variation.

OBJECTIVE

This study compared the 2 main timing strategies of antenatal corticosteroids administration in the Netherlands for early-onset fetal growth restriction pregnancies: administration when the umbilical artery shows a pulsatility index above the 95th centile with (A) positive end-diastolic flow vs (B) absent or reversed end-diastolic velocity.

STUDY DESIGN

A multicenter retrospective cohort study was performed in 6 tertiary hospitals in the Netherlands between 2012 and 2021. Three hospitals practiced timing strategy A and 3 strategy B. The primary outcome was defined as a composite of perinatal and in-hospital mortality. Secondary outcomes were in line with the core outcome set for fetal growth restriction. Mixed effects analyses were performed adjusted for birthweight z-score and gestational age at birth to compare the 2 timing strategies.

RESULTS

A total of 1453 patients were included, of whom 871 and 582 were treated according to timing strategy A and B, respectively. Corticosteroids were administered at a mean gestational age of 28 weeks and 3 days (standard deviation 16.0 days) in timing strategy A and 28 weeks and 4 days (standard deviation 15.8 days) in timing strategy B. The median birthweights were 1050 (range 795, 1350) and 1060 (range 801, 1339) in timing strategy A and B, respectively. Although not statistically significant, rates of perinatal and in-hospital mortality were increased in timing strategy B infants (7.2% vs 9.8%; adjusted odds ratio 1.47; 95% confidence interval 0.97-2.22, reference A). 52.8% and 53.6% of patients in strategy A and B, respectively, delivered within the corticosteroids therapeutic window of 2 to 14 days (P value .663), with a median time between corticosteroid administration and delivery of 6 days for strategy A and 6 days for strategy B. Timing strategy B was associated with more necrotizing enterocolitis (3.7% vs 7.6%; adjusted odds ratio 2.18; 95% confidence interval 1.29-3.69), but less respiratory distress syndrome (39.6% vs 34.5%; adjusted odds ratio 0.63; 95% confidence interval 0.45-0.88) and bronchopulmonary dysplasia (18.9% vs 17.4%; adjusted odds ratio 0.69; 95% confidence interval 0.50-0.96). Other outcomes were similar between groups.

CONCLUSION

Timing strategy B seemed to be associated with higher rates of the composite of perinatal and in-hospital mortality, which could not be explained by a difference in time intervals between corticosteroid administration and delivery. Importantly, most pregnant women delivered outside the presumed therapeutic corticosteroid window. Future research should focus on the improvement of the timing of antenatal corticosteroids in pregnancies complicated by early-onset fetal growth restriction and the identification of other differences in ante- and/or postnatal management to explain differences in outcomes, given the high risk for neonatal morbidity and mortality in this setting.

Immunoinflammatory markers SIRI and NAR as predictors of respiratory distress syndrome and secondary infections in premature infants

Background

Premature infants are at high risk for neonatal respiratory distress syndrome (RDS) and secondary infections. This study aims to investigate the association between immunoinflammatory markers-the systemic immune inflammation index (SII), systemic inflammation response index (SIRI), and neutrophil-to-albumin ratio (NAR)-and the risk of developing RDS in premature infants.

Methods

A total of 2164 premature infants were enrolled in this retrospective study. The clinical records of these neonates (respiratory tract infections, adverse pregnancy history, placental abnormalities, birth weight, Apgar scores, and immunoinflammatory indices) were collected. Comparisons were made between infants with and without RDS. Logistic regression analysis was used to evaluate the relationship between SII, SIRI, NAR and RDS.

Results

Among the cohort, 962 infants developed RDS, while 1202 did not. The RDS group showed higher proportions of mothers with adverse pregnancy history, placental abnormalities, birth weight <2.5 kg, and lower Apgar scores at 1 and 5 minutes (all p<0.05). SII, SIRI, and NAR levels were significantly elevated in RDS infants (p<0.05). Logistic regression revealed that adverse pregnancy history (OR: 1.390, p=0.001), placental abnormalities (OR: 2.499, p<0.001), birth weight <2.5 kg (OR: 4.165, p<0.001), high SIRI (OR: 1.338, p=0.035), and high NAR (OR: 1.639, p<0.001) were significant predictors of RDS. Additionally, secondary infections, particularly pneumonia and sepsis, were significantly more common in the RDS group (p<0.001).

Conclusion

Adverse pregnancy history, placental abnormalities, low birth weight, elevated SIRI and NAR were associated with increased risk of RDS and secondary infections in premature infants. These findings suggest that SIRI and NAR could serve as useful markers for early identification and management of RDS and its complications in this vulnerable population.

Acute respiratory distress syndrome: A review of ARDS across the life course

Acute respiratory distress syndrome (ARDS) is a multifactorial, inflammatory lung disease with significant morbidity and mortality that predominantly requires supportive care in its management. Although initially described in adult patients, the diagnostic definitions for ARDS have evolved over time to accurately describe this disease process in pediatric and, more recently, neonatal patients. The management of ARDS in each age demographic has converged in the application of lung-protective ventilatory strategies to mitigate the primary disease process and prevent its exacerbation by limiting ventilator-induced lung injury. However, differences arise in the preferred ventilatory strategies or adjunctive pulmonary therapies used to mitigate each type of ARDS. In this review, we compare and contrast the epidemiology, common etiologies, pathophysiology, diagnostic criteria, and outcomes of ARDS across the lifespan. Additionally, we discuss in detail the different management strategies used for each subtype of ARDS and spotlight how these strategies were applied to mitigate poor outcomes during the COVID-19 pandemic. This review is geared toward both clinicians and clinician-scientists as it not only summarizes the latest information on disease pathogenesis and patient management in ARDS across the lifespan but also highlights knowledge gaps for further investigative efforts. We conclude by projecting how future studies can fill these gaps in research and what improvements may be envisioned in the management of NARDS and PARDS based on the current breadth of literature on adult ARDS treatment strategies.

Association Between Albumin Levels and Neonatal Acute Respiratory Distress Syndrome in Newborn Pneumoniae

Objective

This study aims to investigate the relationship between serum albumin levels and neonatal acute respiratory distress syndrome (NARDS) in patients with newborn pneumonia, providing new insights for clinical interventions targeting NARDS.

Methods

A retrospective analysis of medical records of neonatal pneumonia patients admitted to the neonatal intensive care unit (NICU) at a tertiary medical institution from January 2021 to December 2023 was conducted. Patients were stratified based on hypoalbuminemia (defined as serum albumin levels < 35 g/L), clinical thresholds, and albumin level quartiles. To eliminate the impact of potential confounding factors on the results, multivariable logistic regression and propensity score matching (PSM) analyses were performed to calculate the adjusted odds ratio (OR) and 95% confidence interval (95% CI) for the occurrence of NARDS in these patients. Additionally, subgroup analyses were conducted to explore interaction effects.

Results

In this retrospective cohort study, a total of 342 patients with neonatal pneumonia admitted to the NICU were included. The multivariable logistic regression analysis revealed that the incidence of NARDS in patients with hypoalbuminemia was significantly higher than in those with normal albumin levels (OR = 2.16, 95% CI 1.47-4.06, p = 0.017). Compared to patients in quartile Q1 (≥39 g/L), those in quartile Q4 (≤33 g/L) exhibited a significantly increased risk of NARDS (OR = 4.40, 95% CI 1.53-12.63, p = 0.006). After conducting PSM, these associations remained significant. Furthermore, treating serum albumin levels as a continuous variable revealed that each 1 g/L increase was associated with a 17% reduction in NARDS risk (95% CI, 1.08-1.15).

Conclusion

Low serum albumin levels in patients with neonatal pneumonia are closely associated with NARDS, indicating a significant dose-response relationship between the two.

Multidrug-Resistant Urinary Tract Infections in Pregnant Patients and Their Association with Adverse Pregnancy Outcomes-A Retrospective Study

Background/Objectives: Multidrug-resistant urinary tract infections (MDR UTIs) constitute an important public health problem, especially in pregnant patients. The aim of this retrospective study was to characterize the bacterial spectrum and the profile of microbial resistance in cases of UTIs occurring in pregnant women, as well as their impact on obstetrical and neonatal outcomes. Methods: A total of 371 pregnant patients with UTIs were included in the analysis and were segregated into the following groups based on the type of bacterial resistance to antibiotics: MDR UTIs (70 patients, group 1), UTIs resistant to one class of antibiotics (108 patients, group 2), UTIs resistant to two classes of antibiotics (102 patients, group 3), and sensitive UTIs (91 patients, group 4). We used descriptive statistics for characterizing and comparing the microbial spectrum and the clinical characteristics of the patients. A multinomial logistic regression model for evaluating the relationship between the type of urinary tract infection and adverse obstetric or neonatal outcomes was employed. Results: In the case of MDR UTIs, the bacterial spectrum mainly included Escherichia coli, Enterococcus faecalis, and Klebsiella species. We found almost universal resistance to ampicillin. Our data confirmed an increased risk of preterm birth, premature rupture of membranes, neonatal respiratory distress syndrome, and neonatal intensive care unit admission for patients with MDR infections. Conclusions: The increased incidence of pathogens resistant to commonly used antibiotic classes in pregnancy suggests the need for the development of local and national protocols that adapt therapeutic and prophylactic regimens to clinical realities.

Left atrial strain assessment unveils left ventricular diastolic dysfunction in neonates with transient tachypnea of the newborn: A prospective observational study

INTRODUCTION

An inadequate clearance of lung fluid plays a key role in the pathogenesis of transient tachypnea of the newborn (TTN).

OBJECTIVES

To evaluate if left ventricular diastolic dysfunction contributes to reduced clearance of lung fluid in TTN.

MATERIALS AND METHODS

This was a prospective, observational study. Echocardiography and lung ultrasound were performed at 2, 24 and 48 h of life (HoL) to assess biventricular function and calculate lung ultrasound score (LUS). Left atrial strain reservoir (LASr) provided surrogate measurement of left ventricular diastolic function.

RESULTS

Twenty-seven neonates with TTN were compared with 27 controls with no difference in gestation (36.1 ± 2 vs. 36.9 ± 2 weeks) or birthweight (2508 ± 667 vs. 2718 ± 590 g). Biventricular systolic function was normal in both groups. LASr was significantly lower in cases at 2 (21.0 ± 2.7 vs. 38.1 ± 4.4; p < 0.01), 24 (25.2 ± 4.5 vs. 40.6 ± 4.0; p < 0.01) and 48 HoL (36.5 ± 5.8 and 41.6 ± 5.2; p < 0.01), resulting in a significant group by time interaction (p < 0.001), after adjusting for LUS and gestational diabetes. A logistic regression model including LUS, birth weight and gestational diabetes as covariates, showed that LASr at 2 HoL was a predictor of respiratory support at 24 HoL, with an adjusted odds ratio of 0.60 (CI 0.36-0.99).

CONCLUSIONS

LASr was reduced in neonates with TTN, suggesting diastolic dysfunction, that may contribute to the delay in lung fluid clearance.

The association of gene polymorphisms of adenosine and dopamine receptors with the response to caffeine citrate treatment in infants with apnea of prematurity: a prospective nested case-control study

BACKGROUND

To investigate the potential influence of adenosine and dopamine receptor genes polymorphisms in combination with clinical factors on the response of preterm infants to caffeine citrate treatment in apnea of prematurity (AOP).

METHODS

A prospective nested case-control study enrolled 221 preterm infants with gestational age < 34 weeks. These infants were divided into the response (n = 160) and the non-response groups (n = 61). 22 single-nucleotide polymorphisms in adenosine and dopamine receptor genes were genotyped. The basic characteristics and clinical outcomes of the two groups were compared. Univariate logistic regression analysis was performed to evaluate the differences in genotype distribution between the groups. Multivariable logistic regression analysis was performed to identify independent risk and protective factors and develop a nomogram to predict caffeine citrate response in preterm infants.

RESULTS

Preterm infants in the non-response group had lower gestational age, lower birth weight, longer periods of oxygen supplementation and caffeine citrate use, and higher incidence of patent ductus arteriosus (PDA), bronchopulmonary dysplasia (BPD), neonatal respiratory distress syndrome (NRDS), retinopathy of prematurity (ROP), and brain injury (P < 0.05 for all). The ADORA1 rs10920573, ADORA2B rs2015353, ADORA3 rs10776728, DRD3 rs7625282, and DRD3 rs6280 gene polymorphisms were associated with caffeine citrate response in preterm infants (PFDR < 0.05 for all). The ADORA1 rs10920573 CC (aOR, 3.51; 95% CI, 1.34-9.25) and DRD3 rs6280 CT genotypes (aOR, 3.19; 95% CI, 1.53-6.65) were independent risk factors for non-response, whereas greater gestational age (aOR, 0.631; 95% CI, 0.53-0.75) was an independent protective factor for response. The concordance index of the nomogram was 0.764 (95% CI, 0.687-0.842), and the calibration and decision curve analysis indicated the nomogram had excellent predict performance.

CONCLUSIONS

Adenosine receptor gene and dopamine receptor gene polymorphisms influence caffeine citrate treatment response in AOP. By combining genetic and clinical variables, it is possible to predict the response to caffeine citrate treatment in preterm infants.

Effect of different CPAP levels on ultrasound-assessed lung aeration and gas exchange in neonates

BACKGROUND

Respiratory distress syndrome (RDS) and transient tachypnoea (TTN) are the two commonest neonatal respiratory disorders. The optimal continuous positive airway pressure (CPAP) to treat them is unknown. We aim to clarify the effect of different CPAP levels on lung aeration and gas exchange in patients with RDS and TTN.

METHODS

Prospective, observational, pragmatic, physiological cohort study. CPAP was sequentially increased from 4 to 6 and 8 cmH2O and backwards, with interposed wash-out periods. Lung aeration was assessed with a validated neonatal lung ultrasound score. Gas exchange was non-invasively evaluated with transcutaneous monitoring. Ultrasound score and PtcO2/FiO2 ratio were the co-primary outcomes. PtcCO2 and other oxygenation metrics were the secondary outcomes.

RESULTS

30 neonates with RDS and 30 with TTN were studied. Each CPAP increment significantly (overall always p < 0.001) improved both lung aeration and oxygenation, but the increase from 6 to 8 cmH2O achieved a small absolute benefit. In RDS patients, the absolute improvements were small and the diagnosis of TTN was significantly associated with greater improvement of lung aeration (β= -1.4 (95%CI: -2.4; -0.3), p = 0.01) and oxygenation (β = 39.6 (95%CI: 4.1; 75.1), p = 0.029). Aeration improved in 16 (53.3%) and 27 (90%) patients in the RDS and TTN groups, respectively (p = 0.034). Lung aeration showed significant hysteresis in TTN patients. Secondary outcomes gave similar results.

CONCLUSIONS

Increasing CPAP from 4 to 8 cmH2O improves ultrasound-assessed lung aeration and oxygenation in RDS and TTN. The absolute improvements are small when CPAP is beyond 6 cmH2O or for RDS patients.

Global and Regional Heterogeneity of Lung Aeration in Neonates with Different Respiratory Disorders: A Physiologic Observational Study

BACKGROUND

Aeration heterogeneity affects lung stress and influences outcomes in adults with acute respiratory distress syndrome (ARDS). The authors hypothesize that aeration heterogeneity may differ between neonatal respiratory disorders and is associated with oxygenation, so its evaluation may be relevant in managing respiratory support.

METHODS

This was an observational prospective study. Neonates with respiratory distress syndrome, transient tachypnea of the neonate, evolving bronchopulmonary dysplasia, and neonatal ARDS were enrolled. Quantitative lung ultrasound and transcutaneous blood gas measurements were simultaneously performed. Global aeration heterogeneity (with its intra- and interpatient components) and regional aeration heterogeneity were primary outcomes; oxygenation metrics were the secondary outcomes.

RESULTS

A total of 230 (50 respiratory distress syndrome, transient tachypnea of the neonate or evolving bronchopulmonary dysplasia, and 80 neonatal ARDS) patients were studied. Intrapatient aeration heterogeneity was higher in transient tachypnea of the neonate (mean ± SD, 61 ± 33%) and evolving bronchopulmonary dysplasia (mean ± SD, 57 ± 20%; P < 0.001), with distinctive aeration distributions. Interpatient aeration heterogeneity was high for all disorders (Gini-Simpson index, between 0.6 and 0.72) except respiratory distress syndrome (Gini-Simpson index, 0.5), whose heterogeneity was significantly lower than all others (P < 0.001). Neonatal ARDS and evolving bronchopulmonary dysplasia had the most diffuse injury and worst gas exchange metrics. Regional aeration heterogeneity was mostly localized in the upper anterior and posterior zones. Aeration heterogeneity and total lung aeration had an exponential relationship (P < 0.001; adj-R2 = 0.62). Aeration heterogeneity is associated with greater total lung aeration (i.e., higher heterogeneity means a relatively higher proportion of normally aerated lung zones, thus greater aeration; P < 0.001; adj-R2 = 0.83) and better oxygenation metrics upon multivariable analyses.

CONCLUSIONS

Global aeration heterogeneity and regional aeration heterogeneity differ among neonatal respiratory disorders. Transient tachypnea of the neonate and evolving bronchopulmonary dysplasia have the highest intrapatient aeration heterogeneity. Transient tachypnea of the neonate, evolving bronchopulmonary dysplasia, and neonatal ARDS have the highest interpatient aeration heterogeneity, but the latter two have the most diffuse injury and worst gas exchange. Higher aeration heterogeneity is associated with better total lung aeration and oxygenation.

EDITOR’S PERSPECTIVE

Endotracheal Surfactant and Budesonide Combination Therapy in Neonatal Acute Respiratory Distress Syndrome due to Late-Onset Sepsis

BACKGROUND

Neonatal acute respiratory distress syndrome (NARDS) is an important cause of hypoxemic respiratory failure. This study aimed to investigate the short-term effects of endotracheal surfactant and budesonide combination therapy on NARDS secondary to late-onset neonatal sepsis (LONS).

METHODS

This was a retrospective, cross-sectional, and observational study. Newborns with NARDS due to LONS who received endotracheal surfactant and budesonide combination therapy between August 2022 and September 2023 were included in this study. Oxygenation status before endotracheal surfactant and budesonide treatment were compared with the values obtained two hours after treatment.

RESULTS

Among 20 neonates, 10 (50%) were diagnosed with severe NARDS, and 10 (50%) were diagnosed with moderate NARDS. The mean corrected gestational age was 33.3±2.9 w when endotracheal surfactant and budesonide were administered to the neonates. The need for the fraction of inspired oxygen (0.75 [0.57-1.00]% vs. 0.55 [0.44-0.80]%; mean difference [MD]: 17.50%, 95% confidence interval [CI]: 14.99 to 22.50) and oxygen saturation index (OSI; 8.03 [4.98-13.94] vs. 4.71 [4.11-8.93]; MD: 2.23, 95% CI: 1.22 to 3.24) decreased (P=0.001 and P<0.001, respectively) after endotracheal surfactant and budesonide treatment. However, preductal oxygen saturation (SpO2 ; 93 [91-94]% vs. 95 [94-96]%; MD: -3.50%, 95% CI: -5.00 to -2.00) increased significantly after endotracheal surfactant and budesonide treatment when compared to pre-treatment values (P<0.001).

CONCLUSION

The reduction in oxygen demand and OSI, along with an increase in SpO2 after treatment compared to pre-treatment values, suggests that endotracheal surfactant and budesonide combination therapy could be an effective option to improve oxygenation in NARDS secondary to LONS.

Implementation of a standardized lung ultrasound protocol for respiratory distress in a neonatal intensive care unit: an observational study

OBJECTIVE

To assess the feasibility of implementing a simple point-of-care lung ultrasound (LU) evaluation and reporting protocol in a neonatal intensive care unit (NICU) and its effect on patient management.

STUDY DESIGN

Retrospective observational study of LU examinations performed in a level III NICU. Each examination was performed according to a standardized protocol. An independent radiologist-assessed chest X-ray (CXR) was used to compare the LU diagnosis. The impact on patient management was also evaluated.

RESULT

A total of 206 LU studies in 158 neonates were reviewed. There was significant agreement between LU and CXR diagnoses (84.95%, 95% CI 80.07-89.83%). LU affected patient management in 87.8% of the cases (95% CI 83.33-92.28%).

CONCLUSION

Implementation of a simplified, sign-based protocol for LU in the NICU is feasible. LU is not inferior to CXR studies and supports patient management as an imaging modality.

Setting the Standards: Neonatal Lung Ultrasound in Clinical Practice

The use of lung ultrasonography in neonates is increasing at a very fast rate. Evidence-based guidelines on the use of lung ultrasound (LU) in neonates and children have been published and well received across the world. However, there remains a lack of standardized curriculum for lung ultrasound training and standards for its application at the bedside. This article focuses on providing a standardized approach to the application of lung ultrasonography in neonates for the common neonatal conditions and how it can be integrated into bedside clinical decision-making.

The Complex Interrelationship Between Mechanical Ventilation and Therapeutic Hypothermia in Asphyxiated Newborns. A Review

Asphyxiated newborns often require both therapeutic hypothermia (TH) and mechanical ventilation (MV) and the complex interrelationship between these two therapeutic interventions is very interesting, which could not only have several synergistic positive effects but also some risks. Perinatal asphyxia is the leading cause of neonatal hypoxic-ischemic encephalopathy (HIE) and TH is the only approved neuroprotective treatment to limit brain injury, improving the mortality rate and long-term neurological outcomes. HIE is often associated with severe respiratory failure, requiring MV, due to different lung diseases or an impairment of the respiratory drive. The respiratory support management of asphyxiated newborns is very difficult, considering (a) various pathophysiological contexts, (b) the strong impact of TH on gas metabolism and (c) on lung mechanics, and (d) complex TH-MV interactions. Therefore, it is necessary to evaluate the real indications of MV for cooled newborns, considering the risks of respiratory overassistance (hypocapnia/hyperoxia), as well as the adequate monitoring systems. To date, specific randomized studies about the optimal respiratory approach for cooled newborns are lacking, and strategies for MV support vary from center to center. Moreover, there are many open questions about the real effects of cooling on lung mechanics and on surfactant, most appropriate method of blood gas analysis, and clear indications for pharmacological sedation. The aim of this review is to propose a reasoned approach for respiratory management of cooled newborns, considering the pathophysiological context, multiple actions of TH, and consequences of TH-MV matched action and its related risks.

Thoracic fluid content (TFC) using electrical cardiometry versus lung ultrasound in the diagnosis of transient tachypnea of newborn

This study aimed to evaluate TFC by EC versus lung ultrasound (LUS) findings for diagnosing and follow-up of TTN in late preterm and term neonates. This prospective observational study was conducted on 80 neonates with gestational age ≥ 34 weeks. TTN group included 40 neonates diagnosed with TTN, and no lung disease (NLD) group included 40 neonates without respiratory distress. LUS and EC were performed within the first 24 h of life and repeated after 72 h. There was a statistically significant increase in TFC in TTN group on D1 [48.48 ± 4.86 (1 KOhm-1)] compared to NLD group [32.95 ± 4.59 (1 KOhm-1)], and then significant decrease in TFC in D3 [34.90 ± 4.42 (1 KOhm-1)] compared to D1 in the TTN group. There was a significant positive correlation between both TFC and LUS with Downes' score, TTN score, and duration of oxygen therapy in the TTN group.   Conclusion: Both LUS and TFC by EC provide good bedside tools that could help to diagnose and monitor TTN. TFC showed a good correlation with LUS score and degree of respiratory distress. What is Known: • Transient tachypnea of the newborn (TTN) is the most common cause of respiratory distress in newborns. • TTN is a diagnosis of exclusion, there are no specific clinical parameters or biomarker has been identified for TTN. What is New: • Thoracic fluid content (TFC) by electrical cardiometry is a new parameter to evaluate lung fluid volume and could help to diagnose and monitor TTN and correlates with lung ultrasound score.

Risk Factors of Neonatal Acute Respiratory Distress Syndrome Based on the Montreux Definition in Neonates with Sepsis: A Retrospective Case-Control Study

OBJECTIVE

The aim of the study is to analyze the risk factors for neonatal acute respiratory distress syndrome (NARDS) development based on the Montreux definition among near- and full-term neonates with sepsis and received meropenem.

STUDY DESIGN

This was a single-center, case-control, retrospective trial from January 2019 to June 2020. Newborns of gestational ages (GAs) ≥35 weeks, diagnosed with sepsis and received meropenem were included. Patients who developed NARDS subsequently were defined as the study group (NARDS group), while the others without NARDS were enrolled in the control group (non-NARDS group).

RESULTS

Out of 213 eligible neonates, NARDS occurred in 52 (24.4%) cases. In univariate analysis, infants with NARDS had a lower GA and birth weight, but a higher rate of premature birth (p <0.05). The median onset times of sepsis were earlier among neonates with NARDS compared with those without NARDS (1 [1,1] vs. 6 [1,15] days, p <0.001). Neonates with NARDS were more likely to suffer from early-onset sepsis (EOS), persistent pulmonary hypertension of newborns, pulmonary hemorrhage, septic shock, and patent ductus arteriosus (p <0.05). During labor, women whose neonates experienced NARDS were more likely to have a cesarean delivery (67.3 vs. 46.6%, p = 0.009) and likely to receive at least one dose of corticosteroids (21.2 vs. 5.0%, p = 0.001). In multivariable analyses, factors remaining independently associated with NARDS were premature birth, cesarean delivery, EOS, and septic shock. Compared with conventional inflammatory markers for NARDS, procalcitonin (PCT) was correlated with septic neonates who developed NARDS (p = 0.012) but had a low diagnostic value (area under the curve [AUC] = 0.609). C-reactive protein, white blood cells, and PLT did not correlate with morbidity of NARDS (AUC <0.05 and p >0.05).

CONCLUSION

Premature birth, cesarean delivery, EOS, and septic shock were independently associated with NARDS among near- and full-term septic neonates. PCT showed limited predictive value for NARDS.

KEY POINTS

· NARDS is serious and sepsis is proved as a cause for it.. · But rare study suggests the risk factors of NARDS based on the Montreux definition.. · This study may first found the independent risk factors associated with NARDS in septic neonates..

Assessment of Autoregulation of the Cerebral Circulation during Acute Lung Injury in a Neonatal Porcine Model

In neonates with acute lung injury (ALI), targeting lower oxygenation saturations is suggested to limit oxygen toxicity while maintaining vital organ function. Although thresholds for cerebral autoregulation are studied for the management of premature infants, the impact of hypoxia on hemodynamics, tissue oxygen consumption and extraction is not well understood in term infants with ALI. We examined hemodynamics, cerebral autoregulation and fractional oxygen extraction, as measured by near-infrared spectroscopy (NIRS) and blood gases, in a neonatal porcine oleic acid injury model of moderate ALI. We hypothesized that in ALI animals, cerebral oxygen extraction would be increased to a greater degree than kidney or gut oxygen extraction as indicative of the brain's adaptive efforts to increase cerebral oxygen extraction at the expense of splanchnic end organs. Fifteen anesthetized, ventilated 5-day-old neonatal piglets were divided into moderate lung injury by treatment with oleic acid or control (sham injection). The degree of lung injury was quantified at baseline and after establishment of ALI by blood gases, ventilation parameters and calculated oxygenation deficit, hemodynamic indices by echocardiography and lung injury score by ultrasound. PaCO2 was maintained constant during ventilation. Cerebral, renal and gut oxygenation was determined by NIRS during stepwise decreases in inspired oxygen from 50% to 21%, correlated with PaO2 and PvO2; changes in fractional oxygen extraction (ΔFOE) were calculated from NIRS and from regional blood gas samples. The proportion of cerebral autoregulation impairment attributable to blood pressure, and to hypoxemia, was calculated from autoregulation nomograms. ALI manifested as hypoxemia with increasing intrapulmonary shunt fraction, decreased lung compliance and increased resistance, and marked increase in lung ultrasound score. Brain, gut and renal NIRS, obtained from probes placed over the anterior skull, central abdomen and flank, respectively, correlated with concurrent SVC (brain) or IVC (gut, renal) PvO2 and SvO2. Cerebral autoregulation was impaired after ALI as a function of blood pressure at all FiO2 steps, but predominantly by hypoxemia at FiO2 < 40%. Cerebral ΔFOE was higher in ALI animals at all FiO2 steps. We conclude that in an animal model of neonatal ALI, cerebrovascular blood flow regulation is primarily dependent on oxygenation. There is not a defined oxygenation threshold below which cerebral autoregulation is impaired in ALI. Cerebral oxygen extraction is enhanced in ALI, reflecting compensation for exhausted cerebral autoregulation due to the degree of hypoxemia and/or hypotension, thereby protecting against tissue hypoxia.

Lung-Gut Microbiota and Tryptophan Metabolites Changes in Neonatal Acute Respiratory Distress Syndrome

Purpose

Neonatal Acute Respiratory Distress Syndrome (NARDS) is a severe respiratory crisis threatening neonatal life. We aim to identify changes in the lung-gut microbiota and lung-plasma tryptophan metabolites in NARDS neonates to provide a differentiated tool and aid in finding potential therapeutic targets.

Patients and Methods

Lower respiratory secretions, faeces and plasma were collected from 50 neonates including 25 NARDS patients (10 patients with mild NARDS in the NARDS_M group and 15 patients with moderate-to-severe NARDS in the NARDS_S group) and 25 control patients screened based on gestational age, postnatal age and birth weight. Lower airway secretions and feces underwent 16S rRNA gene sequencing to understand the microbial communities in the lung and gut, while lower airway secretions and plasma underwent LC-MS analysis to understand tryptophan metabolites in the lung and blood. Correlation analyses were performed by comparing differences in microbiota and tryptophan metabolites between NARDS and control, NARDS_S and NARDS_M groups.

Results

Significant changes in lung and gut microbiota as well as lung and plasma tryptophan metabolites were observed in NARDS neonates compared to controls. Proteobacteria and Bacteroidota were increased in the lungs of NARDS neonates, whereas Firmicutes, Streptococcus, and Rothia were reduced. Lactobacillus in the lungs decreased in NARDS_S neonates. Indole-3-carboxaldehyde decreased in the lungs of NARDS neonates, whereas levels of 3-hydroxykynurenine, indoleacetic acid, indolelactic acid, 3-indole propionic acid, indoxyl sulfate, kynurenine, and tryptophan decreased in the lungs of the NARDS_S neonates. Altered microbiota was significantly related to tryptophan metabolites, with changes in lung microbiota and tryptophan metabolites having better differentiated ability for NARDS diagnosis and grading compared to gut and plasma.

Conclusion

Significant changes occurred in the lung-gut microbiota and lung-plasma tryptophan metabolites of NARDS neonates. Alterations in lung microbiota and tryptophan metabolites were better discriminatory for the diagnosis and grading of NARDS.

Quantitative Lung Ultrasonography to Guide Surfactant Therapy in Neonates Born Late Preterm and Later

Importance

Surfactant administration may be needed in late preterm through full-term neonates, but the pathophysiology of their respiratory failure can be different from that of early preterm neonates. The lung ultrasonography score (LUS) is accurate to guide surfactant replacement in early preterm neonates, but to our knowledge, it has not yet been studied in the late preterm through full-term neonatal population.

Objective

To assess whether LUS is equally accurate to predict surfactant need in late preterm through full-term neonates as in early preterm neonates.

Design, Setting, and Participants

This prospective, international, multicenter diagnostic study was performed between December 2022 and November 2023 in tertiary academic neonatal intensive care units in France, Italy, Spain, and the US. Late preterm through full-term neonates (≥34 weeks' gestation) with respiratory failure early after birth were enrolled.

Exposure

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

Main Outcomes and Measures

The main outcomes were the area under the curve (AUC) in receiver operating characteristic analysis and derived accuracy variables, considering LUS as a replacement for other tests (ie, highest global accuracy) and as a triage test (ie, highest sensitivity). Sample size was calculated to assess noninferiority of LUS to predict surfactant need in the study population compared with neonates born more prematurely. 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) were assessed.

Results

A total of 157 neonates (96 [61.1%] male) were enrolled and underwent lung ultrasonography at a median of 3 hours (IQR, 2-7 hours) of life; 32 (20.4%) needed surfactant administration (pretest probability, 20%). The AUC was 0.87 (95% CI, 0.81-0.92). 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; 95% CI, 0.81-0.97; n = 111) and early term and later (AUC, 0.84; 95% CI, 0.73-0.96; n = 46). After adjusting for gestational age, LUS was significantly correlated with SpO2:FiO2 (adjusted β, -10.4; 95% CI, -14.0 to -6.7; P < .001) and OSI (adjusted β, 0.2; 95% CI, 0.1-0.3; P < .001).

Conclusions and Relevance

In this diagnostic study of late preterm through full-term neonates with respiratory failure early after birth, LUS accuracy to predict surfactant need was not inferior to that observed in earlier preterm neonates. An LUS higher than 8 was associated with highest global accuracy (replacement test), suggesting that it can be used to guide surfactant administration. An LUS value of 4 or lower was associated with the highest sensitivity (triage test), suggesting it is unlikely for this population to need surfactant.

The current clinical landscape of neonatal respiratory failure in Jiangsu Province of China: patient demographics, NICU treatment interventions, and patient outcomes

INTRODUCTION

Neonatal respiratory failure (NRF) is a serious condition that often has high mortality and morbidity, effective interventions can be delivered in the future by identifying the risk factors associated with morbidity and mortality. However, recent advances in respiratory support have improved neonatal intensive care units (NICUs) care in China. We aimed to provide an updated review of the clinical profile and outcomes of NRF in the Jiangsu province.

METHODS

Infants treated for NRF in the NICUs of 28 hospitals between March 2019 and March 2022 were retrospectively reviewed. Data collected included baseline perinatal and neonatal parameters, NICU admission- and treatment-related data, and patient outcomes in terms of mortality, major morbidity, and survival without major morbidities.

RESULTS

A total of 5548 infants with NRF were included in the study. The most common primary respiratory disorder was respiratory distress syndrome (78.5%). NRF was managed with non-invasive and invasive respiratory support in 59.8% and 14.5% of patients, respectively. The application rate of surfactant therapy was 38.5%, while that of neonatal extracorporeal membrane oxygenation therapy was 0.2%. Mortality and major morbidity rates of 8.5% and 23.2% were observed, respectively. Congenital anomalies, hypoxic-ischemic encephalopathy, invasive respiratory support only and inhaled nitric oxide therapy were found to be significantly associated with the risk of death. Among surviving infants born at < 32 weeks of gestation or with a birth weight < 1500 g, caffeine therapy and repeat mechanical ventilation were demonstrated to significantly associate with increased major morbidity risk.

CONCLUSION

Our study demonstrates the current clinical landscape of infants with NRF treated in the NICU, and, by proxy, highlights the ongoing advancements in the field of perinatal and neonatal intensive care in China.

Neonatal point-of-care lung ultrasound: what should be known and done out of the NICU?

Lung ultrasound is rapidly becoming a useful tool in the care of neonates: its ease of use, reproducibility, low cost, and negligible side effects make it a very suitable tool for the respiratory care of all neonates. This technique has been extensively studied by different approaches in neonatal intensive care unit (NICU), both for diagnostic and prognostic aims and to guide respiratory treatments. However, many neonates are being born in level I/II hospitals without NICU facilities so all pediatricians, not just neonatal intensivists, should be aware of its potential. This is made possible by the increasing access to ultrasound machines in a modern hospital setting. In this review, we describe the ultrasonographic characteristics of the normal neonatal lung. We also discuss the ultrasound features of main neonatal respiratory diseases: transient tachypnea of the neonate (TTN), respiratory distress syndrome (RDS), meconium aspiration syndrome (MAS), pneumothorax (PNX), pleural effusion (PE), or pneumonia. Finally, we mention two functional approaches to lung ultrasound: 1. The use of lung ultrasound in level I delivery centers as a mean to assess the severity of neonatal respiratory distress and request a transport to a higher degree structure in a timely fashion. 2. The prognostic accuracy of lung ultrasound for early and targeted surfactant replacement.

CONCLUSION

 LU is still a useful tool in level I/II neonatal units, both for diagnostic and functional issues.

WHAT IS KNOWN

• Neonatal lung ultrasound has been recently introduced in the usual care in many Neonatal Intensive Care Units.

WHAT IS NEW

• It also has many advantages in level I/II neonatal units, both for neonatologist or even pediatricians that treat neonates in those sites.

Critical care of severe bronchiolitis during shortage of ICU resources

Large seasonal outbreaks of bronchiolitis put pressure on healthcare systems and particularly on intensive care units (ICUs). ICU admission is necessary to provide respiratory support to the severest cases, otherwise bronchiolitis can result in substantial mortality. ICU resources are often insufficient and there is scant evidence to guide the ICU clinical management. Most available studies do not cover the ICU-admitted cases and do not consider the associated public health issues. We review this topic through a multidisciplinary approach from both the clinical and public health perspectives, with an analysis based on pathophysiology and cost-effectiveness. We suggest ways to optimise respiratory care, minimise ICU stay, "protect" ICU beds and, whenever possible, make them available for other critically ill children. We also provide guidance on how to prepare ICUs to work under stressful conditions due to outbreaks and to reduce the risk of nosocomial cross-contamination, particularly in ICUs caring for high-risk children.

Funding

None.

The value of lung ultrasound score in neonatal respiratory distress syndrome: a prospective diagnostic cohort study

Rationale

The accurate diagnosis of critically ill patients with respiratory failure can be achieved through lung ultrasound (LUS) score. Considering its characteristics, it is speculated that this technique might also be useful for patients with neonatal respiratory distress syndrome (NRDS). Thus, there is a need for precise imaging tools to monitor such patients.

Objectives

This double-blind randomized cohort study aims to investigate the impact of LUS and related scores on the severity of NRDS patients.

Methods

This study was conducted as a prospective double-blind randomized study. Bivariate correlation analysis was conducted to investigate the relationship between LUS score and Oxygenation Index (OI), Respiratory Index (RI), and Sequential Organ Failure Assessment (SOFA) score. Spearman's correlation coefficient was used to generate correlation heat maps, elucidating the associations between LUS and respective parameters in different cohorts. Receiver Operating Characteristic (ROC) curves were employed to calculate the predictive values, sensitivity, and specificity of different scores in determining the severity of NRDS.

Results

This study ultimately included 134 patients admitted to the intensive care unit (ICU) between December 2020 and June 2022. Among these patients, 72 were included in the NRDS cohort, while 62 were included in the Non-NRDS (N-NRDS) cohort. There were significant differences in the mean LUS scores between NRDS and N-NRDS patients (p < 0.01). The LUS score was significantly negatively correlated with the OI (p < 0.01), while it was significantly positively correlated with the RI and SOFA scores (p < 0.01). The correlation heatmap revealed the highest positive correlation coefficient between LUS and RI (0.82), while the highest negative correlation coefficient was observed between LUS and OI (-0.8). ROC curves for different scores demonstrated that LUS score had the highest area under the curve (0.91, 95% CI: 0.84-0.98) in predicting the severity of patients' conditions. The combination of LUS and other scores can more accurately predict the severity of NRDS patients, with the highest AUC value of 0.93, significantly higher than using a single indicator alone (p < 0.01).

Conclusion

Our double-blind randomized cohort study demonstrates that LUS, RI, OI, and SOFA scores can effectively monitor the lung ventilation and function in NRDS. Moreover, these parameters and their combination have significant predictive value in evaluating the severity and prognosis of NRDS patients. Therefore, these results provide crucial insights for future research endeavors.

Assessing the diagnostic accuracy of lung ultrasound in determining invasive ventilation needs in neonates on non-invasive ventilation: An observational study from a tertiary NICU in India

Effective management of neonatal respiratory distress requires timely recognition of when to transition from non-invasive to invasive ventilation. Although the lung ultrasound score (LUS) is useful in evaluating disease severity and predicting the need for surfactants, its efficacy in identifying neonates requiring invasive ventilation has only been explored in a few studies. This study aims to assess the accuracy of LUS in determining the need for invasive ventilation in neonates on non-invasive ventilation (NIV) support. From July 2021 to June 2023, we conducted a prospective study on 192 consecutively admitted neonates with respiratory distress needing NIV within 24 h of birth at our NICU in Hyderabad, India. The primary objective was the diagnostic accuracy of LUS in determining the need for invasive ventilation within 72 h of initiating NIV. We calculated LUS using the scoring system of Brat et al. (JAMA Pediatr 169:e151797, [10]). Treating physicians' assessments of the need for invasive ventilation served as the reference standard for evaluating LUS effectiveness. Out of 192 studied neonates, 31 (16.1%) required invasive ventilation. The median LUS was 5 (IQR: 2-8) for those on NIV and 10 (IQR: 7-12) for those needing invasive ventilation. The LUS had a strong discriminative ability for invasive ventilation with an AUC (area under the curve) of 0.825 (CI: 0.75-0.86, p = 0.0001). An LUS > 7 had 77.4% sensitivity (95% CI: 58.9-90.8%), 75.1% specificity (95% CI: 67.8-81.7%), 37.5% positive predictive value (PPV) (95% CI: 30.15-45.5%), 94.5% negative predictive value (NPV) (95% CI: 89.9-97.1%), 3.1 positive likelihood ratio (PLR) (95% CI: 2.2-4.3), 0.3 negative likelihood ratio (NLR) (95% CI: 0.15-0.58), and 75.5% overall accuracy (95% CI: 68.8-81.4%) for identifying invasive ventilation needs. In contrast, SAS, with a cutoff point greater than 5, has an AUC of 0.67. It demonstrates 62.5% sensitivity, 61.9% specificity, 24.7% PPV, 89.2% NPV, and an overall diagnostic accuracy of 61.9%. The DeLong test confirms the significance of this difference (AUC difference: 0.142, p = 0.04), underscoring LUS's greater reliability for NIV failure.  Conclusion: This study underscores the diagnostic accuracy of the LUS cutoff of > 7 in determining invasive ventilation needs during the initial 72 h of NIV. Importantly, while lower LUS values typically rule out the need for ventilation, higher values, though indicative, are not definitive. What is known? • The effectiveness of lung ultrasound in evaluating disease severity and the need for surfactants in neonates with respiratory distress is well established. However, traditional indicators for transitioning from non-invasive to invasive ventilation, like respiratory distress and oxygen levels, have limitations, underscoring the need for reliable, non-invasive assessment tools. What is new? • This study reveals that a LUS over 7 accurately discriminates between neonates requiring invasive ventilation and those who do not. Furthermore, the lung ultrasound score outperformed the Silverman Andersen score for NIV failure in our population.

Inspiratory-expiratory variation of pleural line thickness in neonates with and without acute respiratory failure

BACKGROUND

There are relatively few data about the ultrasound evaluation of pleural line in patients with respiratory failure. We measured the pleural line thickness during different phases of the respiratory cycle in neonates with and without acute respiratory failure as we hypothesized that this can significantly change.

METHODS

Prospective, observational, cohort study performed in an academic tertiary neonatal intensive care unit recruiting neonates with transient tachypnoea of the neonate (TTN), respiratory distress syndrome (RDS) or neonatal acute respiratory distress syndrome (NARDS). Neonates with no lung disease (NLD) were also recruited as controls. Pleural line thickness was measured with high-frequency ultrasound at end-inspiration and end-expiration by two different raters.

RESULTS

Pleural line thickness was slightly but significantly higher at end-expiration (0.53 [0.43-0.63] mm) than at end-inspiration (0.5 [0.4-0.6] mm; p = 0.001) for the whole population. End-inspiratory (NLD: 0.45 [0.38-0.53], TTN: 0.49 [0.43-0.59], RDS: 0.53 [0.41-0.62], NARDS: 0.6 [0.5-0.7] mm) and -expiratory (NLD: 0.47 [0.42-0.56], TTN: 0.48 [0.43-0.61], RDS: 0.53 [0.46-0.65], NARDS: 0.61 [0.54-0.72] mm) thickness were significantly different (overall p = 0.021 for both), between the groups although the absolute differences were small. The inter-rater agreement was optimal (ICC: 0.95 (0.94-0.96)). Coefficient of variation was 2.8% and 2.5% for end-inspiratory and end-expiratory measurements, respectively. These findings provide normative data of pleural line thickness for the most common forms of neonatal acute respiratory failure and are useful to design future studies to investigate possible clinical applications.

Construction and evaluation of neonatal respiratory failure risk prediction model for neonatal respiratory distress syndrome

BACKGROUND

Neonatal respiratory distress syndrome (NRDS) is a common respiratory disease in preterm infants, often accompanied by respiratory failure. The aim of this study was to establish and validate a nomogram model for predicting the probability of respiratory failure in NRDS patients.

METHODS

Patients diagnosed with NRDS were extracted from the MIMIC-iv database. The patients were randomly assigned to a training and a validation cohort. Univariate and stepwise Cox regression analyses were used to determine the prognostic factors of NRDS. A nomogram containing these factors was established to predict the incidence of respiratory failure in NRDS patients. The area under the receiver operating characteristic curve (AUC), receiver operating characteristic curve (ROC), calibration curves and decision curve analysis were used to determine the effectiveness of this model.

RESULTS

The study included 2,705 patients with NRDS. Univariate and multivariate stepwise Cox regression analysis showed that the independent risk factors for respiratory failure in NRDS patients were gestational age, pH, partial pressure of oxygen (PO2), partial pressure of carbon dioxide (PCO2), hemoglobin, blood culture, infection, neonatal intracranial hemorrhage, Pulmonary surfactant (PS), parenteral nutrition and respiratory support. Then, the nomogram was constructed and verified.

CONCLUSIONS

This study identified the independent risk factors of respiratory failure in NRDS patients and used them to construct and evaluate respiratory failure risk prediction model for NRDS. The present findings provide clinicians with the judgment of patients with respiratory failure in NRDS and help clinicians to identify and intervene in the early stage.

Integration of multiomics analysis to reveal the major pathways of vitamin A deficiency aggravates acute respiratory distress syndrome in neonatal rats

Acute respiratory distress syndrome (ARDS) is a major disease that threatens the life and health of neonates. Vitamin A (VA) can participate in early fetal lung development and affect lung immune function. Researches revealed that the serum VA level in premature infants with ARDS was lower than that in premature infants without ARDS of the same gestational age, and premature infants with VA deficiency (VAD) were more likely to develop ARDS. Moreover, the VA levels can be used as a predictor of the development and severity of neonatal ARDS. However, the critical question here is; Does ARDS develop due to VAD in these systemic diseases? Or does ARDS develop because these diseases cause VAD? We hypothesize that VAD may aggravate neonatal ARDS by affecting immunity, metabolism, barriers and other pathways. In this article, we used multiomics analysis to find that VAD may aggravate ARDS mainly through the Fc epsilon RI signaling pathway, the HIF-1 signaling pathway, glutathione metabolism, and valine, leucine and isoleucine degradation signaling pathways, which may provide the molecular pathogenic mechanism behind the pathology of VAD-aggravated ARDS and can also provide potential molecular targets for subsequent research on ARDS.

Neonatal surfactant therapy beyond respiratory distress syndrome

Whilst exogenous surfactant therapy is central to the management of newborn infants with respiratory distress syndrome, its use in other neonatal lung diseases remains inconsistent and controversial. Here we discuss the evidence and experience in relation to surfactant therapy in newborns with other lung conditions in which surfactant may be deficient or dysfunctional, including meconium aspiration syndrome, pneumonia, congenital diaphragmatic hernia and pulmonary haemorrhage. We find that, for all of these diseases, administration of exogenous surfactant as bolus therapy is frequently associated with transient improvement in oxygenation, likely related to temporary mitigation of surfactant inhibition in the airspaces. However, for none of them is there a lasting clinical benefit of surfactant therapy. By virtue of interrupting disease pathogenesis, lavage therapy with dilute surfactant in MAS offers the greatest possibility of a more pronounced therapeutic effect, but this has yet to be definitively proven. Lavage therapy also involves a greater degree of procedural risk.

Surfactant status assessment and personalized therapy for surfactant deficiency or dysfunction

Surfactant is a pivotal neonatal drug used both for respiratory distress syndrome due to surfactant deficiency and for more complex surfactant dysfunctions (such as in case of neonatal acute respiratory distress syndrome). Despite its importance, indications for surfactant therapy are often based on oversimplified criteria. Lung biology and modern monitoring provide several diagnostic tools to assess the patient surfactant status and they can be used for a personalized surfactant therapy. This is desirable to improve the efficacy of surfactant treatment and reduce associated costs and side effects. In this review we will discuss these diagnostic tools from a pathophysiological and multi-disciplinary perspective, focusing on the quantitative or qualitative surfactant assays, lung mechanics or aeration measurements, and gas exchange metrics. Their biological and technical characteristics are described with practical information for clinicians. Finally, available evidence-based data are reviewed, and the diagnostic accuracy of the different tools is compared. Lung ultrasound seems the most suitable tool for assessing the surfactant status, while some other promising tests require further research and/or development.

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.

Cumulative evidence of the genetic association between SP-B C1580T polymorphisms and risk of neonatal respiratory distress syndrome

Objective: Surfactant protein SP-B, an important protein in pulmonary surfactant, is required for the stabilization of surfactant films in the lung and maintenance of postnatal lung function. Although the association between SP-B polymorphisms and the risk of neonatal respiratory distress syndrome (RDS) has been evaluated, the results have been inconsistent. We investigated the association between SP-B polymorphisms and the risk of neonatal RDS.Methods: Relevant studies were systematically searched in PubMed, EMBASE, Web of Science, and Chinese National Knowledge Infrastructure (CNKI) electronic databases until June 2022. Data were collected independently by two reviewers and converted to odds ratios (ORs) with 95% confidence intervals (CIs). Meta-analysis, subgroup analysis, sensitivity analysis, and publication bias assessment were performed using Stata 12.1 software and Review Manager 5.3.Results: Fourteen studies were included. SP-B C1580T polymorphism was significantly associated with neonatal RDS in five genetic models (T vs. C: OR = 0.70, 95% CI 0.57-0.86, I² = 78%; TT vs. CC: OR = 0.63, 95% CI 0.53-0.86, I² = 39%; CT vs. CC: OR = 0.65, 95% CI 0.50-0.84, I² = 54%; TT + CT vs. CC: OR = 0.62, 95% CI 0.49-0.78, I² = 59%; TT vs. CC + CT: OR = 0.78, 95% CI 0.67-0.91, I² = 43%). The CT and TT genotypes may decrease the risk of RDS in neonates. Subgroup analyses revealed that the association of SP-B C1580T polymorphism with neonatal RDS was stable, independent of preterm birth and Hardy-Weinberg equilibrium. In addition, the Han Chinese were more likely to be affected by SP-B C1580T polymorphisms than Caucasians and Finnish.Conclusions: Our findings suggest that SP-B C1580T polymorphism may be a protective factor against neonatal RDS.

Development and validation of a predictive model for early diagnosis of neonatal acute respiratory distress syndrome based on the Montreux definition

Objective

Based on the Montreux definition, we aim to develop and validate a predictive model for the early diagnosis of neonatal acute respiratory distress syndrome (ARDS).

Methods

A retrospective analysis of clinical data on 198 neonates with respiratory distress from January 2018 to January 2022 was conducted. Neonates meeting Montreux definition were classified as ARDS group (n = 79), while the rest were non-ARDS group (n = 119). Univariate analysis identified indicators for neonatal ARDS, followed by logistic regression to construct a predictive model for early diagnosis. The ability of predictors and models to predict neonatal ARDS was evaluated using area under the curve (AUC), and model performance was estimated through bootstrap resampling.

Results

Maternal prenatal fever, abnormal fetal heart beat, meconium-stained amniotic fluid (MSAF), white blood cell (WBC), absolute neutrophil count (ANC), neutrophil percentage (NE%), platelet count (PLT), C-reactive protein (CRP), procalcitonin (PCT), creatine kinase (CK), activated partial thromboplastin time (APTT), serum calcium (Ca) and sodium (Na)exhibited significant differences between the ARDS group and the non-ARDS group (P < 0.05). MSAF (OR=5.037; 95% CI: 1.523-16.657; P < 0.05), ANC (OR = 1.324; 95% CI: 1.172-1.495; P < 0.05), PLT (OR = 0.979; 95% CI: 0.971-0.986; P < 0.05), Ca (OR = 0.020; 95% CI: 0.004-0.088; P < 0.05) emerged as independent risk factors for the development of ARDS. The respective AUC values for MSAF, ANC, PLT, Ca, and the combined prediction models were 0.606, 0.691, 0.808, 0.761 and 0.931. Internal validation showed that the C-index for the model was 0.931.

Conclusions

Early application of the model combining MSAF, ANC, PLT and Ca may have a good predictive effect on the early diagnosis of neonatal ARDS.

Ultra-high frequency lung ultrasound in preterm neonates: a test validation study on interpretation agreement and reliability

OBJECTIVE

To verify if increasing frequency, through the use of ultra-high frequency transducers, has an impact on lung ultrasound pattern recognition.

DESIGN

Test validation study.

SETTING

Tertiary academic referral neonatal intensive care unit.

PATIENTS

Neonates admitted with respiratory distress signs.

INTERVENTIONS

Lung ultrasound performed with four micro-linear probes (10, 15, 20 and 22 MHz), in random order. Anonymised images (600 dpi) were randomly included in a pictorial database: physicians with different lung ultrasound experience (beginners (n=7), competents (n=6), experts (n=5)) blindly assessed it. Conformity and reliability of interpretation were analysed using intraclass correlation coefficient (ICC), area under the curve (AUC) of the multi-class ROC analysis, correlation and multivariate linear regressions (adjusting for frequency, expertise and their interaction).

OUTCOME MEASURES

A (0-3) score based on classical lung ultrasound semiology was given to each image as done in the clinical routine.

RESULTS

ICC (0.902 (95% CI: 0.862 to 0.936), p<0.001) and AUC (0.948, p<0.001) on the whole pictorial database (48 images acquired on 12 neonates), and irrespective of the frequency and physicians' expertise, were excellent. Physicians detected more B-lines with increasing frequency: there was a positive correlation between score and frequency (ρ=0.117, p=0.001); multivariate analysis confirmed the score to be higher using 22 MHz-probes (β=0.36 (0.02-0.7), p=0.041).

CONCLUSION

Overall conformity and reliability of interpretations of lung ultrasound patterns were excellent. There were differences in the identification of the B-patterns and severe B-patterns as increasing probe frequency is associated with higher score given to these patterns.

Effect of preterm chorioamnionitis on lung ultrasound score used to guide surfactant replacement

OBJECTIVE

Lung ultrasound score (LUS) accurately guides surfactant replacement in preterm neonates with respiratory distress syndrome due to surfactant deficiency. However, surfactant deficiency is not the unique pathobiological feature, as there may be relevant lung inflammation, such as in certain cases of clinical chorioamnionitis (CC). We aim to investigate if CC influences LUS and ultrasound-guided surfactant treatment.

DESIGN

Retrospective (2017-2022), large, cohort study targeted to recruit a homogeneous population treated with unchanged respiratory care policy and lung ultrasound protocol. Patients with (CC+: 207) and without (CC-: 205) chorioamnionitis were analyzed with propensity score matching and subsequent additional multivariate adjustments.

RESULTS

LUS was identical at unmatched and matched comparisons. Consistently, at least one surfactant dose was given in 98 (47.3%) and 83 (40.5%) neonates in the CC+ and CC- matched cohorts, respectively (p = .210). Multiple doses were needed in 28 (13.5%) and 21 (10.2%) neonates in the CC+ and CC- cohorts, respectively (p = .373). Postnatal age at surfactant dosing was also similar. LUS was higher in patients who were diagnosed with neonatal acute respiratory distress syndrome (NARDS) (CC+ cohort: 10.3 (2.9), CC- cohort: 11.4 (2.6)), than in those without NARDS (CC+ cohort: 6.1 (3.7), CC- cohort: 6.2 (3.9); p < .001, for both). Surfactant use was more frequent in neonates with, than in those without NARDS (p < .001). Multivariate adjustments confirmed NARDS as the variable with greater effect size on LUS.

CONCLUSIONS

CC does not influence LUS in preterm neonates, unless inflammation is enough severe to trigger NARDS. The occurrence of NARDS is key factor influencing the LUS.