Global and regional heterogeneity of lung aeration in neonates with different respiratory disorders: a physiological, observational study.

BACKGROUND.: Aeration heterogeneity affects lung stress and influences outcomes in adults with acute respiratory distress syndrome (ARDS). We 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.: Observational, prospective study. Neonates with respiratory distress syndrome (RDS), transient tachypnea (TTN), evolving bronchopulmonary dysplasia (BPD) and neonatal ARDS (NARDS) were enrolled. Quantitative lung ultrasound and transcutaneous blood gas measurements were simultaneously performed. Global aeration heterogeneity (with its intra- and inter-patient components) and regional aeration heterogeneity were primary outcomes; oxygenation metrics were the secondary outcomes. RESULTS.: 230 (50 RDS, TTN or evolving BPD and 80 NARDS) patients were studied. Intra-patient aeration heterogeneity was higher in TTN (mean: 61% [standard deviation: 33%]) and evolving BPD (mean: 57% [standard deviation: 20%], p<0.001), with distinctive aeration distributions. Inter-patient aeration heterogeneity was high for all disorders (Gini-Simpson index: between 0.6 and 0.72) except RDS (Gini-Simpson index: 0.5) whose heterogeneity was significantly lower than all others (p<0.001). NARDS and evolving BPD had the most diffuse injury and worst gas exchange metrics. Regional aeration heterogeneity was mostly localized in upper anterior and posterior zones. Aeration heterogeneity and total lung aeration had an exponential relationship (p<0.001; adj-R 2=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-R 2=0.83) and better oxygenation metrics upon multivariable analyses. CONCLUSIONS.: Global aeration heterogeneity and regional aeration heterogeneity differ amongst neonatal respiratory disorders. TTN and evolving BPD have the highest intra-patient aeration heterogeneity. TTN, evolving BPD and NARDS have the highest inter-patient 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.

Neonatal Mortality Disparities by Gestational Age in European Countries.

Importance: There are wide disparities in neonatal mortality rates (NMRs, deaths <28 days of life after live birth per 1000 live births) between countries in Europe, indicating potential for improvement. Comparing country-specific patterns of births and deaths with countries with low mortality rates can facilitate the development of effective intervention strategies. Objective: To investigate how these disparities are associated with the distribution of gestational age (GA) and GA-specific mortality rates. Design, Setting, and Participants: This was a cross-sectional study of all live births in 14 participating European countries using routine data compiled by the Euro-Peristat Network. Live births with a GA of 22 weeks or higher from 2015 to 2020 were included. Data were analyzed from May to October 2023. Exposures: GA at birth. Main Outcomes and Measures: The study investigated excess neonatal mortality, defined as a rate difference relative to the pooled rate in the 3 countries with the lowest NMRs (Norway, Sweden, and Finland; hereafter termed the top 3). The Kitagawa method was used to divide this excess into the proportion explained by the GA distribution of births and by GA-specific mortality rates. A sensitivity analysis was conducted among births 24 weeks' GA or greater. Results: There were 35 094 neonatal deaths among 15 123 428 live births for an overall NMR of 2.32 per 1000. The pooled NMR in the top 3 was 1.44 per 1000 (1937 of 1 342 528). Excess neonatal mortality compared with the top 3 ranged from 0.17 per 1000 in the Czech Republic to 1.82 per 1000 in Romania. Excess deaths were predominantly concentrated among births less than 28 weeks' GA (57.6% overall). Full-term births represented 22.7% of the excess deaths in Belgium, 17.8% in France, 40.6% in Romania and 17.3% in the United Kingdom. Heterogeneous patterns were observed when partitioning excess mortality into the proportion associated with the GA distribution vs GA-specific mortality. For example, these proportions were 9.2% and 90.8% in France, 58.4% and 41.6% in the United Kingdom, and 92.9% and 7.1% in Austria, respectively. These associations remained stable after removing births under 24 weeks' GA in most, but not all, countries. Conclusions and Relevance: This cohort study of 14 European countries found wide NMR disparities with varying patterns by GA. This knowledge is important for developing effective strategies to reduce neonatal mortality.

Use of neonatal lung ultrasound in European neonatal units: a survey by the European Society of Paediatric Research.

OBJECTIVE: Regarding the use of lung ultrasound (LU) in neonatal intensive care units (NICUs) across Europe, to assess how widely it is used, for what indications and how its implementation might be improved. DESIGN AND INTERVENTION: International online survey. RESULTS: Replies were received from 560 NICUs in 24 countries between January and May 2023. LU uptake varied considerably (20%-98% of NICUs) between countries. In 428 units (76%), LU was used for clinical indications, while 34 units (6%) only used it for research purposes. One-third of units had <2 years of experience, and only 71 units (13%) had >5 years of experience. LU was mainly performed by neonatologists. LU was most frequently used to diagnose respiratory diseases (68%), to evaluate an infant experiencing acute clinical deterioration (53%) and to guide surfactant treatment (39%). The main pathologies diagnosed by LU were pleural effusion, pneumothorax, transient tachypnoea of the newborn and respiratory distress syndrome. The main barriers for implementation were lack of experience with technical aspects and/or image interpretation. Most units indicated that specific courses and an international guideline on neonatal LU could promote uptake of this technique. CONCLUSIONS: Although LU has been adopted in neonatal care in most European countries, the uptake is highly variable. The main indications are diagnosis of lung disease, evaluation of acute clinical deterioration and guidance of surfactant. Implementation may be improved by developing courses and publishing an international guideline.