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

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.

Lung ultrasound in early prediction of bronchopulmonary dysplasia in pre-term babies

PURPOSE

Bronchopulmonary dysplasia (BPD) is a respiratory morbidity related to prematurity. Early prediction of BPD allows the selection of patients who would benefit from new therapies. Lung ultrasound (LUS) is a non-invasive diagnostic tool that has proven to be reliable for many neonatal diseases recently. The study aimed to detect the role of LUS in predicting BPD at days 7 and 14 of life in preterm babies.

METHODS

This was a prospective cohort study that included 95 preterm babies ≤ 34 weeks. Lung ultrasounds were performed on days 7 and 14 of life.

RESULTS

The mean gestational age of the studied neonates was 30.25 ± 2.21 weeks. The mean birth weight was 1347.66 ± 432.14 gm. Patients who developed BPD had statistically significantly higher LUS scores on both days 7 and 14 of life. At first examination, a LUS score > 8 showed a sensitivity of 83.33% and a specificity of 60.87%, whereas at follow-up, a LUS score > 8 showed a sensitivity of 76.39% and a specificity of 82.61%. The multivariate logistic regression analysis shows that the most important factors associated with BPD were gestational age ≤ 30 weeks, LUS score at first examination > 8, platelets ≤ 245 × 109/L, segment neutrophils ≤ 42%, and CRP > 5 mg/l.

CONCLUSIONS

The LUS score predicts BPD at 7 and 14 days of life. LUS scores increased with increasing BPD severity. LUS score > 8 was an independent factor in the prediction of BPD.

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.

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

BACKGROUND

The management of respiratory distress syndrome (RDS) in premature newborns is based on different types of non-invasive respiratory support and on surfactant replacement therapy (SRT) to avoid mechanical ventilation as it may eventually result in lung damage. European guidelines currently recommend SRT only when the fraction of inspired oxygen (FiO2) exceeds 0.30. The literature describes that early SRT decreases the risk of bronchopulmonary dysplasia (BPD) and mortality. Lung ultrasound score (LUS) in preterm infants affected by RDS has proven to be able to predict the need for SRT and different single-center studies have shown that LUS may increase the proportion of infants that received early SRT. Therefore, the aim of this study is to determine if the use of LUS as a decision tool for SRT in preterm infants affected by RDS allows for the reduction of the incidence of BPD or death in the study group.

METHODS/DESIGN

In this study, 668 spontaneously-breathing preterm infants, born at 25+0 to 29+6 weeks' gestation, in nasal continuous positive airway pressure (nCPAP) will be randomized to receive SRT only when the FiO2 cut-off exceeds 0.3 (control group) or if the LUS score is higher than 8 or the FiO2 requirements exceed 0.3 (study group) (334 infants per arm). The primary outcome will be the difference in proportion of infants with BPD or death in the study group managed compared to the control group.

DISCUSSION

Based on previous published studies, it seems that LUS may decrease the time to administer surfactant therapy. It is known that early surfactant administration decreases BPD and mortality. Therefore, there is rationale for hypothesizing a reduction in BPD or death in the group of patients in which the decision to administer exogenous surfactant is based on lung ultrasound scores.

TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT05198375 . Registered on 20 January 2022.

Neonatal cardiorespiratory imaging-a multimodality state-of-the-art review

Advanced cardiorespiratory imaging of the chest with ultrasound (US), computed tomography (CT) and magnetic resonance imaging (MRI) plays an important role in diagnosing respiratory and cardiac conditions in neonates when radiography and echocardiography alone are not sufficient. This pictorial essay highlights the particularities, clinical indications and technical aspects of applying chest US, cardiac CT and cardiorespiratory MRI techniques specifically to neonates, summarising the first session of the European Society of Paediatric Radiology's cardiothoracic task force.

Cardiopulmonary Ultrasound Patterns of Transient Acute Respiratory Distress of the Newborn: A Retrospective Pilot Study

Acute transient respiratory distress in the first hours of life is usually defined as transient tachypnea of the newborn (TTN). TTN is a respiratory self-limiting disorder consequent to delayed lung fluid clearance at birth. While TTN is the most common etiology of respiratory distress near term, its pathogenesis and diagnostic criteria are not well-defined. Lung ultrasound and targeted neonatal echocardiography are increasingly being used to assess critically ill infants, although their combined use to improve diagnostic precision in neonatal intensive care units has not yet been described. This retrospective pilot analysis aimed to identify possible cardiopulmonary ultrasound (CPUS) patterns in term and late preterm infants suffering from transient respiratory distress and requiring non-invasive respiratory support. After retrospectively revising CPUS images, we found seven potential sonographic phenotypes of acute neonatal respiratory distress. Up to 50% of the patients presented with signs of increased pulmonary vascular resistance, suggesting that those patients may be diagnosed with mild forms of persistent pulmonary hypertension of the newborn. Approximately 80% of the infants with a history of meconium-stained amniotic fluid displayed irregular atelectasis, indicating that they may have suffered from mild meconium aspiration syndrome. CPUS evaluation may improve accuracy in the approach to the infants presenting with transient acute respiratory distress, supporting communication with the parents and carrying important epidemiological consequences.

Accuracy of lung and diaphragm ultrasound in predicting successful extubation in extremely preterm infants: A prospective observational study

OBJECTIVE

Chest ultrasound has emerged as a promising tool in predicting extubation readiness in adults and children, yet its utility in preterm infants is lacking. Our aim was to assess the utility of lung ultrasound severity score (LUSS) and diaphragmatic function in predicting extubation readiness in extremely preterm infants.

STUDY DESIGN

In this prospective cohort study, preterm infants < 28 weeks gestational age (GA) who received invasive mechanical ventilation for ≥12 h were enrolled. Chest ultrasound was performed before extubation. The primary outcome was lung ultrasound accuracy for predicting successful extubation at 3 days. Descriptive statistics and logistic regression were done using SPSS version 22.

RESULTS

We enrolled 45 infants, of whom 36 (80%) were successfully extubated. GA and postmenstrual age (PMA) at extubation were significantly higher in the successful group. The LUSS was significantly lower in the successful group compared to failed group (11.9 ± 3.2 vs. 19.1 ± 3.1 p < 0.001). The two groups had no statistically significant difference in diaphragmatic excursion or diaphragmatic thickness fraction. Logistic regression analysis controlling for GA and PMA at extubation showed LUSS was an independent predictor for successful extubation (odd ratio 0.46, 95% confidence interval [0.23-0.9], p = 0.02). The area under the receiver operating characteristic curve was 0.95 (p ˂ 0.001) for LUSS, and a cut-off value of ≥15 had 95% sensitivity and 85% specificity in detecting extubation failure.

CONCLUSION

In extremely preterm infants, lung ultrasound has good accuracy for predicting successful extubation. However, diaphragmatic measurements were not reliable predictors.

A scoping review of echocardiographic and lung ultrasound biomarkers of bronchopulmonary dysplasia in preterm infants

Despite recent improvements in neonatal care, moderate to severe bronchopulmonary dysplasia (BPD) is still associated with high mortality and with an increased risk of developing pulmonary hypertension (PH). This scoping review provides an updated overview of echocardiographic and lung ultrasound biomarkers associated with BPD and PH, and the parameters that may prognosticate their development and severity, which could be clinically helpful to undertake preventive strategies. A literature search for published clinical studies was conducted in PubMed using MeSH terms, free-text words, and their combinations obtained through appropriate Boolean operators. It was found that the echocardiography biomarkers for BPD, and especially those assessing right ventricular function, are reflective of the high pulmonary vascular resistance and PH, indicating a strong interplay between heart and lung pathophysiology; however, early assessment (e.g., during the first 1-2 weeks of life) may not successfully predict later BPD development. Lung ultrasound indicating poor lung aeration at day 7 after birth has been reported to be highly predictive of later development of BPD at 36 weeks' postmenstrual age. Evidence of PH in BPD infants increases risk of mortality and long-term PH; hence, routine PH surveillance in all at risk preterm infants at 36 weeks, including an echocardiographic assessment, may provide useful information. Progress has been made in identifying the echocardiographic parameters on day 7 and 14 to predict later development of pulmonary hypertension. More studies on sonographic markers, and especially on echocardiographic parameters, are needed for the validation of the currently proposed parameters and the timing of assessment before recommendations can be made for the routine clinical practice.

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

INTRODUCTION

Lung ultrasound (LU) is a noninvasive, bedside imaging technique that is attracting growing interest in the evaluation of neonatal respiratory diseases. We conducted a nationwide survey of LU usage in Italian neonatal intensive care units (NICUs).

METHODS

A structured questionnaire was developed and sent online to 114 Italian NICUs from June to September 2021.

RESULTS

The response rate was 79%. In the past 4 years (range: 2-6), LU has been adopted in 82% of Italian NICUs. It is the first-choice diagnostic test in 23% of the centers surveyed. The main LU diagnostic applications reported were: pneumothorax (95%), respiratory distress syndrome (89%), transient tachypnea of the newborn (89%), plural effusion (88%), atelectasis (66%), pneumonia (64%), bronchopulmonary dysplasia (43%), congenital pulmonary airway malformation (41%), and congenital diaphragmatic hernia (34%). Thirty percent of participating centers calculated LU score routinely, but only seven units used it to predict the need for surfactant replacement. Sixty-six percent of respondents learned the LU technique via a self-training process, while 34% of them visited an expert in the field for one-to-one tuition.

CONCLUSIONS

LU has a widespread use in Italian NICUs. However, the use of LU is extremely heterogeneous among centers. There is an urgent need to ensure standardization of clinical practice guidelines and to design and implement a formalized and accredited training program.