Point-of-care lung ultrasound in neonatology: classification into descriptive and functional applications

Improving early diagnosis of bronchopulmonary dysplasia

INTRODUCTION

Bronchopulmonary disease (BPD) is associated with long-term neurodevelopmental and cardiorespiratory complications, often requiring significant use of resources. To reduce this healthcare burden, it is essential that those at high risk of BPD are identified early so that strategies are introduced to prevent disease progression. Our aim was to discuss potential methods for improving early diagnosis in the first week after birth.

AREAS COVERED

A narrative review was undertaken. The search strategy involved searching PubMed, Embase and Cochrane databases from 1967 to 2024. The results of potential biomarkers and imaging modes are discussed. Furthermore, the value of scoring systems is explored.

EXPERT OPINION

BPD occurs as a result of disruption to pulmonary vascular and alveolar development, thus abnormal levels of factors regulating those processes are promising avenues to explore with regard to early detection of high-risk infants. Data from twin studies suggests genetic factors can be attributed to 82% of the observed difference in moderate to severe BPD, but large genome-wide studies have yielded conflicting results. Comparative studies are required to determine which biomarker or imaging mode may most accurately diagnose early BPD development. Models which include the most predictive factors should be evaluated going forward.

Lung ultrasound for prediction of surfactant requirement in Indian preterm neonates: a diagnostic accuracy study

Surfactant replacement for respiratory distress syndrome (RDS) is currently guided by oxygen (FiO2) requirement in preterm neonates. Lung ultrasound (LUS) has emerged as an important predictive tool; however, there is a paucity of evidence from developing countries. The objective of this study was to determine the diagnostic accuracy of the LUS score in comparison to standard criteria based on FiO2 requirement for prediction of surfactant requirement. In this prospective study, preterm neonates of < 34 weeks' gestation with RDS were included within 2 h of life. Surfactant was administered if the FiO2 requirement exceeded 30%. Baseline characteristics, respiratory parameters, and LUS clips were recorded soon after birth and compared between the surfactant and non-surfactant groups. LUS scoring was later performed by masked assessors which was not used in the management of neonates. Among 82 neonates (mean gestation 30.6 weeks and weight 1375 g) included in the study, 33 (40.2%) received surfactant. The surfactant group had a higher Silverman score, required higher FiO2 and mean airway pressure, and needed invasive ventilation more frequently. The mean (± SD) LUS score was significantly higher in the surfactant (9.4 ± 3.2) compared to the non-surfactant group (5.1 ± 2.1). The diagnostic accuracy of LUS scoring was determined by ROC curve analysis (AUC (95% CI): 0.83 (0.74-0.92), p < 0.01). A cutoff score of ≥ 8 for LUS was considered optimal for the prediction of surfactant requirement (sensitivity and specificity (95% CI) of 70% (51-84) and 80% (66-90), respectively).    Conclusion: Lung ultrasound is a valid diagnostic tool for the prediction of surfactant requirements in resource-limited settings. What is Known: • Lung ultrasound has a good diagnostic accuracy in predicting the need for surfactant administration in preterm neonates in developed countries, but its role in developing countries is unclear. What is New: • Lung ultrasound proved to be a valid diagnostic tool in predicting surfactant replacement therapy in resource-limited settings. • The diagnostic performance of lung ultrasound was better in neonates on non-invasive ventilation, compared to invasive ventilation.

Point of care lung ultrasound in preschool children with cystic fibrosis: a case-controlled, prospective, pilot study

AIMS

Respiratory complications in Cystic Fibrosis (CF) are still the leading cause of death nowadays in these patients. High-Resolution Computed Tomography is the gold standard method for staging lung disease in CF. In this study we assessed lung ultrasound findings in asymptomatic preschool patients affected by CF.

METHODS

This is a case-control study with a total of 70 enrolled patients (20 patients affected by CF, 50 healthy controls) aged from 31 to 6 years. All included patients were without intercurrent lung problems and without antibiotic therapy in the last 30 days. For each patient a lung Point of Care Ultrasound (POCUS) of lung was performed.

RESULTS

B lines < 3 and sub-pleural consolidations < 1 cm were statistically more frequent in CF patients, both in terms of number of affected patients (p 0.02 and p 0.0001 respectively) and frequency (p 0.0181 and p 0.0001 respectively); the prevalence of B lines < 3 in control group was high (47.73%) however the prevalence of sub-pleural consolidations was very low (2.27%). In both groups coalescent B lines affected a greater number of infants and were in higher number of findings than patients aged between 2 and 6 years.

CONCLUSIONS

The presence of multiple subpleural pulmonary consolidations < 1 cm in asymptomatic preschool children could be a ultrasound markers of subclinical pulmonary disease such as CF. POCUS of lung is confirmed as a useful tool for the clinician as confirmation of a clinical suspicion, help reduce the use of ionizing radiation.

Current perception and barriers to implementing lung ultrasound in Canadian neonatal intensive care units: a national survey

Despite the growing body of literature supporting the use of point-of-care lung ultrasound (POC-LU) in neonates, its adoption in Canadian neonatal intensive care units (NICUs) remains limited. This study aimed to identify healthcare providers' perceptions and barriers to implementing POC-LU in Canadian NICUs. We conducted an electronic survey targeting neonatologists, neonatal fellows, neonatal nurse practitioners, and registered respiratory therapists in 20 Canadian NICUs. The survey comprised a 28-item questionnaire divided into four sections: (1) participants' demographics and availability of POC-LU equipment, (2) experience and interest in POC-LU learning, (3) perception of POC-LU as a diagnostic tool, and (4) barriers to POC-LU implementation in NICUs. A total of 194 participants completed the survey, with neonatologists comprising the majority (45%). Nearly half of the participants (48%) reported prior experience with POC-LU. The most prevalent indications for POC-LU use were diagnosis of pleural effusion (90%), pneumothorax (87%), and respiratory distress syndrome (76%). Participants identified the primary barrier to POC-LU adoption as the lack of trained providers available for both training and clinical integration. Notably, most respondents (87%) expressed keen interest in learning neonatal POC-LU. A subgroup analysis based on the responses collected from NICU-directors of 12 institutions yielded results consistent with those of the overall participant pool.     Conclusion: This survey underscores the perceived importance of POC-LU among NICU healthcare providers. A Canadian consensus is required to facilitate the development of widespread training programs as well as standardized clinical practice guideline for its implementation. What is Known: • In recent years, point-of-care lung ultrasound (POC-LU) has emerged as an important tool in neonatology, revolutionizing the assessment and management of critically ill infants. However, its adoption in Canadian Neonatal Intensive Care Units remains limited. What is New: • Most Canadian healthcare providers showed high level of interest in learning POC-LU techniques. Additionally, POC-LU was perceived as a useful tool for diagnosis and guiding intervention in various neonatal respiratory diseases. Nonetheless, the lack of expertise emerged as the primary barrier to its adoption and practice across different groups of participants regardless of their clinical experience level.

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.

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.

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.

Lung ultrasound in the evaluation of pulmonary edema in newborns with critical congenital heart disease

BACKGROUND

Newborns with critical congenital heart disease (CCHD) with increased pulmonary blood flow (PBF) are at high risk for congestive heart failure. In this study, we aimed to evaluate the presence and degree of pulmonary edema in newborns with CCHD using lung ultrasound (LUS) during the perioperative period.

METHODS

Prospective clinical trial, 44 newborn patients with CCHD were evaluated in this prospective clinical trial. LUS was repeatedly performed to determine the course of pulmonary edema during the perioperative period. LUS was performed simultaneously with chest radiography (CXR), which was the main part of patient management. The primary outcome of this study was to identify whether a correlation existed between LUS and CXR findings. The secondary outcomes were to determine the relationship between LUS and the need for respiratory support, diuretic use, vasoactive inotropic score (VIS), and pro-B-type natriuretic peptide (pro-BNP) levels during the perioperative period.

RESULTS

The mean gestational age of the patients was 38.3 ± 1.7 weeks, with a mean birth weight of 3026 ± 432 g. In the preoperative period, both LUS and CXR images were consistent with clinical signs of pulmonary edema. On the first postoperative day, pulmonary edema increased compared to the preoperative period but gradually decreased by the 6th day of surgery (p < 0.05). Positive correlations were observed between the LUS and CXR findings at all study points (p < 0.05). The LUS findings exhibited trends parallel to those of VIS, serum pro-BNP levels, need for respiratory support, and diuretic requirements. As expected, these trends were more pronounced in CCHDs where PBF increased.

CONCLUSION

In CCHD, serial lung ultrasound (LUS) assessments, particularly in cases with increased PBF, can provide valuable guidance for managing patients during the perioperative period.

Point-of-care ultrasound for non-vascular invasive procedures in critically ill neonates and children: current status and future perspectives

Point-of-care ultrasound (POCUS) has been established as an essential bedside tool for real-time image guidance of invasive procedures in critically ill neonates and children. While procedural guidance using POCUS has become the standard of care across many adult medicine subspecialties, its use has more recently gained popularity in neonatal and pediatric medicine due in part to improvement in technology and integration of POCUS into physician training programs. With increasing use, emerging data have supported its adoption and shown improvement in pediatric outcomes. Procedures that have traditionally relied on physical landmarks, such as thoracentesis and lumbar puncture, can now be performed under direct visualization using POCUS, increasing success, and reducing complications in our most vulnerable patients. In this review, we describe a global and comprehensive use of POCUS to assist all steps of different non-vascular invasive procedures and the evidence base to support such approach.

CONCLUSION

There has been a recent growth of supportive evidence for using point-of-care ultrasound to guide neonatal and pediatric percutaneous procedural interventions. A global and comprehensive approach for the use of point-of-care ultrasound allows to assist all steps of different, non-vascular, invasive procedures.

WHAT IS KNOWN

• Point-of-care ultrasound has been established as a powerful tool providing for real-time image guidance of invasive procedures in critically ill neonates and children and allowing to increase both safety and success.

WHAT IS NEW

• A global and comprehensive use of point-of-care ultrasound allows to assist all steps of different, non-vascular, invasive procedures: from diagnosis to semi-quantitative assessment, and from real-time puncture to follow-up.

Combining lung ultrasound and oscillatory mechanics for assessing lung disease in very preterm infants

BACKGROUND

We investigated whether combining lung ultrasound scores (LUSs) and respiratory system reactance (Xrs) measured by respiratory oscillometry explains the severity of lung disease better than individual parameters alone.

METHODS

We performed a prospective observational study in very preterm infants. Forced oscillations (10 Hz) were applied using a neonatal mechanical ventilator (Fabian HFOi, Vyaire). We used the simultaneous respiratory severity score (RSS = mean airway pressure × FIO2) as a primary outcome. We built linear mixed-effect models to assess the relationship between Xrs z-score, LUS and RSS and compared nested models using the likelihood ratio test (LRT).

RESULTS

We enrolled 61 infants (median (Q1, Q3) gestational age = 30.00 (26.86, 31.00) weeks) and performed 243 measurements at a postnatal age of 26 (13, 41) days and postmenstrual age of 33.14 (30.46, 35.86) weeks. Xrs z-score and LUS were independently associated with simultaneous RSS (p < 0.001 for both). The model including Xrs and LUS explained the RSS significantly better than Xrs (p value LRT < 0.001) or LUS alone (p value LRT < 0.001).

CONCLUSIONS

Combining LUS and Xrs z-score explains the severity of lung disease better than each parameter alone and has the potential to improve the understanding of the underlying pathophysiology.

IMPACT

Combining respiratory system reactance by oscillometry and lung ultrasound score explains the respiratory support requirement (e.g., proxy of the severity of lung disease) significantly better than each parameter alone. We assessed the relationship between lung ultrasound and respiratory system reactance in very preterm infants for the first time. Combining respiratory oscillometry and lung ultrasound has the potential to improve the understanding of respiratory pathophysiology.

Lung ultrasound-guided fluid resuscitation in neonatal septic shock: A randomized controlled trial

This randomized controlled trial aimed to determine whether lung ultrasound-guided fluid resuscitation improves the clinical outcomes of neonates with septic shock. Seventy-two patients were randomly assigned to undergo treatment with lung ultrasound-guided fluid resuscitation (LUGFR), or with usual fluid resuscitation (Control) in the first 6 h since the start of the sepsis treatment. The primary study outcome was 14-day mortality after randomization. Fourteen-day mortalities in the two groups were not significantly different (LUGFR group, 13.89%; control group, 16.67%; p = 0.76; hazard ratio 0.81 [95% CI 0.27-2.50]). The LUGFR group experienced shorter length of neonatal intensive care unit (NICU) stays (21 vs. 26 days, p = 0.04) and hospital stays (32 vs. 39 days, p = 0.01), and less fluid was used in the first 6 h (77 vs. 106 mL/kg, p = 0.02). Further, our study found that ultrasound-guided fluid resuscitation can significantly reduce the incidence of acute kidney injury (25% vs. 47.2%, p = 0.05) and intracranial hemorrhage (grades I-II) within 72 h (13.9% vs. 36.1%, p = 0.03). However, no significant difference was found in the resolution of shock within 1 h or 6 h, use of mechanical ventilation or vasopressor support, time to achieve lactate level < 2 mmol/L, and the number of participants developing hepatomegaly in the first 6 h.

CONCLUSION

Lung ultrasound is a noninvasive and convenient tool for predicting fluid overload in neonatal septic shock. Fluid resuscitation guided by lung ultrasound can shorten the length of hospital and NICU stays, reduce the amount of fluid used in the first 6 h, and reduce the risk of acute kidney injury and intracranial hemorrhage.

TRIAL REGISTRATION

Registered in Guangdong Second Provincial General Hospital: 2021-IIT-156-EK, date of registration: November 13, 2021. And ClinicalTrials.gov: NCT06144463 (retrospectively registered).

WHAT IS KNOWN

• Excessive fluid resuscitation in neonates with septic shock had worse outcomes.

WHAT IS NEW

• Lung ultrasound should be routinely used to guide fluid resuscitation in neonatal septic shock.

The role of point-of-care ultrasound in the management of neonates with congenital diaphragmatic hernia

In the last few years, current evidence has supported the use of point-of-care ultrasound (POCUS) for a number of diagnostic and procedural applications. Considering the valuable information that POCUS can give, we propose a standardized protocol for the management of neonates with a congenital diaphragmatic hernia (CDH-POCUS protocol) in the neonatal intensive care unit. Indeed, POCUS could be a valid tool for the neonatologist through the evaluation of 1) cardiac function and pulmonary hypertension; 2) lung volumes, postoperative pleural effusion or pneumothorax; 3) splanchnic and renal perfusion, malrotations, and/or signs of necrotizing enterocolitis; 4) cerebral perfusion and eventual brain lesions that could contribute to neurodevelopmental impairment. In this article, we discuss the state-of-the-art in neonatal POCUS for which concerns congenital diaphragmatic hernia (CDH), and we provide suggestions to improve its use. IMPACT: This review shows how point-of-care ultrasound (POCUS) could be a valid tool for managing neonates with congenital diaphragmatic hernia (CDH) after birth. Our manuscript underscores the importance of standardized protocols in neonates with CDH. Beyond the well-known role of echocardiography, ultrasound of lungs, splanchnic organs, and brain can be useful. The use of POCUS should be encouraged to improve ventilation strategies, systemic perfusion, and enteral feeding, and to intercept any early signs related to future neurodevelopmental impairment.

Stratifying Disease Severity in Pediatric COVID-19: A Correlative Study of Serum Biomarkers and Lung Ultrasound-A Retrospective Observational Dual-Center Study

The COVID-19 pandemic, caused by SARS-CoV-2, has manifested distinct impacts on infants and children. This study delves into the intricate connection between lung ultrasound (LUS) findings and serum biomarkers in neonates and infants with COVID-19. Exploring factors contributing to the mild symptoms in this demographic, including immune responses and pre-existing immunity, the study spans 3 years and 9 months, involving 42 patients. Respiratory and gastrointestinal symptoms predominate, and LUS emerges as a vital, non-irradiating tool for evaluating pulmonary abnormalities. Serum biomarkers like CRP, procalcitonin, and cytokines provide key insights into the pathophysiology. Correlations reveal nuanced links between LUS score and clinical parameters, unveiling associations with hospitalization duration (rho = 0.49), oxygen saturation (rho = -0.88), and inflammatory markers, like ferritin (rho = 0.62), LDH (rho = 0.73), and D-dimer (rho = 0.73) with significance level (p < 0.05). The absence of large consolidations in LUS suggests unique pulmonary characteristics. The novelty of these findings lies in the comprehensive integration of LUS with serum biomarkers to assess and monitor the severity of lung involvement in neonates and infants affected by SARS-CoV-2. This approach offers valuable insights into disease severity, biomarker levels, the duration of hospitalization, and oxygen saturation, providing a multifaceted understanding of COVID-19's impact on this vulnerable population.

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.

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.

Lung ultrasound detects regional aeration inhomogeneity in ventilated preterm lambs

BACKGROUND

Inhomogeneous lung aeration is a significant contributor to preterm lung injury. EIT detects inhomogeneous aeration in the research setting. Whether LUS detects inhomogeneous aeration is unknown. The aim was to determine whether LUS detects regional inhomogeneity identified by EIT in preterm lambs.

METHODS

LUS and EIT were simultaneously performed on mechanically ventilated preterm lambs. LUS images from non-dependent and dependent regions were acquired and reported using a validated scoring system and computer-assisted quantitative LUS greyscale analysis (Q-LUSMGV). Regional inhomogeneity was calculated by observed over predicted aeration ratio from the EIT reconstructive model. LUS scores and Q-LUSMGV were compared with EIT aeration ratios using one-way ANOVA.

RESULTS

LUS was performed in 32 lambs (~125d gestation, 128 images). LUS scores were greater in upper anterior (non-dependent) compared to lower lateral (dependent) regions of the left (3.4 vs 2.9, p = 0.1) and right (3.4 vs 2.7, p < 0.0087). The left and right upper regions also had greater LUS scores compared to right lower (3.4 vs 2.7, p < 0.0087) and left lower (3.7 vs 2.9, p = 0.1). Q-LUSMGV yielded similar results. All LUS findings corresponded with EIT regional differences.

CONCLUSION

LUS may have potential in measuring regional aeration, which should be further explored in human studies.

IMPACT

Inhomogeneous lung aeration is an important contributor to preterm lung injury, however, tools detecting inhomogeneous aeration at the bedside are limited. Currently, the only tool clinically available to detect this is electrical impedance tomography (EIT), however, its use is largely limited to research. Lung ultrasound (LUS) may play a role in monitoring lung aeration in preterm infants, however, whether it detects inhomogeneous lung aeration is unknown. Visual LUS scores and mean greyscale image analysis using computer assisted quantitative LUS (Q-LUSMGV) detects regional lung aeration differences when compared to EIT. This suggests LUS reliably detects aeration inhomogeneity warranting further investigation in human trials.

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.

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.

Bile Acids Pneumonia: A Respiratory Distress Syndrome in Early-Term Neonates

Intrahepatic cholestasis of pregnancy (ICP) complicates among 0.2-2% of pregnancies and has been associated with adverse perinatal outcomes, including sudden stillbirth, meconium strained fluid, preterm birth, perinatal asphyxia, and transient tachypnea of the newborn. The diagnosis of "bile acids pneumonia" was previously proposed and a causative role of bile acids (BA) was supposed with a possible mechanism of action including surfactant dysfunction, inflammation, and chemical pneumonia. In the last few years, the role of lung ultrasound (LUS) in the diagnosis and management of neonatal respiratory distress syndrome has grown, and LUS scores have been introduced in the literature, as an effective predictor of the need for surfactant treatment among neonates with respiratory distress syndrome. We present four cases of infants born from pregnancies complicated by ICP, who developed respiratory distress syndrome early after birth. Lung ultrasound showed the same pattern for all infants, corresponding to a homogeneous alveolar-interstitial syndrome characterized by a diffuse coalescing B-line pattern (white lung). All infants evaluated require non-invasive respiratory support and in three cases surfactant administration, despite the near-term gestational age, with rapid improvement of respiratory disease and a good clinical outcome.

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.

Early life surfactant protein-D levels in bronchoalveolar lavage fluids of extremely preterm neonates

Surfactant protein-D (SP-D) is a hydrophilic protein with multiple crucial anti-inflammatory and immunological functions. It might play a role in the development and course of pulmonary infections, acute respiratory distress syndrome, and other respiratory disorders. Only few small neonatal studies have investigated SP-D: we aimed to investigate the links between this protein, measured in the first hours of life in extremely preterm neonates, and clinical outcomes, as well its relationship with pulmonary secretory phospholipase A2 (sPLA2). Bronchoalveolar lavage fluids were obtained within the first 3 h of life. SP-D and sPLA2 were measured with ELISA and radioactive method, respectively; epithelial lining fluid concentrations were estimated with urea ratio. Clinical data were prospectively collected. One hundred extremely preterm neonates were nonconsecutively studied. SP-D was significantly raised with increasing gestational age (24-26 wk: 68 [0-1,694], 27 or 28 wk: 286 [0-1,328], 29 or 30 wk: 1,401 [405-2,429] ng/mL, overall P = 0.03). SP-D was significantly higher in cases with clinical chorioamnionitis with fetal involvement (1,138 [68-3,336]) than in those without clinical chorioamnionitis with fetal involvement (0 [0-900] ng/mL, P < 0.001). SP-D was lower in infants with bronchopulmonary dysplasia (BPD) (251 [0-1,550 ng/mL]) compared with those without bronchopulmonary dysplasia (BPD) or who died before its diagnosis (977 [124-5,534 ng/mL], P = 0.05) and this was also significant upon multivariate analysis [odds ration (OR): 0.997 (0.994-0.999), P = 0.024], particularly in neonates between 27- and 28-wk gestation. SP-D significantly correlated with the duration of hospital stay (ρ = -0.283, P = 0.002), invasive ventilation (ρ = -0.544, P = 0.001), and total sPLA2 activity (ρ = 0.528, P = 0.008). These findings help understanding the role of SP-D early in life and support further investigation about the role of SP-D in developing BPD.NEW & NOTEWORTHY Surfactant protein-D increases with gestational age and is inversely associated with BPD development. These results have been obtained in the first hours of life of extremely preterm neonates with optimal perinatal care.

Accuracy of lung ultrasound in predicting extubation failure in neonates: A systematic review and meta-analysis

OBJECTIVE

To systematically review and meta-analyze the diagnostic accuracy of lung ultrasound score (LUS) in predicting extubation failure in neonates.

STUDY DESIGN

MEDLINE, COCHRANE, EMBASE, CINAHL, and clinicaltrials.gov were searched up to 30 November 2022, for studies evaluating the diagnostic accuracy of LUS in predicting extubation outcome in mechanically ventilated neonates.

METHODOLOGY

Two investigators independently assessed study eligibility, extracted data, and assessed study quality using the Quality Assessment for Studies of Diagnostic Accuracy 2 tool. We conducted a meta-analysis of pooled diagnostic accuracy data using random-effect models. Data were reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We calculated pooled sensitivity and specificity, pooled diagnostic odds ratios with 95% confidence intervals (CI), and area under the curve (AUC).

RESULTS

Eight observational studies involving 564 neonates were included, and the risk of bias was low in seven studies. The pooled sensitivity and specificity for LUS in predicting extubation failure in neonates were 0.82 (95% CI: 0.75-0.88) and 0.83 (95% CI: 0.78-0.86), respectively. The pooled diagnostic odds ratio was 21.24 (95% CI: 10.45-43.19), and the AUC for LUS predicting extubation failure was 0.87 (95% CI: 0.80-0.95). Heterogeneity among included studies was low, both graphically and by statistical criteria (I2  = 7.35%, p = 0.37).

CONCLUSIONS

The predictive value of LUS in neonatal extubation failure may hold promise. However, given the current level of evidence and the methodological heterogeneity observed, there is a clear need for large-scale, well-designed prospective studies that establish standardized protocols for lung ultrasound performance and scoring.

REGISTRATION

The protocol was registered in OSF (https://doi.org/10.17605/OSF.IO/ZXQUT).

Impact of patent ductus arteriosus on non-invasive assessments of lung fluids in very preterm infants during the transitional period

This prospective observational study aimed to evaluate whether lung fluids, assessed by lung ultrasonography and transthoracic electrical bioimpedance (TEB), may be influenced by the presence of a haemodynamically significant patent ductus arteriosus (hsPDA) in very preterm infants during the transitional period. Infants < 32 weeks of gestational age (GA) admitted to the neonatal intensive care units of IRCCS AOU Bologna and Niguarda Metropolitan Hospital of Milan (Italy) underwent a daily assessment of a lung ultrasound score (LUS) and of a TEB-derived index of thoracic fluid contents (TFC) during the first 72 h after birth. Echocardiographic scans were simultaneously performed to evaluate the concomitant ductal status (hsPDA vs. restrictive or closed duct). The correlation between LUS, TFC, and the ductal status was tested using generalized estimating equations. Forty-six infants (median GA: 29 [interquartile range, IQR: 27-31] weeks; median birth weight: 1099 [IQR: 880-1406] g) were included. At each daily evaluation, the presence of a hsPDA was associated with significantly higher LUS and TFC compared with a restrictive or closed ductus (p < 0.01 for all comparisons). These results were confirmed significant even after adjustment for GA and for the ongoing modality of respiratory support. Conclusion: Even during the first 72 h of life, the presence of a hsPDA determines a significant increase in pulmonary fluids which can be non-invasively detected and monitored over time using lung ultrasonography and TEB. What is Known: • Lung ultrasonography provides a non-invasive assessment of lung fluids and is widely used in neonatal settings. • In preterm infants, the persistence of a haemodynamically significant patent ductus arteriosus (hsPDA) over the first weeks can negatively affect pulmonary outcomes. What is New: • The presence of aan hsPDA is associated with increased lung fluids since early postnatal phases. • Lung ultrasonography and transthoracic electrical bioimpedance can effectively monitor lung fluid clearance in preterm infants with a hsPDA during the transitional period, with potential clinical implications.

Lung ultrasound and postoperative follow-up of congenital diaphragmatic hernia

Lung ultrasound (LU) has emerged as a valuable tool for assessing pulmonary aeration noninvasively, rapidly, and reliably in different neonatal conditions. However, its role in the preoperative and postoperative evaluation in congenital diaphragmatic hernia (CDH) is still poorly analyzed. We present a cohort of 8 patients diagnosed with CDH who underwent lung ultrasound examinations at various time points before and after surgical correction. The lung ultrasound patterns were compared between two groups: mechanical ventilation ≤ 7 days (MV ≤ 7) and mechanical ventilation > 7 days (MV > 7). The ultrasound findings were also compared to CT scans and chest X-ray images to assess its diagnostic capacity for identifying postoperative complications: pneumothorax, pleural effusion, and pneumonia. Group MV ≤ 7 exhibited a normal pattern even at 48 h postsurgery, while group MV > 7 presented interstitial or alveolointerstitial pattern in both lungs for prolonged periods (2-3 weeks). Furthermore, contralateral LU pattern may be predictive of respiratory evolution.  Conclusion: Lung ultrasound is a valuable tool for evaluating the progressive reaeration of the lung following surgical correction in CDH patients. It demonstrates the ability to diagnose common postoperative complications without the need for radiation exposure while offering the advantages of quick and serial assessments. These findings highlight the potential of lung ultrasound as an effective alternative to conventional imaging methods in the management of CDH. What is Known: • Lung ultrasound evaluates lung aeration and predicts respiratory outcomes in neonatal patients. What is New: • Lung ultrasound is useful in the postsurgical management of congenital diaphragmatic hernia patients, detecting reaeration and respiratory complications.

Ultrasound-assessed lung aeration, oxygenation and respiratory care in neonatal bile acid pneumonia: A nested case-control study

AIM

Neonatal bile acid pneumonia (NBAP) occurs in neonates following obstetric cholestasis. We aimed to study the lung aeration and respiratory support of NBAP.

METHODS

Nested, case/control study enrolling age-matched neonates with NBAP, respiratory distress syndrome (RDS) or transient tachypnoea (TTN). Lung aeration and oxygenation were assessed with lung ultrasound score, oxygenation index and SpO2 /FiO2 .

RESULTS

Nineteen, 22 and 25 neonates with NBAP, RDS and TTN, respectively were studied (mean gestational age = 33 (2.2) weeks, 30 (45.5%) males). Upon admission, RDS patients had the worst lung ultrasound score (p = 0.022) and oxygenation index (p = 0.001), while NBAP and TTN neonates had similar values. At the worst time-point, NBAP and RDS patients showed similar oxygenation index (NBAP: 4.6 [2], RDS: 5.7 [3]) and SpO2 /FiO2 (NBAP: 3.1 [1.1], RDS: 2.7 [1]) which were worse than those of TTN patients (oxygenation index: p = 0.015, SpO2 /FiO2 : p = 0.001). RDS neonates needed the longest continuous positive airway pressure and highest mean airway pressure, but NBAP neonates needed invasive ventilation (26.3%, p = 0.01) and surfactant (31.6%, p = 0.003) more often than TTN patients who never needed these.

CONCLUSION

NBAP was a mild disorder in the first hours of life but subsequently worsened and became similar to RDS.

Optimal timing and cutoff range of lung ultrasound in predicting surfactant administration in neonates: A meta-analysis and systematic review

OBJECTIVE

Timely application of surfactant replacement therapy is critical for neonates with respiratory distress syndrome (RDS). Presently, early clinical decision on surfactant use relies solely on ventilator parameters. However, ventilator parameters are unable to truly recapitulate the extent of surfactant deficiency. Lung ultrasound has been increasingly used in the early prediction of surfactant use in recent years, but its predictive value remains unclear. Therefore, we conducted this study to examine its predictive value in surfactant use and determine the optimal timing and cutoff value.

METHODS

Studies on neonates with respiratory distress or diagnosed with RDS were collected from PubMed, Embase, Cochrane Library, and Web of Science. Primary outcomes included sensitivity, specificity, and positive and negative predictive values of lung ultrasound.

RESULTS

Ten eligible studies with 1162 participants were included. The sensitivity and specificity of lung ultrasound in predicting surfactant use were 0.86 (95% CI: 0.81-0.90) and 0.82 (95% CI: 0.71-0.90), respectively. Lung ultrasound performed within 1-3 h after birth had a sensitivity of 0.89 (95% CI: 0.79-0.95) and a Youden's index of 0.67. Compared with a lung ultrasound score (LUS) cutoff of ≤6/7, ≤8, >5, >6/7, and >8, a LUS cutoff of ≤5 had higher Youden's index (0.73) and sensitivity (0.94, 95% CI: 0.85-0.97) in predicting surfactant use.

CONCLUSIONS

Lung ultrasound is effective for predicting surfactant use in neonates. Lung ultrasound within 1-3 h after birth and a LUS cutoff of 5 are recommended. However, the symptoms and oxygenation of the neonatal patients must also be considered.

Lung ultrasound in a nutshell. Lines, signs, some applications, and misconceptions from a radiologist's point of view

In recent years, lung ultrasound (LUS) has developed rapidly, and it is growing in popularity in various scenarios. It has become especially popular among clinicians. There are constant attempts to introduce it in new fields, with quite a strong resistance in the radiological community. In addition, knowledge regarding lung and LUS has been augmented by the recent COVID-19 pandemic. Unfortunately, this has led to many misconceptions. The aim of this review is to discuss lines, signs, and phenomena that can be seen in LUS in order to create a single, easily available compendium for radiologists and promote consistency in LUS nomenclature. Some simplified suggestions are presented.

Can lung ultrasound score accurately predict surfactant replacement? A systematic review and meta-analysis of diagnostic test studies

BACKGROUND

Clinical and radiographic criteria are traditionally used to determine the need for surfactant therapy in preterm infants. Lung ultrasound is a bedside test that offers a rapid, radiation-free, alternative to this approach.

OBJECTIVE

To conduct a systematic review and meta-analysis to determine the accuracy of a lung ultrasound score (LUS) in identifying infants who would receive at least one surfactant dose. Secondary aims were to evaluate the predictive accuracy for ≥2 doses and the accuracy of a different image classification system based on three lung ultrasound profiles.

METHODS

PubMed, SCOPUS, Biomed Central, and the Cochrane library between January 2011 and December 2021 were searched. Full articles enrolling preterm neonates who underwent lung ultrasound to predict surfactant administration were assessed and analyzed following Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) and QUADAS-2 guidelines.

RESULTS

Seven prospective studies recruiting 697 infants met the inclusion criteria. Risk of bias was generally low. Oxygen requirement, clinical and radiographic signs of respiratory distress syndrome were used as reference standards for surfactant replacement. The summary receiver operator characteristic (sROC) curve for LUS predicting first surfactant dose showed an area under the curve (AUC) = 0.88 (95% confidence interval [CI]: 0.82-0.91); optimal specificity and sensitivity (Youden index) were 0.83 and 0.81 respectively. Pooled estimates of sensitivity, specificity, diagnostic odds ratio, negative predictive value, and positive predictive value for LUS predicting the first surfactant dose were 0.89 (0.82-0.95), 0.86 (0.78-0.95), 3.78 (3.05-4.50), 0.92 (0.87-0.97), 0.79 (0.65-0.92). The sROC curve for the accuracy of Type 1 lung profile in predicting first surfactant dose showed an AUC of 0.88; optimal specificity and sensitivity were both 0.86. Two studies addressing the predictive accuracy of LUS for ≥2 surfactant doses had high heterogeneity and were unsuitable to combine in a meta-analysis.

DISCUSSION

Despite current significant variation in LUS thresholds, lung ultrasound is highly predictive of the need for early surfactant replacement. This evidence was derived from studies with homogeneous patient characteristics and low risk of bias.

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.

Lung Ultrasound Score in Neonates with Congenital Diaphragmatic Hernia (CDH-LUS): A Cross-Sectional Study

Introduction: The use of a lung ultrasound (LUS) score has been described in the early phases of neonatal respiratory distress syndrome; however, there is still no data regarding the application of the LUS score to neonates with a congenital diaphragmatic hernia (CDH). The objective of this observational cross-sectional study was to explore, for the first time, the postnatal changes in LUS score patterns in neonates with CDH, with the creation of a new specific CDH-LUS score. Methods: We included all consecutive neonates with a prenatal diagnosis of CDH admitted to our Neonatal Intensive Care Unit (NICU) from June 2022 to December 2022 who underwent lung ultrasonography. Lung ultrasonography (LUS) was determined at scheduled time points: (T0) during the first 24 h of life; (T1) at 24-48 h of life; (T2) within 12 h of surgical repair; (T3) a week after the surgical repair. We used a modified LUS score (CDH-LUS), starting from the original 0-3 score. We assigned 4 as a score in the presence of herniated viscera in the hemithorax (liver, small bowel, stomach, or heart in the case of a mediastinal shift) in the preoperative scans or pleural effusions in the postoperative scans. Results: We included in this observational cross-sectional study 13 infants: twelve/13 had a left-sided hernia (2 severe, 3 moderate, and 7 mild cases), while one patient had a right-sided severe hernia. The median CDH-LUS score was 22 (IQR 16-28) during the first 24 h of life (T0), 21 (IQR 15-22) at 24-48 h of life (T1), 14 (IQR 12-18) within 12 h of surgical repair (T2) and 4 (IQR 2-15) a week after the surgical repair (T3). The CDH-LUS significantly dropped over time from the first 24 h of life (T0) to a week after the surgical repair (T3), according to ANOVA for repeated measures. Conclusion: We showed a significant improvement in CDH-LUS scores from the immediate postoperative period, with normal ultrasonographic evaluations a week after surgery in most patients.

Incidence of ultrasonographic signs of pneumothorax in asymptomatic neonates

INTRODUCTION

Pneumothorax in neonates can be life-threatening. In neonates without respiratory distress, spontaneous pneumothorax can also develop under certain conditions.

OBJECTIVES

To determine the incidence of ultrasonographic signs of pneumothorax in asymptomatic neonates using lung ultrasound as the diagnostic tool.

METHODS

This was an observational prospective study conducted at the Basurto University Hospital (Bilbao, Spain) between January 2018 and December 2020. Lung ultrasound was performed during routine examination of asymptomatic neonates admitted to the maternity ward.

RESULTS

Of a total of 204 asymptomatic neonates included in the study, 21 (10.3%) presented ultrasound signs of pneumothorax (Group A), and 183 (89.7%) had a normal lung ultrasound (Group B). Lung ultrasound was performed after a mean of 19 h of life (range 9-34). The presence of A-lines behind the sternum in the anterior transverse plane, at the intermammillary level, was observed in 100% of patients in Group A compared to no cases in Group B (p < 0.0001). The neonates of Group A presented the lung point located in the midclavicular line, indicative of a mild air leak.

CONCLUSIONS

Lung ultrasound allows precise detection of suspected small-sized air leaks that can be detected in asymptomatic neonates. The true incidence of pneumothorax in asymptomatic neonates may be substantially higher than previously described in the literature.

Alveolar capillary dysplasia with misalignment of pulmonary veins in a premature newborn: the role of lung ultrasound

BACKGROUND

Alveolar capillary dysplasia with misalignment of pulmonary veins (ACD/MPV) is a lethal neonatal lung disorder characterized by the decrease of the alveolar units, abnormalities in the air-blood barrier of the lung, and impaired gas exchange. Typically, it affects a full-term newborn; the symptoms usually start within a few hours after birth, resulting in severe respiratory distress and pulmonary hypertension. In most of the cases, this disorder is refractory to conventional pulmonary support.

CASE PRESENTATION

We report a case of a newborn male of 29 weeks gestational age, with birth weight of 850 g and intrauterine growth restriction. Severe respiratory distress appeared a few minutes after birth; non-invasive ventilatory support was provided in the delivery room and, as a consequence of persistent respiratory failure, he was admitted to the neonatal intensive care unit (NICU) where mechanical ventilation was required. Due to the symptoms and pulmonary ultrasound pattern suggestive of respiratory distress syndrome, surfactant treatment was administered. Lung ultrasound (LU) was used for monitoring the responsiveness to surfactant; severe pulmonary hypertension ensued, followed by respiratory failure, refractory shock, and death within 48 h. Owing to the poor response to the established therapy, ACD/MPV was suspected. The diagnosis was confirmed through autopsy. The main goal of this case report is to show the role of LU for monitoring the evolution of this disorder.

CONCLUSION

LU could provide essential information to help diagnose and follow-up the underlying cause of persistent pulmonary hypertension of the newborn in an earlier and more effective way than chest X-ray. LU is suitable for routine monitoring of lung disease in the NICU.

Pulmonary Sonography - Neonatal Diagnosis Part 1

Diseases of the respiratory system are among the main problems of premature patients in the neonatal intensive care unit. Radiography of the thorax is the gold standard of imaging. This results in high cumulative radiation exposure with potential negative long-term consequences. Ultrasound examination of thoracic structures represents a promising radiation-free and ubiquitously available alternative.A healthy, ventilated lung can only be imaged via artifacts, since total reflection of the sound waves occurs due to the high impedance difference between tissue and air-filled lung. Pathologies of pleura and subpleural lung tissue lead to changes in the acoustic properties of the tissue and thus to variations in the artifacts that can be imaged. The main sonographic characteristics of pulmonary pathology are: pleural line abnormalities, increased B-lines and comet-tail artifacts, lung consolidations, a visible pulmonary pulse, pleural sliding abnormalities, and visualization of effusions. Deviations from normal sonographic findings can be assigned to specific underlying pathophysiologies, so that conclusions about the disease can be drawn in conjunction with the clinical symptoms.

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.

Lung Ultrasound Role in Diagnosis of Neonatal Respiratory Disorders: A Prospective Cross-Sectional Study

Lung ultrasound (LUS) has become one of the most exciting applications in neonatal point-of-care ultrasound (POCUS), yet still lacks routine clinical use. This study assesses the utility of LUS for neonatal respiratory disorders (NRDs) diagnosis and follow-up compared to chest X-ray (CXR). A prospective cross-sectional study was conducted on 100 neonates having NRDs with a gestational age ≥28 weeks, excluding those having multiple congenital anomalies, chromosomal aberrations, hydrops fetalis and/or heart failure. CXR and LUS were done on admission for diagnosis and were repeated after 7 days, or if needed earlier within the 7 days. The diagnosis of NRDs by CXR and LUS on admission and after 7 days was comparable (p > 0.05). LUS diagnosis sensitivity and specificity for respiratory distress syndrome, pneumonia, meconium aspiration syndrome, pneumothorax and pulmonary atelectasis were 94.7/100%, 97.5/95%, 92.3/100%, 90.9/98.9% and 100/97.8%, respectively. The total agreement between LUS and CXR was 98.5% with 95% CI (0.88 to 0.92). LUS and CXR had considerable agreement in the diagnosis of NRDs. Being a reliable bedside modality of diagnosis and safer than CXR, LUS may be considered an alternative method for the diagnosis of neonates with NRDs.

Targeted neonatal echocardiography and lung ultrasound in preterm infants with chronic lung disease with and without pulmonary hypertension, screened using a standardized algorithm

Introduction

Increased recognition of the development of chronic pulmonary hypertension (cPH) in preterm infants with chronic lung disease (CLD) has prompted enhanced monitoring for the identification of different phenotypes.

Methods

All newborns consulted for oxygen/respiratory support dependency (CLD assessment) from January 2018 to December 2021 were included. TnECHO and LUS screening for cPH-CLD were performed at 36 weeks postmenstrual age. Cases of cPH related to increased pulmonary blood flow (cPH-IPBF) were referred to Pediatric Cardiology. The objective of the study was to identify all cases of cPH (cPH-CLD/IPBF) in the CLD patients screened and to compare outcomes. Following a standardized algorithm, cPH-CLD patients were treated with diuretics; ultrasounds taken before and after treatment were analyzed.

Results

Seventy-two patients with CLD were screened. Twenty-two (30%) had cPH-CLD, and nine (12%) had cPH-IPBF. cPH infants underwent more days of mechanical ventilation, were more likely to have retinopathy of prematurity, and showed increased mortality. The LUS pattern observed in the 72 CLD patients consisted of a thickened pleural line and a B-line interstitial heterogeneous pattern; 29% of patients were found to have lung consolidations. After diuretic therapy, step-down in respiratory support occurred in 59% of neonates with cPH-CLD. A decrease in respiratory rate (RR), right ventricular output (RVO), markers of pulmonary vascular resistance (PVR), and B-line pattern was observed. In tissue Doppler imaging, biventricular diastolic function was found to be modified after diuretics.

Conclusions

CLD infants with cPH showed increased morbidity and mortality. In cPH-CLD patients, a decrease in RR and step-down in respiratory support was observed after diuretic treatment. Follow-up ultrasound showed a decrease in RVO, markers of PVR, and B-lines.

To B or not to B. The rationale for quantifying B-lines in pediatric lung diseases

Lung ultrasound (LUS) is emerging as adjunct tool to be used during clinical assessment. Among the different hallmarks of LUS, B-lines are well known artifacts, which are not correlated with identifiable structures, but which can be used for pathological classification. The presence of multiple B-lines is a sonographic sign of lung interstitial syndrome. It has been demonstrated in adults that there is a direct correlation between the number of B-lines and the severity of the interstitial involvement of lung disease. Counting B-lines is an attempt to enrich the clinical assessment and clinical information, beyond obtaining a simple dichotomous answer. Semiquantitative or quantitative B-line assessment has been shown to correlate with fluid overload and demonstrated prognostic implications in specific neonatal and pediatric conditions. LUS with quantitative B-lines assessment is promising. Current evidence allows for quantification of B-lines in a limited number of neonatal and pediatric diseases.

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 to diagnose infectious pneumonia of newborns: A prospective multicenter study

INTRODUCTION

Whether lung ultrasound (LUS) can be used for pathogenic diagnosis remains controversial. This study was conducted to clarify whether ultrasound has diagnostic value for etiology.

METHODS

A total of 135 neonatal pneumonia patients with an identified pathogen were enrolled from the newborn intensive care units of 10 tertiary hospitals in China. The study ran from November 2020 to December 2021. The infants were divided into various groups according to pathogens, time of infection, gestational age, and disease severity. The distribution of pleural line abnormalities, B-line signs, and pulmonary consolidation, as well as the incidence of air bronchogram and pleural effusion based on LUS, were compared between these groups.

RESULTS

There were significant differences in pulmonary consolidation. The sensitivity and specificity of the diagnosis of severe pneumonia based on the extent of pulmonary consolidation were 83.3% and 85.2%, respectively. The area under the receiver operating characteristic curve for the identification of mild or severe pneumonia based on the distribution of pulmonary consolidation was 0.776.

CONCLUSION

LUS has good performance in diagnosing and differentiating the severity of neonatal pneumonia but cannot be used for pathogenic identification in the early stages of pneumonia.

Unnecessary radiation exposure during diagnostic radiography in infants in a neonatal intensive care unit: a retrospective cohort study

Unnecessary radiation exposure (URE) during radiographic examination is an issue among infants in neonatal intensive care units (NICUs). The causes of URE have not been fully explored. This study investigated the incidence and identified the causes of URE in infants during diagnostic radiography in a NICU. This was a retrospective cohort study. We retrieved and analysed requests and radiographs taken at a tertiary NICU between September and November 2018. URE was defined as the rate of discordance between requests and images taken (DisBRI) and unnecessary radiation exposure in irrelevant regions (UREIR) during radiography. We compared the rates of URE between very low-birth-weight (VLBW, birth weight < 1500 g) infants and non-VLBW infants. A total of 306 radiographs from 88 infants were taken. The means ± standard deviations (SDs) of gestational age and birth weight were 35.7 ± 3.6 weeks and 2471 ± 816 g, respectively. Each infant underwent an average of 3.5 radiographs. The DisBRI rate was 1.3% and was mostly related to poor adherence to requests. The UREIR rates in thoraco-abdominal babygrams were 89.6% for the head, 14.8% for the elbows and 18.4% for the knee and were mainly related to improper positioning of and collimation in infants while performing radiography. The UREIR rates for the head, knee and ankle were higher in VLBW infants than in non-VLBW infants (94.6% vs. 85.6%, 27.0% vs. 11.5% and 5.4% vs. 0.7%, respectively, p < 0.05).

CONCLUSIONS

URE during diagnostic radiography is common in sick infants and is mainly related to improper positioning and collimation during examinations. Adherence to protocols when performing radiographic examination or using ultrasonography may be a solution to reduce URE in infants in NICUs.

WHAT IS KNOWN

• The risk of unnecessary radiation exposure (URE) during radiography has been a common and important issue in sick infants in neonatal intensive care units (NICUs). • The new point-of-care ultrasound (POCUS) technique decreases the need for chest films and prevents radiation exposure in neonates.

WHAT IS NEW

• In the NICU, URE is still a common issue in critically ill infants during radiographic examinations. The causes of URE during diagnostic radiography are mainly due to improper positioning and collimation during examinations. • The incidence of URE in irrelevant regions is higher in very low-birth-weight (VLBW) infants than in non-VLBW infants.

Evolution of Ultrasound-Assessed Lung Aeration and Gas Exchange in Respiratory Distress Syndrome and Transient Tachypnea of the Neonate

OBJECTIVE

To use clinical, lung ultrasound, and gas exchange data to clarify the evolution of lung aeration and function in neonates with respiratory distress syndrome (RDS) and transient tachypnea of the neonate (TTN), the most common types of neonatal respiratory failure.

STUDY DESIGN

In this prospective observational cohort study, lung aeration and function were measured with a semiquantitative lung ultrasound score (LUS) and transcutaneous blood gas measurement performed at 1 hour (time point 0), 6 hours (time point 1), 12 hours (time point 2), 24 hours (time point 3) and 72 hours (time point 4) of life. Endogenous surfactant was estimated using lamellar body count (LBC). LUS, oxygenation index (OI), oxygen saturation index (OSI), and transcutaneous pressure of carbon dioxide (PtcCO₂) were the primary outcomes. All results were adjusted for gestational age.

RESULTS

Sixty-nine neonates were enrolled in the RDS cohort, and 58 neonates were enrolled in the TTN cohort. LUS improved over time (within-subjects, P < .001) but was worse for the RDS cohort than for the TTN cohort at all time points (between-subjects, P < .001). Oxygenation improved over time (within-subjects, P = .011 for OI, P < .001 for OSI) but was worse for the RDS cohort than for the TTN cohort at all time points (between-subjects, P < .001 for OI and OSI). PtcCO₂ improved over time (within-subjects, P < .001) and was similar in the RDS and TTN cohorts at all time points. Results were unchanged after adjustment for gestational age. LBC was associated with RDS (β = -0.2 [95% CI, -0.004 to -0.0001]; P = .037) and LUS (β = -3 [95% CI, -5.5 to -0.5]; P = .019).

CONCLUSIONS

For the first 72 hours of life, the RDS cohort had worse lung aeration and oxygenation compared with the TTN cohort at all time points. CO₂ clearance did not differ between the cohorts, whereas both lung aeration and function improved in the first 72 hours of life.

The Essentials about Neonatal Severe Acute Respiratory Syndrome Coronavirus 2 Infection and Coronavirus Disease: A Narrative Review

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can occur in neonates as the virus can be transmitted both horizontally (from the environment) and vertically (during the pregnancy or at the delivery). Compared to the adult outbreak, neonatal infections do not represent a public health problem. Nonetheless, severe and life-threatening cases may rarely occur and both obstetricians and neonatologists should have a good knowledge of perinatal SARS-CoV-2 infection and related consequences. A high suspicion index must be applied and ruling out neonatal SARS-CoV-2 infection must become a part of the routine clinical workout. Moreover, neonates may be affected by the multisystem inflammatory syndrome, due to a dysregulated host response in the absence of any SARS-CoV-2 infection. We performed a narrative review to summarize here the available literature describing the essentials that should be known by every neonatologist and obstetrician, starting from what has been discovered in 2020 and adding what has been learned in the following years. The paper describes the mechanisms of transmission, clinical features, diagnostic tools, and criteria, as well as possible treatment and prevention strategies. The goal is to provide the practical points to be remembered at the bedside while caring for a pregnant woman or a neonate with suspected or proven coronavirus disease 2019 or multisystem inflammatory syndrome. KEY POINTS: · SARS-CoV-2 neonatal infections occur both vertically (30%) and horizontally (70%).. · Approximately, half of patients do not have clinical manifestations; clinical and laboratory signs are similar to those of adults but usually milder.. · Remdesivir and steroids can be used as a treatment..

Lung ultrasound score follows the chronic pulmonary insufficiency of prematurity trajectory in early infancy

Extremely preterm birth is associated with a high risk of chronic pulmonary insufficiency of prematurity (CPIP). Lung ultrasound score (LUS) proved capable to characterise CPIP progression beyond the acute setting, but still, post-discharge data remain lacking. We hypothesised a priori that LUS in both BPD and no-BPD infants declines with postnatal age from birth through early infancy. This observational retrospective cohort study included preterm infants < 32 gestational weeks, who underwent the follow-up for CPIP. LUS was assessed from birth to 8 months postnatal age, over antero-lateral (LUS) and posterior (pLUS) pulmonary areas, placing the transducer longitudinally over the midclavicular and midaxillary lines and medial to the scapular line respectively. Extended LUS (eLUS) including LUS and pLUS was calculated. The primary outcome was LUS time course. Secondary outcomes included the correlation between LUS and pLUS. Sixty-two infants were included: 22 (35.5%) in the BPD group and 40 (64.5%) in the no-BPD group. BPD group infants were smaller (weight 841 g (± 228) vs 1226 (± 328), p < 0.001) and younger (26.8 weeks (± 2.0) vs 28.9 (± 1.9), p < 0.001). LUS declined over time in the entire population (ß =  - 1.75, p < 0.001) and in both no-BPD and BPD groups (ß =  - 1.64, p < 0.001 and ß =  - 1.93, p < 0.001, respectively). eLUS declined correspondingly (p < 0.001). LUS and likewise eLUS were significantly different between BPD and no-BPD groups over time (p < 0.001).  Conclusion: LUS trajectory progressively decreased from birth to early infancy. BPD cohort tracked higher, implying a worse respiratory status. pLUS had a similar timepoint course, adding no further information to LUS. To the best of our knowledge, this is the first study that describes preterm LUS time course after discharge. LUS may help track the CPIP progression. What is Known: • Extremely preterm birth is associated with high risk of chronic pulmonary insufficiency of prematurity (CPIP). • Several studies investigated the ability of lung ultrasound score (LUS) to characterize CPIP progression beyond the acute setting, still post-discharge data remain lacking. What is New: • LUS trajectory progressively decreases from birth to early infancy; BPD cohort tracks higher, implying a worse respiratory status. pLUS has similar timepoint course, adding no further information to LUS. • The use of LUS may contribute to better characterising and monitoring CPIP in BPD and no-BPD infants.

Use of Point-of-Care Ultrasonography in the NICU for Diagnostic and Procedural Purposes

Point-of-care ultrasonography (POCUS) refers to the use of portable imaging performed by the provider clinician at the bedside for diagnostic, therapeutic, and procedural purposes. POCUS could be considered an extension of the physical examination but not a substitute for diagnostic imaging. Use of POCUS in emergency situations can be lifesaving in the NICU if performed in a timely fashion for cardiac tamponade, pleural effusions, pneumothorax, etc, with potential for enhancing quality of care and improving outcomes.

In the past 2 decades, POCUS has gained significant acceptance in clinical medicine in many parts of the world and in many subspecialties. Formal accredited training and certification programs are available for neonatology trainees as well as for many other subspecialties in Canada, Australia, and New Zealand. Although no formal training program or certification is available to neonatologists in Europe, POCUS is widely available to providers in NICUs. A formal institutional POCUS fellowship is now available in Canada. In the United States, many clinicians have the skills to perform POCUS and have incorporated it in their daily clinical practice. However, appropriate equipment remains limited, and many barriers exist to POCUS program implementation.

Recently, the first international evidence-based POCUS guidelines for use in neonatology and pediatric critical care were published. Considering the potential benefits, a recent national survey of neonatologists confirmed that the majority of clinicians were inclined to adopt POCUS in their clinical practice if the barriers could be resolved.

This technical report describes many potential POCUS applications in the NICU for diagnostic and procedural purposes.

Lung ultrasound to evaluate lung recruitment in neonates with respiratory distress (RELUS study)

BACKGROUND

Lung ultrasound (LUS) is a bedside tool useful to diagnose neonatal respiratory disease and to guide surfactant therapy. LUS scores have emerged as useful tool for newborn respiratory distress but is unknown if respiratory support settings may influence it. The aim of the study was to evaluate the feasibility of LUS scores evaluating lung recruitment in term newborns with respiratory distress when noninvasive respiratory it is increased.

MATERIAL AND METHODS

Prospective study in a tertiary neonatal intensive care unit. Inclusion criteria were term neonates with respiratory distress requiring noninvasive respiratory support with nasal continuous positive airway pressure (nCPAP) within first 6 h of life with an LUS score higher than 8 were enrolled. LUS was performed three times. First LUS (LUS-1) was done in patients in nCPAP (Fabian Device) (Acutronic) (pressure of 6 cmH₂ O). Afterwards patients were placed in duo positive airway pressure (12/6 cmH₂ O), a second LUS (LUS-2) was performed immediately and a third (LUS-3) was done 2 h later on the same respiratory support. The primary outcome was to compare LUS scores in the different timelines. Second outcomes were to evaluate the level of respiratory distress and oxygenation were evaluated with SpO₂ /fraction of inspired oxygen (FiO₂ ) ratio (S/F ratio), FiO₂  ratio, respiratory rate, and blood gas analysis which were analyzed during the LUS-1 and the LUS-3. To evaluate newborn discomfort, patients were evaluated with Crying Requires oxygen Increased vital signs Expression Sleep (CRIES) scale.

RESULTS

Forty neonates were enrolled. Fifty percent were female (n = 20), median gestational age was 38 + 4 (interquartile range [IQR]: 37 + 5-39 + 4) with a median weight of 3155 g (IQR: 2637-3532). Duration of non invasive ventilation support was 72 h (IQR: 54-96). None of the patients required surfactant therapy or mechanical ventilation. LUS scores were no different between LUS-1 9 (IQR: 8.3-10) and LUS-2 9 (IQR: 8.3-10) (p = 0.675) but there were differences between LUS-1 and LUS-3 7 (IQR: 6.3-8.5) (p = 0.036). There was an improvement in the oxygen parameters, respiratory rate, and CO₂ between LUS-1 and LUS-3 (p < 0.001). There were no changes in the CRIES scale.

CONCLUSIONS

There is an improvement in clinical and laboratory parameters after the increasing of respiratory support in newborns with noninvasive ventilation. We observe a correlation with an improvement in the assessment of lung aeration were evaluated with LUS score.

Lung ultrasound findings in asymptomatic healthy children with asthma

BACKGROUND

Lung ultrasound (LUS) has been shown to be an effective tool to rapidly diagnose certain causes of pediatric respiratory distress. However, very little is known about LUS findings in pediatric asthma.

OBJECTIVES

The primary objective of this study was to characterize LUS findings in a cohort of pediatric patients with a definitive diagnosis of asthma, outside of an asthma exacerbation.

METHODS

Eligible patients, aged 6-17 years old and diagnosed with asthma, underwent LUS during an outpatient visit. LUS was conducted using a six-zone scanning protocol. Presence of a LUS artifact was defined by one or more of the following: ≥3 B-lines per intercostal space, pulmonary consolidation, and/or pleural abnormality. Images were interpreted by an expert sonographer blinded to patient clinical characteristics.

RESULTS

Fifty-two patients were included. 10/52 (19.2%) patients demonstrated the presence of LUS artifacts: 8 with ≥3 B-lines, 1 with consolidation >1 cm, and 7 with subpleural consolidations <1 cm, 1 with a pleural line abnormality. Artifacts were seen in the right anterior and lateral zones in 60% of participants and were limited to 1-2 intercostal space(s) within one lung zone in all participants. No association was found between presence of LUS artifacts and asthma control or severity.

CONCLUSION

To our knowledge, this is the first report of LUS findings in outpatient pediatric asthma. LUS artifacts in asthmatic children can be seen outside of acute exacerbations. Such baseline findings need to be taken into consideration when using LUS for the acute evaluation of a pediatric patient with asthma.

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.