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

The efficacy of lung ultrasound scores-directed pulmonary surfactant treatment in preterm infants with respiratory distress syndrome: a randomized controlled pilot study

BACKGROUND

Pulmonary surfactant therapy is critical for preterm infants with respiratory distress syndrome (RDS). Lung ultrasound (LUS) offers a noninvasive, radiation-free alternative for assessing RDS severity and guiding surfactant therapy.

METHODS

Eighty-two preterm infants with RDS were randomized to receive surfactant based on either LUS scores or a conventional clinical-radiological assessment, comparing the duration of mechanical ventilation, supplemental oxygen need, NICU stay, incidence of bronchopulmonary dysplasia (BPD), and mortality.

RESULTS

No significant differences were found between the groups in terms of mechanical ventilation duration (average 4.1 vs. 4.3 days), supplemental oxygen need (average 5.7 vs. 6.1 days), or NICU stay (average 15.4 vs. 15.9 days). The incidence of BPD was 4.9% in both groups, and there were no deaths reported.

CONCLUSIONS

LUS-directed surfactant treatment did not show significant difference compared to the traditional methods, suggesting its potential as a noninvasive alternative for RDS management in preterm infants.

Serial lung ultrasound in predicting the need for surfactant and respiratory course in preterm infants-multicentre observational study (SLURP)

Lung ultrasound (LUS) scores may predict surfactant need early and the progression of the respiratory course in preterm infants. The objective of this study is to report the diagnostic value of LUS scores performed by operators of varying levels of experience to predict the need for surfactant in preterm infants. A prospective observational study was conducted across 3 UK-based neonatal intensive care units. Preterm infants ≤ 34 weeks on non-invasive respiratory support within 3 h of birth were included. Ten lung zones were scored serially, first within the first 3 h of life, then at 12-24-h intervals (a total of four scans). All scans were performed by the local team members with formal training on LUS and varying levels of expertise. All the LUS videos were scored by an expert investigator who was blinded to clinical details. Written retrospective parental consents were obtained. We recruited 83 preterm infants ≤ 34 weeks (May 2023 to June 2024). A total of 325 LUS scans were performed by 27 clinical staff. The median birth gestational age and birth weight were 31 weeks and 1515 g, respectively. Twenty-eight (34%) babies received surfactants. The first LUS using a 6-zone method within 3 h of life predicted surfactant need and bronchopulmonary dysplasia with an AUC of 0.80 for both outcomes, offering sensitivity (79% and 73%) and specificity (75% and 76%), respectively.

CONCLUSIONS

 LUS performed by operators of varying levels of experience within the first 3 h of life is a reliable tool for predicting surfactant need in preterm infants ≤ 34 weeks.

TRIAL REGISTRATION

ClinicalTrials.gov ( https://clinicaltrials.gov/ ): NCT05782569.

WHAT IS KNOWN

• There are considerable variations in the selection criteria of preterm infants for surfactant administration. • Lung ultrasound score has been shown to predict the need for surfactant early and the progression of respiratory course in preterm infants.

WHAT IS NEW

• LUS performed within 3 h of life by operators of varying levels of experience and interpreted by expert predicted the need for surfactant deficiency in preterm infants. • Our research with a structured training programme enabled novice operators to perform LUS and achieve reasonable competency.

ESICM-ESPNIC international expert consensus on quantitative lung ultrasound in intensive care

PURPOSE

To provide an international expert consensus on technical aspects and clinical applications of quantitative lung ultrasound in adult, paediatric and neonatal intensive care.

METHODS

The European Society of Intensive Care (ESICM) and the European Society of Paediatric and Neonatal Intensive Care (ESPNIC) endorsed the project. We selected an international panel of 20 adult, paediatric and neonatal intensive care experts with clinical and research expertise in quantitative lung ultrasound, plus two non-voting methodologists. Fourteen clinical questions were proposed by the chairs to the panel, who voted for their priority (1-9 Likert-type scale) and proposed modifications/supplementing (two-round vote). All the questions achieved the predefined threshold (mean score > 5) and 14 groups of 3 mixed adult/paediatric experts were identified to develop the statements for each clinical question; predefined groups of experts in the fields of adult and paediatric/neonatal intensive care voted statements specific for these subgroups. An iterative approach was used to obtain the final consensus statements (two-round vote, 1-9 Likert-type scale); statements were classified as with agreement (range 7-9), uncertainty (4-6), disagreement (1-3) when the median score and ≥ 75% of votes laid within a specific range.

RESULTS

A total of 46 statements were produced (4 adults-only, 4 paediatric/neonatal-only, 38 interdisciplinary); all obtained agreement. This result was also achieved by acknowledging in the statements the current limitations of quantitative lung ultrasound.

CONCLUSION

This consensus guides the use of quantitative lung ultrasound in adult, paediatric and neonatal intensive care and helps identify the fields where further research will be needed in the future.

Predicting Surfactant Need at Birth: Failed Validation of a Bedside Method Using Gastric Aspirates

AIM

To validate a prototype point-of-care (POC) test for the lecithin/sphingomyelin (L/S) ratio by identifying the optimal L/S cut-off for predicting surfactant need in preterm infants < 30 weeks' gestation using gastric aspirates (GAS) sampled at birth and to assess clinical feasibility.

METHODS

GAS was sampled within 45 min of birth and analysed using the only available prototype POC L/S test. The primary outcome was the optimal L/S cut-off and diagnostic accuracy in predicting rescue surfactant treatment per European RDS guidelines, assessed by receiver operating characteristics. L/S results were blinded to clinicians. Due to a dispute between clinical investigators and patent holders, legal restrictions prohibit reporting of the primary outcome.

RESULTS

Of 93 eligible infants, 25 were not included: Six cases (6%) had no GAS available, 12 infants (13%) received surfactant before sampling and 7 (8%) other reasons. Of 68 included, 42 (62%) received surfactant, and 40% were treated within 2 h of life (median: 147 min [IQR: 89; 327]).

CONCLUSION

We aimed to validate a POC L/S test but are legally restricted from disclosing results. Clinical applicability seems limited, as a substantial proportion of infants had no GAS available or required surfactant before sampling. The potential to accelerate treatment appears limited.

Characteristics of scores used for quantitative lung ultrasound in neonates: a systematic review

BACKGROUND

Quantitative lung ultrasound is increasingly being used in neonatology. The aim of this study is to identify the lung ultrasound scores (LUS) available for use in neonates, describe their characteristics and determine which LUS are most used and validated.

METHODS

A systematic review of the literature was conducted following PRISMA-S (Preferred Reporting Items for Systematic Reviews and Meta-analysis Protocols extension for reporting literature searches in systematic reviews) guidelines. Articles describing LUS in newborn animals and human neonates, published up to March 2024, were searched in the PubMed and Embase databases.

RESULTS

Out of 757 identified studies, 121 were included. Most of the articles were published in the past 5 years, predominantly by European investigators. They described 32 different LUS. Only 10 (31.4%) of these LUS had undergone at least one validation attempt and only 15 (48.4%) used the four-step scoring scale (i.e. scored from 0 to 3) based on classical lung ultrasound patterns originally described and well established in adult critical care medicine. The most common (49 (40.5%) of all the articles) neonatal score (published by Brat et al. in 2015) was based on this classical grading system. The most commonly used score was also validated using the greatest number of techniques and applied to all major neonatal respiratory disorders. Its simplified version is used to analyse six chest areas (anterior and lateral) to guide surfactant administration, while its extended version includes 10 areas by adding four posterior ones.

CONCLUSIONS

The most commonly used and validated score, consistent with adult critical care practice, should be the standard for assessing lung aeration in neonates.

Guidelines for the use of lung ultrasound to optimise the management of neonatal respiratory distress: international expert consensus

BACKGROUND

Respiratory distress is the main reason for the admission of infants to the neonatal intensive care unit (NICU). Rapid identification of the causes of respiratory distress and selection of appropriate and effective treatment strategies are important to optimise favourable short- and long-term patient outcomes. Lung ultrasound (LUS) technology has become increasingly important in this field. According to the scientific literature, LUS has high sensitivity (92-99%) and specificity (95-97%) in diagnosing neonatal respiratory distress syndrome. This diagnostic power helps guide timely interventions, such as surfactant therapy and mechanical ventilation.

METHODS

Our objective was to outline consensus guidelines among an international panel of experts on the use of LUS to support the decision-making process in managing respiratory distress in the NICU. We used a three-round Delphi process. In each Delphi round, 28 panellists rated their level of agreement with each statement using a four-point Likert scale.

RESULTS

In round 1, the panellists reviewed 30 initially proposed statements. In rounds 2 and 3, the statements were redeveloped based on the reviewers' comments, leading to the final approval of 18 statements. Among the 18 consensus statements, grade A was assigned a value of 10, grade B was assigned a value of 7, and grade C was assigned a value of 1.

CONCLUSIONS

A panel of experts agreed on 18 statements regarding managing infants with respiratory distress. Using LUS may help design future interventional studies and improve the benchmarking of respiratory care outcomes.

A Refined Score, Namely Thoracic Ultrasound Score, to Predict the Need for Surfactant in Preterm Neonates: A Prospective, Multicenter, Observational Study

INTRODUCTION

Lung ultrasound score (LUS) is used to predict the need for surfactant in preterm neonates. Its performance is lower in neonates with a gestational age (GA) ≥ 34 weeks. We developed a score, thoracic ultrasound score (TUS), to overcome the shortcomings of LUS.

OBJECTIVES

To assess the feasibility and diagnostic accuracy of TUS to evaluate oxygenation and predict the need for surfactant administration, compared to LUS.

MATERIALS AND METHODS

This was a prospective, multicenter, observational study. Preterm neonates in noninvasive ventilation with GA between 24 + 0 and 36 + 6 weeks were assessed for eligibility. Lung ultrasound were performed within 3 h of life, and TUS and LUS were calculated.

RESULTS

Fifty-eight neonates who received surfactant were compared with 112 neonates who did not receive surfactant: GA 30.2 ± 3.1 weeks versus 32.6 ± 2.3 weeks, (p < 0.001), and birth weight 1466 ± 674 g versus 1725 ± 519 g, (p = 0.006), respectively. TUS and LUS showed a similar association with S/F ratio (r = -0.670 and r = 0.615) and OSI (r = 0.524 and r = 0.423), all p < 0.001. In neonates with GA < 34 weeks, the AUC (95% CI) was similar: 0.956 (0.923-0.989) versus 0.952 (0.921-0.984). In neonates with GA ≥ 34 weeks, the AUC (95% CI) of TUS was superior to LUS: 0.971 (0.914-1.000) versus 0.797 (0.639-0.980), p = 0.02.

CONCLUSION

Compared to LUS, TUS showed a similar association with the oxygenation status and a superior ability to predict the need for surfactant in neonates with GA ≥ 34 weeks. The latter was similar in neonates with GA < 34 weeks.

A Novel and Promising Method for Prediction of Early Surfactant Requirement in Preterm Infants With Respiratory Distress Syndrome: Pulmonary Near-Infrared Spectroscopy

INTRODUCTION

Non-invasive monitoring techniques have been used more commonly in neonatal clinical practice. The aim of this study was to evaluate the role of lung near-infrared spectroscopy (NIRS) for determination of the severity of Respiratory Distress Syndrome (RDS) and the requirement of surfactant therapy in preterm infants.

METHODS

A total of 60 preterm infants with RDS were evaluated in terms of the requirement of surfactant therapy, as surfactant group (SG) or no-surfactant group (CG). Lung NIRS (L-NIRS), including both basal (bL-rSO2) and apex (aL-rSO2) lung oxygenation monitoring, was performed.

RESULTS

The mean bL-rSO2 values before surfactant treatment were significantly lower in SG (83 ± 10%) than CG (89 ± 5%), (p < 0.01). The mean bL-rSO2 levels of 85% were found to significantly predict early surfactant requirement with 57% sensitivity and 73% specificity (p = 0.02). The mean bL-rSO2 values in the first 4 h were found to be significantly lower in SG who required repeated surfactant (all p < 0.05).

CONCLUSIONS

L-NIRS ≤ 85% values at NICU admission may be used for determination of surfactant therapy in RDS. In addition, lower mean basal L-NIRS values in the first 4 h of life can also be used to guide repeated doses of surfactant. L-NIRS, either alone or in combination with other methods may be used for management of preterm infants with RDS after confirmation of our results by larger clinical studies.

Clinical predictors for surfactant retreatment in preterm infants with respiratory distress syndrome: the results of a pooled analysis

BACKGROUND

The issue of retreatment with surfactant of infants with respiratory distress syndrome (RDS) has been poorly investigated. Our aim was to identify possible clinical predictors of the need for multiple doses of surfactant in a large cohort of very preterm infants.

METHODS

Data were analyzed from three previous studies on infants born between 25+ 0 and 31+ 6 weeks of gestation with RDS who were treated with surfactant.

RESULTS

We studied 448 infants. Among them 306 (68%) were treated with a single dose of surfactant and 142 (32%) were treated with multiple doses. Multivariable mixed effects logistic regression analysis showed that the odd of requiring multiple doses of surfactant was significantly lower in patients with higher gestational age (27-28 vs. 25-26 wks: OR 0.46, 95% C.l. 0.26-0.79; ≥29 vs. 25-26 wks: OR 0.34, 95% C.l. 0.13-0.85; overall P = 0.013), while it increased in infants born to mothers with hypertensive disorders of pregnancy (OR 2.53, 95% C.l. 1.49-4.31; P < 0.001) and with hemodynamically significant PDA (OR 2.74, 95% C.l. 1.66-4.53, P < 0.001).

CONCLUSIONS

Gestational age, hypertension in pregnancy, and hemodynamically significant PDA can predict the need for multiple doses of surfactant. Further investigation is needed to evaluate if these sub-groups of preterm infants represent specific phenotypes of RDS who deserve a peculiar surfactant treatment.

Deep learning approaches for automated classification of neonatal lung ultrasound with assessment of human-to-AI interrater agreement

Neonatal respiratory disorders pose significant challenges in clinical settings, often requiring rapid and accurate diagnostic solutions for effective management. Lung ultrasound (LUS) has emerged as a promising tool to evaluate respiratory conditions in neonates. This evaluation is mainly based on the interpretation of visual patterns (horizontal artifacts, vertical artifacts, and consolidations). Automated interpretation of these patterns can assist clinicians in their evaluations. However, developing AI-based solutions for this purpose is challenging, primarily due to the lack of annotated data and inherent subjectivity in expert interpretations. This study aims to propose an automated solution for the reliable interpretation of patterns in LUS videos of newborns. We employed two distinct strategies. The first strategy is a frame-to-video-level approach that computes frame-level predictions from deep learning (DL) models trained from scratch (F2V-TS) along with fine-tuning pre-trained models (F2V-FT) followed by aggregation of those predictions for video-level evaluation. The second strategy is a direct video classification approach (DV) for evaluating LUS data. To evaluate our methods, we used LUS data from 34 neonatal patients comprising of 70 exams with annotations provided by three expert human operators (3HOs). Results show that within the frame-to-video-level approach, F2V-FT achieved the best performance with an accuracy of 77% showing moderate agreement with the 3HOs. while the direct video classification approach resulted in an accuracy of 72%, showing substantial agreement with the 3HOs, our proposed study lays down the foundation for reliable AI-based solutions for newborn LUS data evaluation.

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.

Less Invasive Surfactant Administration for Preterm Infants - State of the Art

BACKGROUND

Less invasive surfactant administration (LISA) has become the preferred method of surfactant administration for spontaneously breathing babies on continuous positive airway pressure (CPAP).

SUMMARY

The development of LISA followed the need to combine CPAP and surfactant replacement as mainstay treatment options for respiratory distress syndrome, thereby avoided exposure to positive pressure ventilation.

KEY MESSAGES

This review summarises the current knowns and unknowns of LISA including the physiological concept, its relevance for short-term and long-term outcomes and the challenges for practical implementation of LISA as part of a less invasive respiratory care bundle. Further, we provide an update of the evidence on alternatives to LISA, for example, nebulised surfactant administration, pharyngeal deposition of surfactant and delivery via supraglottic airway.

Substantiating and Adopting Lung Ultrasound Scores to Predict Surfactant Need in Preterm Neonates with Respiratory Distress Syndrome within an Institution

OBJECTIVE

 Administering surfactant timely and appropriately is important to minimize lung injury but remains challenging in preterm neonates with respiratory distress syndrome. The published literature supports that lung ultrasound (LUS) score can predict surfactant need. Neonatal LUS scanning specification and parameter setting guidelines have been recently published for standardization. However, variations in scanning protocols and machine settings hinder its clinical implementation widely. This observational study aims to internally validate the suggested LUS protocol in a neonatal intensive care unit to establish a correlation between LUS scores and surfactant need as the first step of integrating LUS in the clinical practice.

STUDY DESIGN

 LUS was performed on 40 eligible preterm neonates within 3 hours after birth or before surfactant administration between May 2020 and March 2021. The neonates were between 27 and 32 weeks' gestational age, and all had respiratory distress. Neonates with known congenital anomalies were excluded. A high-frequency linear probe was used to obtain LUS images from six lung zones which were scored using a 0 to 3 system, yielding a maximum of 18 points. Treating physicians were blinded to the LUS score. Receiver operating characteristic analysis determined the optimal LUS score cut-off for predicting surfactant need.

RESULTS

 Fifteen of the 40 neonates (38%) required higher oxygen fraction and received surfactant. In our cohort, an LUS score ≥10 was identified as the optimal cut-off for predicting surfactant need, with a sensitivity of 80% and specificity of 84%. The area under the curve was 0.8 (p = 0.0003). LUS predicted surfactant need at a median of 3.5 hours earlier than traditional clinical decision (p < 0.0037).

CONCLUSION

 LUS is a helpful adjunct for predicting surfactant need in preterm neonates. This study describes an approach to implement the LUS protocol and score for clinical decision-making in the clinical practice.

KEY POINTS

· LUS is a helpful adjunct for predicting surfactant need in preterm neonates.. · Machine setting variation and probe selection may affect LUS image and score.. · LUS score should be validated at the local unit before clinical implementation..

Lung Ultrasound Score for Prediction of Surfactant Administration in Preterm Infants with Respiratory Failure

OBJECTIVE

We investigated the predictive value of a lung ultrasound score (LUS) for surfactant administration in a United States Level 4 Neonatal Intensive Care Unit.

STUDY DESIGN

Thirty infants born at <37 weeks gestational age with respiratory distress syndrome associated respiratory failure requiring continuous positive airway pressure were included. A LUS was obtained within six hours of life. Surfactant administration in the first five days of life was recorded. Receiver operating characteristic (ROC) analysis for LUS and surfactant administration was performed.

RESULTS

Median completed gestational age was 33 weeks (31-34 weeks interquartile range) and median birth weight was 2.0 kg (1.5-2.3 kg). LUS for predicting an initial surfactant dose had an area under the ROC curve of 0.97. A score > 9 provided 100% sensitivity and 91% specificity for predicting administration of an initial surfactant dose.

CONCLUSION

A LUS > 9 provided excellent sensitivity and specificity for predicting which infants will receive surfactant for associated respiratory failure.

Predictors of CPAP failure after less-invasive surfactant administration in preterm infants

Introduction

Less-invasive surfactant administration (LISA) is associated with better respiratory outcomes in preterm infants with respiratory distress syndrome. However, mechanical ventilation (MV) shortly after the LISA procedure has been related to lower survival. This study aimed to analyze the trends and main predictors of continuous positive airway pressure (CPAP) failure after LISA.

Material and methods

Preterm infants born between 230 and 336 weeks gestational age (GA) in two level III neonatal units who received surfactant were included (2017-2022). Demographic data, lung ultrasound (LUS) scores, the saturation/fraction of inspired oxygen (SF) ratio, technique, time to surfactant administration, and the main neonatal outcomes were collected.

Results

Over the study period, 289 inborn preterm infants received surfactant, 174 with the LISA method (60.2%). Patients who received surfactant after intubation in the delivery room (n = 56) were more immature and exhibited worse outcomes. Patients who received surfactant via an endotracheal tube in the neonatal intensive care unit (n = 59) had higher LUS scores and a lower SF ratio than those treated with LISA. The LISA method was associated with less death or bronchopulmonary dysplasia (BPD), with an adjusted odds ratio (aOR) = 0.37 [95% confidence interval (CI), 0.18-0.74, p = 0.006]. CPAP failure after LISA (defined as the need for intubation and MV in the first 72 h of life) occurred in 38 patients (21.8%), inversely proportional to GA (38.7% at 23-26 weeks, 26.3% at 27-30 weeks, and 7.9% at 30-33 weeks (p < 0.001). CPAP failure after LISA was significantly related to death, with an aOR = 12.0 (95% CI, 3.0-47.8, p < 0.001), and moderate to severe BPD, with an aOR = 2.9 (95% CI, 1.1-8.0, p = 0.035), when adjusting for GA. The best predictors of CPAP failure after LISA were GA, intrauterine growth restriction, temperature at admission, the SF ratio, and the LUS score, with a Nagelkerke's R 2 = 0.458 (p < 0.001). The predictive model showed an area under the curve = 0.84 (95% CI, 0.75-0.93, p < 0.001).

Conclusions

CPAP failure after LISA is still common in extremely preterm infants, leading to an increase in death or disability. Clinicians must acknowledge the main risk factors of CPAP failure to choose wisely the right patient and the best technique. LUS and the SF ratio at admission can be useful when making these decisions.

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.

Setting the Standards: Neonatal Lung Ultrasound in Clinical Practice

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

Lung and diaphragm ultrasound as predictors of successful weaning from nasal continuous positive airway pressure in preterm infants

OBJECTIVE

Assessment of the utility of lung and diaphragm ultrasound in the prediction of successful weaning from nasal continuous positive airway pressure (NCPAP) in preterm infants.

STUDY DESIGN

This prospective cohort study was conducted on preterm infants who were considered ready for weaning off NCPAP. Lung and diaphragm ultrasound were performed just before and 3 h after weaning off NCPAP. The primary outcome was to evaluate the accuracy of lung ultrasound (LUS) in predicting successful weaning from NCPAP.

RESULTS

Out of 65 enrolled preterm infants, 30 (46.2%) were successfully weaned from NCPAP to room air. The successful weaning group had higher gestational ages, lower incidences of previous invasive mechanical ventilation, and treated hemodynamically significant patent ductus arteriosus before the trial weaning. A LUS score of ≤6, measured before discontinuation of NCPAP, exhibited a predictive sensitivity of 80% and specificity of 75% for successful weaning (Area under the curve (AUC) = 0.865,  ≤.001). When the LUS score was assessed 3 h after weaning from NCPAP, a cutoff point of ≤7 predicted successful weaning with a sensitivity and specificity of 90% and 60% respectively (AUC = 0.838, p ≤ .001). The diaphragmatic thickness fraction (DTF) was significantly lower in the successful weaning group. After adjustment for various factors, LUS score remained the only independent predictor of successful weaning.

CONCLUSION

LUS score before weaning from NCPAP has a good sensitivity and specificity for predicting successful weaning from NCPAP in preterm infants. Diaphragmatic excursion and DTF were not good predictors.

Lung ultrasound for the sick child: less harm and more information than a radiograph

In the realm of emergency medicine, the swift adoption of lung ultrasound (LU) has extended from the adult population to encompass pediatric and neonatal intensivists. LU stands out as a bedside, replicable, and cost-effective modality, distinct in its avoidance of ionizing radiations, a departure from conventional chest radiography. Recent years have witnessed a seamless adaptation of experiences gained in the adult setting to the neonatal and pediatric contexts, underscoring the versatility of bedside Point of care ultrasound (POCUS). This adaptability has proven reliable in diagnosing common pathologies and executing therapeutic interventions, including chest drainage, and central and peripheral vascular cannulation. The surge in POCUS utilization among neonatologists and pediatric intensivists is notable, spanning economically advanced Western nations with sophisticated, high-cost intensive care facilities and extending to low-income countries. Within the neonatal and pediatric population, POCUS has become integral for diagnosing and monitoring respiratory infections and chronic and acute lung pathologies. This, in turn, contributes to a reduction in radiation exposure during critical periods of growth, thereby mitigating oncological risks. Collaboration among various national and international societies has led to the formulation of guidelines addressing both the clinical application and regulatory aspects of operator training. Nevertheless, unified guidelines specific to the pediatric and neonatal population remain lacking, in contrast to the well-established protocols for adults. The initial application of POCUS in neonatal and pediatric settings centered on goal-directed echocardiography. Pivotal developments include expert statements in 2011, the UK consensus statement on echocardiography by neonatologists, and European training recommendations. The Australian Clinician Performed Ultrasound (CPU) program has played a crucial role, providing a robust academic curriculum tailored for training neonatologists in cerebral and cardiac assessment. Notably, the European Society for Paediatric and Neonatal Intensive Care (ESPNIC) recently disseminated evidence-based guidelines through an international panel, delineating the use and applications of POCUS in the pediatric setting. These guidelines are pertinent to any professional tending to critically ill children in routine or emergency scenarios. In light of the burgeoning literature, this paper will succinctly elucidate the methodology of performing an LU scan and underscore its primary indications in the neonatal and pediatric patient cohort. The focal points of this review comprise as follows: (1) methodology for conducting a lung ultrasound scan, (2) key ultrasonographic features characterizing a healthy lung, and (3) the functional approach: Lung Ultrasound Score in the child and the neonate.  Conclusion: the aim of this review is to discuss the following key points: 1. How to perform a lung ultrasound scan 2. Main ultrasonographic features of the healthy lung 3. The functional approach: Lung Ultrasound Score in the child and the neonate What is Known: • Lung Ultrasound (LUS) is applied in pediatric and neonatal age for the diagnosis of pneumothorax, consolidation, and pleural effusion. • Recently, LUS has been introduced into clinical practice as a bedside diagnostic method for monitoring surfactant use in NARDS and lung recruitment in PARDS. What is New: • Lung Ultrasound (LUS) has proven to be useful in confirming diagnoses of pneumothorax, consolidation, and pleural effusion. • Furthermore, it has demonstrated effectiveness in monitoring the response to surfactant therapy in neonates, in staging the severity of bronchiolitis, and in PARDS.

Timing of surfactant treatment in respiratory distress syndrome

The introduction of exogenous surfactant in the 1980s has resulted in an improved survival of very preterm infants with respiratory distress syndrome (RDS). Randomized controlled trials conducted before 2000 have shown that the magnitude of this beneficial effect strongly depends on the timing of surfactant treatment, i.e. the earlier surfactant is administered after birth the better. However, the initial mode of respiratory support in infants with RDS has changed dramatically over the last decades, moving from invasive to non-invasive support. Furthermore, new, less invasive techniques to administer surfactant have been introduced to match this non-invasive approach. This review summarizes the evidence on how these practice changes impacted the effect of surfactant timing on mortality and morbidity in preterm infants with RDS.

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.

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.

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).

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.

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.

Prevention of Chronic Morbidities in Extremely Premature Newborns with LISA-nCPAP Respiratory Therapy and Adjuvant Perinatal Strategies

Less invasive surfactant administration techniques, together with nasal continuous airway pressure (LISA-nCPAP) ventilation, an emerging noninvasive ventilation (NIV) technique in neonatology, are gaining more significance, even in extremely premature newborns (ELBW), under 27 weeks of gestational age. In this review, studies on LISA-nCPAP are compiled with an emphasis on short- and long-term morbidities associated with prematurity. Several perinatal preventative and therapeutic investigations are also discussed in order to start integrated therapies as numerous organ-saving techniques in addition to lung-protective ventilations. Two thirds of immature newborns can start their lives on NIV, and one third of them never need mechanical ventilation. With adjuvant intervention, these ratios are expected to be increased, resulting in better outcomes. Optimized cardiopulmonary transition, especially physiologic cord clamping, could have an additively beneficial effect on patient outcomes gained from NIV. Organ development and angiogenesis are strictly linked not only in the immature lung and retina, but also possibly in the kidney, and optimized interventions using angiogenic growth factors could lead to better morbidity-free survival. Corticosteroids, caffeine, insulin, thyroid hormones, antioxidants, N-acetylcysteine, and, moreover, the immunomodulatory components of mother's milk are also discussed as adjuvant treatments, since immature newborns deserve more complex neonatal interventions.