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

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.

Respiratory Management of the Extremely Premature Infant

Advancements in the fields of obstetrics and neonatal medicine, notably the use of antenatal corticosteroids and exogenous surfactant, have significantly improved the chances of survival for babies born prematurely. Extremely premature infants, born before 28 weeks of gestation, have underdeveloped lungs and pulmonary vasculature, necessitating a carefully tailored respiratory management strategy that incorporates both noninvasive and invasive methods throughout their NICU stay. The primary goal of respiratory management in this cohort is to provide the least amount of support necessary while oxygenating and ventilating the lungs. Noninvasive ventilation (NIV) methods are preferred to invasive methods to minimize the risk of damaging the lungs from mechanical ventilation. Nasal continuous positive airway pressure, high-flow nasal cannula, noninvasive positive pressure ventilation, noninvasive neurally adjusted ventilatory assist, and noninvasive high-frequency oscillatory ventilation are the types of NIV most readily available for use in extremely premature infants. Invasive methods such as conventional mechanical ventilation, high-frequency oscillatory ventilation, high-frequency jet ventilation, and neurally adjusted ventilatory assist are used to manage these fragile infants when intubation is required. Despite attempts to use noninvasive methods, many extremely premature infants may still require intubation. The main goal remains to improve outcomes while minimizing risks, although bronchopulmonary dysplasia still remains a challenge. Ongoing research and a consistent approach are essential for enhancing outcomes for these babies.

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.

Predicting extubation failure in preterm infants using lung ultrasound: a diagnostic accuracy study

OBJECTIVE

To determine the accuracy of pre-extubation lung ultrasound (LUS) to predict reintubation in preterm infants born <32 weeks' gestation.

DESIGN

Prospective diagnostic accuracy study.

SETTING

Two neonatal intensive care units.

METHODS

Anterior and lateral LUS was performed pre-extubation. The primary outcome was the accuracy of LUS scores (range 0-24) to predict reintubation within 72 hours. Secondary outcomes were accuracy in predicting (1) reintubation within 7 days, (2) reintubation stratified by postnatal age and (3) accuracy of lateral imaging only (range 0-12). Pre-specified subgroup analyses were performed in extremely preterm infants born <28 weeks' gestation. Cut-off scores, sensitivities and specificities were calculated using receiver operating characteristic analysis and reported as area under the curves (AUCs).

RESULTS

One hundred preterm infants with a mean (SD) gestational age of 27.4 (2.2) weeks and birth weight of 1059 (354) g were studied. Thirteen were subsequently reintubated. The AUC (95% CI) of the pre-extubation LUS score for predicting reintubation was 0.63 (0.45-0.80). Accuracy was greater in extremely preterm infants: AUC 0.70 (0.52-0.87) and excellent in infants who were <72 hours of age at the time of extubation: AUC 0.90 (0.77-1.00). Accuracy was poor in infants who were >7 days of age. Lateral imaging alone demonstrated similar accuracy to scanning anterior and lateral regions.

CONCLUSIONS

In contrast to previous studies, LUS was not a strong predictor of reintubation in preterm infants. Accuracy is increased in extremely preterm infants. Future research should focus on infants at highest risk of extubation failure and consider simpler imaging protocols.

TRIAL REGISTRATION NUMBER

Australian New Zealand Clinical Trials Registry: ACTRN12621001356853.

Cardiorespiratory interactions during the transitional period in extremely preterm infants: a narrative review

We aimed to review the physiology and evidence behind cardiorespiratory interactions during the transitional circulation of extremely preterm infants with fragile physiology and to propose a framework for future research. Cord clamping strategies have a great impact on initial haemodynamic changes, and appropriate transition can be facilitated by establishing spontaneous ventilation before cord clamping. Mechanical ventilation modifies preterm transitional haemodynamics, with positive pressure ventilation affecting the right and left heart loading conditions. Pulmonary vascular resistances can be minimized by ventilating with optimal lung volumes at functional residual capacity, and other pulmonary vasodilator treatments such as inhaled nitric oxide can be used to improve ventilation/perfusion mismatch. Different cardiovascular drugs can be used to provide support during transition in this population, and it is important to understand both their cardiovascular and respiratory effects, in order to provide adequate support to vulnerable preterm infants and improve outcomes. Current available non-invasive bedside tools, such as near-infrared spectroscopy, targeted neonatal echocardiography, or lung ultrasound offer the opportunity to precisely monitor cardiorespiratory interactions in preterm infants. More research is needed in this field using precision medicine to strengthen the benefits and avoid the harms associated to early neonatal interventions. IMPACT: In extremely preterm infants, haemodynamic and respiratory transitions are deeply interconnected, and their changes have a key impact in the establishment of lung aireation and postnatal circulation. We describe how mechanical ventilation modifies heart loading conditions and pulmonary vascular resistances in preterm patients, and how hemodynamic interventions such as cord clamping strategies or cardiovascular drugs affect the infant respiratory status. Current available non-invasive bedside tools can help monitor cardiorespiratory interactions in preterm infants. We highlight the areas of research in which precision medicine can help strengthen the benefits and avoid the harms associated to early neonatal interventions.

Predictors and Outcomes of Extubation Failure in Preterm Neonates: A Systematic Review

CONTEXT

Extubation failure (EF) is common in preterm neonates and may be associated with adverse outcomes.

OBJECTIVE

To systematically review and meta-analyze the existing literature on predictors and outcomes of EF in preterm neonates.

DATA SOURCES

MEDLINE, Epub Ahead of Print, In-Process & Other Non-Indexed Citations, Embase (OvidSP), CINAHL (EBSCOHost), and Cochrane Library (Wiley) from 1995 onward. The search strategy was developed by a reference librarian.

STUDY SELECTION

Experimental or observational studies reporting on predictors and/or outcomes related to EF (defined as reintubation within 7 days) in preterm neonates less than 37 weeks were eligible. Predictors included machine learning (ML) algorithms and lung ultrasound (LUS). Main outcome of interest was association of EF with mortality and/or bronchopulmonary dysplasia (BPD).

DATA EXTRACTION

Studies identified by the search strategy were screened based on title and abstract. Data from included studies were extracted independently by 2 authors, along with adjudication of risk of bias. RevMan Web was used to conduct meta-analyses.

RESULTS

Out of 8336 studies screened, 120 were included. Neonates with lower gestational age at birth, birthweight, postmenstrual age, and weight at extubation were more likely to experience EF. Higher level of pre-extubation respiratory support, indicated by lower pre-extubation pH and higher pre-extubation mean airway pressure, fraction of inspired oxygen, and Pco2 were associated with EF risk. ML models showed variable accuracy and lower external validity. LUS may be a promising predictor, though scoring systems varied. EF was associated with higher odds of mortality and/or BPD (pooled odds ratio [OR], 4.7; 95% CI, 2.84-7.76) as well as the individual components of the composite: mortality (pooled OR, 3.87; 95% CI, 2.35-6.36) and BPD (pooled OR, 3.27; 95% CI, 2.54-4.21).

LIMITATIONS

Associations were derived from unadjusted data, precluding a definitive causal relationship between EF and predictors/outcomes.

CONCLUSIONS

Lower gestational and chronological age and higher levels of pre-extubation ventilation support were associated with EF. ML models and LUS scores require further validation in larger studies. EF was associated with mortality and/or BPD.

Predicting extubation failure in neonates: The role of lung ultrasound and corrected gestational age in safe weaning in the NICU

To evaluate the accuracy of the lung ultrasound score (LUS) in predicting ventilatory weaning failure during neonatal hospitalization in the NICU and to identify factors associated with weaning failure, including corrected gestational age (CGA). This prospective, longitudinal, pragmatic and observational cohort study included neonates on mechanical ventilation for at least 48 h. The primary outcome was the accuracy of lung ultrasound in predicting 3-day weaning failure, with the ROC curve used to determine the best LUS cutoff (sensitivity and specificity). Among 55 neonates, the pre-extubation LUS did not show statistical significance in predicting weaning failure (AUC 0.61; 95% CI: 0.46-0.76, p = 0,169). In the subgroup analysis, a score ≥ 4 suggests the need for ventilatory support after extubation (area under the curve [AUC] = 0.91, 95% CI: 0.80-1.0, p < 0.001) in neonates with GA ≥ 28 weeks. In extremely preterm infants, the pre-extubation LUS was not statistically significant in predicting weaning failure (AUC = 0.38, 95% CI: 0-0.77, p = 0.535). In contrast, CGA ≥ 28.7 weeks at extubation was predictor of successful weaning within 3 days (AUC = 0.95, 95% CI: 0.85-1.0, p < 0.001).

CONCLUSION

LUS show promise in predicting weaning failure, though its accuracy may be limited in extremely preterm infants, highlighting the need for further well-powered studies. CGA at extubation also emerges as a key consideration in this population, warranting confirmation through robust future research.

WHAT IS KNOWN

• Identifying the optimal timing for extubation is crucial, as both prolonged mechanical ventilation and failed extubation are linked to increased morbidity. • Lung ultrasound plays a well-established role in diagnosing various neonatal lung pathologies, allowing clinicians to make rapid, bedside decisions for the treatment of newborns.

WHAT IS NEW

• LUS appears to be accurate in predicting weaning failure, though its accuracy may be lower in extremely preterm infants. • In extremely preterm infants, CGA may play an important role in extubation decision-making. • These findings are hypothesis-generating and warrant further investigation in future studies.

Serial sonographic assessment of diaphragmatic atrophy and lung injury patterns in mechanically ventilated preterm infants to predict extubation failure: a prospective observational study

Diaphragmatic atrophy (DA) and lung injury (LI) have been associated with mechanical ventilation (MV). We aimed to assess the ultrasonographic changes in diaphragmatic thickness and LI during MV and their prediction for extubation failure in preterm infants. In this prospective observational study, mechanically ventilated preterm infants, < 30 weeks gestation, within the first 24 h of life underwent a baseline, within 24 h of MV, and serial diaphragmatic and lung ultrasounds scans until their first extubation attempt. DA was defined as a decline in pre-extubation expiratory diaphragmatic thickness (DTexp) by ≥ 10% compared to baseline. A total of 251 ultrasound scans were performed on 38 preterm infants with a mean gestational age of 26.6 ± 1.7 weeks. Of these, 18 infants (47%) had DA. Among infants with DA, a pattern of progressive decline in DTexp was associated with a concomitant pattern of increase in the lung ultrasound score (LUS). Infants in the DA group experienced a significantly higher percentage of extubation failure [13 (72%) versus 5 (25%), p = 0.004] compared to the no-DA group. Pre-extubation LUS was significantly higher in the DA compared to the no-DA group (14.2 ± 6.0 versus 10.3 ± 5.2, p = 0.04). Logistic regression analysis controlling for gestational age, pre-extubation weight, and mean airway pressure at extubation showed that LUS [OR 1.27, 95% CI (1.04-1.56), p = 0.02] was an independent predictor of for extubation failure.

CONCLUSION

In this cohort of preterm infants, lung ultrasound score has proved to be a stronger predictor of successful extubation compared to diaphragmatic thickness.

WHAT IS KNOWN

• Ultrasonographic assessment of the diaphragm and lungs is a sensitive tool in diagnosis of ventilator induced diaphragmatic atrophy and lung injury in preterm infants. Accuracy of lung and diaphragmatic ultrasound in predicting extubation outcome in preterm infants is questionable.

WHAT IS NEW

• A pattern of progressive decline in diaphragmatic thickness was associated with a concomitant pattern of increase in the lung ultrasound score in mechanically ventilated preterm infants. Lung ultrasound score has proved to be a stronger predictor of successful extubation compared to diaphragmatic thickness.

Diagnostic accuracy of lung ultrasound to predict weaning outcome: a systematic review and meta-analysis

Background

This systematic review and meta-analysis aim to systematically assess the diagnostic accuracy of lung ultrasound in predicting weaning failure from mechanical ventilation in critically ill patients.

Methods

We searched the relevant literature up to January 2024 in the databases Web of Science, Cochrane Library, Embase, and PubMed. Two researchers independently screened eligible studies and extracted data; disagreements, if any, were resolved through discussion or consultation with a third-party expert. The quality of the included studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. Statistical analyses were performed using Review Manager version 5.3 and Stata version 18.0, applying bivariate random-effects models to estimate sensitivity, specificity, diagnostic odds ratios, and their 95% confidence intervals, as well as to summarize receiver operating characteristic curves. Inter-study heterogeneity was assessed using the I-squared statistic, and potential sources of heterogeneity were explored by meta-regression analysis. The study follows the guidelines for Preferred Reporting Items for Systematic Reviews and Meta-Analyses in reporting.

Results

Fourteen studies were included in the systematic review, of which 13 studies (totaling 988 patients) were included in the meta-analysis. The meta-analysis revealed an overall sensitivity of 0.86 (95% confidence interval: 0.77-0.91) and a specificity of 0.75 (95% confidence interval: 0.66-0.83) for lung ultrasound in predicting extubation failure. The area under the receiver operating characteristic curve was 0.87 (95% confidence interval: 0.84-0.89). Meta-regression analysis identified lung ultrasound thresholds, reference standards (extubation outcomes), and study flow and time bias as significant factors influencing diagnostic accuracy.

Conclusion

This systematic review and meta-analysis demonstrated that lung ultrasound has high diagnostic accuracy in predicting extubation failure in mechanically ventilated critically ill patients. Despite some study heterogeneity, lung ultrasound proved to be a reliable predictive tool for extubation failure. Future research should focus on standardizing the definition of extubation failure, exploring the impact of different thresholds on the predictive ability of lung ultrasound, and validating its application in various clinical settings to enhance its utility and accuracy in clinical practice.

Systematic review registration

This systematic review and meta-analysis was registered with PROSPERO (registration number: CRD42024555909). The study adhered to the guidelines set by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Details of the PROSPERO protocol can be found in Supplementary Table 1.

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.

Diagnostic Accuracy of Lung Ultrasound in Neonatal Diseases: A Systematized Review

Background: Respiratory problems are frequent in newborns, and are mainly studied with chest X-rays, whereas CT scans are usually needed for the evaluation of rare malformations and diseases. Lung ultrasound (LUS] has been proposed as an alternative method of diagnosing a variety of respiratory conditions. In recent years, there has been a rapid increase in LUS studies, thanks to the ability of LUS to rapidly exclude complications and significantly reduce radiation exposure in this fragile population. We aimed to summarize the current knowledge about LUS. Methods: A literature search was conducted on the Medline and Cochrane databases using appropriate terms. The inclusion criteria were: English language and human species. Exclusion criteria were: non-English language, animal species, case reports, case series, non-systematic reviews, and editorials. Results: The search returned 360 results. No Cochrane reviews were found. Titles and abstracts were screened, and 37 were finally considered. Studies concerning the use of lung ultrasound for the following conditions were presented: neonatal respiratory distress syndrome, transient tachypnea of the newborn, pneumothorax, pulmonary hemorrhage, pneumonia, bronchopulmonary dysplasia, and prediction of extubation success. Conclusions: We discussed the utility of LUS for the diagnosis and treatment of neonatal diseases according to the most recent literature.

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.

Weaning from mechanical ventilation and assessment of extubation readiness

Tremendous advancements in neonatal respiratory care have contributed to the improved survival of extremely preterm infants (gestational age ≤ 28 weeks). While mechanical ventilation is often considered one of the most important breakthroughs in neonatology, it is also associated with numerous short and long-term complications. For those reasons, clinical research has focused on strategies to avoid or reduce exposure to mechanical ventilation. Nonetheless, in the extreme preterm population, 70-100% of infants born 22-28 weeks of gestation are exposed to mechanical ventilation, with nearly 50% being ventilated for ≥ 3 weeks. As contemporary practices have shifted towards selectively reserving mechanical ventilation for those patients, mechanical ventilation weaning and extubation remain a priority yet offer a heightened challenge for clinicians. In this review, we will summarize the evidence for different strategies to expedite weaning and assess extubation readiness in preterm infants, with a particular focus on extremely preterm infants.

Optimal timing of extubation in preterm infants

In neonatal intensive care, endotracheal intubation is usually performed as an urgent or semi-urgent procedure in infants with critical or unstable conditions related to progressive respiratory failure. Extubation is not. Patients undergoing extubation are typically stable, with improved respiratory function. The key elements to facilitating extubation are to recognize improvement in respiratory status, promote weaning of mechanical ventilation, and accurately identify readiness for removal of the endotracheal tube. Therefore, extubation should be a planned and well-organized procedure. In this review, we will appraise the evidence for existing predictors of extubation readiness and provide patient-specific, pathophysiology-derived strategies to optimize the timing and success of extubation in neonates, with a focus on extremely preterm infants.