Comparison of chest radiograph and lung ultrasound in children with acute respiratory failure.

PURPOSE: Chest x-ray (CXR) is the standard imaging used to evaluate children in acute respiratory distress and failure. Our objective was to compare the lung-imaging techniques of CXR and lung ultrasound (LUS) in the evaluation of children with acute respiratory failure (ARF) to quantify agreement and to determine which technique identified a higher frequency of pulmonary abnormalities. METHODS: This was a secondary analysis of a prospective observational study evaluating the sensitivity and specificity of LUS in children with ARF from 12/2018 to 02/2020 completed at the University of Wisconsin-Madison (USA). Children > 37.0 weeks corrected gestational age and ≤ 18 years of age admitted to the PICU with ARF were evaluated with LUS. We compared CXR and LUS completed within 6 h of each other. Kappa statistics (k) adjusted for maximum attainable agreement (k/kmax) were used to quantify agreement between imaging techniques and descriptive statistics were used to describe the frequency of abnormalities. RESULTS: Eighty-eight children had LUS completed, 32 with concomitant imaging completed within 6 h are included. There was fair agreement between LUS and CXR derived diagnoses with 58% agreement (k/kmax = 0.36). Evaluation of imaging patterns included: normal, 57% agreement (k = 0.032); interstitial pattern, 47% agreement (k = 0.003); and consolidation, 65% agreement (k = 0.29). CXR identified more imaging abnormalities than LUS. CONCLUSIONS: There is fair agreement between CXR and LUS-derived diagnoses in children with ARF. Given this, clinicians should consider the benefits and limitations of specific imaging modalities when evaluating children with ARF. Additional studies are necessary to further define the role of LUS in pediatric ARF given the small sample size of our study.

Lung Ultrasound Artifact Findings in Pediatric Patients Admitted to the Intensive Care Unit for Acute Respiratory Failure.

PURPOSE: To describe point-of-care lung ultrasound (POC-LUS) artifact findings in children admitted to the pediatric intensive care unit (PICU) for acute respiratory failure (ARF). METHODS: This is a secondary analysis of a prospective observational study completed in a 21-bed PICU. Children > 37 weeks gestational age and ≤ 18 years were enrolled from December 2018 to February 2020. POC-LUS was completed and interpreted by separate physicians blinded to all clinical information. POC-LUS was evaluated for the presence of lung sliding, pleural line characteristics, ultrasound artifacts, and the ultrasound diagnosis. RESULTS: Eighty-seven subjects were included. A-lines were the most frequent artifact, occurring in 58% of lung zones (163/281) in those with bronchiolitis, 39% of lung zones (64/164) in those with pneumonia, and 81% of lung zones (48/59) in those with status asthmaticus. Sub-pleural consolidation was second most common, occurring in 28% (80/281), 30% (50/164), and 12% (7/59) of those with bronchiolitis, pneumonia, and status asthmaticus, respectively. The pattern a priori defined as bronchiolitis, pneumonia, and status asthmaticus was demonstrated in 31% (15/48), 10% (3/29), and 40% (4/10) of subjects with bronchiolitis, pneumonia, and status asthmaticus, respectively. CONCLUSION: We found significant heterogeneity and overlap of POC-LUS artifacts across the most common etiologies of ARF in children admitted to the PICU. We have described the POC-LUS artifact findings in pediatric ARF to support clinicians using POC-LUS and to guide future pediatric POC-LUS studies. Determining the optimal role of POC-LUS as an adjunct in the care of pediatric patients requires further study.

The Inter-Rater Reliability of Pediatric Point-of-Care Lung Ultrasound Interpretation in Children With Acute Respiratory Failure.

OBJECTIVES: Use of point-of-care lung ultrasound (POC-LUS) has increased significantly in pediatrics yet it remains under-studied in the pediatric intensive care unit (PICU). No studies explicitly evaluate the reliability of POC-LUS artifact interpretation among critically ill children with acute respiratory failure (ARF) in the PICU. We thus designed this study to determine the inter-rater reliability of POC-LUS interpretation in pediatric ARF among pediatric intensivists trained in POC-LUS and an expert intensivist. METHODS: We compared the interpretation of lung sliding, pleural line characteristics, ultrasound artifacts, and POC-LUS diagnoses among pediatric intensivists and an expert intensivist in a cohort of children admitted to the PICU for ARF. Kappa statistics (k) adjusted for maximum attainable agreement (k/kmax ) were used to quantify chance-correct agreement between the pediatric intensivist and expert physician. RESULTS: We enrolled 88 patients, evaluating 3 zones per hemithorax (anterior, lateral, and posterior) for lung sliding, pleural line characteristics, ultrasound artifacts, and diagnosis. There was moderate agreement between the PICU intensivist and expert-derived diagnoses with 56% observed agreement (k/kmax  = 0.46, 95% confidence interval [CI] 0.31-0.65). Agreement in identification of lung sliding (k = 0.19, 95% CI -0.17 to 0.56) and pleural line characteristics (k = 0.24, 95% CI 0.08-0.40) was slight and fair, respectively, while agreement in the interpretation of ultrasound artifacts ranged from moderate to substantial. CONCLUSIONS: Evidence supporting the evaluation of neonatal and adult patients with POC-LUS should not be extrapolated to critically ill pediatric patients. This study adds to the evidence supporting use of POC-LUS in the PICU by demonstrating moderate agreement between PICU intensivist and expert-derived POC-LUS diagnoses.

Point-of-Care Lung Ultrasound to Diagnose the Etiology of Acute Respiratory Failure at Admission to the PICU.

OBJECTIVES: Determine the sensitivity and specificity of point-of-care lung ultrasound in identifying the etiology of acute respiratory failure at admission to the PICU. DESIGN: Prospective observational study. SETTING: Tertiary PICU. PATIENTS: Children older than 37 weeks gestational age and less than or equal to 18 years old admitted to the PICU with acute respiratory failure from December 2018 to February 2020. INTERVENTION: Point-of-care lung ultrasound performed within 14 hours of admission to the PICU by physicians blinded to patient history and clinical course. Two physicians, blinded to all clinical information, independently interpreted the point-of-care lung ultrasound and then established a consensus diagnosis (ultrasound diagnosis). The ultrasound diagnosis was compared with an independent, standardized review of the medical record following hospital discharge (final diagnosis). MEASUREMENTS AND RESULTS: Eighty-eight patients were enrolled in the study. Forty-eight patients had a final diagnosis of bronchiolitis/viral pneumonitis (55%), 29 had pneumonia (33%), 10 had status asthmaticus (11%), and one was excluded because of an inability to differentiate the final diagnosis. Point-of-care lung ultrasound correctly identified the etiology of acute respiratory failure in 56% of patients (49/87; 95% CI, 46-66%). It identified bronchiolitis/viral pneumonitis with 44% sensitivity (95% CI, 0.31-0.58) and 74% specificity (95% CI, 0.59-0.85), pneumonia with 76% sensitivity (95% CI, 0.58-0.88) and 67% specificity (95% CI 0.54-0.78), and status asthmaticus with 60% sensitivity (95% CI, 0.31-0.83) and 88% specificity (95% CI, 0.79-0.94). CONCLUSIONS: In contrast to literature demonstrating high utility differentiating the cause of acute respiratory failure in adults, blinded point-of-care lung ultrasound demonstrates moderate sensitivity and specificity in identifying the etiology of pediatric acute respiratory failure at admission to the PICU among children with bronchiolitis, pneumonia, and status asthmaticus.