Development and Validation of a Point-of-Care-Ultrasound Image Quality Assessment Tool: The POCUS IQ Scale.

OBJECTIVES: We aimed to develop a standardized scoring tool to measure point-of-care ultrasound (POCUS) image quality and to determine validity evidence for its use to assess lung ultrasound image quality. METHODS: The POCUS Image Quality (POCUS IQ) scale was developed by POCUS-trained physicians to assess sonographers' image acquisition skills by evaluating image quality for any POCUS application. The scale was piloted using lung images of healthy standardized patients acquired by three expert sonographers compared to three novices before and after training. All images (experts, novices pre-training, novices post-training) were scored on the POCUS IQ scale by three blinded POCUS-trained physicians. Reliability was assessed with fully-crossed generalizability and decision studies. Validity was assessed using Messick's framework. RESULTS: Content validity was supported by the tool's development process of literature review, expert consensus, and pilot testing. Response process was supported by reviewer training and the blinded scoring process. Relation to other variables was supported by scores relating to sonographer experience: median expert score = 10.5/14 (IQR: 4), median novice pre-training score = 6/14 (IQR: 2.25), and novices' improvement after training (median post-training score = 12/14, IQR: 3.25). Internal structure was supported by internal consistency data (coefficient alpha = 0.84, omega coefficient = 0.91) and the generalizability study showing the main contributor to score variability was the sonographer (51%). The G-coefficient was 0.89, suggesting very good internal structure, however, Gwet's AC2  was 0.5, indicating moderate interrater reliability. The D study projected a minimum of 1 reviewer and 2 patients are needed for good psychometric reliability. CONCLUSIONS: The POCUS scale has good preliminary validity evidence as an assessment tool for lung POCUS image acquisition skills. Further studies are needed to demonstrate its utility for other POCUS applications and as a feedback tool for POCUS learners.

Lack of Association Between a Quantified Lung Ultrasound Score and Illness Severity in Pediatric Emergency Department Patients With Acute Lower Respiratory Infections.

OBJECTIVES: Lung ultrasound (LUS) may help determine illness severity in children with acute lower respiratory tract infections (LRTI) but limited pediatric studies exist. Our objective was to determine the association between LUS findings and illness severity in children with LRTI. METHODS: We conducted a prospective study of patients <20 years with LRTI. Trained investigators performed standardized LUS examinations of 12 regions. Blinded sonologists reviewed examinations for individual pathologic features and also calculated a Quantified Lung Ultrasound Score (QLUS). We defined focal severity as QLUS of ≥2 in ≥1 region, and diffuse severity as QLUS of ≥1 in ≥3 regions. The primary outcome was the Respiratory component of the Pediatric Early Warning Score (RPEWS), a 14-item scale measuring respiratory illness severity. Secondary outcomes included hospital admission, length of stay, supplemental oxygen, and antibiotic use. RESULTS: We enrolled 85 patients with LRTIs, 46 (54%) whom were hospitalized (5.4% intensive care). Median RPEWS was 1 (interquartile range 2). Neither individual features on ultrasound nor total QLUS were associated with RPEWS, hospitalization, length of stay, or oxygen use. Mean RPEWS was similar for participants regardless of focal (1.46 versus 1.26, P = .57) or diffuse (1.47 versus 1.21, P = .47) severity findings, but those with focal or diffuse severity, or isolated consolidation, had greater antibiotic administration (P < .001). CONCLUSIONS: In children with LRTI, neither individual features nor QLUS were associated with illness severity. Antibiotics were more likely in patients with either focal or diffuse severity or presence of consolidation on ultrasound.

Prospective observational study of point-of-care ultrasound for diagnosing pneumonia.

OBJECTIVES: The clinical diagnosis of pneumonia lacks specificity and may lead to antibiotic overuse, whereas radiological diagnoses can lack sensitivity. Point-of-care lung ultrasound is an emerging diagnostic tool. There are limited prospective data, however, on the accuracy of sonologists in the paediatric emergency department setting. We aimed to test the diagnostic accuracy of lung ultrasound for pneumonia using chest radiograph (CR) as the reference standard. METHODS: This prospective observational cohort study in a paediatric emergency department enrolled children aged 1 month to <18 years, who had a CR ordered for possible pneumonia. Lung ultrasounds were performed by two blinded sonologists with focused training. Sonographic pneumonia was defined as lung consolidation with air bronchograms. Radiograph and ultrasound results both required agreement between two readers, with final results determined by an arbiter in cases of disagreement. Patient management was decided by treating clinicians who were blinded to lung ultrasound results. Follow-up was performed by phone and medical record review to obtain final diagnosis and antibiotic use. RESULTS: Of 97 included patients, CR was positive for pneumonia in 44/97 (45%) and lung ultrasound was positive in 57/97 (59%). Ultrasound sensitivity was 91% (95% CI 78% to 98%) and specificity was 68% (95% CI 54% to 80%). Ultrasound results displayed greater consistency with CR and patient outcomes when sonographic consolidation exceeded 1 cm. Thirteen of 57 patients with sonographic consolidation improved without antibiotics. CONCLUSION: Lung ultrasound may have a role as first-line imaging in patients with possible pneumonia, with higher specificity for consolidations exceeding 1 cm. TRIAL REGISTRATION NUMBER: ACTRN12616000361404, http://www.ANZCTR.org.au/ACTRN12616000361404.aspx.