Point-of-care lung sonography is a feasible, rapid, inexpensive, and accurate diagnostic imaging procedure that can be widely used for many clinical indications. An Italian study of nearly 1,000 patients revealed that diagnostic-quality lung sonography may be performed effectively by pulmonologists with a high accuracy rate.
The prospective observational study, published in the Journal of Ultrasound in Medicine, was conducted over a 24-month period at San Paolo Hospital, a large, 605-bed academic teaching hospital in Milan. The authors wanted to document how point-of-care lung sonography was used, how accurate it was, what the clinical impact was, and what barriers existed to prevent its use.
951 patients were enrolled in the study, with 1,150 examinations performed. Sixteen respiratory specialists and residents performed the studies using three cart-based and two handheld ultrasound systems. One-third of the examinations were performed in the pulmonary ambulatory outpatient clinic, and 20% were performed in the pulmonary inpatient wards. Other locations included pediatric wards and outpatient clinics (13%), other medical wards (17%) and unspecified outpatient facilities (9%). Only 9% of the examinations were performed on patients admitted to the hospital’s emergency department.
The pulmonary physicians performing the examinations were experienced, all seven having performed an average of 100 lung sonograms per year. The residents performed the lung sonograms under the tutelage of the experienced pulmonologists. Each physician was asked to score the quality exam immediately (as adequate, sufficient, or poor). The operator also recorded the main clinical indication and the most important findings of the examination. Clinical indications were selected from a predefined list. The type of ultrasound (B-mode, M-mode or color Doppler) was recorded, as well as the duration of the examination, and any notable clinical consequences of the examination.
Physicians performing the examinations were also asked to identify the clinical impact of the exam. These included resolution of equivocal findings on chest radiographs or detection of findings not visible on chest radiographs, such as effusion, congestion, consolidation, sub-pleural infarction, or pneumothorax. They recorded whether findings eliminated the need for additional diagnostic imaging, such as chest radiography and/or computed tomography (CT) scans. Examination findings were subsequently compared with the patient’s medical records.
The most common indications were diagnosis and follow-up of pleural effusion (31%) and evaluation of lung consolidation (28%). Other indications included acute heart failure (17%), guide to pleural procedures (10%), pneumothorax (5%), and acute exacerbations of chronic obstructive pulmonary disease (3%).
Lead author and respiratory physician Giuseppe Francesco Sferrazza Papa, MD, reported that the lung sonograms led to a substantial clinical impact in approximately half of the cases. Lung sonography correctly influenced the clinical decision including treatment in 51% of the cases. It had no consequence in 38% of the cases, and led to additional diagnostic imaging procedures in 12% of the cases.
The assessment of diagnostic accuracy was limited to 574 examinations, representing the first lung sonogram that was performed. The lung sonograph pattern was concordant with the final diagnosis in 98.3% of the clinical cases. Four false positives were identified and six false negatives. The false positives included three cases of small sub-pleural lung consolidations, two of which occurred in children with bronchiolitis. A false positive also occurred in a patient with an asthmatic exacerbation with a negative chest radiograph. The false negatives included four central lesions not reaching the pleural line and two cases of sub-pleural infarctions that were detected on chest CT but not a chest radiograph.
Supporting the use of lung sonography by skilled physicians, the authors wrote, “In many acute respiratory conditions, quick answers to diagnostic dilemmas may potentially affect patient outcomes. The caring physician has the deepest knowledge of the patient’s clinical condition and history and, if adequately trained in the interpretation of point-of-care sonography, may provide immediate answers to key questions regarding early diagnosis and treatment.”
Point-of-care lung sonography effective outside radiology. Appl Radiol.