Semi-quantification of pneumothorax volume by lung ultrasound.

BACKGROUND: Lung ultrasound (LUS) may accurately diagnose pneumothorax. However, there is uncertainty about its usefulness in the quantification of pneumothorax size. To determine the ability of LUS in the semi-quantification of pneumothorax volume, we compared the projection of the lung point (LP) with the pneumothorax volume measured by computerized tomography (CT) and the interpleural distance on chest radiography (CXR). METHODS: We performed LUS in patients with pneumothorax and all the LP located on the chest wall were compared to CXR and CT studies. The primary outcome of the study was the ability of LP to grade pneumothorax volumes measured by CT. The secondary outcome was the accuracy of LP to predict small and large pneumothorax according to the societal guidelines based on CXR reading. RESULTS: A total of 124 patients with pneumothorax were enrolled (76 spontaneous, 20 traumatic and 28 post-procedural). Ninety-four CXR and 58 CT were available for the analysis. An LP posterior to the mid axillary line corresponded to three different CXR criteria for large pneumothorax with sensitivity from 81.4 to 88.2 % and specificity from 64.7 to 72.6 %. The mid axillary line also represented the limit for predicting greater than 15 % of lung collapse when volume is measured at CT, with sensitivity 83.3 % and specificity 82.4 %. CONCLUSIONS: LUS-targeted assessment of LP was a useful predictor of pneumothorax volume in this research study setting. LUS reliably classified pneumothorax size when compared to criteria based on CXR reading, particularly the small sized pneumothorax. However, LUS greatly outperformed conventional CXR reading for a graded quantification of the percentage of lung collapse.

Lung ultrasound predicts well extravascular lung water but is of limited usefulness in the prediction of wedge pressure.

BACKGROUND: Pulmonary congestion is indicated at lung ultrasound by detection of B-lines, but correlation of these ultrasound signs with pulmonary artery occlusion pressure (PAOP) and extravascular lung water (EVLW) still remains to be further explored. The aim of the study was to assess whether B-lines, and eventually a combination with left ventricular ejection fraction (LVEF) assessment, are useful to differentiate low/high PAOP and EVLW in critically ill patients. METHODS: The authors enrolled 73 patients requiring invasive monitoring from the intensive care unit of four university-affiliated hospitals. Forty-one patients underwent PAOP measurement by pulmonary artery catheterization and 32 patients had EVLW measured by transpulmonary thermodilution method. Lung and cardiac ultrasound examinations focused to the evaluation of B-lines and gross estimation of LVEF were performed. The absence of diffuse B-lines (A-pattern) versus the pattern showing prevalent B-lines (B-pattern) and the combination with normal or impaired LVEF were correlated with cutoff levels of PAOP and EVLW. RESULTS: PAOP of 18 mmHg or less was predicted by the A-pattern with 85.7% sensitivity (95% CI, 70.5 to 94.1%) and 40.0% specificity (CI, 25.4 to 56.4%), whereas EVLW 10 ml/kg or less with 81.0% sensitivity (CI, 62.6 to 91.9%) and 90.9% specificity (CI, 74.2 to 97.7%). The combination of A-pattern with normal LVEF increased sensitivity to 100% (CI, 84.5 to 100%) and specificity to 72.7% (CI, 52.0 to 87.2%) for the prediction of PAOP 18 mmHg or less. CONCLUSIONS: B-lines allow good prediction of pulmonary congestion indicated by EVLW, whereas are of limited usefulness for the prediction of hemodynamic congestion indicated by PAOP. Combining B-lines with estimation of LVEF at transthoracic ultrasound may improve the prediction of PAOP.

Sonographic diagnosis of pulmonary embolism with cardiac arrest without major dilation of the right ventricle or direct sign of lower limb venous thrombosis.

Bedside focused echocardiography diagnosis of massive pulmonary embolism during cardiac arrest is mainly based on the detection of a dilated right ventricle, while the lack of compressibility of a deep vein of the lower limbs confirms diagnosis in doubtful cases. We describe a case of unusual sonographic signs in a young woman with cardiac arrest due to massive pulmonary embolism showing spontaneous blood echogenicity in the inferior vena cava ("sludge sign") and nonmodulated ("flat") Doppler waveform in the left lower limb veins, suggesting isolated iliac vein thrombosis.

A comparison of different diagnostic tests in the bedside evaluation of pleuritic pain in the ED.

PURPOSES: Bedside lung ultrasound (LUS) is useful in detecting radio-occult pleural-pulmonary lesions. The aim of our study is to compare the value of LUS with other conventional routine diagnostic tools in the emergency department (ED) evaluation of patients with pleuritic pain and silent chest radiography (CXR). METHODS: Ninety patients consecutively admitted to the ED with pleuritic pain and normal CXR were retrospectively (n = 49) and prospectively (n = 41) studied. All patients were blindly examined by LUS and submitted to clinical examination and blood samples. The ability of blood tests and symptoms to predict any radio-occult pleural-pulmonary condition confirmed by conclusive image techniques and follow-up was evaluated and compared with LUS. RESULTS: In 57 cases, the final diagnosis was chest wall pain. The other 33 patients were diagnosed with a pleural-pulmonary condition (22 pneumonia, 2 pleuritis, 7 pulmonary embolism, 1 lung cancer, 1 pneumothorax). Lung ultrasound showed a sensitivity of 96.97% (95% confidence interval [CI], 84.68%-99.46%) and a specificity of 96.49% (95% CI, 88.08%-99.03%) in predicting radio-occult pleural-pulmonary lesions and significantly higher area under the curve (AUC) of receiver operating characteristic analysis (AUC, 0.967; 95% CI, 0.929-1.00) than d-dimer (AUC, 0.815; 95% CI, 0.720-0.911) and white blood cell count (AUC, 0.778; 95% CI, 0.678-0.858). None of the other routine tests considered or a combination between them better predicted the final diagnosis. CONCLUSIONS: Chest radiography and blood tests may be inadequate in the diagnostic process of pleuritic pain. In case of silent CXR, LUS is critical for identifying patients with pleural-pulmonary radio-occult conditions at bedside and cannot be safely replaced by other conventional methods.

Sonographic detection of radio-occult interstitial lung involvement in measles pneumonitis.

We present the cases of 23- and 38-year-old healthy patients with clinical diagnosis of acute measles who experienced shortness of breath on exertion with nonproductive cough and showed signs of mild respiratory failure at presentation in the emergency department (ED) but with normal chest radiograph and auscultation. In both cases, bedside ultrasound of the lung showed the appearance of signs of interstitial diffuse involvement with vertical B lines spread all over the lateral and posterior chest wall. This sonographic pattern is typical of the interstitial involvement during acute viral pneumonitis that can be missed by physical examination and chest radiography. Even without radiologic infiltrates and pulmonary sounds, based on sonographic and arterial gas signs, a diagnosis of measles pneumonitis was done and patients admitted to the ward for close follow-up and supportive care. We hypothesize a new diagnostic role of bedside lung sonography in screening patients presenting to the ED with initial lung involvement in measles who warrant close follow-up and hospital admission.

Bedside ultrasound of the lung for the monitoring of acute decompensated heart failure.

PURPOSES: Multiple artifacts B lines (B+) at transthoracic lung ultrasound have been proposed as a sonographic sign of pulmonary congestion. Our aim is to assess B+ clearance after medical treatment in acute decompensated heart failure (ADHF) and to compare the usefulness of sonography with other traditional tools in monitoring resolution of pulmonary congestion. METHODS: Eighty-one patients with a diagnosis of ADHF were submitted to lung ultrasound and chest radiography at admission, and 70 of them underwent the same procedures as control group after 4.2 +/- 1.7 days of medical treatment. The ultrasound examination was performed with 11 scans on as many anterolateral thoracic areas (6 on the right side and 5 on the left side). Then, we calculated a sonographic score counting the B+ scans and compared it with radiologic score for extravascular lung water, clinical, and plasma brain natriuretic peptide improvement. MAIN RESULTS: All patients showed B+ pattern at admission and significant clearing after treatment, with median number of 8 positive scans (range, 3-9 scans) vs 0 (range, 0-7 scans) (P < .05). Our sonographic score showed positive linear correlation with radiologic score (r = 0.62; P < .05), clinical score (r = 0.87; P < .01), and brain natriuretic peptide levels (r = 0.44; P < .05). Delta Sonographic score correlated with Delta clinical (r = 0.55; P < .05) and radiologic (r = 0.28; P < .05) scores. CONCLUSIONS: B line pattern mostly clears after adequate medical treatment of ADHF and represents an easy-to-use alternative bedside diagnostic tool for clinically monitoring pulmonary congestion in patients with ADHF.

Detection of sonographic B-lines in patients with normal lung or radiographic alveolar consolidation.

BACKGROUND: Diffuse comet-tail B-line artifacts in lung ultrasound are a sign of alveolar-interstitial syndrome, but isolated transthoracic scans positive for B-lines (multiple B lines or B+) could be detected in other conditions. The aim was to assess the prevalence and distribution of this sonographic sign in patients with normal lung or isolated alveolar consolidation in chest radiography. MATERIAL/METHODS: Two hundred seventeen patients consecutively admitted to this emergency medicine unit with any diagnosis and without radiographic or clinical evidence of diffuse interstitial syndrome were analyzed. Each patient underwent chest radiography and lung sonographic examination with four anterolateral chest scans per side. RESULTS: Of the 1736 sonographic scans performed, 13.2% were positive for the B+ pattern. Positive scans significantly corresponded to laterobasal areas or radiographic opacities due to lung alveolar consolidations (p<0.005). Twenty percent of the laterobasal scans of 145 patients with radiologically normal lung were positive. The negative predictive value of B+ was 83.9% (95% confidence interval: 78.2-89.7%), with a specificity of 90.3% (95%CI: 85.5-95.1%) for predicting any localized radiographic pulmonary opacity. CONCLUSIONS: B+ scans can be detected in the chest areas surrounding an isolated alveolar consolidation and in the laterobasal scans of a radiographic normal lung. These features should always be considered when lung ultrasound is performed to rule out the alveolar-interstitial syndrome in an emergency setting. Moreover, B+ patterns have a satisfactory negative predictive value for radiographic lung opacities, which could have added diagnostic value in the ED evaluation of dyspneic patients.