Modified Lung Ultrasound Score for Assessing and Monitoring Pulmonary Aeration

Abstract

Lung Ultrasound Score (LUSS) is a useful tool for lung aeration assessment but presents two theoretical limitations. First, standard LUSS is based on longitudinal scan and detection of number/coalescence of B lines. In the longitudinal scan pleura visualization is limited by intercostal space width. Moreover, coalescence of B lines to define severe loss of aeration is not suitable for non-homogeneous lung pathologies where focal coalescence is possible. We therefore compared longitudinal vs. transversal scan and also cLUSS (standard coalescence-based LUSS) vs. qLUSS (quantitative LUSS based on % of involved pleura). 38 ICU patients were examined in 12 thoracic areas in longitudinal and transversal scan. B lines (number, coalescence), subpleural consolidations (SP), pleural length and pleural involvement (> or ≤ 50 %) were assessed. cLUSS and qLUSS were computed in longitudinal and transversal scan. Transversal scan visualized wider (3.9 [IQR 3.8 - 3.9] vs 2.0 [1.6 - 2.5] cm, p< 0.0001) and more constant (variance 0.02 vs 0.34 cm, p < 0.0001) pleural length, more B lines (70 vs 59 % of scans, p < 0.0001), coalescence (39 vs 28 %, p < 0.0001) and SP (22 vs 14 %, p < 0.0001) compared to longitudinal scan. Pleural involvement > 50 % was observed in 17 % and coalescence in 33 % of cases. Focal coalescence accounted for 52 % of cases of coalescence. qLUSS-transv generated a different distribution of aeration scores compared to cLUSS-long (p < 0.0001). In unselected ICU patients, variability of pleural length in longitudinal scans is high and focal coalescence is frequent. Transversal scan and quantification of pleural involvement are simple measures to overcome these limitations of LUSS.

Lung Ultrasonography for Assessing Lung Aeration in Acute Respiratory Distress Syndrome: A Narrative Review

“…Although many transducers can be used for lung US scanning, on the basis of authors' views, phased array transducers are preferred, given the simplicity of point‐of‐care US (ie, a single transducer and multiorgan assessment), and, more importantly, because phased array transducers allow practitioners to observe right ventricular dynamics before and during PEEP/lung recruitment maneuvers (Figure and Video 2) and may aid in decision making regarding limiting applied airway pressures or eventually not applying them and choosing another therapy that can also unload the right ventricle, such as prone positioning . Longitudinal or transverse lung scanning can be used; however, the latter is preferred to monitor aeration and best characterize lung patterns, given the resulting wide field of view of the pleura and subpleural lung …”

Using lung ultrasound to quantitatively evaluate pulmonary water content

“…B‐lines correspond to progressive air loss in pulmonary tissues, as well as corresponding increases in relative and absolute EVLW . Typically, the BLS system considers the number and confluency of B‐lines . The B‐lines of each scan were recorded, the score was assessed by two experienced neonatologists independently, and any disagreement between them would be settled by mutual consultation.…”

“…21 Typically, the BLS system considers the number and confluency of B-lines. 10,12 The B-lines of each scan were recorded, the score was assessed by two experienced neonatologists independently, and any disagreement between them would be settled by mutual The sum of the BLS of each ICS represented the total score denoting the EVLW severity for the entire lung. The BLS was assigned as follows ( Table 1) Figure 5 shows the BLS at each ICS.…”

“…In contrast, transthoracic LUS, a technique used on the basis of B‐line visualization, is highly sensitive and specific to the diagnosis of EVLW . LUS scoring systems have been developed to meet the need for standardization and have been shown to correlate with various metrics in adults and neonates . These scoring systems are used to assess the severity, course, and prognosis of the disease and then guide the treatment .…”

“…[1][2][3][4][5] LUS scoring systems have been developed to meet the need for standardization and have been shown to correlate with various metrics in adults and neonates. [10][11][12][13] These scoring systems are used to assess the severity, course, and prognosis of the disease and then guide the treatment. [14][15][16][17] Nevertheless, it remains unclear about the degree of lung water content that can cause pulmonary dysfunction, and how to quantitatively assess lung water content by ultrasound.…”