The use of lung ultrasound in evaluation of extravascular lung water in hemodialysis patients: Systematic review and meta-analysis.

RATIONALE AND OBJECTIVES: Determining dry weight is crucial for optimizing hemodialysis, influencing efficacy, cardiovascular outcomes, and overall survival. Traditional clinical assessment methods for dry weight, relying on factors such as blood pressure and edema, frequently lack reliability. Lung ultrasound stands out as a promising tool for assessing volume status, given its non-invasiveness and reproducibility. This study aims to explore the role of Lung ultrasound in evaluating the impact of hemodialysis and ultrafiltration on extravascular lung water, with a specific focus on changes in B-lines post-hemodialysis compared to pre-hemodialysis. MATERIALS AND METHODS: The research encompassed searches across PubMed, WOS, and Scopus databases for studies related to lung ultrasound and hemodialysis. A meta-analysis was then performed to determine the mean differences in various parameters before compared to after, hemodialysis, including the number of B-lines, indexed end-inspiratory and end-expiratory inferior vena cava diameters, inferior vena cava collapsibility index, weight, blood pressure, and serum levels of NT-pro-BNP. RESULTS: Our meta-analysis, included 33 studies with 2301 hemodialysis patients, revealed a significant decrease in the number of B-lines post-hemodialysis (mean difference = 8.30, 95% CI [3.55 to 13.05]). Furthermore, there was a noteworthy reduction in inspiratory and expiratory inferior vena cava diameters post-hemodialysis (mean difference = 2.32, 95% CI [0.31 to 4.33]; mean difference = 4.05, 95% CI [2.44 to 5.65], respectively). Additionally, a significant positive correlation was observed between B-lines and the maximum inferior vena cava diameter both pre- and post-hemodialysis (correlation coefficient = 0.39; correlation coefficient = 0.32, respectively). CONCLUSION: These findings indicate the effectiveness of lung ultrasound in detection of volume overload and assessment of response to ultrafiltration in hemodialysis patients.

Evaluation of extravascular lung water and cardiac function in normal vaginal delivery by intrapartum bedside ultrasound.

BACKGROUND: Healthy parturients may experience pulmonary edema and disturbed cardiac function during labor. We aimed to evaluate the extravascular lung water (EVLW), intravascular volume, and cardiac function of normal parturients during spontaneous vaginal delivery by bedside ultrasound. And to explore the correlation between EVLW and intravascular volume, cardiac function. METHODS: This was a prospective observational study including 30 singleton-term pregnant women undergoing spontaneous vaginal delivery. Bedside ultrasound was performed at the early labor, the end of the second stage of labor, 2 and 24 h postpartum, and 120 scanning results were recorded. EVLW was evaluated by the echo comet score (ECS) obtained by the 28-rib interspaces technique. Inferior vena cava collapsibility index (IVC-CI), left ventricle ejection fraction, right ventricle fractional area change, left and right ventricular E/A ratio, and left and right ventricular index of myocardial performance (LIMP and RIMP) were measured. Measurements among different time points were compared, and the correlations between ECS and other measurements were analyzed. RESULTS: During the spontaneous vaginal delivery of healthy pregnant women, 2 had a mild EVLW increase at the early labor, 8 at the end of the second stage of labor, 13 at 2 h postpartum, and 4 at 24 h postpartum (P < 0.001). From the early labor to 24 h postpartum, ECS first increased and then decreased, reaching its peak at 2 h postpartum (P < 0.001). IVC-CI first decreased and then increased, reaching its minimum at the end of the second stage of labor (P < 0.001). RIMP exceeded the cut-off value of 0.43 at the end of the second stage of labor. ECS was weakly correlated with IVC-CI (r=-0.373, P < 0.001), LIMP (r = 0.298, P = 0.022) and RIMP (r = 0.211, P = 0.021). CONCLUSIONS: During spontaneous vaginal delivery, the most vital period of perinatal care is between the end of the second stage of labor and 2 h postpartum, because the risk of pulmonary edema is higher and the right ventricle function may decline. IVC-CI can be used to evaluate maternal intravascular volume. The increase in EVLW may be related to the increase in intravascular volume and the decrease in ventricular function.

[Evaluation of extravascular lung water index in critically ill patients based on lung ultrasound radiomics analysis combined with machine learning].

OBJECTIVE: To explore lung ultrasound radiomics features which related to extravascular lung water index (EVLWI), and to predict EVLWI in critically ill patients based on lung ultrasound radiomics combined with machine learning and validate its effectiveness. METHODS: A retrospective case-control study was conducted. The lung ultrasound videos and pulse indicated continuous cardiac output (PiCCO) monitoring results of critically ill patients admitted to the department of critical care medicine of the First Affiliated Hospital of Guangxi Medical University from November 2021 to October 2022 were collected, and randomly divided into training set and validation set at 8:2. The corresponding images from lung ultrasound videos were obtained to extract radiomics features. The EVLWI measured by PiCCO was regarded as the "gold standard", and the radiomics features of training set was filtered through statistical analysis and LASSO algorithm. Eight machine learning models were trained using filtered radiomics features including random forest (RF), extreme gradient boost (XGBoost), decision tree (DT), Naive Bayes (NB), multi-layer perceptron (MLP), K-nearest neighbor (KNN), support vector machine (SVM), and Logistic regression (LR). Receiver operator characteristic curve (ROC curve) was plotted to evaluate the predictive performance of models on EVLWI in the validation set. RESULTS: A total of 151 samples from 30 patients were enrolled (including 906 lung ultrasound videos and 151 PiCCO monitoring results), 120 in the training set, and 31 in the validation set. There were no statistically significant differences in main baseline data including gender, age, body mass index (BMI), mean arterial pressure (MAP), central venous pressure (CVP), heart rate (HR), cardiac index (CI), cardiac function index (CFI), stroke volume index (SVI), global end diastolic volume index (GEDVI), systemic vascular resistance index (SVRI), pulmonary vascular permeability index (PVPI) and EVLWI. The overall EVLWI range in 151 PiCCO monitoring results was 3.7-25.6 mL/kg. Layered analysis showed that both datasets had EVLWI in the 7-15 mL/kg interval, and there was no statistically significant difference in EVLWI distribution. Two radiomics features were selected by using LASSO algorithm, namely grayscale non-uniformity (weight was -0.006 464) and complexity (weight was -0.167 583), and they were used for modeling. ROC curve analysis showed that the MLP model had better predictive performance. The area under the ROC curve (AUC) of the prediction validation set EVLWI was higher than that of RF, XGBoost, DT, KNN, LR, SVM, NB models (0.682 vs. 0.658, 0.657, 0.614, 0.608, 0.596, 0.557, 0.472). CONCLUSIONS: The gray level non-uniformity and complexity of lung ultrasound were the most correlated radiomics features with EVLWI monitored by PiCCO. The MLP model based on gray level non-uniformity and complexity of lung ultrasound can be used for semi-quantitative prediction of EVLWI in critically ill patients.

Lung "Comet Tails" in Healthy Individuals: Accumulation or Clearance of Extravascular Lung Water?

Parks, Jordan K, Courtney M. Wheatley-Guy, Glenn M. Stewart, Caitlin C. Fermoyle, Bryan J. Taylor, Jesse Schwartz, Briana Ziegler, Kay Johnson, Alice Gavet, Loïc Chabridon, Paul Robach, and Bruce D. Johnson. Lung "Comet Tails" in healthy individuals: accumulation or clearance of extravascular lung water? High Alt Med Biol. 24:230-233, 2023-Ultrasound lung comet tails (or B-lines) tend to be limited in number (<5) or absent under ultrasound examination, and the appearance of diffuse B-lines with lung sliding has been suggested to identify pulmonary edema. Clinical evaluation of B-lines has been utilized as a bedside test to assess pulmonary congestion in patients with heart failure. Exposure to altitude or prolonged exercise can alter fluid regulation and can lead to pulmonary congestion or edema. As such, B-lines have been utilized in the field to monitor for pathological lung fluid accumulation. However, ultrasound lung comet lines might not be as reliable for identifying extravascular lung water (EVLW) as previously thought in healthy individuals exercising at altitude where an increase in the number of ultrasound lung comets would reflect fluid buildup in the interstitial space of the alveoli and pulmonary capillaries. This report will focus on reviewing the literature and our data from a group of ultraendurance runners that completed the Ultra Trail Mont Blanc race that demonstrates that lung comet tails may not always be evidence of pathological fluid accumulation in healthy individuals and as such should be used to assess EVLW in concert with other diagnostic testing.

A deep learning model enables accurate prediction and quantification of pulmonary edema from chest X-rays.

BACKGROUND: A quantitative assessment of pulmonary edema is important because the clinical severity can range from mild impairment to life threatening. A quantitative surrogate measure, although invasive, for pulmonary edema is the extravascular lung water index (EVLWI) extracted from the transpulmonary thermodilution (TPTD). Severity of edema from chest X-rays, to date is based on the subjective classification of radiologists. In this work, we use machine learning to quantitatively predict the severity of pulmonary edema from chest radiography. METHODS: We retrospectively included 471 X-rays from 431 patients who underwent chest radiography and TPTD measurement within 24 h at our intensive care unit. The EVLWI extracted from the TPTD was used as a quantitative measure for pulmonary edema. We used a deep learning approach and binned the data into two, three, four and five classes increasing the resolution of the EVLWI prediction from the X-rays. RESULTS: The accuracy, area under the receiver operating characteristic curve (AUROC) and Mathews correlation coefficient (MCC) in the binary classification models (EVLWI < 15, ≥ 15) were 0.93 (accuracy), 0.98 (AUROC) and 0.86(MCC). In the three multiclass models, the accuracy ranged between 0.90 and 0.95, the AUROC between 0.97 and 0.99 and the MCC between 0.86 and 0.92. CONCLUSION: Deep learning can quantify pulmonary edema as measured by EVLWI with high accuracy.

Global longitudinal strain assessment of cardiac function and extravascular lung water formation after diving using semi-closed circuit rebreather.

PURPOSE: The aim of the present investigation is to study the relationship of ventricular global longitudinal strain (GLS) and ultrasound lung comets (ULC) formation to establish a link between extravascular pulmonary water formation and cardiac contractile dysfunction. METHODS: This is a prospective observational study including 14 active military divers. The subjects performed two sea dives of 120 min each with a semi-closed SCUBA circuit at 10 m depth. Divers were examined at baseline, 15 min (D1) and 60 min (D2) after diving. The evaluation included pulmonary and cardiac echography (including speckle tracking techniques). Blood samples were drawn at baseline and after diving, assessing hs-TnT and Endothelin-1. RESULTS: ULC were detected in 9 (64.2%) and 8 (57.1%) of the subjects after D1 and D2 respectively. No differences were found in right and left ventricular GLS after both immersions (RV: Baseline: - 17.9 4.9 vs. D1: - 17.2 6.5 and D2: - 16.7 5.8 s-1; p = 0.757 and p = 0.529; LV: Baseline: - 17.0 2.3 vs. D1: - 17.4 2.1 and D2: - 16.9 2.2 s-1; p = 0.546 and p = 0.783). However, a decrease in atrial longitudinal strain parameters have been detected after diving (RA: Baseline: 35.5 9.2 vs. D1: 30.3 12.8 and D2: 30.7 13.0 s-1; p = 0.088 and p = 0.063; LA: Baseline: 39.0 10.0 vs. D1: 31.6 6.1 and D2: 32.4 10.6 s-1; p = 0.019 and p = 0.054). CONCLUSION: In the present study, no ventricular contractile dysfunction was observed. However, increase pulmonary vasoconstriction markers were present after diving.

Second-order grey-scale texture analysis of pleural ultrasound images to differentiate acute respiratory distress syndrome and cardiogenic pulmonary edema.

Discriminating acute respiratory distress syndrome (ARDS) from acute cardiogenic pulmonary edema (CPE) may be challenging in critically ill patients. Aim of this study was to investigate if gray-level co-occurrence matrix (GLCM) analysis of lung ultrasound (LUS) images can differentiate ARDS from CPE. The study population consisted of critically ill patients admitted to intensive care unit (ICU) with acute respiratory failure and submitted to LUS and extravascular lung water monitoring, and of a healthy control group (HCG). A digital analysis of pleural line and subpleural space, based on the GLCM with second order statistical texture analysis, was tested. We prospectively evaluated 47 subjects: 16 with a clinical diagnosis of CPE, 8 of ARDS, and 23 healthy subjects. By comparing ARDS and CPE patients' subgroups with HCG, the one-way ANOVA models found a statistical significance in 9 out of 11 GLCM textural features. Post-hoc pairwise comparisons found statistical significance within each matrix feature for ARDS vs. CPE and CPE vs. HCG (P ≤ 0.001 for all). For ARDS vs. HCG a statistical significance occurred only in two matrix features (correlation: P = 0.005; homogeneity: P = 0.048). The quantitative method proposed has shown high diagnostic accuracy in differentiating normal lung from ARDS or CPE, and good diagnostic accuracy in differentiating CPE and ARDS. Gray-level co-occurrence matrix analysis of LUS images has the potential to aid pulmonary edemas differential diagnosis.

Lung ultrasound to quantitatively evaluate extravascular lung water content and its clinical significance.

BACKGROUND: As we all know, pulmonary edema can be diagnosed by lung ultrasound (LUS), but how to accurately and quantitatively evaluate lung water content by ultrasound is a difficult problem that needs to be solved urgently. B-line assessment with LUS has recently been proposed as a reliable, noninvasive semiquantitative tool for evaluating extravascular lung water (EVLW). To date, however, there has been no easy quantitative method to evaluate EVLW by LUS. OBJECTIVE: (1) To explore the feasibility of establishing a rabbit model with increased EVLW by injecting warm normal saline (NS) into the lungs via the endotracheal tube. (2) To establish a simple, accurate and clinically operable method for quantitative assessment of EVLW using LUS. (3) To develop LUS into a resource for guiding the clinical treatment of patients with increased EVLW. METHODS: Forty-five New Zealand rabbits were randomized into nine groups (n = 5). After anesthesia, each group of rabbits was injected with different amounts of warm sterile NS (0 ml/kg, 2 ml/kg, 4 ml/kg, 6 ml/kg, 8 ml/kg, 10 ml/kg, 15 ml/kg, 20 ml/kg, 30 ml/kg) via the endotracheal tube. Each rabbit was examined by LUS before and after NS injection. At the same time, the spontaneous respiratory rate (RR, breaths per minute), heart rate (HR, bpm) and arterial blood gas (ABG) of the rabbits were recorded. Then, both lungs were dissected to obtain the wet and dry weight and conduct a complete histological examination. RESULTS: Injecting NS into the lungs through a tracheal tube can successfully establish a rabbit model with increased EVLW. The extent of EVLW increase is related to the volume of NS injected into the lungs. As the EVLW increases, three different types of B-lines can be seen in the LUS. When the NS injection volume is 2-6 ml/kg, comet-tail artifacts and B-lines are the main patterns found on LUS; as additional NS is injected into the lungs, the rabbits' RR gradually increases, while their HR gradually decreases, ABG remains normal or shows mild metabolic acidosis (MA). Confluent B-lines grow gradually but significantly, reaching a dominant position when the NS injection volume reaches 6-8 ml/kg and predominating almost entirely when the NS injection volume is 8-15 ml/kg; at that time, rabbits' RRs and HRs decrease sharply, and the ABG indicated type I respiratory failure (RF).Compact B-lines occur and predominate almost entirely when the NS injection volume reaches 10 ml/kg and 15-20 ml/kg, respectively. At that time, rabbits begin to enter cardiac and respiratory arrest, and ABG shows type II RF and MA. CONCLUSION: In this study, the establishment of an animal model with increased EVLW confirmed that different lung water content had corresponding manifestations in ultrasound and was associated with different degrees of clinical symptoms, and the study results can be used to guide clinical practice.

B-Lines Scores Derived From Lung Ultrasound Provide Accurate Prediction of Extravascular Lung Water Index: An Observational Study in Critically Ill Patients.

INTRODUCTION: Visualization of B-lines via lung ultrasound provides a non-invasive estimation of pulmonary hydration. Extravascular lung water index (EVLWI) and pulmonary vascular permeability index (PVPI) assessed by transpulmonary thermodilution (TPTD) represent the most validated parameters of lung water and alveolocapillary permeability, but measurement is invasive and expensive. This study aimed to compare the correlations of B-lines scores from extensive 28-sector and simplified 4-sector chest scan with EVLWI and PVPI derived from TPTD in the setting of intensive care unit (primary endpoint). METHODS: We performed scoring of 28-sector and 4-sector B-Lines in 50 critically ill patients. TPTD was carried out with the PiCCO-2-device (Pulsion Medical Systems SE, Maquet Getinge Group). Median time exposure for ultrasound procedure was 12 minutes for 28-sector and 4 minutes for 4-sector scan. RESULTS: Primarily, we found close correlations of 28-sector as well as 4-sector B-Lines scores with EVLWI (R2 = 0.895 vs. R2 = 0.880) and PVPI (R2 = 0.760 vs. R2 = 0.742). Both B-lines scores showed high accuracy to identify patients with specific levels of EVLWI and PVPI. The extensive 28-sector B-lines score revealed a moderate advantage compared to simplified 4-sector scan in detecting a normal EVLWI ≤ 7 (28-sector scan: sensitivity = 81.8%, specificity = 94.9%, AUC = 0.939 versus 4-sector scan: sensitivity = 81.8%, specificity = 82.1%, AUC = 0.902). Both protocols were approximately equivalent in prediction of lung edema with EVLWI ≥ 10 (28-sector scan: sensitivity = 88.9%, specificity = 95.7%, AUC = 0.977 versus 4-sector scan: sensitivity = 81.5%, specificity = 91.3%, AUC = 0.958) or severe pulmonary edema with EVLWI ≥ 15 (28-sector scan: sensitivity = 91.7%, specificity = 97.4%, AUC = 0.995 versus 4-sector scan: sensitivity = 91.7%, specificity = 92.1%, AUC = 0.978). As secondary endpoints, our evaluations resulted in significant associations of 28-sector as well as simplified 4-sector B-Lines score with parameters of respiratory function. CONCLUSION: Both B-line protocols provide accurate non-invasive evaluation of lung water in critically ill patients. The 28-sector scan offers a marginal advantage in prediction of pulmonary edema, but needs substantially more time than 4-sector scan.

Utility of Lung Ultrasound in the Estimation of Extravascular Lung Water in a Pediatric Population-A Prospective Observational Study.

OBJECTIVE: Lung ultrasound (LUS) is a promising bedside modality for the estimation of extravascular lung water index (EVLWI), but has not been validated against objective measures in children. This study aimed to investigate the correlation of LUS B-line scoring with EVLWI, thresholds indicating elevated EVLWI, and its outcome following pediatric cardiac surgery. DESIGN: Prospective observational study. SETTING: Cardiothoracic surgical intensive care unit in a tertiary care teaching hospital. PARTICIPANTS: Children younger than 12 years undergoing elective complete surgical correction of cyanotic or acyanotic congenital heart disease (Aristotle score ≤9), excluding neonates, those weighing <3.5 kg, and those with thoracic deformities, pulmonary pathology, and hemodynamic instability. INTERVENTIONS: Extravascular lung water index measurement by transpulmonary thermodilution, along with concurrent LUS B-line and Chest-X ray (CXR) scoring. MEASUREMENTS AND MAIN RESULTS: LUS B-line score had a moderate correlation with EVLWI (Pearson's correlation coefficient 0.57; 95% CI 0.44-0.69). LUS B-line scores showed acceptable discrimination only for higher thresholds of EVLWI (sensitivity 82% and 79%, respectively, for EVLWI >20 mL/kg v sensitivity and specificity 57% and 80% for EVLWI >10 mL/kg). Age, body surface area, vasoactive-inotropic score (VIS), chest X-ray score, and EVLWI but not LUS B-line score were significant predictors for duration of mechanical ventilation in this cohort. CONCLUSIONS: LUS B-line scoring has limited utility in semiquantitative estimation of EVLWI at lower thresholds of EVLWI in pediatric cardiac surgical patients. It may have better discrimination and acceptable sensitivity and specificity at higher thresholds of EVLWI. Contrasting with multiple reports of clinical utility, these results call for wider evaluation of LUS and its clinical modifiers like age, pathology, and pretest probability in estimation of EVLWI.

[Prognostic value of transthoracic lung ultrasound comet-tail and extravascular lung water index in septic patients].

OBJECTIVE: To evaluate the prognostic value of transthoracic lung ultrasound comet-tail and extravascular lung water index (EVLWI) in septic patients. METHODS: A prospective cohort study was conducted. Sixty septic patients admitted to department of intensive care unit (ICU) of Sichuan Provincial People's Hospital from November 2016 to October 2019 were enrolled. The EVLWI and pulmonary vascular permeability index (PVPI) were determined by pulse-indicated continuous cardiac output (PiCCO) system at 0, 24, 48 and 72 hours. At the same time, the numbers of comet tail signs in both lungs (parasternal, midclavicular, axillary to midaxillary) were collected by chest ultrasound. Moreover, arterial blood gas analysis, such as pH value, central venous-to-arterial carbon dioxide difference (Pcv-aCO2), central venous oxygen saturation (ScvO2), blood lactic acid (Lac), PaO2/FiO2 were measured. Pearson correlation analysis was performed between the number of comet-tail sign and EVLWI. Multivariate Logistic regression model was used to analyze the relationship between the number of comet-tail sign, EVLWI and prognosis. Receiver operator characteristic curve (ROC curve) was drawn to predict the prognosis. RESULTS: There were 43 males and 17 females in 60 septic patients. The average age was (64.3±15.5) years old (range: 31-83 years old). There were 35 cases with pulmonary infection, 10 cases with abdominal infection, 6 cases with urinary tract infection, 3 cases with skin and soft tissue infection, 3 cases with intestinal infection, 1 case with meningitis, 1 case with cellulitis and 1 case with multiple injury. Acute respiratory distress syndrome (ARDS) occurred with 8 patients; 40 patients (66.7%) survived and 20 patients (33.3%) died on day 28. Pearson correlation analysis showed that the number of comet-tail sign was positively correlated with EVLWI (r = 0.944, P < 0.001). There was significant difference in the number of comet-tail signs among sepsis patients with different primary infection sites (H = 17.714, P < 0.001). The number of comet-tail signs in sepsis patients with pulmonary infection [19 (13, 27)] was significantly higher than that with other infections. The number of comet-tail sign in patients with ARDS was significantly higher than that in patients without ARDS [27 (19, 30) vs. 15 (9, 24), H = 25.387, P < 0.001]. Multivariate Logistic regression analysis showed that EVLWI, the number of comet-tail signs and PVPI were independent risk factors for death in septic patients [odds ratio (OR) and 95% confidence interval (95%CI) were 10.772 (1.161-99.851), 2.360 (1.070-5.202), 2.042 (1.152-3.622), all P < 0.05]. The accuracy, sensitivity, specificity, positive predictive value, negative predictive value of Logistic regression model based on comet-tail sign and EVLWI were 90.0%, 90.0%, 90.0%, 81.8%, 94.7%, respectively, and area under curve (AUC) were 0.926±0.018, 95%CI was 0.912-0.975, P < 0.001. CONCLUSIONS: The transthoracic lung ultrasound comet-tail in septic patients is significantly correlated with EVLWI monitored by PiCCO. The transthoracic lung ultrasound comet-tail combined with EVLWI can better improve the sensitivity, specificity and accuracy of 28-day prognosis in septic patients.

[Evaluation of extravascular lung water in patients with acute respiratory distress syndrome by syndecan-1 combined with lung ultrasonography].

OBJECTIVE: To investigate the value of plasma syndecan-1 (SDC-1) combined with lung ultrasonography in evaluating the degree of extravascular lung water in patients with acute respiratory distress syndrome (ARDS). METHODS: From July 2018 to July 2019, 50 patients with ARDS admitted to the department of intensive care unit of Wuxi People's Hospital Affiliated to Nanjing Medical University were enrolled. After admission, pulse indicator continuous cardiac output (PiCCO) catheter was established for all patients. PiCCO indexes, including extravascular lung water index (EVLWI) and pulmonary vascular permeability index (PVPI) were monitored by one doctor. Another doctor performed lung ultrasound examination, and calculated the sum of the number of B-lines under 10 ultrasound sections of upper blue point, lower blue point, diaphragm point, Plaps point and rear blue point of both lungs. Then the level of plasma SDC-1 was detected by enzyme linked immunosorbent assay (ELISA). Pearson correlation method was used to analyze the correlation between the number of ultrasonic B-lines, plasma SDC-1 level and EVLWI and PVPI. Taking 10 mL/kg EVLWI as the boundary value, the degree of pulmonary edema in patients with ARDS was divided into mild pulmonary edema and severe pulmonary edema. The receiver operator characteristic curve (ROC curve) was drawn, and the number of B-lines, SDC-1 and the predictive value of the combination of the above two indicators on the severity of pulmonary edema in patients with ARDS were analyzed. RESULTS: The cardiac index (CI) and central venous pressure (CVP) of 50 patients with ARDS were (46.84±6.00) mL×s-1×m-2 and (8.12±1.80) mmHg (1 mmHg = 0.133 kPa), cardiogenic pulmonary edema was excluded. In 50 patients with ARDS, EVLWI was (10.82±2.92) mL/kg, PVPI was 3.02±0.69, the number of ultrasound B-lines was 40.90±13.05, and plasma SDC-1 was (568.25±118.14) µg/L. Pearson correlation analysis showed that the number of ultrasound B-lines in patients with ARDS was significantly positively correlated with EVLWI and PVPI (r1 = 0.802, r2 = 0.799, both P < 0.01). Plasma SDC-1 was also positively correlated with EVLWI and PVPI (r1 = 0.732, r2 = 0.576, both P < 0.01). ROC curve analysis showed that the number of B-lines and SDC-1 had good predictive value for the severity of pulmonary edema in patients with ARDS. The area under ROC curve (AUC) and 95% confidence interval (95%CI) were 0.891 (0.803-0.979) and 0.875 (0.772-0.978), respectively. When the cut-off of B-lines was 40.50, the sensitivity and specificity were 82.1% and 86.4%, respectively. When the cut-off of SDC-1 was 559.37 µg/L, the sensitivity and specificity were 85.7% and 81.8%, respectively. Combining the number of B-lines with SDC-1 could further improve the predictive value of pulmonary water in patients with ARDS. The AUC (95%CI) was 0.958 (0.890-1.000), and the sensitivity and specificity were 92.9% and 91.8%, respectively. CONCLUSIONS: The level of plasma SDC-1 and the number of pulmonary ultrasonic B-lines have a good correlation with the degree of extravascular lung water in patients with ARDS. The combined application of the two noninvasive indexes can be used to evaluate the degree of extravascular lung water in patients with ARDS.

Ultrasonographic Assessment of Extravascular Lung Water in Hospitalized Patients Requiring Hemodialysis: A Prospective Observational Study.

INTRODUCTION: Sonographic technologies can estimate extravascular lung water (EVLW) in hemodialysis (HD) patients. This study investigated the suitability of a handheld scanner in contrast to a portable scanner for quantifying EVLW in hospitalized patients requiring HD. METHODS: In this prospective study, 54 hospitalized HD patients were enrolled. Bedside lung ultrasound was performed within 30 min before and after dialysis using handheld (phased array transducer, 1.7-3.8 MHz) and portable (curved probe, 5-2 MHz) ultrasound devices. Eight lung zones were scanned for total B-lines number (TBLN). The maximum diameter of inferior vena cava (IVC) was measured. We performed Passing-Bablok regression, Deming regression, Bland-Altman, and logistic regression analysis. RESULTS: The 2 devices did not differ in measuring TBLN and IVC (p > 0.05), showing a high correlation (r = 0.92 and r = 0.51, respectively). Passing-Bablok regression had a slope of 1.11 and an intercept of 0 for TBLN, and the slope of Deming regression was 1.02 within the CI bands of 0.94 and 1.11 in the full cohort. TBLN was logarithmically transformed for Bland-Altman analysis, showing a bias of 0.06 (TBLN = 1.2) between devices. The slope and intercept of the Deming regression in IVC measurements were 0.77 and 0.46, respectively; Bland-Altman plot showed a bias of -0.07. Compared with predialysis, TBLN significantly (p < 0.001) decreased after dialysis, while IVC was unchanged (p = 0.16). Univariate analysis showed that cardiovascular disease (odds ratio [OR] 8.94 [2.13-61.96], p = 0.002), smoking history (OR 5.75 [1.8-20.46], p = 0.003), and right pleural effusion (OR 5.0 [1.2-25.99], p = 0.03) were strong predictors of EVLW indicated by TBLN ≥ 4. CONCLUSION: The lung and IVC findings obtained from handheld and portable ultrasound scanners are comparable and concordant. Cardiovascular disease and smoking history were strong predictors of EVLW. The use of TBLN to assess EVLW in hospitalized HD patients is feasible. Further studies are needed to determine if TBLN can help guide volume removal in HD patients.

Extravascular lung water and cardiac function assessed by echocardiography in healthy lowlanders during repeated very high-altitude exposure.

BACKGROUND: High-altitude pulmonary edema is associated with elevated systolic pulmonary artery pressure (sPAP) and increased extravascular lung water (EVLW). We investigated sPAP and EVLW during repeated exposures to high altitude (HA). METHODS: Healthy lowlanders underwent two identical 7-day HA-cycles, where subjects slept at 2900 m and spent 4-8 h daily at 5050 m, separated by a weeklong break at low altitude (LA). Echocardiography and EVLW by B-lines were measured at 520 m (baseline, LA1), on day one, two and six at 5050 m (HA1-3) and after descent (LA2). RESULTS: We included 21 subjects (median 25 years, body mass index 22 kg/m2, SpO2 98%). SPAP rose from 21 mmHg at LA1 to 38 mmHg at HA1, decreased to 30 mmHg at HA3 (both p < 0.05 vs LA1) and normalized at 20 mmHg at LA2 (p = ns vs LA1). B-lines increased from 0 at LA1 to 6 at HA2 and 7 at HA3 (both p < 0.05 vs LA1) and receded to 1 at LA2 (p = ns vs LA1). Overall, in cycle two, sPAP did not differ (mean difference (95% confidence interval) -0.2(-2.3 to 1.9) mmHg, p = 0.864) but B-lines were more prevalent (+2.3 (1.4-3.1), p < 0.001) compared to cycle 1. Right ventricular systolic function decreased significantly but minimally at 5050 m. CONCLUSIONS: Exposure to 5050 m induced a rapid increase in sPAP. B-lines rose during prolonged exposures to 5050 m, despite gradual decrease in sPAP, indicating excessive hydrostatic pressure might not be solely responsible for EVLW-development. Repeated HA-exposure had no acclimatization effect on EVLW. This may affect workers needing repetitive ascents to altitude and could indicate greater B-line development upon repeated exposure.

Assessment of extravascular lung water by measuring the number of pulmonary ultrasound B-lines before and after CBP in patients with MODS.

ABSTRACT: To determine whether the change in the number of pulmonary ultrasound B-line can accurately assess the extravascular lung water (EVLW) before and after continuous bedside blood purification (CBP) in patients with multiple organ dysfunction syndrome (MODS).Seventy-six patients with MODS who underwent CBP were examined within 24 hours before and after CBP using pulmonary ultrasound to detect the number of ultrasound B-line or using pulse indicator continuous cardiac output method to examine extravascular lung water, blood oxygenation index, and B-type natriuretic peptide (BNP) content. The correlation of the change in the number of B lines before and after CBP treatment with the negative balance of 24 hours liquid, the change of oxygenation index, and BNP content were analyzed.In the 76 patients, CBP treatment significantly decreased EVLW, the number of B-line, and BNP (P < .05 for all), while it significantly increased the oxygenation index (P < .05). Correlation analysis showed that the decrease in B-line number after CBP treatment was positively correlated with the 24 hours negative lung fluid balance, decrease of EVLW, oxygenation index improvement, and decreased BNP content. The change in the numbers of pulmonary ultrasound B-line can accurately assess the change of EVLW before and after CBP treatment and reflect the efficiency of ventilation in the lungs and the risk of heart failure.Thus, it can replace pulse indicator continuous cardiac output as an indicator for evaluating EVLW in patients with MODS treated with CBP.

Can the assessment of ultrasound lung water in haemodialysis patients be simplified?

BACKGROUND: Lung ultrasound (US) reliably estimates lung water and it is increasingly applied in clinical practice in dialysis patients. A semi-quantitative US score summing up the US-B lines (an equivalent of B lines in the standard chest X-ray) at 28 sites in the intercostal spaces (Jambrik et al. Usefulness of ultrasound lung comets as a non-radiologic sign of extravascular lung water. Am J Cardiol 2004; 93: 1265-1270) is the most used score. METHODS: We compared the prognostic performance for death, and cardiovascular (CV) events of the 28-sites US score with a score restricted to eight sites in a cohort of 303 haemodialysis (HD) patients. RESULTS: The 8- and the 28-sites scores were highly inter-related (Spearman's ρ = 0.93, P < 0.001), and their concordance index was fairly good (k = 0.79, 95% confidence interval 0.74-0.84). During a mean follow-up of 3 years, 112 patients died, and 129 experienced a CV event. At univariate and multivariate analysis, both scores were associated with mortality (P ≤ 0.01) and CV events (P ≤ 0.05). The explained variances (R2) for death and CV events of the 28-sites score in multivariate models including major risk factors for these outcomes in the end-stage kidney disease (ESKD) population were 3.9 and 2.2%, and those of the 8-sites score were 3.1 and 2.4%, respectively. The median time needed to perform the examination was 3.05 min [interquartile range (IQR) 2.22-5.00 min] for the 28-sites score and 1.35 min (IQR 1.16-2.00 min) for the 8-sites score. CONCLUSION: The 8-sites score is tightly related to the classical Jambrik 28-sites score and this score holds an almost identical predictive power to the reference score. Even though the 28-sites score can be completed just in ∼3 min, the 8-sites score requires only ∼1.30 min, and it is, therefore, better suited for application in everyday clinical practice in HD units.

Chest Ultrasound as a New Tool for Assessment of Volume Status in Hemodialysis Patients.

Accurate assessment of volume status (VS) in hemodialysis (HD) patients is challenging. The use of chest ultrasound (CUS) for detection of extravascular lung water has recently gained wide acceptance. The aim of this study was to evaluate the use of CUS in VS assessment in HD patients in comparison to clinical and inferior vena cava (IVC) indices and to assess their relation with volume displacement after ultrafiltration. This prospective cohort study was carried out on 38 patients on regular HD. VS was assessed using a 13-point clinical score, and IVC indices and CUS score were measured pre- and post-ultrafiltration. Correlation between these parameters and with ultrafiltration volume was tested. There was a statistically significant reduction in post-ultrafiltration CUS score and the 13-point clinical score (P < 0.01). Moreover, reduction in all the IVC indices (inspiratory and expiratory diameters and collapsing index) was detected, but did not reach statistical significance (P = 0.185, P = 0.296, and P = 0.194, respectively). CUS score had statistically significant correlations with ultrafiltration volume and New York Heart Association classes (P < 0.001 and <0.001, respectively). Neither clinical signs nor IVC indices can be used independently for the assessment of VS in HD patients. CUS is a useful guide in VS assessment, and we recommend its routine use in the management of HD patients. Concomitant use of bio- impedance analysis (BIA) may be needed in addition to CUS for more accurate assessment of VS in HD patients.

Lung Ultrasound Score Predicts the Extravascular Lung Water Content in Low-Birth-Weight Neonates with Patent Ductus Arteriosus.

BACKGROUND Patent ductus arteriosus (PDA) is a common congenital cardiac abnormality in premature infants. In low-birth-weight infants weighing less than 2500 g, if the PDA continues to open, abnormal circulation hemodynamics and pulmonary edema may occur. This study aimed to investigate the role of lung ultrasound score in the assessment of pulmonary edema in low-weight neonates with PDA. MATERIAL AND METHODS Two hundred and twenty-one neonates with low birth weight were selected as the subjects, children with PDA as the observation group, and children with closed ductus arteriosus as the control group. On the fourth postnatal day, lung ultrasound examination and 6-segment lung ultrasound scoring were performed. RESULTS All 221 infants (94 in the observation group, 127 controls) underwent ultrasound examinations of the lungs. Intergroup differences in gestational age, birth weight, length of hospital stay, and left ventricular ejection fraction were not statistically significant. There was a significant difference in lung ultrasound score (t=0.005, P=0.000) and aortic root ratio to left atrial (t=0.085, P=0.000), which was negatively correlated with gestational age (r=-0.235, P=0.000) and positively correlated with PDA diameter (r=0.261, P=0.011). CONCLUSIONS Low-birth-weight children often have PDA. Its continued opening changes the circulation hemodynamics in children. Lung ultrasound score can semi-quantitatively evaluate the extravascular lung water content, identifying the need to intervene and follow up the hemodynamic significance of PDA over time.

Assessing Extravascular Lung Water in Critically Ill Patients Using Lung Ultrasound: A Systematic Review on Methodological Aspects in Diagnostic Accuracy Studies.

Lung ultrasound (LUS) is a non-invasive bedside method used to quantify extravascular lung water (EVLW). To evaluate the methodology and diagnostic accuracy of LUS in studies assessing EVLW in intensive care unit patients, PubMed and Embase were searched for studies comparing LUS with imaging modalities. In 14 relevant studies a wide variety of equipment used and training of examiners were noted. Four scoring systems were reported: (i) a binary score (the presence of three or more B-lines); (ii) a categorical score; (iii) a numerical score; (iv) a quantitative LUS score using software. The diagnostic accuracy of LUS varied: sensitivity ranged from 50%-98%, specificity from 76%-100% and r² from 0.20-0.91. Methodology and diagnostic accuracy varies substantially in published reports. Further research is needed to correlate methodological factors with diagnostic accuracy. Hospitals should standardize LUS methodology. Consensus is needed to harmonize LUS methodology for lung water assessment.