Extravascular Lung Water Research Articles

Quantification of pulmonary edema using automated lung segmentation on computed tomography in mechanically ventilated patients with acute respiratory distress syndrome

BackgroundQuantification of pulmonary edema in patients with acute respiratory distress syndrome (ARDS) by chest computed tomography (CT) scan has not been validated in routine diagnostics due to its complexity and time-consuming nature. Therefore, the single-indicator transpulmonary thermodilution (TPTD) technique to measure extravascular lung water (EVLW) has been used in the clinical setting. Advances in artificial intelligence (AI) have now enabled CT images of inhomogeneous lungs to be segmented automatically by an intensive care physician with no prior radiology training within a relatively short time. Nevertheless, there is a paucity of data validating the quantification of pulmonary edema using automated lung segmentation on CT compared with TPTD.MethodsA retrospective study (January 2016 to December 2021) analyzed patients with ARDS, admitted to the intensive care unit of the Department of Anesthesiology and Critical Care Medicine, University Hospital Mannheim, who underwent a chest CT scan and hemodynamic monitoring using TPTD at the same time. Pulmonary edema was estimated using manually and automated lung segmentation on CT and then compared to the pulmonary edema calculated from EVLW determined using TPTD.Results145 comparative measurements of pulmonary edema with TPTD and CT were included in the study. Estimating pulmonary edema using either automated lung segmentation on CT or TPTD showed a low bias overall (− 104 ml) but wide levels of agreement (upper: 936 ml, lower: − 1144 ml). In 13% of the analyzed CT scans, the agreement between the segmentation of the AI algorithm and a dedicated investigator was poor. Manual segmentation and automated segmentation adjusted for contrast agent did not improve the agreement levels.ConclusionsAutomated lung segmentation on CT can be considered an unbiased but imprecise measurement of pulmonary edema in mechanically ventilated patients with ARDS.

Standardization of transthoracic impedance values for estimating heart failure and its utility

Abstract Background The use of intrathoracic impedance for examining pleural effusion in heart failure patients has been explored previously. However, due to concerns about its accuracy and complexity, transthoracic impedance values have had limitations in quantifying extravascular lung water. Our dual objectives were to clarify the relationship between intrathoracic conditions and percutaneous transthoracic impedance values, and to establish a basic model for a new machine learning-based estimation system for assessing intrathoracic conditions in patients with heart failure. Methods First, we developed a live porcine congested lung model that induced pleural effusion by substantial fluid loading, and then longitudinally evaluated its correlation with percutaneous transthoracic impedance values. Second, we conducted multi-frequency bioelectrical impedance analysis to simultaneously collect electrical, physical, and hematological data from 63 hospitalized heart failure patients and 82 healthy volunteers Results In the porcine model, pleural effusion correlated with a concurrent decrease in SpO2 and a gradual decrease in impedance. We indexed and generated features from the measured values and developed an intrathoracic estimation model based on electrical measurements and clinical findings using a decision tree-based machine learning approach. Among the 286 features collected per individual, the model used 16 features. Notably, the model demonstrated high accuracy in discriminating patients with pleural effusion, achieving an AUC of 0.905 (95% CI: 0.870-0.940) in cross-validation, significantly outperforming the conventional frequency-based method. Conclusions Transthoracic impedance values, when indexed, reflect intrathoracic conditions and improve estimation. Our results highlighted the potential of machine learning and thoracic impedance measurement for accurate estimation of pleural effusion. This approach provides an effective means of assessing intrathoracic conditions. Figure: The upper figure shows the relationship between impedance values and pleural effusion in the congested lung model. On these results, human data were collected to construct the estimation model. The lower illustrates the accuracy of the model and provides a comprehensive view of the system.

Deep Phenotyping of Pulmonary Edema and Pulmonary Vascular Permeability in COVID-19 ARDS.

Background Clinical monitoring of pulmonary edema due to vascular hyperpermeability in ARDS poses significant clinical challenges. Presently, no biological or radiological markers are available for quantifying pulmonary edema. Our aim was to phenotype pulmonary edema and pulmonary vascular permeability in patients with COVID-19 ARDS. Methods Transpulmonary thermodilution measurements were conducted in 65 COVID-19 ARDS patients on the day of intubation to determine extravascular lung water index (EVLWi) and pulmonary vascular permeability index (PVPi). In parallel, ventilatory parameters, clinical outcomes, the volume of lung opacity measured by chest CT, and plasma proteomics (358 unique proteins) were compared between tertiles based on the EVLWi and PVPi. Regression models were used to associate EVLWi and PVPi with plasma, radiological, and clinical parameters. Computational pathway analysis was performed on significant plasma proteins in the regression models. Results Patients with the highest EVLWi values at intubation exhibited poorer oxygenation parameters and more days on the ventilator. Extravascular lung water strongly correlated with the total volume of opacity observed on CT(r=0.72), while the PVPi had weaker associations with clinical and radiological parameters. Plasma protein concentrations demonstrated a stronger correlation with PVPi than with EVLWi. The highest tertile of PVPi was associated with proteins linked to the acute phase response (cytokine and chemokine signaling) and extracellular matrix turnover. Conclusions In the clinical setting of COVID-19 ARDS, pulmonary edema (EVLWi) can be accurately quantified through chest CT and parallels deterioration in ventilatory parameters and clinical outcomes. Vascular permeability (PVPi) is strongly reflected by inflammatory plasma proteins.

Physiopathology of High-Altitude Pulmonary Edema.

The air-blood barrier is well designed to accomplish the matching of gas diffusion with blood flow. This function is achieved by maintaining its thickness at ∼0.5 µm, a feature implying to keep extravascular lung water to the minimum. Exposure to hypobaric hypoxia, especially when associated with exercise, is a condition potentially leading to the development of the so-called high-altitude pulmonary edema (HAPE). This article presents a view of the physiopathology of HAPE by merging available data in humans exposed to high altitude with data from animal experimental approaches. A model is also presented to characterize HAPE nonsusceptible versus susceptible individuals based on the efficiency of alveolar-capillary oxygen uptake and estimated morphology of the air-blood barrier.

Beneficial effects of extravascular lung water index-guided volum management in patients with cardiogenic shock

Objective: To evaluate the role of volume management guided by extravascular lung water index(EVLWI) in improving the clinical outcomes and cardiac function for patients with cardiogenic shock. Methods: This study was a single-center, prospective cohort study. Patients with cardiogenic shock admitted to the Department of Cardiovascular Medicine, Shanghai East Hospital from July 2022 to December 2023 were enrolled. Patients were matched 1∶1 by propensity score and divided into EVLWI group and control group. In the control group, the volume management strategy was determined by the attending physician based mainly on conventional factors, including clinical features, biochemical assessments, and certain blood pressure measurements. In EVLWI group, the volume management plan was formulated by integrating conventional factors with EVLWI derived from pulse index continuous cardiac output (PiCCO) monitoring. Baseline clinical data, in-hospital treatment, and hemodynamic data were collected. Major adverse cardiovascular events and cardiac function related parameters were compared at 30 d after treatment between the two groups. Baseline EVLWI levels were compared between the non-survivors and the survivors in the EVLWI group. The receiver operating characteristic curve was plotted to assess the accuracy of baseline EVLWI and central venous pressure in predicting all-cause mortality at 30 d after treatment in patients with cardiogenic shock, and subgroup analysis was performed according to ischemic/non-ischemic etiology and with/without use of inotropic drugs. Kaplan-Meier curve was used for survival analysis, with log-rank tests comparing all-cause mortality, cardiac death, and readmission rate for heart failure at 30 d after treatment. Results: A total of 200 patients with cardiogenic shock were enrolled, aged (71.35±12.82) years, 144(72%) males, EVLWI group and control group 100 patients each. Compared with the control group, EVLWI group had lower all-cause mortality (16%(16/100) vs. 42%(42/100), log-rank P<0.01), cardiac death (14%(14/100) vs. 34%(34/100), log-rank P<0.01), and readmission rate for heart failure (4%(4/100) vs. 12%(12/100), log-rank P=0.03) at 30 d after treatment. Subgroup analysis showed that EVLWI-guided volume management was associated with lower all-cause mortality at 30 d after treatment in patients with cardiogenic shock of ischemic or non-ischemic etiology and with or without inotropic drugs (all P<0.05). In EVLWI group, baseline EVLWI levels were higher in non-survivors than those in survivors [(15.99±6.47) ml/kg vs.(9.75±2.55) ml/kg, P<0.01]. The baseline EVLWI could predicting all-cause mortality at 30 d after treatment in patients with cardiogenic shock, with an area under the receiver operating characteristic curve of 0.84 (95%CI: 0.75-0.94, P<0.01), while the baseline central venous pressure had no predicting value (AUC=0.54, 95%CI: 0.40-0.69, P=0.60). The optimal cutoff value of EVLWI in pridicting all-cause mortality at 30 d after treatment in patients with cardiogenic shock was >10.3 ml/kg. With the optimization of hemodynamic parameters, left ventricular ejection fraction was improved in EVLWI group, and serum levels of N-terminal pro-brain natriuretic peptide, creatinine, alanine aminotransferase and lactic acid were decreased (all P<0.05). Conclusion: EVLWI-guided volume management exerts a beneficial effect on therapeutic decision-making and improves clinical outcomes and cardiac function in patients with cardiogenic shock.

The influence of sex, age, and body height on the pulmonary vascular permeability index – a prospective observational study

The pulmonary vascular permeability index (PVPI) is a quotient of the extravascular lung water (EVLW) and the pulmonary blood volume (PBV). In acute respiratory distress syndrome (ARDS), the alveolar-capillary membrane integrity is disrupted. The result is a disproportionate increase of EVLW compared to the PBV and, hence, an increase in PVPI. Thus, PVPI has repetitively been discussed to extend the definition of ARDS. Besides sex, the influence of other anthropometric variables on PVPI has not been studied so far. However, since it is known that EVLW depends on body height and sex, we hypothesize that PVPI depends on anthropometric variables as well. This prospective single-center observational study included 1533 TPTD measurements of 251 non-critically ill patients (50.6% men) undergoing elective neuro-, thoracic, or abdominal surgery at the Munich Clinic Bogenhausen of the Technical University of Munich. Multivariate regressions were used to measure the influence of sex, age, and body height on PVPI. In all patients, PVPI was significantly higher in women (P < 0.001), with 34.4% having a PVPI > 2 compared to 15.9% of men. Mean PVPI significantly decreased with height (P < 0.001) and age (P < 0.001). Multivariate regressions allowed the calculation of mean reference surfaces. The 95th percentile surface for PVPI was > 3 for small and young women and well above 2 for all but tall and elderly men. In patients who underwent (lung reduction) thoracic surgery, the PVPI before and after surgery did not differ significantly (P = 0.531), and post-surgical PVPI did not correlate with the amount of lung resected (P = 0.536). Hence, we conclude that PVPI may be independent of the extent of lung volume reduction. However, PVPI is heavily dependent on sex, age, and body height. Anthropometric variables thus have a significant impact on the likelihood of misclassified abnormal PVPI. This warrants further studies since an increased PVPI, e.g. in the context of an ARDS, may be overlooked if anthropometric variables are not considered. We suggest reference surfaces based on the 95th-percentile corrected for sex, age, and height as a novel approach to normalize PVPI.

Extravascular lung water assessment by lung ultrasound in infants following pediatric cardiac surgery.

Lung edema is a significant factor in prolonged mechanical ventilation and extubation failure after cardiac surgery. This study assessed the predictive capability of point-of-care Lung Ultrasound (LUS) for the duration of mechanical ventilation and extubation failure in infants following cardiac procedures. We conducted a prospective observational trial on infants under 1 year, excluding those with pre-existing conditions or requiring extracorporeal membrane oxygenation. LUS was performed upon intensive care unit (ICU) admission and prior to extubation attempts. B-line density was scored by two independent observers. The primary outcomes included the duration of mechanical ventilation and extubation failure, the latter defined as the need for reintubation or non-invasive ventilation within 48 h post-extubation. The study included 42 infants, with findings indicating no correlation between initial LUS scores and extubation timing. Extubation failure occurred in 21% of the patients, with higher LUS scores observed in these cases (p = 0.046). However, interobserver variability was high, impacting the reliability of LUS scores to predict extubation readiness. LUS was ineffective in determining the length of postoperative ventilation and extubation readiness, highlighting the need for further research and enhanced training in LUS interpretation.

Effect of different priming fluids on extravascular lung water, cell integrity and oxidative stress in cardiopulmonary bypass surgery.

Discussions continue on the ideal priming fluid in adult cardiac surgery. The purpose of this prospective study was to evaluate the effects of different types of priming fluids on extravascular lung water, cell integrity and oxidative stress status. Thirty elective coronary artery bypass surgery patients were randomised prospectively into two groups. The first group received colloid priming fluid, while the second group received crystalloid priming fluid. Extravascular lung water index, advanced oxidative protein products, total thiol, free haemoglobin, ischaemic modified albumin and sialic acid levels were measured. Moreover, intra-operative and postoperative outcomes were reviewed. There were no significant differences between the groups with regard to extravascular lung water index, oxidative stress parameters or cell integrity (p > 0.05). Similarly, no significant differences were observed between the patients with regard to intra-operative and postoperative outcomes (p > 0.05). The presumed superiority of colloidal priming for cardiopulmonary bypass could not be confirmed in our study.

Study on the correlation between angiopoietin-2 and prognosis in patients with acute respiratory distress syndrome

To evaluate the predictive value of angiopoietin-2 (Ang-2) for the prognosis in patients with acute respiratory distress syndrome (ARDS). A retrospective study was conducted, and ARDS patients admitted to the department of emergency medicine of Tongde Hospital of Zhejiang Province from December 2020 to September 2022 were enrolled. General information including gender, age, causes of ARDS, disease severity scores, plasma Ang-2 levels before treatment and at 24, 48, and 72 hours after treatment, and record the 60-day prognosis were collected. Differences in clinical data between groups were compared. Multivariate Logistic regression analysis was used to identify the independent risk factors affecting the 60-day prognosis of ARDS patients, and the receiver operator characteristic curve (ROC curve) was plotted to assess the predictive value of these risk factors for patient outcomes. Pearson correlation analysis was used to assess the correlation between Ang-2 and pulmonary vascular permeability index (PVPI) and extravascular lung water index (EVLWI). A total of 132 ARDS patients were included, of which 49 patients died within 60 days and 83 patients survived. In the death group, plasma Ang-2 levels showed a gradually increasing trend, all significantly higher than before treatment (μg/L: 12.75±1.81, 12.74±1.48, 13.45±2.21 vs. 5.98±0.57, all P < 0.05), while the trend in the survival group was not significant. At 24, 48, and 72 hours after treatment, plasma Ang-2 levels in the death group were significantly higher than those in the survival group (μg/L: 12.75±1.81 vs. 7.48±1.22, 12.74±1.48 vs. 7.41±1.19, 13.45±1.41 vs. 6.88±1.41, all P < 0.05). After adjusting for confounding variables, increased plasma Ang-2 level was an independent risk factor for prognosis in ARDS patients within 60 days [odds ratio (OR) = 0.998, 95% confidence interval (95%CI) was 0.997-0.999, P < 0.01]. ROC curve analysis demonstrated that Ang-2 levels had predictive value for prognosis in ARDS patients [area under the ROC curve (AUC) = 0.985, 95%CI was 0.971-1.000, approximate maximum Youden's index 0.867, optimal cut-off value 8.43 μg/L]. Pearson correlation analysis showed that plasma Ang-2 levels were positively correlated with PVPI and EVLWI ( r values were 0.620 and 0.712 respectively, both P < 0.01). Elevated level of Ang-2 is an independent risk factor for increased mortality in patients with ARDS. Higher Ang-2 levels within 72 hours after treatment may indicate poorer prognosis.

Combined treatment with vitamin C, hydrocortisone and thiamine does not attenuate morbidity and mortality of septic sheep

BackgroundSepsis is associated with a highest mortality rate in the ICU. Present study tests the efficacy of combined therapy with vitamin C, hydrocortisone and thiamine (combined therapy) in the ovine model of sepsis induced by Pseudomonas aeruginosa. In this study, sepsis was induced in sheep by instillation of Pseudomonas aeruginosa (1 × 1011 CFU) into the lungs via bronchoscope, under anesthesia. Nine hours after injury, intravenous infusion of vitamin C (0.75 g every 6 h), hydrocortisone (25 mg every 6 h), and thiamine (100 mg every 12 h) or saline was given to the treatment and control groups. Cardiopulmonary variables were recorded.ResultsThe survival rate was 16.7% in control and 33.3% in treatment groups. In the control group, mean arterial pressure dropped from 93.6 ± 8.6 to 75.5 ± 9.7 mmHg by 9 h, which was not affected by the combined therapy. Pulmonary dysfunction was not attenuated by the combined therapy either. The combined therapy had no effect on increased extravascular lung water content and fluid effusion into thoracic cavity. The bacterial number in the bronchoalveolar lavage fluid was significantly increased in the treatment group than the control group. The blood bacterial number remained comparable between groups.ConclusionsCombined vitamin C, hydrocortisone, and thiamine did not attenuate severity of ovine sepsis.

Role of Alveolar-Arterial Difference in Estimation of Extravascular Lung Water in COVID-19-Related ARDS.

The dominant feature of COVID-19-associated ARDS is gas exchange impairment. Extravascular lung water index is a surrogate for lung edema and reflects the level of alveolocapillary disruption. The primary aim was the prediction of extravascular lung water index by the alveolar-arterial oxygen difference. The secondary aims were in determining the relationship between the extravascular lung water index and other oxygenation parameters, the FIO2 , end-tidal oxygen concentration, pulmonary oxygen gradient (FIO2 minus end-tidal oxygen concentration), and PaO2 . This observational prospective single-center study was performed at the Department of Anaesthesiology and Intensive Care, The University Hospital in Ostrava, The Czech Republic, during the COVID-19 pandemic, from March 20, 2020, until May 24, 2021. The relationship between the extravascular lung water index and alveolar-arterial oxygen difference showed only a mild-to-moderate correlation (r = 0.33, P < .001). Other extravascular lung water index correlations were as follows: FIO2 (r = 0.33, P < .001), end-tidal oxygen concentration (r = 0.26, P = .0032), FIO2 minus end-tidal oxygen concentration (r = 0.15, P = .0624), and PaO2 (r = -0.15, P = .01). The alveolar-arterial oxygen difference does not reliably correlate with the extravascular lung water index and the degree of lung edema in COVID-19-associated ARDS.

The impact of positive end-expiratory pressure on right ventricular function in patients with moderate-to-severe ARDS: a prospective paired-design study.

To determine the effects of varying positive end-expiratory pressures (PEEPs) on right ventricular function, hemodynamics, oxygenation, and the incidence of acute cor pulmonale (ACP) in patients with moderate-to-severe acute respiratory distress syndrome (ARDS). This prospective paired-design study involved patients with moderate-to-severe ARDS in the ICU. Participants received lung-protective ventilation and hemodynamic monitoring. During the study, mechanical ventilation was administered with PEEPs of 5 cmH2O, 10 cmH2O, and 15 cmH2O, while maintaining an end-inspiratory plateau pressure ≤ 30 cmH2O. Various assessments, including transthoracic echocardiography, cardiac output measurement, and blood gas analysis, were conducted at baseline and after 1 h of ventilation at each PEEP. Subsequently, variations in ventilation oxygenation, echocardiographic parameters, and hemodynamic indicators under different PEEPs were analyzed to explore the potential effects of PEEP on right ventricular function and hemodynamics, as well as the incidence of ACP. A total of 317 ARDS patients were screened. Among them, 104 met the diagnostic criteria for moderate-to-severe ARDS, and 52 completed the study. The baseline PEEP of these 52 participants, acquired before commencement, was 11.5 ± 1.7 cmH2O, and the incidence of ACP was 25.0% (13/52). Intensive care unit mortality, overall hospital mortality, and 28-day mortality rates were 19.2% (10/52), 21.2% (11/52), and 32.7% (17/52), respectively. During the study, ACP incidences at PEEPs of 5 cmH2O, 10 cmH2O, and 15 cmH2O were 17.3% (9/52), 21.2% (11/52), and 38.5% (20/52), respectively. Meanwhile, the PaO2/FiO2 ratio improved with increasing PEEP, reaching 162.0 (140.9, 174.0), 171.0 (144.0, 182.0), and 176.5 (151.0, 196) mmHg at PEEPs of 5 cmH2O, 10 cmH2O, and 15 cmH2O, respectively. In addition, higher PEEPs were associated with a slight increase in PaCO2, showing statistically significant differences compared to moderate and low PEEPs. Compared to a PEEP of 5 cmH2O or 10 cmH2O, right ventricular function exhibited substantial changes at 15 cmH2O PEEP, manifested as increased pulmonary artery systolic pressure, enlarged right ventricular end-diastolic area, and decreased tricuspid annular plane systolic excursion, all with significant differences. Conversely, variations in left ventricular end-diastolic area and ejection fraction were not statistically significant. In terms of hemodynamics, increasing PEEP resulted in a decline in cardiac index (CI), with statistically significant differences between different PEEPs. Specifically, compared to the value at a PEEP of 5 cmH2O, the CI at a PEEP of 15 cmH2O decreased by 14.3% (2.63 [2.20, 2.95] vs. 3.07 [2.69, 3.67], p < 0.001). The decline in the stroke volume index with PEEP was more obvious (22.1 [18.4, 27.1] vs. 27.0 [24.2, 33.0], p < 0.001), reaching 18.1%. Additionally, both end-diastolic volume index and extravascular lung water index decreased significantly with increasing PEEP, while the pulmonary vascular permeability index remained unaffected. Different PEEPs can affect the incidence of ACP in patients with moderate-to-severe ARDS. High PEEP improves oxygenation and reduces extravascular lung water without significantly affecting the pulmonary vascular permeability index and left ventricular systolic function. Nevertheless, it can cause right ventricular dilation, as well as substantial declines in right ventricular systolic function and CI, thereby causing ACP.

Pulmonary Vascular Permeability and Extravascular Lung Water Index in Patients with Liver Cirrhosis and Septic Shock.

Backgrounds and Aims: Patients with cirrhosis are susceptible to sepsis and septic shock. Cirrhotic patients also have increased capillary permeability and are prone to developing volume overload. Patients with septic shock may have an enhanced pulmonary vascular permeability index (PVPI) and extravascular lung water index (EVLWI), both of which are associated with an unfavorable prognosis. It is plausible that pre-existing hyperpermeability may deteriorate when cirrhotic patients develop septic shock. However, it remains unknown whether PVPI and EVLWI can predict the prognosis of cirrhotic patients with septic shock. Pulse Indicator Continuous Cardiac Output (PiCCO) is an established tool to measure PVPI and EVLWI. Therefore, we conducted this retrospective study to investigate the prognostic significance of PVPI and EVLWI in cirrhotic patients with septic shock using PiCCO monitoring. Methods: We included 83 patients with liver cirrhosis and septic shock. EVLW indexed to actual body weight (aEVLWI), EVLW indexed to predicted body weight (pEVLWI), PVPI, disease severity scores, and other biomarkers were analyzed. We collected the PiCCO data on the first 2 days. Results: The overall 28-day mortality was 43.4%. The values of PVPI, aEVLWI, and pEVLWI on day 2 (PVPID2, aEVLWID2, EVLWID2) were significantly higher in non-survivors. The discriminating power of PVPID2 and EVLWID2 to predict 28-day mortality was tested using the area under a ROC curve. The areas under ROC curves (mean ± SEM) were 0.713 ± 0.061 and 0.650 ± 0.063 for PVPID2 and pEVLWID2. In the multivariate analysis, PVPID2, bilirubin, and lactate were independent factors which predicted 28-day mortality. Conclusions: Higher levels of PVPID2 and pEVLWID2 are associated with higher 28-day mortality rates in cirrhotic patients with septic shock. PVPI and pEVLWI may be useful to guide fluid management in this clinical setting.

The potential of the ultrasound method in diagnosing pulmonary edema in critically ill patients with liver failure

Background. Pulmonary edema is a common complication in critically ill patients. The liberal tactics of fluid therapy and pathological accumulation of extravascular lung water increase the risks of mortality in Intensive Care Unit patients. Timely and non-invasive diagnosis of pulmonary edema is a primary goal in the intensive care of patients in the Critical Care Unit. We prefer to use lung ultrasound with the registration of B-lines to diagnose lung edema. However, in our country, this method is not validated due to the lack of a sufficient number of clinical studies and necessary regulatory framework.Objective. To assess the potential of diagnostic ultrasonography for pulmonary edema in critically ill patients.Material and methods. A retrospective study was conducted on 27 patients, including 15 males and 12 females aged from 43 to 67 years old (mean age 45.05±17.2 years). All patients were in critical condition due either to acute liver failure, or acute-on-chronic liver failure, or early post-transplant liver graft failure, or posthepatectomy liver failure. Some patients had a systemic inflammatory response syndrome with the development of multiple organ failure and clinical signs of redistribution shock. All patients underwent ultrasound examination of the lungs, and had hemodynamic parameters measured using the transpulmonary thermodilution technique. The data obtained by the two diagnostic modalities were compared.Results. A significant correlation (p&lt;0.05) was found between the extravascular lung water index and the presence of lung edema. We identified a significant correlation (p&lt;0.05) between the number of B-lines and the presence of pulmonary edema. In assessing the relationship between the "B-line" parameter and the "EVLWI" parameter, a strong positive correlation was identified. The area under the ROC curve (AUC) was 0.9±0.06 with a 95% CI [0.77–1.00].Conclusions. Ultrasound data in diagnosing pulmonary edema have a significant correlation with the level of extravascular pulmonary water. Lung ultrasound is an accurate, non-invasive method for assessing extravascular lung water. It can be used for the rapid and accurate diagnosis of pulmonary edema.

Inflammatory and transudative B-line patterns on lung ultrasound: a brief communication.

Lung ultrasonic B-lines have high accuracy in diagnosing extravascular lung water (ELW) but have not been systematically subcategorized to differentiate the varied etiologies of ELW. This brief communication describes subcategories of B-lines into "inflammatory" and "transudative" patterns, based on their location, pleural morphology and associated subpleural pathologies. This subcategorization was derived using information from trainees undergoing lung ultrasound training in the Learning Ultrasound in Critical Care program, pathophysiological principles and their corresponding ultrasound correlates. This subcategorization helped trainees differentiate inflammatory pathologies of ELW (e.g. pneumonia, acute respiratory distress syndrome) from transudative (congestive) pathologies (e.g. fluid overload, cardiac failure).

Use of lung ultrasound to assess volume status and its association with physical examination in patients with chronic kidney disease.

Defining the optimal hydration status in patients with chronic kidney disease (CKD) is challenging, and the quest for an objective accurate method continues. Lung ultrasound (LUS) is a well-validated technique to estimate volume status. Previous studies examining the relationship between LUS and physical examination demonstrated conflicting results. We aimed to evaluate the correlation between LUS results and physical examination for assessing volume status in patients with CKD, and to compare different LUS protocols. A prospective, single-center trial correlating physical examination findings to LUS results in different CKD groups, including non-dialysis and dialysis patients. Hemodialysis patients were tested twice, before and after dialysis, to compare results with ultrafiltration volume. Different LUS protocols were performed and compared, including 16-, 12-, and 8-zone measurements. We recruited 175 participants. A strong positive correlation was demonstrated between 16- and 12-zone protocols [r=.91 (P<.001)] and between 12- and 8-zone protocols (r=.951, P<.001). Correlation was significant in various CKD groups. While blood pressure did not correlate with LUS score, there was a significant correlation between LUS and other components of the physical examination including lung crackles (OR=1.15 (95%CI 1.096-1.22), P<.01), pleural effusion (OR=1.15 (95%CI 1.09-2.13), P<.01) and peripheral edema (r=.24, P<.001). Ultrafiltration volume did not correlate significantly with change in LUS scores pre- and post-dialysis (r=.169, P=.065). Most components of physical examination findings correlated with extravascular lung water assessment on LUS in CKD patients. The use of a simplified pragmatic LUS protocol may facilitate LUS use in clinical practice.

Point-of-care ultrasonography in cirrhosis-related acute kidney injury: How I do it

Discerning the etiology of acute kidney injury (AKI) in cirrhotic patients remains a formidable challenge due to diverse and overlapping causes. The conventional approach of empiric albumin administration for suspected volume depletion may inadvertently lead to fluid overload. In the recent past, point-of-care ultrasonography (POCUS) has emerged as a valuable adjunct to clinical assessment, offering advantages in terms of diagnostic accuracy, rapidity, cost-effectiveness, and patient satisfaction. This review provides insights into the strategic use of POCUS in evaluating cirrhotic patients with AKI. The review distinguishes basic and advanced POCUS, emphasizing a 5-point basic POCUS protocol for efficient assessment. This protocol includes evaluations of the kidneys and urinary bladder for obstructive nephropathy, lung ultrasound for detecting extravascular lung water, inferior vena cava (IVC) ultrasound for estimating right atrial pressure, internal jugular vein ultrasound as an alternative to IVC assessment, and focused cardiac ultrasound for assessing left ventricular (LV) systolic function and identifying potential causes of a plethoric IVC. Advanced POCUS delves into additional Doppler parameters, including stroke volume and cardiac output, LV filling pressures and venous congestion assessment to diagnose or prevent iatrogenic fluid overload. POCUS, when employed judiciously, enhances the diagnostic precision in evaluating AKI in cirrhotic patients, guiding appropriate therapeutic interventions, and minimizing the risk of fluid-related complications.

A comparison of hemodynamic measurement methods during orthotopic liver transplantation: evaluating agreement and trending ability of PiCCO versus pulmonary artery catheter techniques

BackgroundSignificant hemodynamic changes occur during liver transplantation, emphasizing the importance of precious and continuous monitoring of cardiac output, cardiac index, and other parameters. Although the monitoring of cardiac output by pulse indicator continuous cardiac output (PiCCO) was statistically homogeneous compared to the clinical gold standard pulmonary artery catheterization (PAC) in previous studies of liver transplantation, there are fewer statistical methods for the assessment of its conclusions, and a lack of comparisons of other hemodynamic parameters (e.g., SVRI, systemic vascular resistance index). Some studies have also concluded that the agreement between PiCCO and PAC is not good enough. Overall, there are no uniform conclusions regarding the agreement between PiCCO and PAC in previous studies. This study evaluates the agreement and trending ability of relevant hemodynamic parameters obtained with PiCCO compared to the clinical gold standard PAC from multiple perspectives, employing various statistical methods.MethodsFifty-two liver transplantation patients were included. Cardiac output (CO), cardiac index (CI), SVRI and stroke volume index (SVI) values were monitored at eight time points using both PiCCO and PAC. The results were analyzed by Bland-Altman analysis, Passing-bablok regression, intra-class correlation coefficient (ICC), 4-quadrant plot, polar plot, and trend interchangeability method (TIM).ResultsThe Bland-Altman analysis revealed high percentage errors for PiCCO: 54.06% for CO, 52.70% for CI, 62.18% for SVRI, and 51.97% for SVI, indicating poor accuracy. While Passing-Bablok plots showed favorable agreement for SVRI overall and during various phases, the agreement for other parameters was less satisfactory. The ICC results confirmed good overall agreement between the two devices across most parameters, except for SVRI during the new liver phase, which showed poor agreement. Additionally, four-quadrant and polar plot analyses indicated that all agreement rate values fell below the clinically acceptable threshold of over 90%, and all angular deviation values exceeded ± 5°, demonstrating that PiCCO is unable to meet the acceptable trends. Using the TIM, the interchangeability rates were found to be quite low: 20% for CO and CI, 16% for SVRI, and 13% for SVI.ConclusionsOur study revealed notable disparities in absolute values of CO, CI, SVRI and SVI between PiCCO and PAC in intraoperative liver transplant settings, notably during the neohepatic phase where errors were particularly pronounced. Consequently, these findings highlight the need for careful consideration of PiCCO’s advantages and disadvantages in liver transplantation scenarios, including its multiple parameters (such as the encompassing extravascular lung water index), against its limited correlation with PAC.

#201 Bedside lung ultrasound and bioimpedance spectroscopy for assessment of volume status in chronic kidney disease patients on hemodialysis

Abstract Background and Aims Fluid balance is important in patients with chronic kidney disease undergoing hemodialysis (HD). Majority of HD treatment incorporate a prescription for fluid removal targeted to patient's dry weight. Overestimation of dry weight causes hypertension, left ventricular hypertrophy and heart failure, while underestimation is responsible for chronic dehydration leading to the risk of hypotension. Both complications have a significant impact on the overall morbidity and mortality. Dry weight of the patient is usually assessed by using clinical parameters (edema, BP, JVP etc.), Biochemical parameters (BNP, ANP), Bioimpedance Spectroscopy (BIS) or IVC diameter and collapsibility on ultrasound (VCI index). The use of chest ultrasound to detect lung water has recently received growing attention in clinical research. Ultrasonographic lung comets (counting B-lines artifact) evaluate extravascular lung water and hence is considered as a useful tool to evaluate the hydration status of hemodialysis patients. This study aims to compare the efficacy of body fluid volume status and lung water assessment by clinical methods, Ultrasound chest and Bioimpedance Spectroscopy in chronic kidney disease patients on hemodialysis. Method A cross-sectional study was conducted over a period of 6 months. Dry weight of the patient was assessed by the attending nephrologist based on clinical criteria such as: weight, blood pressure, presence of edema or vascular congestion. A Longitudinal Ultrasound scan of the chest was performed using MicroMaxx Ultrasound System with patient in supine position from second to fourth intercostal space of left hemi-thorax and second to fifth intercostal space of right hemi-thorax along parasternal, midclavicular, anterior axillary and midaxillary lines of each side in a total of 28 sectors. B-lines were defined as hyperechogenic linear artifact emerging from the pleural line, up to the bottom of the screen. Pre and Post dialysis comet score was determined by calculating the total B-lines in each sector. Bioimpedance spectroscopy using Bodystat QuadScan 4000 was performed. Pre and post dialysis total body water (TBW), intracellular water (ICW), extracellular water (ECW) and residual fluid overload (ECW pre HD- ECW post HD) were recorded. Results We conducted 100 assessments on 34 patients presenting to the hospital for maintenance hemodialysis. The mean age of the study population was 54.3 + 11 years with a sex ratio (M/F) of 6:1. Mean systolic blood pressure was 141.1 + 19 mmHg and diastolic blood pressure was 83 + 9.3 mmHg with 3 episodes of intradialytic hypotension. The mean dry weight was 59.8 + 10 Kg and weight gain by clinical assessment was 2.1 + 1.5 Kg. Comet score assessed by ultrasound chest had a mean of 4.54 + 2.53 before dialysis and 1.73 ± 1.36 after dialysis. Residual fluid overload on Bio impedance spectroscopy was 1.11 ± 0.85 litre. The residual fluid overload on Bio impedance spectroscopy and lung ultrasound comet score after dialysis had a significant correlation (p value &amp;lt;0.0001). Of the 100 assessments, 40% had fluid overload after dialysis on Bio impedance and 35% had lung congestion on ultrasound chest even after achieving euvolemia according to the dry weight assessed clinically. Conclusion Lung comets on ultrasound chest and residual volume on bio impedance spectroscopy may precede the development of clinical sign and symptoms in a patient. Therefore, these methods are superior to clinical volume status assessment in chronic kidney disease patients on hemodialysis.

An observational prospective cross-sectional study on extravascular lung water by lung ultrasound as a guide to fluid resuscitation therapy in adult septic shock in tertiary care hospital in central India

Background Septic shock is a life-threatening condition characterized by systemic inflammation and organ dysfunction, with fluid resuscitation being a cornerstone of management. However, indiscriminate fluid administration can lead to fluid overload and worsen outcomes. Extravascular lung water (EVLW) estimation by lung ultrasound has emerged as a promising tool for guiding fluid therapy in septic shock, allowing clinicians to assess pulmonary edema and tailor resuscitation strategies accordingly. Methods This prospective observational study aims to evaluate the utility of EVLW estimation by lung ultrasound in guiding fluid resuscitation therapy in adult patients with septic shock admitted to a rural tertiary care teaching hospital. Eligible patients admitted to the intensive care unit (ICU) will undergo baseline demographic and clinical assessments, including lung ultrasound, to quantify EVLW using B-line analysis. Fluid resuscitation therapy will be initiated based on EVLW findings, with subsequent adjustments guided by repeat lung ultrasound examinations at 6, 12, 24, and 48 hours post-initiation. Outcome measures include changes in mean PaO2/FiO2 ratios, respiratory parameters, renal function, fluid balance, and mortality rates. Expected Outcome We anticipate that EVLW-guided fluid resuscitation therapy will lead to more precise and tailored management of septic shock, potentially reducing the incidence of fluid overload, ARDS, and renal dysfunction. By optimizing fluid management strategies based on individual patient characteristics and responses, we aim to improve clinical outcomes and enhance the delivery of care for patients with septic shock.