Radiographic lung density assessed by computed tomography is associated with extravascular lung water content

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.

Computed tomographic assessment of lung aeration at different positive end-expiratory pressures in a porcine model of intra-abdominal hypertension and lung injury

Background

Intra-abdominal hypertension (IAH) is common in critically ill patients and is associated with increased morbidity and mortality. High positive end-expiratory pressures (PEEP) can reverse lung volume and oxygenation decline caused by IAH, but its impact on alveolar overdistension is less clear. We aimed to find a PEEP range that would be high enough to reduce atelectasis, while low enough to minimize alveolar overdistention in the presence of IAH and lung injury.

Methods

Five anesthetized pigs received standardized anesthesia and mechanical ventilation. Peritoneal insufflation of air was used to generate intra-abdominal pressure of 27 cmH₂O. Lung injury was created by intravenous oleic acid. PEEP levels of 5, 12, 17, 22, and 27 cmH₂O were applied. We performed computed tomography and measured arterial oxygen levels, respiratory mechanics, and cardiac output 5 min after each new PEEP level. The proportion of overdistended, normally aerated, poorly aerated, and non-aerated atelectatic lung tissue was calculated based on Hounsfield units.

Results

PEEP decreased the proportion of poorly aerated and atelectatic lung, while increasing normally aerated lung. Overdistension increased with each incremental increase in applied PEEP. “Best PEEP” (respiratory mechanics or oxygenation) was higher than the “optimal CT inflation PEEP range” (difference between lower inflection points of atelectatic and overdistended lung) in healthy and injured lungs.

Conclusions

Our findings in a large animal model suggest that titrating a PEEP to respiratory mechanics or oxygenation in the presence of IAH is associated with increased alveolar overdistension.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40635-021-00416-5.

Lung Ultrasound-Guided Fluid Management versus Standard Care in Surgical ICU Patients: A Randomised Controlled Trial

The value of lung ultrasound (LU) in assessing extravascular lung water (EVLW) was demonstrated by comparing LU with gold-standard methods for EVLW assessment. However, few studies have analysed the value of B-Line score (BLS) in guiding fluid management during critical illness. The purpose of this trial was to evaluate if a BLS-guided fluid management strategy could improve fluid balance and short-term mortality in surgical intensive care unit (ICU) patients. We conducted a randomised, controlled trial within the ICUs of two university hospitals. Critically ill patients were randomised upon ICU admission in a 1:1 ratio to BLS-guided fluid management (active group) or standard care (control group). In the active group, BLS was monitored daily until ICU discharge or day 28 (whichever came first). On the basis of BLS, different targets for daily fluid balance were set with the aim of avoiding or correcting moderate/severe EVLW increase. The primary outcome was 28-day mortality. Over 24 months, 166 ICU patients were enrolled in the trial and included in the final analysis. Trial results showed that daily BLS monitoring did not lead to a different cumulative fluid balance in surgical ICU patients as compared to standard care. Consecutively, no difference in 28-day mortality between groups was found (10.5% vs. 15.6%, p = 0.34). However, at least 400 patients would have been necessary for conclusive results.

Electrical impedance tomography for non-invasive assessment of stroke volume variation in health and experimental lung injury

BACKGROUND

Functional imaging by thoracic electrical impedance tomography (EIT) is a non-invasive approach to continuously assess central stroke volume variation (SVV) for guiding fluid therapy. The early available data were from healthy lungs without injury-related changes in thoracic impedance as a potentially influencing factor. The aim of this study was to evaluate SVV measured by EIT (SVV_EIT) against SVV from pulse contour analysis (SVV_PC) in an experimental animal model of acute lung injury at different lung volumes.

METHODS

We conducted a randomized controlled trial in 30 anaesthetized domestic pigs. SVV_EIT was calculated automatically analysing heart-lung interactions in a set of pixels representing the aorta. Each initial analysis was performed automatically and unsupervised using predefined frequency domain algorithms that had not previously been used in the study population. After baseline measurements in normal lung conditions, lung injury was induced either by repeated broncho-alveolar lavage (n=15) or by intravenous administration of oleic acid (n=15) and SVV_EIT was remeasured.

RESULTS

The protocol was completed in 28 animals. A total of 123 pairs of SVV measurements were acquired. Correlation coefficients (r) between SVV_EIT and SVV_PC were 0.77 in healthy lungs, 0.84 after broncho-alveolar lavage, and 0.48 after lung injury from oleic acid.

CONCLUSIONS

EIT provides automated calculation of a dynamic preload index of fluid responsiveness (SVV_EIT) that is non-invasively derived from a central haemodynamic signal. However, alterations in thoracic impedance induced by lung injury influence this method.

Quantitative computed tomography in comparison with transpulmonary thermodilution for the estimation of pulmonary fluid status: a clinical study in critically ill patients

Extravascular lung water (index) (EVLW(I)) can be estimated using transpulmonary thermodilution (TPTD). Computed tomography (CT) with quantitative analysis of lung tissue density has been proposed to quantify pulmonary edema. We compared variables of pulmonary fluid status assessed using quantitative CT and TPTD in critically ill patients. In 21 intensive care unit patients, we performed TPTD measurements directly before and after chest CT. Based on the density data of segmented CT images we calculated the tissue volume (TV), tissue volume index (TVI), and the mean weighted index of voxel aqueous density (VMWaq). CT-derived TV, TVI, and VMWaq did not predict TPTD-derived EVLWI values ≥ 14 mL/kg. There was a significant moderate positive correlation between VMWaq and mean EVLWI (EVLWI before and after CT) (r = 0.45, p = 0.042) and EVLWI after CT (r = 0.49, p = 0.025) but not EVLWI before CT (r = 0.38, p = 0.086). There was no significant correlation between TV and EVLW before CT, EVLW after CT, or mean EVLW. There was no significant correlation between TVI and EVLWI before CT, EVLWI after CT, or mean EVLWI. CT-derived variables did not predict elevated TPTD-derived EVLWI values. In unselected critically ill patients, variables of pulmonary fluid status assessed using quantitative CT cannot be used to predict EVLWI.

Lung Tissue Volume is Elevated in Obesity and Reduced by Bariatric Surgery

BACKGROUND

Bariatric surgery (BS) in severely obese subjects causes a significant reduction of body weight with lung function improvement. We have shown that abnormalities in pulmonary gas exchange in morbidly obese subjects are substantially improved with BS. These abnormalities were thought to be related to reduced lung volumes as well as to abnormal endothelial function induced by low-grade chronic inflammation linked to perivascular adipose tissue (PVAT). In this study, we used computed tomography (CT) to assess whether BS also caused measurable structural changes in the lung tissue volume (Vtiss) and cross-sectional vessel analysis, hypothesizing that these measures could be related to the previously reported lung functional changes.

METHODS

This is a post hoc analysis of a previous reported prospective study. Pulmonary vessels and lung volumes, including Vtiss, were quantified in thoracic CT scans. We compared findings in 12 obese women before and after BS and in 8 healthy lean women.

RESULTS

Vtiss was significantly elevated in obese subjects before BS compared to control subjects and systematically reduced after BS (by 8 %); other CT lung volumes or vascular areas were not affected in a consistent manner. No relationship was observed between BS-induced individual changes in Vtiss and pulmonary vessel area.

CONCLUSIONS

Vtiss is elevated in morbidly obese subjects, compared to lean individuals of similar body height, and is systematically reduced by BS. These effects do not appear related to vascular changes but may be caused by elevated extravascular lung water, due to low-grade inflammation, and/or hypertrophic PVAT in severe obesity.

Electrical impedance tomography (EIT) for quantification of pulmonary edema in acute lung injury

Background

Assessment of pulmonary edema is a key factor in monitoring and guidance of therapy in critically ill patients. To date, methods available at the bedside for estimating the physiologic correlate of pulmonary edema, extravascular lung water, often are unreliable or require invasive measurements. The aim of the present study was to develop a novel approach to reliably assess extravascular lung water by making use of the functional imaging capabilities of electrical impedance tomography.

Methods

Thirty domestic pigs were anesthetized and randomized to three different groups. Group 1 was a sham group with no lung injury. Group 2 had acute lung injury induced by saline lavage. Group 3 had vascular lung injury induced by intravenous injection of oleic acid. A novel, noninvasive technique using changes in thoracic electrical impedance with lateral body rotation was used to measure a new metric, the lung water ratio_EIT, which reflects total extravascular lung water. The lung water ratio_EIT was compared with postmortem gravimetric lung water analysis and transcardiopulmonary thermodilution measurements.

Results

A significant correlation was found between extravascular lung water as measured by postmortem gravimetric analysis and electrical impedance tomography (r = 0.80; p < 0.05). Significant changes after lung injury were found in groups 2 and 3 in extravascular lung water derived from transcardiopulmonary thermodilution as well as in measurements derived by lung water ratio_EIT.

Conclusions

Extravascular lung water could be determined noninvasively by assessing characteristic changes observed on electrical impedance tomograms during lateral body rotation. The novel lung water ratio_EIT holds promise to become a noninvasive bedside measure of pulmonary edema.

Validation of extravascular lung water measurement by transpulmonary thermodilution in a pediatric animal model

OBJECTIVE

The measurement of extravascular lung water using the transpulmonary thermodilution technique enables the bedside quantification of the amount of pulmonary edema. Children have higher indexed to body weight values of extravascular lung water compared with adults. Transpulmonary thermodilution measurements of extravascular lung water in children have not yet been validated. The purpose of this study was to validate the extravascular lung water measurements with the transpulmonary thermodilution method over a wide range of lung water values in a pediatric animal model.

DESIGN

Experimental animal intervention study.

SETTING

Animal laboratory at the Radboud University Nijmegen, The Netherlands.

SUBJECTS

Eleven lambs.

INTERVENTION

Pulmonary edema was induced using a surfactant washout model.

MEASUREMENTS AND MAIN RESULTS

Between the lavages, extravascular lung water index was estimated using transpulmonary single and double indicator dilution. Two additional lambs were used to estimate extravascular lung water index in lungs without pulmonary edema. The final extravascular lung water index results were compared with the extravascular lung water index estimations by postmortem gravimetry (EVLWIG). The results were analyzed using both correlation and Bland-Altman statistics. Extravascular lung water index by transpulmonary thermodilution (EVLWITPTD) correlated significantly with either EVLWIG (r = 0.88) or with extravascular lung water index by transpulmonary double indicator dilution (EVLWITPDD) (r = 0.98). The mean bias with EVLWIG was 12.2 mL/kg (limits of agreement ± 10.9 mL/kg) and with EVLWITPDD 2.4 mL/kg (limits of agreement ± 3.8 mL/kg). The percentage errors were 41% and 14%, respectively. The bias became more positive when the mean of EVLWITPTD and EVLWIG increased (r = 0.72; p = 0.003).

CONCLUSIONS

EVLWITPTD was significantly correlated to the postmortem gravimetric gold standard, although a significant overestimation was demonstrated with increasing pulmonary edema.

Comparison of quantitative computed tomography analysis and single-indicator thermodilution to measure pulmonary edema in patients with acute respiratory distress syndrome

Objective

To compare quantitative computed tomography (CT) analysis and single-indicator thermodilution to measure pulmonary edema in patients with acute respiratory distress syndrome (ARDS).

Method

Ten patients with ARDS were included. All underwent spiral CT of the thorax for estimating gas content of lung (GV_CT), tissue volume of lung (TV_CT), tissue volume index (TVI), mean radiographic attenuation (CTmean) for the whole lung and gas-to-tissue ratio (g/t). Pulmonary thermal volume (PTV) and extravascular lung water index (ELWI) were determined by the PiCCO plus system. CT or single-indicator thermodilution variables were correlated with respiratory system compliance (Crs), PaO₂/FiO₂, and Acute Physiology And Chronic Health EvaluationII (APACHE II) and Sequential Organ Failure Assessment (SOFA) scores.

Results

1) TV_CT and PTV were positively correlated (r =0.8878; P = 0.0006; equation of regression line: PTV = 1.0793 × TV_CT + 179.8) as were TVI and ELWI (r =0.9459; P < 0.0001; equation of regression line: ELWI = 1.4506 × TVI-8.7792). The bias between TV_CT and PTV as well as TVI and ELWI was -277 ± 217 and 0.62 ± 4.56, respectively. 2) ELWI and CT distribution of lung-tissue compartments were not correlated. 3) CT or single-indicator thermodilution variables were not correlated with Crs, PaO2/FiO2 or APACHE II or SOFA score.

Conclusion

Quantitative CT analysis and single-indicator thermodilution showed good agreement in measuring pulmonary edema.

How to perform indexing of extravascular lung water: a validation study

BACKGROUND

Extravascular lung water is a quantitative marker of the amount of fluid in the thoracic cavity besides the vasculature. Indexing to both predicted and actual body weight have been proposed to compare different individuals and provide a uniform range of normal.

OBJECTIVE

We explored extravascular lung water measured by single-indicator transpulmonary thermodilution in a large cohort of patients without cardiopulmonary instability, in order to evaluate current and alternative indexing methods.

DESIGN

Prospective, observational.

SETTING

Neurosurgical ICU in a tertiary referral academic teaching hospital.

PATIENTS

One hundred and one consecutive patients requiring elective brain tumor surgery and postoperative ICU surveillance.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Indexed to predicted body weight, females had a mean extravascular lung water of 9.1 (SD=3.1, range: 5-23) mL/kg and males of 8.0 (SD=2.0, range: 4-19) mL/kg (p<0.001). Values indexed to predicted body weight were inversely correlated with the patient's height (p<0.001). Indexed to the traditionally used actual body weight, data showed a significant relationship to weight (p<0.001) and gender (p<0.05). In contrast, indexing to body height presented a method without dependencies on height, weight, or gender, yielding a uniform 95% confidence interval of 218-430 mL/m. Extravascular lung water increased with positive perioperative fluid balance (p=0.04).

CONCLUSIONS

Using either predicted or actual body weight for indexing extravascular lung water does not lead to independence of height, weight, and gender of the patient. Specifying a fixed range of normal or a uniform upper threshold for all patients is misleading for either method, despite widespread use. Our data suggest that indexing extravascular lung water to height is superior to weight-based methods. As we are not aware of any abnormal hemodynamic profile for brain tumor patients, we propose our findings to be a close approximation to normal values.

Methods of Measuring Lung Water

Pulmonary oedema can result from both cardiogenic and non-cardiogenic aetiologies and is a cause of considerable morbidity and mortality. Accurate methods of quantifying pulmonary oedema are needed for both clinical and research purposes. Applications could include early recognition, and thus prevention, of impending decompensation in heart failure patients, guidance of fluid management in patients with established pulmonary oedema, and as a pharmacodynamic outcome measure for early clinical trials of drugs for the treatment of pulmonary oedema. Magnetic resonance imaging, computed tomography, positron emission tomography, electrical impedance, and thermodilution methods have all been used with the aim of measuring lung water. These methods differ in their accuracy, cost, ionising radiation dose, invasiveness, portability, and ability to provide dynamic measures. To date, none have been established as a ‘gold standard’ clinical measurement to improve clinical outcomes or to assist drug development. This review aims to discuss each of these methods in turn, focussing on advantages, limitations, and possible future development and applications.

Clinical validation of a new thermodilution system for the assessment of cardiac output and volumetric parameters

INTRODUCTION

Transpulmonary thermodilution is used to measure cardiac output (CO), global end-diastolic volume (GEDV) and extravascular lung water (EVLW). A system has been introduced (VolumeView/EV1000™ system, Edwards Lifesciences, Irvine CA, USA) that employs a novel algorithm for the mathematical analysis of the thermodilution curve. Our aim was to evaluate the agreement of this method with the established PiCCO™ method (Pulsion Medical Systems SE, Munich, Germany, clinicaltrials.gov identifier: NCT01405040) METHODS: Seventy-two critically ill patients with clinical indication for advanced hemodynamic monitoring were included in this prospective, multicenter, observational study. During a 72-hour observation period, 443 sets of thermodilution measurements were performed with the new system. These measurements were electronically recorded, converted into an analog resistance signal and then re-analyzed by a PiCCO2™ device (Pulsion Medical Systems SE).

RESULTS

For CO, GEDV, and EVLW, the systems showed a high correlation (r(2) = 0.981, 0.926 and 0.971, respectively), minimal bias (0.2 L/minute, 29.4 ml and 36.8 ml), and a low percentage error (9.7%, 11.5% and 12.2%). Changes in CO, GEDV and EVLW were tracked with a high concordance between the two systems, with a traditional concordance for CO, GEDV, and EVLW of 98.5%, 95.1%, and 97.7% and a polar plot concordance of 100%, 99.8% and 99.8% for CO, GEDV, and EVLW, respectively. Radial limits of agreement for CO, GEDV and EVLW were 0.31 ml/minute, 81 ml and 40 ml, respectively. The precision of GEDV measurements was significantly better using the VolumeView™ algorithm compared to the PiCCO™ algorithm (0.033 (0.03) versus 0.040 (0.03; median (interquartile range), P = 0.000049).

CONCLUSIONS

For CO, GEDV, and EVLW, the agreement of both the individual measurements as well as measurements of change showed the interchangeability of the two methods. For the VolumeView method, the higher precision may indicate a more robust GEDV algorithm.

TRIAL REGISTRATION

clinicaltrials.gov NCT01405040.

Increased extravascular lung water reduces the efficacy of alveolar recruitment maneuver in acute respiratory distress syndrome

Introduction. In acute respiratory distress syndrome (ARDS) the recruitment maneuver (RM) is used to reexpand atelectatic areas of the lungs aiming to improve arterial oxygenation. The goal of our paper was to evaluate the response to RM, as assessed by measurements of extravascular lung water index (EVLWI) in ARDS patients. Materials and Methods. Seventeen adult ARDS patients were enrolled into a prospective study. Patients received protective ventilation. The RM was performed by applying a continuous positive airway pressure of 40 cm H₂O for 40 sec. The efficacy of the RM was assessed 5 min later. Patients were identified as responders if PaO₂/FiO₂ increased by >20% above the baseline. EVLWI was assessed by transpulmonary thermodilution before the RM, and patients were divided into groups of low EVLWI (<10 mL/kg) and high EVLWI (≥10 mL/kg). Results. EVLWI was increased in 12 patients. Following RM, PaO₂/FiO₂ increased by 33 (4–65) % in the patients with low EVLWI, whereas those in the high EVLWI group experienced a change by only −1((−13)–(+5)) % (P = 0.035). Conclusion. In ARDS, the response to a recruitment maneuver might be related to the severity of pulmonary edema. In patients with incresed EVLWI, the recruitment maneuver is less effective.

Comparison of values in critically ill patients for global end-diastolic volume and extravascular lung water measured by transcardiopulmonary thermodilution: a meta-analysis of the literature

INTRODUCTION

Hemodynamic parameters such as the global end-diastolic volume index (GEDVI) and extravascular lung water index (EVLWI), derived by transpulmonary thermodilution, have gained increasing interest for guiding fluid therapy in critically ill patients. The proposed normal values (680-800ml/m(2) for GEDVI and 3-7ml/kg for EVLWI) are based on measurements in healthy individuals and on expert opinion, and are assumed to be suitable for all patients. We analyzed the published data for GEDVI and EVLWI, and investigated the differences between a cohort of septic patients (SEP) and patients undergoing major surgery (SURG), respectively.

METHODS

A PubMed literature search for GEDVI, EVLWI or transcardiopulmonary single/double indicator thermodilution was carried out, covering the period from 1990 to 2010.

INTERVENTION

Meta-regression analysis was performed to identify any differences between the surgical (SURG) and non-surgical septic groups (SEP).

RESULTS

Data from 1925 patients corresponding to 64 studies were included. On comparing both groups, mean GEDVI was significantly higher by 94ml/m(2) (95%CI: [54; 134]) in SEP compared to SURG patients (788ml/m(2) 95%CI: [762; 816], vs. 694ml/m(2), 95%CI: [678; 711], p<0.001). Mean EVLWI also differed significantly by 3.3ml/kg (95%CI: [1.4; 5.2], SURG 7.2ml/kg, 95%CI: [6.9; 7.6] vs. SEP 11.0ml/kg, 95%CI: [9.1; 13.0], p=0.001).

CONCLUSIONS

The published data for GEDVI and EVLWI are heterogeneous, particularly in critically ill patients, and often exceed the proposed normal values derived from healthy individuals. In the group of septic patients, GEDVI and EVLWI were significantly higher than in the group of patients undergoing major surgery. This points to the need for defining different therapeutic targets for different patient populations.

Computed tomography to estimate cardiac preload and extravascular lung water. A retrospective analysis in critically ill patients

Background

In critically ill patients intravascular volume status and pulmonary edema need to be quantified as soon as possible. Many critically ill patients undergo a computed tomography (CT)-scan of the thorax after admission to the intensive care unit (ICU). This study investigates whether CT-based estimation of cardiac preload and pulmonary hydration can accurately assess volume status and can contribute to an early estimation of hemodynamics.

Methods

Thirty medical ICU patients. Global end-diastolic volume index (GEDVI) and extravascular lung water index (EVLWI) were assessed using transpulmonary thermodilution (TPTD) serving as reference method (with established GEDVI/EVLWI normal values). Central venous pressure (CVP) was determined. CT-based estimation of GEDVI/EVLWI/CVP by two different radiologists (R1, R2) without analyzing software. Primary endpoint: predictive capabilities of CT-based estimation of GEDVI/EVLWI/CVP compared to TPTD and measured CVP. Secondary endpoint: interobserver correlation and agreement between R1 and R2.

Results

Accuracy of CT-estimation of GEDVI (< 680, 680-800, > 800 mL/m²) was 33%(R1)/27%(R2). For R1 and R2 sensitivity for diagnosis of low GEDVI (< 680 mL/m²) was 0% (specificity 100%). Sensitivity for prediction of elevated GEDVI (> 800 mL/m²) was 86%(R1)/57%(R2) with a specificity of 57%(R1)/39%(R2) (positive predictive value 38%(R1)/22%(R2); negative predictive value 93%(R1)/75%(R2)). Estimated CT-GEDVI and TPTD-GEDVI were significantly different showing an overestimation of GEDVI by the radiologists (R1: mean difference ± standard error (SE): 191 ± 30 mL/m², p < 0.001; R2: mean difference ± SE: 215 ± 37 mL/m², p < 0.001). CT GEDVI and TPTD-GEDVI showed a very low Lin-concordance correlation coefficient (ccc) (R1: ccc = +0.20, 95% CI: +0.00 to +0.38, bias-correction factor (BCF) = 0.52; R2: ccc = -0.03, 95% CI: -0.19 to +0.12, BCF = 0.42). Accuracy of CT estimation in prediction of EVLWI (< 7, 7-10, > 10 mL/kg) was 30% for R1 and 40% for R2. CT-EVLWI and TPTD-EVLWI were significantly different (R1: mean difference ± SE: 3.3 ± 1.2 mL/kg, p = 0.013; R2: mean difference ± SE: 2.8 ± 1.1 mL/kg, p = 0.021). Again ccc was low with -0.02 (R1; 95% CI: -0.20 to +0.13, BCF = 0.44) and +0.14 (R2; 95% CI: -0.05 to +0.32, BCF = 0.53). GEDVI, EVLWI and CVP estimations of R1 and R2 showed a poor interobserver correlation (low ccc) and poor interobserver agreement (low kappa-values).

Conclusions

CT-based estimation of GEDVI/EVLWI is not accurate for predicting cardiac preload and extravascular lung water in critically ill patients when compared to invasive TPTD-assessment of these variables.