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.

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.

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.

B-Lines for the assessment of extravascular lung water: Just focused or semi-quantitative?

BACKGROUND: B-lines as typical artefacts of lung ultrasound are considered as surrogate measurement for extravascular lung water. However, B-lines develop in the sub-pleural space and do not allow assessment of the whole lung. Here, we present data from the first observational multi-centre study focusing on the correlation between a B-lines score and extravascular lung water in critically ill patients suffering from a variety of diseases. PATIENTS AND METHODS: In 184 adult patients, 443 measurements were obtained. B-lines were counted and expressed in a score which was compared to extravascular lung water, measured by single-indicator transpulmonary thermodilution. Appropriate correlation coefficients were calculated and receiver operating characteristics (ROC-) curves were plotted. RESULTS: Overall, B-lines score was correlated with body weight-indexed extravascular lung water characterized by r = .59. The subgroup analysis revealed a correlation coefficient in patients without an infection of r = .44, in those with a pulmonary infection of r = .75 and in those with an abdominal infection of r = .23, respectively. Using ROC-analysis the sensitivity and specificity of B-lines for detecting an increased extravascular lung water (>10 mL/kg) was 63% and 79%, respectively. In patients with a P/F ratio <200 mm Hg, sensitivity and specificity to predict an increased extravascular lung water was 71% and 93%, respectively. CONCLUSIONS: Assessment of B-lines does not accurately reflect actual extravascular lung water. In presence of an impaired oxygenation, B-lines may reliably indicate increased extravascular lung water as cause of the oxygenation disorders.

Assessment of extravascular lung water by ultrasound after congenital cardiac surgery.

BACKGROUND: Lung ultrasounds show vertical artifacts known as B-lines in the presence of increased extravascular lung water (EVLW). We aimed to investigate whether lung ultrasound could estimate EVLW after congenital cardiac surgery. METHODS: This prospective observational study comprised 61 children (age range 3 days to 7.4 years) undergoing congenital cardiac surgery. We compared postoperative B-line scores from lung ultrasounds, early postoperative ultrasound as our primary interest, with corresponding postoperative chest radiography (CXR) lung edema scores, with static lung compliance, and with short-term clinical outcome interpreted as time on mechanical ventilation and length of pediatric intensive care unit (PICU) stay. RESULTS: Our findings showed lung ultrasound B-line scores and CXR lung edema scores as correlating 1-6 hr postoperatively (r2 = 0.41, P < 0.0001), on the first postoperative day (r2 = 0.15, P = 0.004) and on the fourth postoperative day (r2 = 0.28, P = 0.008). The B-line score or CXR lung edema score showed no correlation with lung compliance. We found that in multivariable analyses, with length of perfusion and presence of postoperative complications as covariates, both lung ultrasound (P ≤ 0.02) and CXR (P ≤ 0.002) 1-6 hr postoperatively predicted the length of mechanical ventilation and PICU stay. The interobserver variability was less for lung ultrasound B-line score than for CXR lung edema score (P = 0.001). CONCLUSIONS: Our results show that lung ultrasound in assessment of postoperative EVLW predicted length of mechanical ventilation and stay in the PICU, and it had less interobserver variability than CXR. Accordingly, lung ultrasound may complement CXR in assessment of lung edema after surgery for congenital heart defect. Pediatr Pulmonol. 2017;52:345-352. © 2016 Wiley Periodicals, Inc.

[ASSESSMENT OF EXTRAVASCULAR LUNG WATER BY QUANTITATIVE COMPUTER IMAGE ANALYSIS IN PATIENTS WITH ACUTE RESPIRATORY DISTRESS SYNDROME].

PURPOSE: To evaluate the possibility of quantitative computed tomography (CT) of the lungs in patients with acute respiratory distress syndrome (ARDS) for assessment of the severity of the condition and the effectiveness of treatment. MATERIALS AND METHODS: The study included 29 patients with ARDS and 22 with no signs of lung disease (control group). We measured extravascular lung water (EVLW) by transpulmonary thermodilution (TTD) and analysed CT of the lungs in patients with ARDS. Patients in the control group underwent CT of the lungs only. CT images were processed using the "Gamma Multivoks". RESULTS: According to CT poorly ventilated lung areas accounted for 2% of the total in the control group. Normally ventilated and hyper-ventilated lung areas prevailed in these patients. In the group of ARDS hyper-ventilated areas almost were not identified and normality and poorly ventilated areas we found. In patients with ARDS total lung volume was 1.5 times less than in the control group (median volume of 3393 and 4955 mL respectively). Pulmonary weight in ARDS group was bigger than in controls (median weight of the lungs 1233 and 812 g respectively). Effects of treatment according to quantitative CT evaluated in 14 survived patients. Notes the increase in lung volume (median 4656.5 ml) (p = 0.0001) and a decrease in lung weight (median 862 g) (p = 0.0012). The weight and volume of the lungs, the ratio of hyper, normal and poorly ventilated areas of the lung in patients with acute respiratoy distress syndrome after treatment did not differ from those in the control group. CONCLUSIONS: Quantitative analysis of CT reveals changes in the mass and volume of the lungs and can be used to diagnose and evaluate the effectiveness of the treatment. Pulmonary weight calculated by CT correlates with EVLW determined by TTD.

Assessment of extravascular lung water by quantitative ultrasound and CT in isolated bovine lung.

Lung ultrasonography (LUS) and computed tomography (CT) were compared for quantitative assessment of extravascular lung water (EVLW) in 10 isolated bovine lung lobes. LUS and CT were obtained at different inflation pressures before and after instillation with known amounts of hypotonic saline. A video-based quantitative LUS analysis was superior to both single-frame quantitative analysis and visual scoring in the assessment of EVLW. Video-based mean LUS intensity was strongly correlated with EVLW density (r(2)=0.87) but weakly correlated with mean CT attenuation (r(2)=0.49) and physical density (r(2)=0.49). Mean CT attenuation was weakly correlated with EVLW density (r(2)=0.62) but strongly correlated with physical density (r(2)=0.99). When the effect of physical density was removed by partial correlation analysis, EVLW density was significantly correlated with video-based LUS intensity (r(2)=0.75) but not mean CT attenuation (r(2)=0.007). In conclusion, these findings suggest that quantitative LUS by video gray-scale analysis can assess EVLW more reliably than LUS visual scoring or quantitative CT.

Lung ultrasonography for the assessment of rapid extravascular water variation: evidence from hemodialysis patients.

Chest ultrasonography is a useful tool to assess extravascular lung water at bedside. In presence of interstitial-alveolar imbibition, vertical artifacts arising from the pleura are detected; these are called B-lines. Although a positive linear correlation between B-lines and extravascular lung water has been shown in symptomatic heart failure patients, the subclinical phase of pulmonary imbibition and the clearance of B-lines after rapid body fluid removal have been less investigated. The aim of this study was to assess if chest ultrasound could detect lung water imbibition and its variations induced by dialysis, an experimental model of controlled rapid fluid loss. Forty-one patients undergoing hemodialysis were studied. Total number of B-lines from ultrasound chest scanning and vena cava diameters were measured before and after treatment. Before dialysis, most of the patients presented ultrasound signs of pulmonary imbibition despite the absence of dyspnea; the number of B-lines was associated with the accumulated weight before treatment (p < 0.05) as well as with the residual weight after dialysis (p < 0.01); B-lines and end-inspiratory and end-expiratory vena cava diameters were also significantly reduced after dialysis. Moreover, B-lines reduction was significantly related to weight loss. Ultrasound performed at the bedside can detect lung water and intravascular overload and their reduction after dialysis in yet asymptomatic patients. These observations add further evidence regarding the use of lung ultrasound and inferior vena cava measurement in estimating volume overload and monitoring the response to therapy both in hemodialysis and congestive heart failure patients.

Lung water assessment by lung ultrasonography in intensive care: a pilot study.

OBJECTIVE: To investigate the accuracy of lung ultrasonography (LUS) in the quantification of lung water in critically ill patients by using quantitative computed tomography (CT) as the gold standard for the determination of lung weight. METHODS: Twenty consecutive patients admitted to an intensive care unit who underwent chest CT as a step in their clinical management were evaluated within 4 h by LUS. Lung weight, lung volume, and physical lung density were calculated from the CT scans using ad hoc software. Semiquantitative ultrasound assessment of lung water was performed by determining the ultrasound B-line score, defined as the total number of B-lines detectable in an anterolateral LUS examination. RESULTS: Good correlations were found between the B-line score and lung weight (r = 0.75, p < 0.05) and density (r = 0.82, p < 0.01), that only marginally increased when the lung density of the first 10 mm of subpleural lung tissue was evaluated (r = 0.83, p < 0.01). Moreover, values of subpleural lung density were not significantly different from values of the whole lung density (0.34 ± 0.11 vs. 0.37 ± 0.16 g/ml, p = ns). Very good correlations were found between the B-line score and both the weight (r = 0.85, p < 0.01) and the density (r = 0.88, p < 0.01) of the upper lobes. The weight of the lower lobes was not correlated with the B-line score (r = 0.14, p = ns). CONCLUSIONS: Lung ultrasound B-lines are correlated with lung weight and density determined by CT. LUS may provide a reliable, simple and radiation-free lung densitometry in the intensive care setting.

Assessment of extravascular lung water and cardiac function in trimix SCUBA diving.

UNLABELLED: An increasing number of recreational self-contained underwater breathing apparatus (SCUBA) divers use trimix of oxygen, helium, and nitrogen for dives deeper than 60 m of sea water. Although it was seldom linked to the development of pulmonary edema, whether SCUBA diving affects the extravascular lung water (EVLW) accumulation is largely unexplored. METHODS: Seven divers performed six dives on consecutive days using compressed gas mixture of oxygen, helium, and nitrogen (trimix), with diving depths ranging from 55 to 80 m. The echocardiographic parameters (bubble grade, lung comets, mean pulmonary arterial pressure (PAP), and left ventricular function) and the blood levels of the N-terminal part of pro-brain natriuretic peptide (NT-proBNP) were assessed before and after each dive. RESULTS: Venous gas bubbling was detected after each dive with mean probability of decompression sickness ranging from 1.77% to 3.12%. After each dive, several ultrasonographically detected lung comets rose significantly, which was paralleled by increased pulmonary artery pressure (PAP) and decreased left ventricular contractility (reduced ejection fraction at higher end-systolic and end-diastolic volumes) as well as the elevated NT-proBNP. The number of ultrasound lung comets and mean PAP did not return to baseline values after each dive. CONCLUSIONS: This is the first report that asymptomatic SCUBA dives are associated with accumulation of EVLW with concomitant increase in PAP, diminished left ventricular contractility, and increased release of NT-proBNP, suggesting a significant cardiopulmonary strain. EVLW and PAP did not return to baseline during repetitive dives, indicating possible cumulative effect with increasing the risk for pulmonary edema.

Ultrasound assessment for extravascular lung water in patients undergoing hemodialysis. Time course for resolution.

BACKGROUND: Sonographic B-lines, also known as lung comets, have been shown to correlate with the presence of extravascular lung water (EVLW). Absent in normal lungs, these sonographic findings become prominent as interstitia and alveoli fill with fluid. Characterization of the dynamics of B-lines, specifically their rate of disappearance as volume is removed, has not been previously described. In this study, we describe the dynamics of B-line resolution in patients undergoing hemodialysis. METHODS: Patients undergoing hemodialysis underwent three chest ultrasound examinations: before, at the midpoint, and after dialysis. We followed a previously described chest ultrasound protocol that counts the number of B-lines visualized in 28 lung zones. Baseline demographics, assessment of ejection fraction, time elapsed, net volume of fluid removed, and subjective degree of shortness of breath were recorded for each patient. RESULTS: Forty of 45 patients completed full dialysis runs and had all three lung scans performed; 6 of 40 patients had zero or one B-line predialysis, and none of these 6 patients gained B-lines during dialysis. Thirty-four of 40 patients had statistically significant reductions in the number of B-lines from predialysis to the midpoint scan and from predialysis to postdialysis with a p value < 0.001. There was no association between subjective dyspnea scores and number of B-lines removed. CONCLUSIONS: B-line resolution appears to occur real-time as fluid is removed from the body, and this change was statistically significant. These data support thoracic ultrasound as a useful method for evaluating real-time changes in EVLW and in assessing a patient's physiologic response to the removal of fluid. TRIAL REGISTRATION: Massachusetts General Hospital trial registration protocol No. 2007P 002226.

Assessment of stress-induced pulmonary interstitial edema by chest ultrasound during exercise echocardiography and its correlation with left ventricular function.

Ultrasound lung comet images (ULC) are useful for the noninvasive assessment of extravascular lung water (EVLW). We investigated the modification of EVLW, its relation to indices of left ventricular systolic and diastolic function, and noninvasively determined pulmonary capillary wedge pressure (PCWP) (PCWP = 1.24 ratio of early diastolic mitral inflow velocity to early diastolic velocity of the mitral annulus [E/Em] + 1.9) at rest and its variation during exercise echocardiography. A total of 72 patients (mean age 66.4 +/- 8.4 years) with mean ejection fraction of 41.2 +/- 14.4% underwent symptoms-limited exercise echocardiography. The sum of the ULC yielded a score of EVLW. The ULC increased significantly from baseline to postexercise (5.9 +/- 14.9 vs 11 +/- 20.7, P = .0001). Positive linear correlations were found between baseline ULC score and baseline ejection fraction (r = -0.37, P = .002), systolic pulmonary artery pressure (r = 0.69, P = .0001), E/Em (r = 0.70, P = .0001), and estimated PCWP (r = 0.69, P = .0001). The variation between postexercise and baseline ULC score correlated significantly with the variation between peak stress and rest PCWP (r = 0.62, P = .0001), systolic pulmonary artery pressure (r = 0.44, P = .0001), wall-motion score index (r = 0.30, P = .01), and peak stress E/Em (r = 0.71, P = .0001), whereas no significant correlations were found between variations of ULC score and ejection fraction. This study shows that ULC represents a simple way to assess the presence of excess EVLW. Increased EVLW is associated with estimated PCWP and indices of left ventricular systolic and diastolic dysfunction. The additional exercise-induced increase of PCWP, the worsening of left ventricular diastolic function, and extensive wall-motion abnormalities correlate with variations of EVLW.

Computed tomography assessment of lung structure and function in pulmonary edema.

By definition pulmonary edema is an abnormal accumulation of water in the lung. Consequently, the computed tomography (CT) appearance of pulmonary edema reflects the sequence of this accumulation. In early hydrostatic pulmonary edema, CT shows vascular engorgement and peribronchovascular cuffing that increases with the severity of edema and that is associate in late stage, with consolidations. In acute respiratory distress syndrome (ARDS), CT shows the proportion of injured parenchyma and depicts associated alterations as parenchymal infiltrate and consolidation, pleural effusion, pneumothorax. These merely morphological findings can be complemented with data from objective CT analysis of the lung parenchyma. Indeed CT can assess lung water noninvasively. Correlated with hydrodynamic parameter, these objective measurements show that the increase of lung density parallels parenchymal fluid overload. These data also show that the occurrence of ground glass opacities can precede the hemodynamic evidence of edema.

Radionuclide assessment of pulmonary microvascular permeability.

The literature has been reviewed to evaluate the technique and clinical value of radionuclide measurements of microvascular permeability and oedema formation in the lungs. Methodology, modelling and interpretation vary widely among studies. Nevertheless, most studies agree on the fact that the measurement of permeability via pulmonary radioactivity measurements of intravenously injected radiolabelled proteins versus that in the blood pool, the so-called pulmonary protein transport rate (PTR), can assist the clinician in discriminating between permeability oedema of the lungs associated with the adult respiratory distress syndrome (ARDS) and oedema caused by an increased filtration pressure, for instance in the course of cardiac disease, i.e. pressure-induced pulmonary oedema. Some of the techniques used to measure PTR are also able to detect subclinical forms of lung microvascular injury not yet complicated by permeability oedema. This may occur after cardiopulmonary bypass and major vascular surgery, for instance. By paralleling the clinical severity and course of the ARDS, the PTR method may also serve as a tool to evaluate new therapies for the syndrome. Taken together, the currently available radionuclide methods, which are applicable at the bedside in the intensive care unit, may provide a gold standard for detecting minor and major forms of acute microvascular lung injury, and for evaluating the severity, course and response to treatment.