Changes In Extravascular Lung Water Research Articles

Lung Ultrasound Reproducibly Outperforms Computed Tomography in the Detection of Extravascular Lung Water in Patients Undergoing Haemodialysis.

Lung ultrasound (LUS) is increasingly used as an extension of physical examination, informing clinical diagnosis, and decision making. There is particular interest in the assessment of patients with pulmonary congestion and extravascular lung water, although gaps remain in the evidence base underpinning this practice as a result of the limited evaluation of its inter-rater reliability and comparison with more established radiologic tests. 30 patients undergoing haemodialysis were prospectively recruited to an observational cohort study (NCT01949402). Patients underwent standardised LUS assessment before, during and after haemodialysis; their total LUS B-line score was generated, alongside a binary label of whether appearances were consistent with an interstitial syndrome. LUS video clips were recorded and independently scored by two blinded expert clinician sonographers. Low-dose non-contrast thoracic CT, pre- and post dialysis, was used as a "gold standard" radiologic comparison. LUS detected a progressive reduction in B-line scores in almost all patients undergoing haemodialysis, correlating with the volume of fluid removed once individuals with no or minimal B-lines upon pre-dialysis examination were discounted. When comparing CT scans pre- and post dialysis, radiologic evidence of the change in fluid status was only identified in a single patient. This is the first study to demonstrate that LUS detects changes in extravascular lung water caused by changing fluid status during haemodialysis using a blinded outcome assessment and that LUS appears to be more sensitive than CT for this purpose. Further research is needed to better understand the role of LUS in this and similar patient populations, with the aim of improving clinical care and outcomes.

Evaluation of lung ultrasound to detect volume overload in children undergoing dialysis.

Lung ultrasound is a well-established technique to assess extravascular lung water, a proxy for volume status, in the adult population. Despite its utility, the data are limited supporting the use of ultrasound to evaluate fluid volume status among pediatric patients. Our study uses a simplified ultrasound protocol to evaluate changes in extravascular lung water, represented by b-lines, among pediatric patients undergoing hemodialysis. This prospective single-center study included children from birth to 18years of age. The number of b-lines per ml/kg of fluid removed was compared prior to, at the midpoint, and following termination of dialysis. An 8-zone protocol was utilized, and b-lines were correlated to hemoconcentration measured by the CRIT-LINE® hematocrit. Six patients with a total of 26 hemodialysis sessions were included in this study. The b-line measurements post-dialysis were 2.27 (p < 0.001; 94%CI -3.31, -1.22) lower relative to pre-dialysis. The number of b-lines was reduced by 1.69 (p < 0.001; -2.58, -0.80) between pre-dialysis and at the midpoint of dialysis and by 0.58 (p = 0.001; -0.90, -0.24) between the midpoint of dialysis and post-dialysis. A 1mL/kg fluid loss correlated to a decrease in the original b-lines by 0.079. An inverse relationship (r = -0.54; 95% CI: -0.72, -0.34; p < 0.001) was noted between the b-lines and the patients' hematocrit levels. A simplified 8-zone ultrasound protocol can assess fluid volume change in real time and correlates with hematocrit levels obtained throughout dialysis. This provides a valuable method for monitoring fluid status in volume overloaded patient populations. A higher resolution version of the Graphical abstract is available asSupplementary information.

Transpulmonary thermodilution detects rapid and reversible increases in lung water induced by positive end-expiratory pressure in acute respiratory distress syndrome

PurposeIt has been suggested that, by recruiting lung regions and enlarging the distribution volume of the cold indicator, increasing the positive end-expiratory pressure (PEEP) may lead to an artefactual overestimation of extravascular lung water (EVLW) by transpulmonary thermodilution (TPTD).MethodsIn 60 ARDS patients, we measured EVLW (PiCCO2 device) at a PEEP level set to reach a plateau pressure of 30 cmH2O (HighPEEPstart) and 15 and 45 min after decreasing PEEP to 5 cmH2O (LowPEEP15′ and LowPEEP45′, respectively). Then, we increased PEEP back to the baseline level (HighPEEPend). Between HighPEEPstart and LowPEEP15′, we estimated the degree of lung derecruitment either by measuring changes in the compliance of the respiratory system (Crs) in the whole population, or by measuring the lung derecruited volume in 30 patients. We defined patients with a large derecruitment from the other ones as patients in whom the Crs changes and the measured derecruited volume were larger than the median of these variables observed in the whole population.ResultsReducing PEEP from HighPEEPstart (14 ± 2 cmH2O) to LowPEEP15′ significantly decreased EVLW from 20 ± 4 to 18 ± 4 mL/kg, central venous pressure (CVP) from 15 ± 4 to 12 ± 4 mmHg, the arterial oxygen tension over inspired oxygen fraction (PaO2/FiO2) ratio from 184 ± 76 to 150 ± 69 mmHg and lung volume by 144 [68–420] mL. The EVLW decrease was similar in “large derecruiters” and the other patients. When PEEP was re-increased to HighPEEPend, CVP, PaO2/FiO2 and EVLW significantly re-increased. At linear mixed effect model, EVLW changes were significantly determined only by changes in PEEP and CVP (p < 0.001 and p = 0.03, respectively, n = 60). When the same analysis was performed by estimating recruitment according to lung volume changes (n = 30), CVP remained significantly associated to the changes in EVLW (p < 0.001).ConclusionsIn ARDS patients, changing the PEEP level induced parallel, small and reversible changes in EVLW. These changes were not due to an artefact of the TPTD technique and were likely due to the PEEP-induced changes in CVP, which is the backward pressure of the lung lymphatic drainage.Trial registration ID RCB: 2015-A01654-45. Registered 23 October 2015

Changes of Extravascular Lung Water as an Independent Prognostic Factor for Early Developed ARDS in Severely Burned Patients.

An important feature of acute respiratory distress syndrome (ARDS) is fluid lost into the interstitium of lung combined with its compromised reabsorption, resulting in the elevation of extravascular lung water (EVLW). Although ARDS is known as an early, common, and life-threatening complication in major burns, the issue of whether or how the EVLW index (EVLWI) correlates with its prognosis has not been identified yet. In this retrospectively study, 121 severely burned adults with ARDS occurred in 2 weeks postburn were analyzed and divided into two groups: survivors (73 patients) and nonsurvivors (48 patients) according to the 28-day outcome after injury. Compared with nonsurvivors, survivors exhibited bigger EVLWI reduction in day 2 after ARDS onset (ΔEVLWI2), with no differences in ARDS timing and other EVLWI variables. ΔEVLWI2, rather than EVLWI on 2 days after ARDS onset, was identified as an independent prognostic factor even after adjusting other significant factors by Cox proportional hazard analysis. ROC curve analysis showed that ΔEVLWI2 [AUC = 0.723, 95% CI = (0.631-0.816), P < .001] was a relative predictor for survival on 28-day postburn, with a threshold of 1.9 ml/kg (63.0% sensitivity, 77.1% specificity). Kaplan-Meier survival curve analysis confirmed a significantly higher survival rate on 28-day postburn in patients with ΔEVLWI2 > 1.9 ml/kg (log-rank test: χ 2 =14.780, P < .001). Taken together, our study demonstrated that ΔEVLWI2 is an independent prognostic factor for early ARDS in severe burns. ΔEVLWI2 higher than 1.9 ml/kg might predict a higher survival rate in those patients.

Application of lung ultrasound surface wave elastography for assessment of extravascular lung water in patients hospitalized with congestive heart failure

Lung ultrasound (LUS) detects the presence of extravascular lung water (EVLW) through the visualization of B-Line artifacts. However, the qualitative nature of LUS limits its effectiveness in serial or longitudinal studies such as evaluating changes in EVLW at different time points in patients undergoing diuretic therapy for congestive heart failure. Lung ultrasound surface wave elastography (LUSWE) is a novel technique using a small handheld device that can measure superficial lung tissue elastic properties. We aimed to evaluate the use of LUSWE to measure quantitative changes in lung elasticity caused by acute changes in EVLW. We performed LUSWE on consecutive days in 14 patients hospitalized for acute congestive heart failure with evidence of pulmonary edema (clinical EVLW). From day#1 to day#2, the patients had an average diuresis of net negative 2.1 l associated with an average decrease in 13 B-Lines by lung ultrasound, signifying a reduction in EVLW. LUSWE analysis demonstrated a significant reduction (p < 0.05) in surface wave velocity in all interrogated intercostal spaces from day#1 to day#2. In summary, LUSWE performed at the bedside was able to demonstrate improvement in lung compliance (decreased elasticity) correlating with a reduction in EVLW in hospitalized patients being treated for congestive heart failure.

Volume Assessment in Hemodialysis: A Comparison of Present Methods in Clinical Practice with Sonographic Lung Comets.

Dry weight assessment in dialysis patients remains a challenging endeavor owing to the limitations of the available methods for volume assessment. Lung ultrasound is emerging as an invaluable tool to assist in the appropriate assessment and assignment of dry weight. The objectives of this study are (1) to determine the reliability of clinical signs and symptoms for volume assessment, (2) to compare lung ultrasound with High Resolution Computed Tomography (HRCT) chest-A noninvasive gold standard tool for detecting pulmonary congestion and with inferior vena cava diameter (IVCD) – another time-tested volume assessment method, and (3) to analyze if lung ultrasound could detect dialysis induced fluid status variations. The cross-sectional study involves 50 patients on maintenance hemodialysis. Lung ultrasound for B line estimation and ultrasonographic measurement of IVCD performed before and after hemodialysis by a nephrologist trained in ultrasonography. Limited HRCT was obtained just before hemodialysis. Edema, crackles, and dyspnea had a poor sensitivity of 37.9%, 11.5%, and 52.6%, respectively, to detect clinically significant pulmonary congestion by lung ultrasound. A highly significant correlation was obtained between B-line score and HRCT signs of pulmonary congestion (P < 0.001) before dialysis. B lines showed statistically significant reduction with dialysis. The absolute reduction of B lines showed significant correlation with ultrafiltration volume and weight loss. Bedside lung ultrasound appears a sensitive tool for evaluating real-time changes in extravascular lung water and would serve to optimize volume status in dialysis patients.

Effect of Fluid Bolus Therapy on Extravascular Lung Water Measured by Lung Ultrasound in Children With a Presumptive Clinical Diagnosis of Sepsis.

Fluid bolus therapy for the treatment of sepsis may lead to the accumulation of extravascular lung water (EVLW) and result in respiratory dysfunction. We aimed to assess changes in EVLW using lung ultrasound (US) in children with a presumptive clinical diagnosis of sepsis after fluid bolus therapy and correlate these changes with respiratory signs. This work was a prospective observational study set in the emergency department of the Royal Children's Hospital. Children meeting international consensus criteria for sepsis receiving fluid bolus therapy were included. Respiratory signs were recorded, and lung US examinations were performed immediately before, 5 minutes after, and 60 minutes after fluid bolus therapy. A pediatric emergency physician blinded to the participants' identities and timing of US calculated an EVLW score from lung US. Results-Fifty fluid boluses were recorded in 41 children. The lung US score (range, 0-8) increased over the study period: median, 1 (interquartile range, 0-2) before fluid bolus therapy, 1 (interquartile range, 0-3) 5 minutes after fluid bolus therapy, and 3 (interquartile range, 1-4) 60 minutes after fluid bolus therapy. Respiratory effort, but not the respiratory rate or the presence of rales, increased over the study period and was correlated with the lung US score (ρ = 0.33; P = .02). Extravascular lung water as measured by lung US increased after fluid bolus therapy in septic children and was correlated with an increase in the respiratory distress score. The respiratory rate and the presence of rales did not change over the study period. The role of lung US for titrating fluid bolus therapy in sepsis warrants further investigation.

An observational study using ultrasound to assess physiological changes following fluid bolus administration in paediatric sepsis in the emergency department

BackgroundFluid bolus administration is widely recommended as part of the initial treatment of paediatric sepsis, though the physiological benefits and harms are unclear. The primary aim of this study is to determine the effect of fluid bolus administration on cardiac index (CI). Secondary aims are to determine the effect of fluid bolus administration on extra-vascular lung water (EVLW), whether fluid responsiveness can be predicted by inferior vena cava (IVC) collapsibility, and whether fluid responsiveness correlates with changes in vital signs.Methods/designA prospective observational study of children presenting to the Emergency Department of The Royal Children’s Hospital with clinically diagnosed sepsis requiring fluid bolus administration. Prior to fluid bolus administration, an echocardiogram, lung ultrasound, and IVC ultrasound will be performed, and vital signs recorded. These will be repeated 5 min after and 60 min after fluid bolus administration. Recorded echocardiograms and lung/IVC ultrasound will be evaluated independently by a paediatric cardiologist and paediatric emergency physician, respectively, blinded to the patient identity and time of examination relative to time of fluid bolus administration. Fifty patients will be enrolled in the study based on a precision based sample size calculation. Results will be analysed for change in CI and change in EVLW 5 min after and 60 min after fluid bolus administration compared to baseline, IVC collapsibility as a predictor of fluid responsiveness, and the relationship between fluid responsiveness and changes in vital signs.DiscussionThis study will explore assumptions about the effect of fluid boluses on CI in children with sepsis, and will provide evidence for secondary effects on other organ systems. This may lead to novel methods for assessment and decision making in the initial resuscitation of paediatric sepsis in clinical and research settings, and will likely influence the design of future interventional studies in this arena.Trial registrationThe study is registered with the Australian and New Zealand Clinical Trials Registry (ACTRN12614000824662; 04 August 2014).

Estimation of extravascular lung water using the transpulmonary ultrasound dilution (TPUD) method: a validation study in neonatal lambs.

Increased extravascular lung water (EVLW) may contribute to respiratory failure in neonates. Accurate measurement of EVLW in these patients is limited due to the lack of bedside methods. The aim of this pilot study was to investigate the reliability of the transpulmonary ultrasound dilution (TPUD) technique as a possible method for estimating EVLW in a neonatal animal model. Pulmonary edema was induced in 11 lambs by repeated surfactant lavages. In between the lavages, EVLW indexed by bodyweight was estimated by TPUD (EVLWItpud) and transpulmonary dye dilution (EVLWItpdd) (n = 22). Final EVLWItpud measurements were also compared with EVLWI estimations by gold standard post mortem gravimetry (EVLWIgrav) (n = 6). EVLWI was also measured in two additional lambs without pulmonary edema. Bland–Altman plots showed a mean bias between EVLWItpud and EVLWItpdd of −3.4 mL/kg (LOA ± 25.8 mL/kg) and between EVLWItpud and EVLWIgrav of 1.7 mL/kg (LOA ± 8.3 mL/kg). The percentage errors were 109 and 43 % respectively. The correlation between changes in EVLW measured by TPUD and TPDD was r2 = 0.22. Agreement between EVLWI measurements by TPUD and TPDD was low. Trending ability to detect changes between these two methods in EVLWI was questionable. The accuracy of EVLWItpud was good compared to the gold standard gravimetric method but the TPUD lacked precision in its current prototype. Based on these limited data, we believe that TPUD has potential for future use to estimate EVLW after adaptation of the algorithm. Larger studies are needed to support our findings.

Transpulmonary Thermodilution Enables to Detect Small Short-Term Changes in Extravascular Lung Water Induced by a Bronchoalveolar Lavage

To take the opportunity of a bronchoalveolar lavage to challenge the transpulmonary thermodilution for detecting the time course of changes in extravascular lung water. Observational study. Medical ICU. Mechanically ventilated patients in whom a bronchoalveolar lavage by bronchoscopy was performed. Transpulmonary thermodilution before and after bronchoalveolar lavage. Before and at different times after bronchoalveolar lavage, transpulmonary thermodilution was performed to record the value of indexed extravascular lung water. For each measurement, the values of three thermodilution measurements were averaged at the following steps: before bronchoalveolar lavage, after bronchoalveolar lavage, and 1 hour, 2 hours, 4 hours, and 6 hours after bronchoalveolar lavage. The amount of saline infusion left in the lungs after bronchoalveolar lavage was also recorded. Twenty-five patients with suspicion of pneumonia were included. Twenty-eight bronchoalveolar lavages were finally analyzed. On average, 200 mL (180-200 mL) of saline were injected and 130 mL (100-160 mL) were left in the lungs. Between before and immediately after bronchoalveolar lavage, indexed extravascular lung water significantly increased from 12 ± 4 to 15 ± 5 mL/kg, respectively, representing a 169 ± 166 mL increase in nonindexed extravascular lung water. After bronchoalveolar lavage, the value of indexed extravascular lung water was significantly different from the baseline value until 2 hours after bronchoalveolar lavage and became similar to the baseline value thereafter. Transpulmonary thermodilution enabled to detect small short-term changes of indexed extravascular lung water secondary to bronchoalveolar lavage.

Extravascular Lung Water, B-Type Natriuretic Peptide, and Blood Volume Contraction Enable Diagnosis of Weaning-Induced Pulmonary Edema*

We tested whether the changes in extravascular lung water indexed for ideal body weight could detect weaning-induced pulmonary edema. We also studied the diagnostic value of blood volume contraction indices and B-type natriuretic peptide variations. Prospective study. Twenty-one patients who failed a first spontaneous breathing trial. None. We performed a second 60-minute T-tube spontaneous breathing trial. Before and at the end of spontaneous breathing trial, we recorded pulmonary artery occlusion pressure, the extravascular lung water indexed for ideal body weight, plasma B-type natriuretic peptide level, hemoglobin, and plasma protein concentrations. Weaning-induced pulmonary edema was defined by the association of signs of clinical intolerance and a pulmonary artery occlusion pressure greater than or equal to 18 mm Hg at the end of spontaneous breathing trial. Because some patients performed several spontaneous breathing trial, a primary analysis included all spontaneous breathing trial and a secondary analysis included only the first spontaneous breathing trial of each patient. In primary analysis, 36 spontaneous breathing trials were analyzed, 21 spontaneous breathing trial with weaning-induced pulmonary edema and 15 without. During spontaneous breathing trial, extravascular lung water indexed for ideal body weight increased only in cases with weaning-induced pulmonary edema (25% ± 23%). Plasma protein concentration, hemoglobin concentration, and B-type natriuretic peptide also significantly increased only in cases with weaning-induced pulmonary edema (9% ± 3%, 9% ± 4%, 21% ± 23%, respectively). The areas under the receiver operating characteristics curves to detect weaning-induced pulmonary edema were 0.89 (95% CI, 0.78-0.99) for extravascular lung water indexed for ideal body weight, 0.97 (0.93-1.01) for spontaneous breathing trial-induced changes in plasma protein concentration, 0.96 (0.90-1.01) for changes in hemoglobin concentration, and 0.76 (0.60-0.93) for changes in B-type natriuretic peptide. An increase in extravascular lung water indexed for ideal body weight greater than or equal to 14% diagnosed weaning-induced pulmonary edema with a sensitivity of 67% (95% CI, 43-85%) and a specificity of 100% (95% CI, 78-100%). The secondary analysis confirmed these results. Spontaneous breathing trial-induced increases in extravascular lung water indexed for ideal body weight, plasma protein concentrations, hemoglobin concentration, and B-type natriuretic peptide are reliable alternatives to the pulmonary artery catheter for diagnosing weaning-induced pulmonary edema.

Comparison of thermodilution measured extravascular lung water with chest radiographic assessment of pulmonary oedema in patients with acute lung injury

BackgroundAcute lung injury and the acute respiratory distress syndrome (ALI/ARDS) are characterized by pulmonary oedema, measured as extravascular lung water (EVLW). The chest radiograph (CXR) can potentially estimate the quantity of lung oedema while the transpulmonary thermodilution method measures the amount of EVLW. This study was designed to determine whether EVLW as estimated by a CXR score predicts EVLW measured by the thermodilution method and whether changes in EVLW by either approach predict mortality in ALI/ARDS.MethodsClinical data were collected within 48 hours of ALI/ARDS diagnosis and daily up to 14 days on 59 patients with ALI/ARDS. Two clinicians scored each CXR for the degree of pulmonary oedema, using a validated method. EVLW indexed to body weight was measured using the single indicator transpulmonary thermodilution technique.ResultsThe CXR score had a modest, positive correlation with the EVLWI measurements (r = 0.35, p < 0.001). There was a 1.6 ml/kg increase in EVLWI per 10-point increase in the CXR score (p < 0.001, 95% confidence interval 0.92-2.35). The sensitivity of a high CXR score for predicting a high EVLWI was 93%; similarly the negative predictive value was high at 94%; the specificity (51%) and positive predictive value (50%) were lower. The CXR scores did not predict mortality but the EVLW thermodilution did predict mortality.ConclusionEVLW measured by CXR was modestly correlated with thermodilution measured EVLW. Unlike CXR findings, transpulmonary thermodilution EVLWI measurements over time predicted mortality in patients with ALI/ARDS.

Clinical review: The role of ultrasound in estimating extra-vascular lung water

The estimation of extra-vascular lung water (EVLW) is an essential component in the assessment of critically ill patients. EVLW is independently associated with mortality and its manipulation has been shown to improve outcome. Accurate assessment of lung water is possible with CT and MR imaging but these are impractical for real-time measurement in sick patients and have been superseded by single thermal dilution techniques. While useful, single thermo-dilution requires repeated calibration and is prone to error, suggesting a need for other monitoring methods. Traditionally the lung was not thought amenable to ultrasound examination owing to the high acoustic impedance of air; however, the identification of artefacts in diseased lung has led to increased use of ultrasound as a point of care investigation for both diagnosis and to monitor response to interventions. Following the initial description of B-lines in association with increased lung water, accumulating evidence has shown that they are a useful and responsive measure of the presence and dynamic changes in EVLW. Animal models have confirmed a correlation with lung gravimetry and the utility of B-lines has been demonstrated in many clinical situations and correlated against other established measures of EVLW. With increasing availability and expertise the role of ultrasound in estimating EVLW should be embedded in clinical practice and incorporated into clinical algorithms to aid decision making. This review looks at the evidence for ultrasound as a valid, easy to use, non-invasive point of care investigation to assess EVLW.

Predictors of pulmonary edema formation during fluid loading in the critically ill with presumed hypovolemia*

It is largely unknown why extravascular lung water may increase during fluid loading in the critically ill with presumed hypovolemia. In this study we evaluated the hemodynamic predictors of such an increase. A prospective observational study. Sixty-three presumed hypovolemic mechanically ventilated patients (22 septic and 41 nonseptic patients). Fluid loading with saline or colloid fluids guided by (changes in) cardiac filling pressures. Before and after fluid-loading, hemodynamic and respiratory variables were recorded, including variables obtained by transpulmonary dilution such as cardiac index, pulmonary blood volume index, and extravascular lung water. Baseline parameters and change in parameters were compared between patients with a change in extravascular lung water <10% and patients with a change in extravascular lung water ≥ 10%. Predictive values for change in extravascular lung water ≥ 10% were evaluated. Baseline cardiac index and pulmonary blood volume index were higher, whereas change in cardiac index, change in pulmonary blood volume index, and change in PaO2/FIO2 ratio were lower in patients with a change in extravascular lung water ≥ 10% than in patients with a change in extravascular lung water <10%. The change in extravascular lung water correlated to baseline cardiac index (r = 0.17; p = .001), baseline pulmonary blood volume index (r = 0.15; p = .001), change in pulmonary blood volume index (r = 0.16; p < .001), and change in PaO2/FIO2 ratio (r = 0.13; p = .004). In multiple logistic regression analysis baseline cardiac index, baseline pulmonary blood volume index, the change in cardiac index, change in pulmonary blood volume index, and change in PaO2/FIO2 ratio individually contributed to prediction of a change in extravascular lung water ≥ 10%, independent of the presence of sepsis, pulmonary vascular permeability, and cardiac filling pressures. A change in extravascular lung water ≥ 10% was predicted by baseline cardiac index (77% sensitivity, 98% specificity) and pulmonary blood volume index (92% sensitivity, 68% specificity), and by change in cardiac index (69% sensitivity, 59% specificity), change in pulmonary blood volume index (77% sensitivity, 82% specificity), and change in PaO2/FIO2 ratio (77% sensitivity, 66% specificity). Extravascular lung water increase during fluid loading in the critically ill is predicted by a plateau of cardiac function and pulmonary vascular filling at baseline, rather than by pulmonary vascular permeability and filling pressures. Increasing extravascular lung water is further reflected by a decrease of PaO2/FIO2 ratio. These observations may help preventing pulmonary fluid overloading.

Continuous elevation of lung sound amplitudes, recorded at fixed flow rate, may indicate an increase in lung water content

Vibration response imaging (VRI) is a bedside lung sound monitoring system. We previously reported that vibration intensity can be significantly elevated in patients with congestion, as opposed to pleural effusion, atelectasis, or normal lung [1]. We hypothesized that changes in lung water content (that is, pulmonary edema) may influence breath sound amplitude and explored the possibility of using continuous digitalized lung sound monitoring as a means to track changes in extravascular lung water (EVLW).

Effects of small tidal volume combined with PEEP on extravascular lung water during one-lung ventilation in patients undergoing thoracic surgery

Objective To investigate the effects of small tidal volume combined with PEEP on extravascular lung water during one-lung ventilation （OLV） in patients undergoing thoracic surgery. Methods Forty ASA I or II patients of both sexes aged 45-80 yr undergoing esophagectomy for esophageal cancer were randomly assigned into 2 groups （ n = 20 each） ： group I IPPV （VT 9 ml/kg ,RR 12 bpm） and group IT IPPV ＋ PEEP （VT 6 ml/kg, RR 15 bpm, PEEP 5 cm H2O）. FiO2 was 100% and I：E 1：2 in both groups. Anesthesia was induced with fentanyl 3-5 ug/kg, propofol 1.0-1.5 mg/kg and vecuronium 0.10-0.15 mg/kg and maintained with continuous infusion of propofol 4-7 mg·kg- 1 · h- 1 and vecuronium 0.07-0.08 mg· kg- 1 · h-1 and intermittent iv boluses of fentanyl. Double lumen endobronchial tube was inserted. Correct position was confirmed by bronchoscopy. Right internal jugular vein was cannulated. A 4F thermodilution catheter was inserted into right femoral artery and connected to PICCO monitor. Extravascular lung water （EVLW）, EVLW index （EVLWI）, pulmonary vascular permeability index （PVPI）, cardiac output （CO） and oxygenation index （OI） were recorded before anesthesia （To, baseline）, at 30 min of two lung ventilation （T1）, 30 min and 1 h of OLV （T2, T3 ）, before extubation （ T4 ） and 18 h after operation （ T5 ）. Airway peak pressure （Ppeak） was recorded at T1-4 , Results EVLWI and PVPI were significantly higher in group IPPV ＋ PEEP than in group IPPV. There was no significant difference in Ppcak, CO and OI at any time point between the 2 groups. In group IPPV there was no significant change in EVLW and EVLWI during and after mechanical ventilation, while PVPI was significantly increased at TI as compared with the baseline before anesthesia. In group IPPV ＋ PEEP EVLW was significantly increased at T2 and PVPI was significantly increased at T1 and T2 compared with the baseline at T0 . Conclusion OLV with IPPV ＋ PEEP results in more EVLW and it exerts no significant effect on lung function. Key words: Tidal volume ; Positive- pressure respiration; Extravascular lung water; Respiration,artificial

Ultrasound Assessment for Extravascular Lung Water in Patients Undergoing Hemodialysis: Time Course for Resolution

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.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.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.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.Massachusetts General Hospital trial registration protocol No. 2007P 002226.

The relationship between the extravascular lung water and the prognosis of patients with septic shock

Objective To analyze the variable characteristics of the extravascular lung water(EVLW)in the patients with septic shock,to chrify its value in the prognosis of these patients,and to find out a determinent in objective assessment of the capillary leakage syndrome.Method The investigation was carried out with prospective design and retrospective analysis.The patients with hyperkinetic septic shock confirmed by the monitor of the pulse-indicated continuous cardiac output(PICCO),admitted into the medical intensive care unit of the Nou-vel H(o)pital Civil of Louis·Pasteur University,were divided into survival group and fatal group.The hemodynamic status including EVLW was measured in 3 consecutive days.and the relationship between the EVLW and the prog-nosis of patients was analyzed.Results Totally 20 patients with average age of 69.1 years old(ranging from 48 to 84),13 male and 7 female,were 12 survivors and 8 deaths.On the first day of diagnosis,EVLW were higher in both groups in comparison with normal value.They were 19.9±8.0 mL/kg in survival patients and 18.7±8.1 mL/kg in fatal patients.However,on the second day,the EVLW in the survival patients dropped significantly af-ter intensive intervention,but the fatal patients did not responded well to the treatment and the EVLW declined slightly.The values of EVLW of both groups began to diverge significantly from each other,showing values in means of 13.8±4.5 and 18.6±6.3,respectively(P＜0.05).On the third day,this diffence between two groups was still more remarkable,resulting in 10.1±2.7 vs.16.6±6.3(P＜0.05).Conclusions The changes of EVLW could be used to evaluate the effectiveness of treatment and to predict the prognosis of the pa-tients with septic shock.EVLW would likely be an indicator to evaluale the pulmonary capillary leakage. Key words: Septic shock; Extravascular lung water(EVLW); Prognosis

Effects of High-Frequency Oscillatory Ventilation on Oleic Acid-Induced Lung Injury in Sheep

High-frequency oscillatory ventilation (HFOV) is a possible mechanical method for open lung strategies. The aim of this study was to examine whether HFOV has a beneficial effect on oleic acid-induced lung injury, with emphasis on changes in extravascular lung water. Thirteen anesthetized sheep prepared with a lung lymph fistula and vascular catheters for monitoring were randomly allocated to two experimental groups. In experiment 1, sheep (n = 6) were ventilated using conventional mechanical ventilation [CMV; 10 ml/kg of tidal volume, 70% oxygen, and positive end-expiratory pressure (PEEP) of 6 cmH(2)O after oleic acid administration (0.08 ml/kg)]. In experiment 2, sheep (n=7) were ventilated using HFOV (frequency=15 Hz, stroke volume=120 ml, mean airway pressure=15 cmH(2)O) after administration of the same dose of oleic acid as in experiment 1. Observation was continued for 4 h after oleic acid administration, then bronchoalveolar lavage (BAL) was performed and the lung wet-to-dry weight ratio was determined. Compared with CMV, HFOV significantly improved the deteriorated oxygenation during the late phase (2-4 h) of oleic acid-induced lung injury without any deterioration effects on pulmonary or systemic hemodynamics. HFOV showed significantly reduced lung lymph protein clearance, which paralleled significant decreases in wet-to-dry ratios and neutrophil counts in BAL fluid in the HFOV group. These findings suggest that HFOV could contribute to decreased lung lymph filtration in pulmonary microcirculation and improved oxygenation following oleic acid-induced lung injury in sheep.

Measurement of extravascular lung water in patients with pulmonary edema

measurement of extravascular lung water has been a topic of major interest for more than two decades ([1][1], [5][2], [19][3]). In the recent article by Effros et al. ([2][4]), they provide a review of current and past efforts to measure extravascular lung water with thermal and osmotic dilution