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 (SVVEIT) against SVV from pulse contour analysis (SVVPC) 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. SVVEIT 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 SVVEIT was remeasured. RESULTS: The protocol was completed in 28 animals. A total of 123 pairs of SVV measurements were acquired. Correlation coefficients (r) between SVVEIT and SVVPC 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 (SVVEIT) that is non-invasively derived from a central haemodynamic signal. However, alterations in thoracic impedance induced by lung injury influence this method.

[ASSESSMENT OF PULMONARY VENTILATION FUNCTION AT INTENSIVE CARE UNIT PATIENTS].

The article presents the functional characteristics of lung tissue in reanimation profile patients with different pathologies with forced ventilation and auxiliary support on the background. The aim of this study was to analyze the dynamics properties of lung tissue in intensive care unit patients with symptoms of severe violations of restrictive lung tissue being on ventilatory support. Results were subjected to analysis of acid-base status and dynamics of the main indicators of the biomechanical properties of the lung in 32 patients with severe concomitant injury (n=21), acute bilateral community-acquired pneumonia (n=7), septic shock (n=4) during the entire period of the respiratory "prosthetics "(before and after the beginning of mechanical ventilation). Using during ventilatory support of patients with initial symptoms of the syndrome of acute lung damage and reduced lung function restrictive positive end-expiratory pressure of 6-10 cm of water column when the conventional (1:2; 1:2.5 at p≤0.05) and invert (2:1 at p≤0,1) ratio inhale/exhale, relatively low tidal volume (6-8 ml/kg) allows increase the compliance of the lung tissue to 11-29%. Increased expiratory time constant has a direct correlation with the value of airway resistance was due not only to the maintenance of optimal parameters for MVV (mechanical voluntary ventilation), but regular lavage of the tracheobronchial tree, which allows to maintain patency of the lower respiratory tract. The main areas during mechanical ventilation of lungs in patients with a sharp decline in restrictive lung function (ARDS, pneumonia), regardless of the reason it was summoned, optimal value is the observance of the positive end-expiratory pressure, the ratio of inhale/exhale (depending on the degree of hypoxemia), to maintain sufficient blood oxygen saturation and partial pressure of oxygen in the blood plasma.

[Assessment of positive end-expiratory pressure induced lung volume change by ultrasound in mechanically ventilated patients].

OBJECTIVE: To investigate the value of lung ultrasound for assessing positive end-expiratory pressure (PEEP) -induced lung volume change in mechanically ventilated patients with acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) . METHODS: Eighteen patients with ALI or ARDS were prospectively studied. P-V curves and lung ultrasound were performed at PEEP 12, 8, 4 and 0 cm H2O (1 cm H2O = 0.098 kPa). PEEP-induced lung volume change was measured using the P-V curve method and lung ultrasound. RESULTS: Four lung ultrasound entities were defined: consolidation, multiple irregularly spaced B lines, multiple abutting B lines and normal aeration.For each of the 12 lung regions examined, PEEP-induced ultrasound changes were measured and an lung ultrasound score (LUS) was calculated. A highly significant correlation was found between PEEP-induced lung volume change measured by P-V curves and LUS change (r = 0.82, P < 0.01) . A statistically significant correlation was found between LUS change and PEEP-induced increase in PaO2 (r = 0.66, P < 0.01). CONCLUSION: PEEP-induced lung volume change can be adequately estimated with bedside lung ultrasound. Since lung ultrasound cannot assess PEEP-induced lung hyperinflation, it should not be the sole method for PEEP titration.

Noninvasive quantitative assessment of pulmonary blood flow with 18F-FDG PET.

UNLABELLED: Pulmonary blood flow (PBF) is a critical determinant of oxygenation during acute lung injury (ALI). PET/CT with (18)F-FDG allows the assessment of both lung aeration and neutrophil inflammation as well as an estimation of the regional fraction of blood (FB) if compartmental modeling is used to quantify (18)F-FDG pulmonary uptake. The aim of this study was to validate the use of FB to assess PBF, with PET and compartmental modeling of (15)O-H2O kinetics as a reference method, in both control animals and animals with ALI. For the purpose of studying a wide range of PBF values, supine and prone positions and various positive end-expiratory pressures (PEEPs) and tidal volumes (V(T)s) were selected. METHODS: Pigs were randomized into 3 groups in which ALI was induced by HCl inhalation: pigs studied in the supine position with a low PEEP (5 ± 3 [mean ± SD] cm of H2O; n = 9) or a high PEEP (12 ± 1 cm of H2O; n = 8) and pigs studied in the prone position with a low PEEP (6 ± 3 cm of H2O; n = 9). Also included were a control group that did not have ALI (n = 6) and 2 additional groups (n = 6 each) that had a high V(T) to maintain a transpulmonary pressure of greater than or equal to 35 cm of H2O and that either received HCl inhalation or did not receive HCl inhalation. PBF and FB were measured with PET and compartmental modeling of (15)O-H2O and (18)F-FDG kinetics in 10 lung regions along the anterior-to-posterior lung dimension, and both were expressed in each region as a fraction of their values in the whole lung. RESULTS: PBF and FB were strongly correlated (R(2) = 0.9), with a slope of the regression line close to unity and a negligible intercept. The mean difference between PBF and FB was 0, and the 95% limits of agreement were -0.035 to 0.035. This good agreement between methods was obtained in both normal and injured lungs and under a wide range of V(T), PEEP, and regional PBF values (7-71 mL/kg, 0-15 cm of H2O, and 24-603 mL·min(-1)·100 mL of lung(-1), respectively). CONCLUSION: FB assessed with (18)F-FDG is a good surrogate for PBF in both normal animals and animals with ALI. PET/CT has the potential to be used to study ventilation, perfusion, and lung inflammation with a single tracer.

Inhalation toxicity of soman vapor in non-anesthetized rats: a preliminary assessment of inhaled bronchodilator or steroid therapy.

Respiratory toxicity, injury and treatment following vapor inhalational exposure to the chemical warfare nerve agent (CWNA) soman (GD) were examined in non-anesthetized rats. This study exposed male Sprague-Dawley rats (250-300g) to 520, 560, 600, 825 or 1410mg×min/m(3) of soman in a customized head-out inhalation system. Signs of CWNA-induced cholinergic crises were observed in all soman-exposed animals. The LCt50 of vaporized soman as determined by probit analysis was 593.1mg×min/m(3). All animals exposed to 825 and 1410mg×min/m(3) developed severe convulsions and died within 4-8min post-exposure. Edema measured by wet/dry weight ratio of the left lung lobe increased in a dose-dependent manner in all soman-exposed animals. Bronchoalveolar lavage (BAL) fluid and blood acetylcholinesterase (AChE) activities were inhibited dose-dependently in soman-exposed groups at 24h. A significant increase in total BAL protein was observed in soman-exposed animals at all doses. AChE activity was inhibited in lung and whole brain tissues in all soman-exposed animals. Histopathological analysis of the lungs of animals exposed to 600mg×min/m(3) of soman revealed prominent morphological changes including alveolar histiocytosis, hemorrhage and inflammation consisting of neutrophilic exudate. Exposure of animals to 600mg×min/m(3) of soman followed by treatment with two actuations for 10s of Combivent (21µg of ipratropium bromide and 120µg of albuterol sulfate) and Symbicort (80µg budesonide and 4.5µg formoterol) by inhalation into a modified metered dose inhaler (MDI) 10min post-exposure resulted in increased minute volume, but did not decrease mortality. These results indicate that inhalation exposure to soman vapor causes acute respiratory toxicity and injury in untreated, un-anesthetized rats and that inhalation treatment with Combivent or Symbicort did improve the respiratory outcomes, but did not influence lethality.

Visual anatomical lung CT scan assessment of lung recruitability.

PURPOSE: The computation of lung recruitability in acute respiratory distress syndrome (ARDS) is advocated to set positive end-expiratory pressure (PEEP) for preventing lung collapse. The quantitative lung CT scan, obtained by manual image processing, is the reference method but it is time consuming. The aim of this study was to evaluate the accuracy of a visual anatomical analysis compared with a quantitative lung CT scan analysis in assessing lung recruitability. METHODS: Fifty sets of two complete lung CT scans of ALI/ARDS patients computing lung recruitment were analyzed. Lung recruitability computed at an airway pressure of 5 and 45 cm H(2)O was defined as the percentage decrease in the collapsed/consolidated lung parenchyma assessed by two expert radiologists using a visual anatomical analysis and as the decrease in not aerated lung regions using a quantitative analysis computed by dedicated software. RESULTS: Lung recruitability was 11.3 % (interquartile range 7.39-16.41) and 15.5 % (interquartile range 8.18-21.43) with the visual anatomical and quantitative analysis, respectively. In the Bland-Altman analysis, the bias and agreement bands between the visual anatomical and quantitative analysis were -2.9 % (-11.8 to +5.9 %). The ROC curve showed that the optimal cutoff values for the visual anatomical analysis in predicting high versus low lung recruitability was 8.9 % (area under the ROC curve 0.9248, 95 % CI 0.8550-0.9946). Considering this cutoff, the sensitivity, specificity, and diagnostic accuracy were 0.96, 0.76, and 0.86, respectively. CONCLUSIONS: Visual anatomical analysis can classify patients into those with high and low lung recruitability allowing more intensivists to get access to lung recruitability assessment.

Positive end-expiratory pressure lung recruitment: comparison between lower inflection point and ultrasound assessment.

BACKGROUND: Maintenance of the open lung alveoli in the expiration on mechanical ventilation in acute lung injury/acute respiratory distress syndrome (ALI/ARDS) remains challenging despite advances in lung imaging. The inspiratory lower inflection point (LIP) on the ventilator pressure-volume (P-V) curve estimates the required end-expiratory pressure for recruitment of alveolar consolidation. Alternatively, the end-expiratory pressure for recruitment of crater-like subpleural alveolar consolidation could be simply followed with ultrasound. These two methods for setting the ventilators positive end-expiratory pressure (PEEP) were compared. METHODS: The observational study in surgical/neurosurgical intensive care between October 2009 and November 2011 included 17 deeply sedated or relaxed patients. LIP was measured with continuous low-flow method, as a pressure in cmH(2)O. Expiratory levelling between lower border of subpleural consolidation and adjacent pleural line, which means lung recruitment, was followed with linear ultrasound probe. PEEP in cmH(2)O at which the levelling occurs was compared with LIP pressure. RESULTS: LIP pressure never exceeds the PEEP for recruitment of subpleural consolidations followed with ultrasound. A significant correlation (r = 0.839; p < 0.05) was found between two methods. CONCLUSIONS: In this study, positive end-expiratory pressures for recruitment of subpleural consolidations followed by ultrasound always exceed the pressures measured with LIP. Respecting this, ultrasound method could be the guide for PEEP lung recruitment.

Hydroxymethylglutaryl-CoA reductase inhibition with simvastatin in acute lung injury to reduce pulmonary dysfunction (HARP-2) trial: study protocol for a randomized controlled trial.

BACKGROUND: Acute lung injury (ALI) is a common devastating clinical syndrome characterized by life-threatening respiratory failure requiring mechanical ventilation and multiple organ failure. There are in vitro, animal studies and pre-clinical data suggesting that statins may be beneficial in ALI. The Hydroxymethylglutaryl-CoA reductase inhibition with simvastatin in Acute lung injury to Reduce Pulmonary dysfunction (HARP-2) trial is a multicenter, prospective, randomized, allocation concealed, double-blind, placebo-controlled clinical trial which aims to test the hypothesis that treatment with simvastatin will improve clinical outcomes in patients with ALI. METHODS/DESIGN: Patients fulfilling the American-European Consensus Conference Definition of ALI will be randomized in a 1:1 ratio to receive enteral simvastatin 80 mg or placebo once daily for a maximum of 28 days. Allocation to randomized groups will be stratified with respect to hospital of recruitment and vasopressor requirement. Data will be recorded by participating ICUs until hospital discharge, and surviving patients will be followed up by post at 3, 6 and 12 months post randomization. The primary outcome is number of ventilator-free days to day 28. Secondary outcomes are: change in oxygenation index and sequential organ failure assessment score up to day 28, number of non pulmonary organ failure free days to day 28, critical care unit mortality; hospital mortality; 28 day post randomization mortality and 12 month post randomization mortality; health related quality of life at discharge, 3, 6 and 12 months post randomization; length of critical care unit and hospital stay; health service use up to 12 months post-randomization; and safety. A total of 540 patients will be recruited from approximately 35 ICUs in the UK and Ireland. An economic evaluation will be conducted alongside the trial. Plasma and urine samples will be taken up to day 28 to investigate potential mechanisms by which simvastatin might act to improve clinical outcomes. TRIAL REGISTRATION: Current Controlled Trials ISRCTN88244364.

Assessment of a volume-dependent dynamic respiratory system compliance in ALI/ARDS by pooling breathing cycles.

New methods were developed to calculate the volume-dependent dynamic respiratory system compliance (C(rs)) in mechanically ventilated patients. Due to noise in respiratory signals and different characteristics of the methods, their results can considerably differ. The aim of the study was to establish a practical procedure to validate the estimation of intratidal dynamic C(rs). A total of 28 patients from intensive care units of eight German university hospitals with acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) were studied retrospectively. Dynamic volume-dependent C(rs) was determined during ongoing mechanical ventilation with the SLICE method, dynostatic algorithm and adaptive slice method. Conventional two-point compliance C(2P) was calculated for comparison. A number of consecutive breathing cycles were pooled to reduce noise in the respiratory signals. C(rs)-volume curves produced with different methods converged when the number of pooling cycles increased (n ≥ 7). The mean volume-dependent C(rs) of 20 breaths was highly correlated with mean C(2P) (C(2P,mean) = 0.945 × C(rs,mean) - 0.053, r(2) = 0.968, p < 0.0001). The Bland-Altman analysis indicated that C(2P,mean) was lower than C(rs,mean) (-2.4 ± 6.4 ml cm(-1) H(2)O, mean bias ± 2 SD), but not significant according to the paired t-test (p > 0.05). Methods for analyzing dynamic respiratory mechanics are sensitive to noise and will converge to a unique solution when the number of pooled cycles increases. Under steady-state conditions, assessment of the volume-dependent C(rs) in ALI/ARDS patients can be validated by pooling respiratory data of consecutive breaths regardless of which method is applied. Confidence in dynamic C(rs) determination may be increased with the proposed pooling.

Bedside ultrasound assessment of positive end-expiratory pressure-induced lung recruitment.

RATIONALE: In the critically ill patients, lung ultrasound (LUS) is increasingly being used at the bedside for assessing alveolar-interstitial syndrome, lung consolidation, pneumonia, pneumothorax, and pleural effusion. It could be an easily repeatable noninvasive tool for assessing lung recruitment. OBJECTIVES: Our goal was to compare the pressure-volume (PV) curve method with LUS for assessing positive end-expiratory pressure (PEEP)-induced lung recruitment in patients with acute respiratory distress syndrome/acute lung injury (ARDS/ALI). METHODS: Thirty patients with ARDS and 10 patients with ALI were prospectively studied. PV curves and LUS were performed in PEEP 0 and PEEP 15 cm H2O2. PEEP-induced lung recruitment was measured using the PV curve method. MEASUREMENTS AND MAIN RESULTS: Four LUS entities were defined: consolidation; multiple, irregularly spaced B lines; multiple coalescent B lines; and normal aeration. For each of the 12 lung regions examined, PEEP-induced ultrasound changes were measured, and an ultrasound reaeration score was calculated. A highly significant correlation was found between PEEP-induced lung recruitment measured by PV curves and ultrasound reaeration score (Rho = 0.88; P < 0.0001). An ultrasound reaeration score of +8 or higher was associated with a PEEP-induced lung recruitment greater than 600 ml. An ultrasound lung reaeration score of +4 or less was associated with a PEEP-induced lung recruitment ranging from 75 to 450 ml. A statistically significant correlation was found between LUS reaeration score and PEEP-induced increase in Pa(O2) (Rho = 0.63; P < 0.05). CONCLUSIONS: PEEP-induced lung recruitment can be adequately estimated with bedside LUS. Because LUS cannot assess PEEP-induced lung hyperinflation, it should not be the sole method for PEEP titration.

A porcine model for initial surge mechanical ventilator assessment and evaluation of two limited-function ventilators.

OBJECTIVES: To adapt an animal model of acute lung injury for use as a standard protocol for a screening initial evaluation of limited function, or "surge," ventilators for use in mass casualty scenarios. DESIGN: Prospective, experimental animal study. SETTING: University research laboratory. SUBJECTS: Twelve adult pigs. INTERVENTIONS: Twelve spontaneously breathing pigs (six in each group) were subjected to acute lung injury/acute respiratory distress syndrome via pulmonary artery infusion of oleic acid. After development of respiratory failure, animals were mechanically ventilated with a limited-function ventilator (simplified automatic ventilator [SAVe] I or II; Automedx, Germantown, MD) for 1 hr or until the ventilator could not support the animal. The limited-function ventilator was then exchanged for a full-function ventilator (Servo 900C; Siemens-Elema, Solna, Sweden). MEASUREMENTS AND MAIN RESULTS: Reliable and reproducible levels of acute lung injury/acute respiratory distress syndrome were induced. The SAVe I was unable to adequately oxygenate five animals with Pao2 (52.0±11.1 torr) compared to the Servo (106.0±25.6 torr; p=.002). The SAVe II was able to oxygenate and ventilate all six animals for 1 hr with no difference in Pao2 (141.8±169.3 torr) compared to the Servo (158.3±167.7 torr). CONCLUSIONS: We describe a novel in vivo model of acute lung injury/acute respiratory distress syndrome that can be used to initially screen limited-function ventilators considered for mass respiratory failure stockpiles and that is intended to be combined with additional studies to definitively assess appropriateness for mass respiratory failure. Specifically, during this study we demonstrate that the SAVe I ventilator is unable to provide sufficient gas exchange, whereas the SAVe II, with several more functions, was able to support the same level of hypoxemic respiratory failure secondary to acute lung injury/acute respiratory distress syndrome for 1 hr.

Computed tomography assessment of exogenous surfactant-induced lung reaeration in patients with acute lung injury.

INTRODUCTION: Previous randomized trials failed to demonstrate a decrease in mortality of patients with acute lung injury treated by exogenous surfactant. The aim of this prospective randomized study was to evaluate the effects of exogenous porcine-derived surfactant on pulmonary reaeration and lung tissue in patients with acute lung injury and acute respiratory distress syndrome (ALI/ARDS). METHODS: Twenty patients with ALI/ARDS were studied (10 treated by surfactant and 10 controls) in whom a spiral thoracic computed tomography scan was acquired before (baseline), 39 hours and 7 days after the first surfactant administration. In the surfactant group, 3 doses of porcine-derived lung surfactant (200 mg/kg/dose) were instilled in both lungs at 0, 12 and 36 hours. Each instillation was followed by recruitment maneuvers. Gas and tissue volumes were measured separately in poorly/nonaerated and normally aerated lung areas before and seven days after the first surfactant administration. Surfactant-induced lung reaeration was defined as an increase in gas volume in poorly/non-aerated lung areas between day seven and baseline compared to the control group. RESULTS: At day seven, surfactant induced a significant increase in volume of gas in poorly/non-aerated lung areas (320 ± 125 ml versus 135 ± 161 ml in controls, P = 0.01) and a significant increase in volume of tissue in normally aerated lung areas (189 ± 179 ml versus -15 ± 105 ml in controls, P < 0.01). PaO2/FiO2 ratio was not different between the surfactant treated group and control group after surfactant replacement. CONCLUSIONS: Intratracheal surfactant replacement induces a significant and prolonged lung reaeration. It also induces a significant increase in lung tissue in normally aerated lung areas, whose mechanisms remain to be elucidated. TRIAL REGISTRATION: NCT00742482.

Cost-effectiveness of implementing low-tidal volume ventilation in patients with acute lung injury.

BACKGROUND: Despite widespread guidelines recommending the use of lung-protective ventilation (LPV) in patients with acute lung injury (ALI), many patients do not receive this lifesaving therapy. We sought to estimate the incremental clinical and economic outcomes associated with LPV and determined the maximum cost of a hypothetical intervention to improve adherence with LPV that remained cost-effective. METHODS: Adopting a societal perspective, we developed a theoretical decision model to determine the cost-effectiveness of LPV compared to non-LPV care. Model inputs were derived from the literature and a large population-based cohort of patients with ALI. Cost-effectiveness was determined as the cost per life saved and the cost per quality-adjusted life-years (QALYs) gained. RESULTS: Application of LPV resulted in an increase in QALYs gained by 15% (4.21 years for non-LPV vs 4.83 years for LPV), and an increase in lifetime costs of $7,233 per patient with ALI ($99,588 for non-LPV vs $106,821 for LPV). The incremental cost-effectiveness ratios for LPV were $22,566 per life saved at hospital discharge and $11,690 per QALY gained. The maximum, cost-effective, per patient investment in a hypothetical program to improve LPV adherence from 50 to 90% was $9,482. Results were robust to a wide range of economic and patient parameter assumptions. CONCLUSIONS: Even a costly intervention to improve adherence with low-tidal volume ventilation in patients with ALI reduces death and is cost-effective by current societal standards.

[Assessment of early-stage physiological response to acute lung injury in canine models using balloon catheter system for measuring esophageal and gastric pressure].

OBJECTIVE: To explore feasible and reliable methods for estnbolishment and of acute lung injury model in animal models. METHODS: Twenty-four healthy adult mongrel dogs with oleic acid-induced acute lung injury were evaluated for early-stage physiological response to acute lung injury using a balloon catheter system for measuring esophageal and gastric pressure. RESULTS: In canine models of early-stage oleic acid-induced acute lung injury that sustained spontaneous breathing, in terms of respiratory mechanics, some parameters obviously increased including the respiratory rate (RR), minute ventilation (VE), peak inspiratory volume (Vinsp, peak), mean inspiratory volume (VT/Ti), inspiratory airway resistance (Raw, insp) (P<0.001 for all the parameters), with also significantly increased peak transdiaphragmatic pressure (Pdi, peak, P=0.0185). The tidal volume (VT) and dynamic lung compliance (CL,dyn), however, were significantly decreased (P<0.001), and significant variation occurred in the ratio of inspiratory time to duration of one breath (Ti/Ttot, P=0.163). In terms of gas exchange, the pH, PaO(2), SaO(2), PaO(2)/FiO(2), and end tidal partial pressure of carbon dioxide (PETCO(2)) all evidently declined (P<0.001), but PaCO(2) and ratio of alveolar dead space to tidal volume [VD(alv)/VT] increased significantly (P<0.001). CONCLUSION: Application of balloon catheter system for measuring esophageal and gastric pressures allows objective evaluation of the various physiological responses in early stage of acute lung injury.

[Assessment on pathophysiological indexes of acute lung injury induced by lipopolysaccharide in rats].

OBJECTIVE: To observe and evaluate the pathophysiological indexes of acute lung injury (ALI) induced by lipopolysaccharide (LPS) in rats. METHODS: Thirty-three Wistar rats were randomly divided into normal control group and experiment group. Respiratory rate , mortality, arterial blood gases, compliance and wet weight of right lung/body weight ratio, tumor necrosis factor-alpha (TNF-alpha) in serum and bronchoalveolar lavage fluid (BALF) were determined 2, 4 and 6 hours after injection of LPS or normal saline in both groups. RESULTS: In the experiment group,the following changes were found. Arterial partial pressure of oxygen (PaO(2)) was reduced to 69.18 mm Hg (1 mm Hg=0.133 kPa), marked blood stasis, and edema in lung tissues could be grossly seen and pathological examination showed that there was a large number of inflammation cell infiltration and edema in interstitial spaces with disappearance of normal construction of alveolar. There was also dilatation of capillaries with congestion and adherent leukocytes. Furthermore, compliance was decreased to 47% of the normal value, and wet weight of right lung/body weight ratio increased to 137% of the normal value. Blood TNF-alpha level increased markedly in serum and BALF. CONCLUSION: Specific pathological changes and decreased PaO(2) over 30% of the baseline value are the main signs of successful reproduction of ALI model in rats. Compliance and weight of right lung/body weight value can also reflect the status of ALI as helpful indexes.