Quantifying Myeloperoxidase-DNA and Neutrophil Elastase-DNA Complexes from Neutrophil Extracellular Traps by Using a Modified Sandwich ELISA.

Certain stimuli, such as microorganisms, cause neutrophils to release neutrophil extracellular traps (NETs), which are basically web-like structures composed of DNA with granule proteins, such as myeloperoxidase (MPO) and neutrophil elastase (NE), and cytoplasmic and cytoskeletal proteins. Although interest in NETs has increased recently, no sensitive, reliable assay method is available for measuring NETs in clinical settings. This article describes a modified sandwich enzyme-linked immunosorbent assay to quantitatively measure two components of circulating NETs, MPO-DNA and NE-DNA complexes, which are specific components of NETs and are released into the extracellular space as breakdown products of NETs. The assay uses specific monoclonal antibodies for MPO or NE as the capture antibodies and a DNA-specific detection antibody. MPO or NE binds to one site of the capture antibody during the initial incubation of samples containing MPO-DNA or NE-DNA complexes. This assay shows good linearity and high inter-assay and intra-assay precision. We used it in 16 patients with COVID-19 with accompanying acute respiratory distress syndrome and found that the plasma concentrations of MPO-DNA and NE-DNA were significantly higher than in the plasma obtained from healthy controls. This detection assay is a reliable, highly sensitive, and useful method for investigating the characteristics of NETs in human plasma and culture supernatants.

Combined, converted, and prophylactic use of resuscitative endovascular balloon occlusion of the aorta for severe torso trauma: a retrospective study.

Introduction: Resuscitative endovascular balloon occlusion of the aorta (REBOA) is used as an intra-aortic balloon occlusion in Japan; however, protocols for its effective use in different conditions have not been established. This study aimed to summarize the strategies of REBOA use in severe torso trauma. Methods: Twenty-nine cases of REBOA for torso trauma treated at our hospital over 5 years were divided into hemodynamically unstable (HU) (n = 12), cardiac arrest (CA) (n = 13), and hemodynamically stable (HS) (n = 4) groups. We retrospectively examined patient characteristics, trauma mechanism, injury site, severity score, intervention type, and survival rates at 24 h in each group. Results: In the HU group, 9 and 3 patients survived and died within 24 h, respectively; time to intervention (56.6 versus 130.7 min, P = 0.346) tended to be shorter and total occlusion time (40.2 versus 337.7 min, P = 0.009) was significantly shorter in survivors than in nonsurvivors. In the CA group, 10 patients were converted from resuscitative thoracotomy with aortic cross-clamp (RTACC); one patient survived. All four patients in the HS group survived, having received prophylactic REBOA. Conclusion: The efficacy of REBOA for severe torso trauma depends on the patient's condition. If the patients are hemodynamically unstable, time to intervention and total occlusion time could correlate with survival. The combined use of REBOA with definitive hemostasis could improve outcomes. Conversion from RTACC in the cardiac arrest patients and prophylactic use in the hemodynamically stable patients can be one of the potentially effective options, although further studies are needed.

A longitudinal change of syndecan-1 predicts risk of acute respiratory distress syndrome and cumulative fluid balance in patients with septic shock: a preliminary study.

BACKGROUND: The purpose of this study is to investigate the time course of syndecan-1 (Syn-1) plasma levels, the correlation between Syn-1 and organ damage development, and the associations of Syn-1 level with cumulative fluid balance and ventilator-free days (VFD) in patients with septic shock. METHODS: We collected blood samples from 38 patients with septic shock upon their admission to ICU and for the first 7 days of their stay. Syn-1 plasma level, acute respiratory distress syndrome (ARDS), other organ damage, VFD, and cumulative fluid balance were assessed daily. RESULTS: Over the course of 7 days, Syn-1 plasma levels increased significantly more in patients with ARDS than in those without ARDS. Patients with high levels of Syn-1 in the 72 h after ICU admission had significantly higher cumulative fluid balance, lower PaO2/FiO2, and fewer VFD than patients with low levels of Syn-1. Syn-1 levels did not correlate with sequential organ failure assessment score or with APACHE II score. CONCLUSIONS: In our cohort of patients with septic shock, higher circulating level of Syn-1 of cardinal glycocalyx component is associated with more ARDS, cumulative positive fluid balance, and fewer VFD. Measurement of Syn-1 levels in patients with septic shock might be useful for predicting patients at high risk of ARDS.

Neuromuscular Electrical Stimulation Improves Energy Substrate Metabolism and Survival in Mice With Acute Endotoxic Shock.

This study investigated the therapeutic benefits of neuromuscular electrical stimulation (NMES).C57BL/6 mice were administered lipopolysaccharide (LPS; 20 mg/kg body weight) by intraperitoneal injection and divided into control (C) and NMES groups (n = 10-12 each). The latter received NMES to the bilateral gastrocnemius muscle for 1 h at low or high frequency (LF = 2 Hz and HF = 50 Hz, respectively) and low or high voltage (LV = 10 V and HV = 50 V, respectively). In LF-LV and LF-HV groups, NMES was performed twice and the results were compared with those for mice that received one round of NMES. Changes in energy metabolism were measured by indirect calorimetry up to 24 h; survival was evaluated up to 72 h after LPS administration; peroxisome proliferator-activated receptor gamma coactivator (PGC)-1α expression in the liver and gastrocnemius muscle was evaluated by quantitative PCR; and plasma concentration of interleukin (IL)-6 was determined by enzyme-linked immunosorbent assay.Survival was improved only in the LF-LV group with one round of NMES (P < 0.01) and the LF-HV group with two rounds of NMES (P < 0.05). Fatty acid oxidation (FAO) was slightly increased in these two groups, whereas carbohydrate oxidation (CHO) was decreased or not changed. Significant upregulation of PGC-1α in muscle as well as a decrease in plasma IL-6 level were also observed in these two groups (P < 0.05).Thus, NMES exerts therapeutic effects under conditions that induce a mild switch in energy metabolism from glucose to lipid predominant metabolism through PGC-1α upregulation and suppression of inflammation, and may be an effective early intervention even in hemodynamically unstable patients.

Alterations in energy substrate metabolism in mice with different degrees of sepsis.

BACKGROUND: Nutritional management is crucial during the acute phase of severe illnesses. However, the appropriate nutritional requirements for patients with sepsis are poorly understood. We investigated alterations in carbohydrate, fat, and protein metabolism in mice with different degrees of sepsis. MATERIALS AND METHODS: C57BL/6 mice were divided into three groups: control mice group, administered with saline, and low- and high-dose lipopolysaccharide (LPS) groups, intraperitoneally administered with 1 and 5 mg of LPS/kg, respectively. Rectal temperature, food intake, body weight, and spontaneous motor activity were measured. Indirect calorimetry was performed using a respiratory gas analysis for 120 h, after which carbohydrate oxidation and fatty acid oxidation were calculated. Urinary nitrogen excretion was measured to evaluate protein metabolism. The substrate utilization ratio was recalculated. Plasma and liver carbohydrate and lipid levels were evaluated at 24, 72, and 120 h after LPS administration. RESULTS: Biological reactions decreased significantly in the low- and high-LPS groups. Fatty acid oxidation and protein oxidation increased significantly 24 h after LPS administration, whereas carbohydrate oxidation decreased significantly. Energy substrate metabolism changed from glucose to predominantly lipid metabolism depending on the degree of sepsis, and protein metabolism was low. Plasma lipid levels decreased, whereas liver lipid levels increased at 24 h, suggesting that lipids were transported to the liver as the energy source. CONCLUSIONS: Our findings revealed that energy substrate metabolism changed depending on the degree of sepsis. Therefore, in nutritional management, such metabolic alterations must be considered, and further studies on the optimum nutritional intervention during severe sepsis are necessary.

The Effect of Lactoferrin and Pepsin-Treated Lactoferrin on IEC-6 Cell Damage Induced by Clostridium Difficile Toxin B.

Clostridium difficile infections (CDI) have recently increased worldwide. Some CDI progress to fulminant and recurrent CDI and are associated with high mortality and morbidity. CD produces toxins A and B, which cause intestinal mucosal damage, although toxin B exhibits greater cytotoxicity. Pepsin-treated lactoferrin (PLF) is the decomposed product of lactoferrin (LF), a multifunctional glycoprotein with anti-inflammatory properties. Here, we investigate the effects of LF and PLF in toxin B-stimulated rat intestinal epithelial (IEC-6) cells. Different toxin B concentrations were added to IEC-6 cells with or without LF or PLF. Mitochondrial function and cell cytotoxicity were assessed by measuring WST-1 and LDH levels, respectively. WST-1 levels were higher in IEC-6 cells treated with toxin B and LF or PLF than in the toxin B-only control (P < 0.05). Compared with the toxin B-only control, LDH levels significantly decreased after toxin B and LF or PLF addition (P < 0.05). Wound restitution measurement using microscopy demonstrated significantly greater levels of wound restitution in cells treated with toxin B and LF or PLF than in those treated with toxin B alone after 12 h (P < 0.001). Furthermore, changes in IEC-6 cell tight junctions (TJs) were evaluated by immunofluorescence microscopy and zonula occludens-1 (ZO-1) protein expression. When LF or PLF were added to IEC-6 cells, TJ structures were maintained, and ZO-1 and occludin expression was upregulated. Taken together, these results demonstrate that LF and PLF prevent the cytotoxicity of toxin B and might have the potential to control CDI.

Low-intensity exercise in the acute phase of lipopolysaccharide-induced sepsis improves lipid metabolism and survival in mice by stimulating PGC-1α expression.

BACKGROUND: The effect of exercise during the acute phase following sepsis onset is poorly understood. We investigated how low-intensity exercise during acute sepsis alters energy-substrate metabolism and survival in mice with lipopolysaccharide (LPS)-induced sepsis. METHODS: Mice were divided into control (C, saline), low-dose LPS (L, 1 mg/kg), medium-dose LPS (M, 5 mg/kg), and high-dose LPS (H, 10 mg/kg) groups. Each group was subdivided into sedentary (SED) and exercise (EX) groups; the EX group mice were exercised at low intensity on a treadmill after LPS administration. Survival proportions and vital functions were measured, and indirect calorimetry through respiratory gas analysis was performed until 72 hours after treatment. Organ weight and lipid levels in the plasma and liver were measured, and the messenger RNA and protein levels of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) were evaluated using quantitative polymerase chain reaction and Western blotting. RESULTS: Survival proportions of H-EX mice were higher than those of H-SED mice. At 16 hours after LPS administration, fatty acid oxidation was decreased in M-SED and H-SED groups but increased in all EX groups and was higher in surviving mice in H-SED and H-EX groups than in nonsurviving mice, suggesting that fatty acid oxidation is related to survival. Epididymal fat weight was lower in the EX groups than in the SED groups, whereas plasma and liver lipid levels were elevated in all EX groups; this suggests that exercise induces the transport of lipids from endogenous fat into the blood and the liver for use as the energy source. Lastly, PGC-1α messenger RNA and protein levels were lower in L-, M-, and H-SED groups than in the C-SED group but were high in all EX groups. CONCLUSION: Our study provides the revolutionary finding that exercise during the acute phase following sepsis onset might exert a therapeutic effect.

Retrospective study of the effectiveness of Intra-Aortic Balloon Occlusion (IABO) for traumatic haemorrhagic shock.

INTRODUCTION: Intra-aortic balloon occlusion (IABO) is useful for proximal vascular control, by clamping the descending aorta, in traumatic haemorrhagic shock. However, there are limited clinical studies regarding its effectiveness. This study aimed at investigating the effectiveness of IABO for traumatic haemorrhagic shock. METHODS: This retrospective, observational study included trauma patients who underwent IABO at the Emergency and Critical Care Center of Nippon Medical School Tama-Nagayama Hospital between January 2009 and March 2013. 14 patients were included to this study who were in shock on arrival (systolic blood pressure [SBP] <90 mmHg or shock index ≥1), underwent IABO for resuscitation and temporary haemostasis, and subsequently underwent haemostatic intervention (operation or transcatheter arterial embolization). Patient characteristics, physiological status, SBP, heart rate (HR), initial fluid and blood transfusion, time course, and total occlusion time were compared before and after IABO as well as between the survived (n = 5) and non-survived (n = 9) groups. RESULTS: The majority of patients experienced blunt injuries, with an average injury severity score of 29.5. The liver, pelvis, spleen, and mesenterium represented the majority of injured organs. SBP, but not HR, was significantly higher after IABO than before IABO (123.1 vs. 65.5 mmHg, P = 0.0001). The revised trauma score and probability of survival were significantly different between the survived and non-survived groups (both, P = 0.04). The survived group required significantly less blood transfusion volume than the non-survived group (20 vs. 33.7 red blood cell units, P = 0.04). In addition, the survived group required a significantly shorter total occlusion time than the non-survived group (46.2 vs. 224.1 min, P = 0.002). CONCLUSIONS: IABO was used for relatively severe trauma patients. SBP was significantly higher after IABO, but was not related to survival. However, blood transfusion volume and total occlusion time were related to survival; therefore, it is important to reduce or shorten these parameters, i.e., immediate definitive haemostasis. IABO is effective for traumatic haemorrhagic shock; however, it is also important to consider these points and potential complications.

Difference in pulmonary permeability between indirect and direct acute respiratory distress syndrome assessed by the transpulmonary thermodilution technique: a prospective, observational, multi-institutional study.

BACKGROUND: Acute respiratory distress syndrome (ARDS) is characterized by the increased pulmonary permeability secondary to diffuse alveolar inflammation and injuries of several origins. Especially, the distinction between a direct (pulmonary injury) and an indirect (extrapulmonary injury) lung injury etiology is gaining more attention as a means of better comprehending the pathophysiology of ARDS. However, there are few reports regarding the quantitative methods distinguishing the degree of pulmonary permeability between ARDS patients due to pulmonary injury and extrapulmonary injury. METHODS: A prospective, observational, multi-institutional study was performed in 23 intensive care units of academic tertiary referral hospitals throughout Japan. During a 2-year period, all consecutive ARDS-diagnosed adult patients requiring mechanical ventilation were collected in which three experts retrospectively determined the pathophysiological mechanisms leading to ARDS. Patients were classified into two groups: patients with ARDS triggered by extrapulmonary injury (ARDSexp) and those caused by pulmonary injury (ARDSp). The degree of pulmonary permeability using the transpulmonary thermodilution technique was obtained during the first three intensive care unit (ICU) days. RESULTS: In total, 173 patients were assessed including 56 ARDSexp patients and 117 ARDSp patients. Although the Sequential Organ Failure Assessment (SOFA) score was significantly higher in the ARDSexp group than in the ARDSp group, measurements of the pulmonary vascular permeability index (PVPI) were significantly elevated in the ARDSp group on all days: at day 0 (2.9 ± 1.3 of ARDSexp vs. 3.3 ± 1.3 of ARDSp, p = .008), at day 1 (2.8 ± 1.5 of ARDSexp vs. 3.2 ± 1.2 of ARDSp, p = .01), at day 2 (2.4 ± 1.0 of ARDSexp vs. 2.9 ± 1.3 of ARDSp, p = .01). There were no significant differences in mortality at 28 days, mechanical ventilation days, and hospital length of stay between the two groups. CONCLUSIONS: The results of this study suggest the existence of several differences in the increased degree of pulmonary permeability between patients with ARDSexp and ARDSp. TRIAL REGISTRATION: This report is a sub-group analysis of the study registered with UMIN-CTR (IDUMIN000003627).

Global end-diastolic volume is an important contributor to increased extravascular lung water in patients with acute lung injury and acuterespiratory distress syndrome: a multicenter observational study.

BACKGROUND: Extravascular lung water (EVLW), as measured by the thermodilution method, reflects the extent of pulmonary edema. Currently, there are no clinically effective treatments for preventing increases in pulmonary vascular permeability, a hallmark of lung pathophysiology, in patients with acute lung injury/acute respiratory distress syndrome (ALI/ARDS). In this study, we examined the contributions of hemodynamic and osmolarity factors, for which appropriate interventions are expected in critical care, to EVLW in patients with ALI/ARDS. METHODS: We performed a subgroup analysis of a multicenter observational study of patients with acute pulmonary edema. Overall, 207 patients with ALI/ARDS were enrolled in the study. Multivariate regression analysis was used to evaluate the associations of hemodynamic and serum osmolarity parameters with the EVLW index (EVLWI; calculated as EVLW/Ideal body weight). We analyzed factors measured on the day of enrollment (day 0), and on days 1 and 2 after enrollment. RESULTS: Multivariate regression analysis showed that global end-diastolic volume index (GEDVI) was significantly associated with EVLWI measured on days 0, 1, and 2 (P = 0.002, P < 0.001, and P = 0.003, respectively), whereas other factors were not significantly associated with EVLWI measured on all 3 days. CONCLUSIONS: Among several hemodynamic and serum osmolarity factors that could be targets for appropriate intervention, GEDVI appears to be a key contributor to EVLWI in patients with ALI/ARDS. TRIAL REGISTRATION: University Hospital Medical Information Network (UMIN) Clinical Trials Registry UMIN000003627.

Early-phase changes of extravascular lung water index as a prognostic indicator in acute respiratory distress syndrome patients.

BACKGROUND: The features of early-phase acute respiratory distress syndrome (ARDS) are leakage of fluid into the extravascular space and impairment of its reabsorption, resulting in extravascular lung water (EVLW) accumulation. The current study aimed to identify how the initial EVLW values and their change were associated with mortality. METHODS: This was a post hoc analysis of the PiCCO Pulmonary Edema Study, a multicenter prospective cohort study that included 23 institutions. Single-indicator transpulmonary thermodilution-derived EVLW index (EVLWi) and conventional prognostic factors were prospectively collected over 48 h after enrollment. Associations between 28-day mortality and each variable including initial (on day 0), mean, maximum, and Δ (subtracting day 2 from day 0) EVLWi were evaluated. RESULTS: We evaluated 192 ARDS patients (median age, 69 years (quartile, 24 years); Sequential Organ Failure Assessment (SOFA) score on admission, 10 (5); all-cause 28-day mortality, 31%). Although no significant differences were found in initial, mean, or maximum EVLWi, Δ-EVLWi was significantly higher (i.e., more reduction in EVLWi) in survivors than in non-survivors (3.0 vs. -0.3 mL/kg, p = 0.006). Age, maximum, and Δ-SOFA scores and Δ-EVLW were the independent predictors for survival according to the Cox proportional hazard model. Patients with Δ-EVLWi > 2.8 had a significantly higher incidence of survival than those with Δ-EVLWi ≤ 2.8 (log-rank test, χ (2) = 7.08, p = 0.008). CONCLUSIONS: Decrease in EVLWi during the first 48 h of ARDS may be associated with 28-day survival. Serial EVLWi measurements may be useful for understanding the pathophysiologic conditions in ARDS patients. A large multination confirmative trial is required.

Effect of a selective neutrophil elastase inhibitor on mortality and ventilator-free days in patients with increased extravascular lung water: a post hoc analysis of the PiCCO Pulmonary Edema Study.

BACKGROUND: Neutrophil elastase plays an important role in the development and progression of acute respiratory distress syndrome (ARDS). Although the selective elastase inhibitor, sivelestat, is widely used in Japan for treating ARDS patients, its effectiveness remains controversial. The aim of the current study was to investigate the effects of sivelestat in ARDS patients with evidence of increased extravascular lung water by re-analyzing a large multicenter study database. METHODS: A post hoc analysis of the PiCCO Pulmonary Edema Study was conducted. This multicenter prospective cohort study included 23 institutions in Japan. Adult mechanically ventilated ARDS patients with an extravascular lung water index of >10 mL/kg were included and propensity score analyses were performed. The endpoints were 28-day mortality and ventilator-free days (VFDs). RESULTS: Patients were categorized into sivelestat (n = 87) and control (n = 77) groups, from which 329 inverse probability-weighted group patients (162 vs. 167) were generated. The overall 28-day mortality was 31.1% (51/164). There was no significant difference in 28-day mortality between the study groups (sivelestat vs. control; unmatched: 29.9% vs. 32.5%; difference, -2.6%, 95% confidence interval (CI), -16.8 to 14.2; inverse probability-weighted: 24.7% vs. 29.5%, difference, -4.8%, 95% CI, -14.4 to 9.6). Although administration of sivelestat did not alter the number of ventilator-free days (VFDs) in the unmatched (9.6 vs. 9.7 days; difference, 0.1, 95% CI, -3.0 to 3.1), the inverse probability-weighted analysis identified significantly more VFDs in the sivelestat group than in the control group (10.7 vs. 8.4 days, difference, -2.3, 95% CI, -4.4 to -0.2). CONCLUSIONS: Although sivelestat did not significantly affect 28-day mortality, this treatment may have the potential to increase VFDs in ARDS patients with increased extravascular lung water. Prospective randomized controlled studies are required to confirm the results of the current study.

Relationship between extravascular lung water and severity categories of acute respiratory distress syndrome by the Berlin definition.

INTRODUCTION: The Berlin definition divides acute respiratory distress syndrome (ARDS) into three severity categories. The relationship between these categories and pulmonary microvascular permeability as well as extravascular lung water content, which is the hallmark of lung pathophysiology, remains to be elucidated. The aim of this study was to evaluate the relationship between extravascular lung water, pulmonary vascular permeability, and the severity categories as defined by the Berlin definition, and to confirm the associated predictive validity for severity. METHODS: The extravascular lung water index (EVLWi) and pulmonary vascular permeability index (PVPI) were measured using a transpulmonary thermodilution method for three consecutive days in 195 patients with an EVLWi of ≥10 mL/kg and who fulfilled the Berlin definition of ARDS. Collectively, these patients were seen at 23 ICUs. Using the Berlin definition, patients were classified into three categories: mild, moderate, and severe. RESULTS: Compared to patients with mild ARDS, patients with moderate and severe ARDS had higher acute physiology and chronic health evaluation II and sequential organ failure assessment scores on the day of enrollment. Patients with severe ARDS had higher EVLWi (mild, 16.1; moderate, 17.2; severe, 19.1; P <0.05) and PVPI (2.7; 3.0; 3.2; P <0.05). When categories were defined by the minimum PaO2/FIO2 ratio observed during the study period, the 28-day mortality rate increased with severity categories: moderate, odds ratio: 3.125 relative to mild; and severe, odds ratio: 4.167 relative to mild. On independent evaluation of 495 measurements from 195 patients over three days, negative and moderate correlations were observed between EVLWi and the PaO2/FIO2 ratio (r = -0.355, P<0.001) as well as between PVPI and the PaO2/FIO2 ratio (r = -0.345, P <0.001). ARDS severity was associated with an increase in EVLWi with the categories (mild, 14.7; moderate, 16.2; severe, 20.0; P <0.001) in all data sets. The value of PVPI followed the same pattern (2.6; 2.7; 3.5; P <0.001). CONCLUSIONS: Severity categories of ARDS described by the Berlin definition have good predictive validity and may be associated with increased extravascular lung water and pulmonary vascular permeability. TRIAL REGISTRATION: UMIN-CTR ID UMIN000003627.

Limitations of global end-diastolic volume index as a parameter of cardiac preload in the early phase of severe sepsis: a subgroup analysis of a multicenter, prospective observational study.

BACKGROUND: In patients with severe sepsis, depression of cardiac performance is common and is often associated with left ventricular (LV) dilatation to maintain stroke volume. Although it is essential to optimize cardiac preload to maintain tissue perfusion in patients with severe sepsis, the optimal preload remains unknown. This study aimed to evaluate the reliability of global end-diastolic volume index (GEDI) as a parameter of cardiac preload in the early phase of severe sepsis. METHODS: Ninety-three mechanically ventilated patients with acute lung injury/acute respiratory distress syndrome secondary to sepsis were enrolled for subgroup analysis in a multicenter, prospective, observational study. Patients were divided into two groups-with sepsis-induced myocardial dysfunction (SIMD) and without SIMD (non-SIMD)-according to a threshold LV ejection fraction (LVEF) of 50% on the day of enrollment. Both groups were further subdivided according to a threshold stroke volume variation (SVV) of 13% as a parameter of fluid responsiveness. RESULTS: On the day of enrollment, there was a positive correlation (r = 0.421, p = 0.045) between GEDI and SVV in the SIMD group, whereas this paradoxical correlation was not found in the non-SIMD group and both groups on day 2. To evaluate the relationship between attainment of cardiac preload optimization and GEDI value, GEDI with SVV ≤13% and SVV >13% was compared in both the SIMD and non-SIMD groups. SVV ≤13% implies the attainment of cardiac preload optimization. Among patients with SIMD, GEDI was higher in patients with SVV >13% than in patients with SVV ≤13% on the day of enrollment (872 [785-996] mL/m(2) vs. 640 [597-696] mL/m(2); p < 0.001); this finding differed from the generally recognized relationship between GEDI and SVV. However, GEDI was not significantly different between patients with SVV ≤13% and SVV >13% in the non-SIMD group on the day of enrollment and both groups on day 2. CONCLUSIONS: In the early phase of severe sepsis in mechanically ventilated patients, there was no constant relationship between GEDI and fluid reserve responsiveness, irrespective of the presence of SIMD. GEDI should be used as a cardiac preload parameter with awareness of its limitations.

The clinical usefulness of extravascular lung water and pulmonary vascular permeability index to diagnose and characterize pulmonary edema: a prospective multicenter study on the quantitative differential diagnostic definition for acute lung injury/acute respiratory distress syndrome.

INTRODUCTION: Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is characterized by features other than increased pulmonary vascular permeability. Pulmonary vascular permeability combined with increased extravascular lung water content has been considered a quantitative diagnostic criterion of ALI/ARDS. This prospective, multi-institutional, observational study aimed to clarify the clinical pathophysiological features of ALI/ARDS and establish its quantitative diagnostic criteria. METHODS: The extravascular lung water index (EVLWI) and the pulmonary vascular permeability index (PVPI) were measured using the transpulmonary thermodilution method in 266 patients with PaO2/FiO2 ratio ≤ 300 mmHg and bilateral infiltration on chest radiography, in 23 ICUs of academic tertiary referral hospitals. Pulmonary edema was defined as EVLWI ≥ 10 ml/kg. Three experts retrospectively determined the pathophysiological features of respiratory insufficiency by considering the patients' history, clinical presentation, chest computed tomography and radiography, echocardiography, EVLWI and brain natriuretic peptide level, and the time course of all preceding findings under systemic and respiratory therapy. RESULTS: Patients were divided into the following three categories on the basis of the pathophysiological diagnostic differentiation of respiratory insufficiency: ALI/ARDS, cardiogenic edema, and pleural effusion with atelectasis, which were noted in 207 patients, 26 patients, and 33 patients, respectively. EVLWI was greater in ALI/ARDS and cardiogenic edema patients than in patients with pleural effusion with atelectasis (18.5 ± 6.8, 14.4 ± 4.0, and 8.3 ± 2.1, respectively; P < 0.01). PVPI was higher in ALI/ARDS patients than in cardiogenic edema or pleural effusion with atelectasis patients (3.2 ± 1.4, 2.0 ± 0.8, and 1.6 ± 0.5; P < 0.01). In ALI/ARDS patients, EVLWI increased with increasing pulmonary vascular permeability (r = 0.729, P < 0.01) and was weakly correlated with intrathoracic blood volume (r = 0.236, P < 0.01). EVLWI was weakly correlated with the PaO2/FiO2 ratio in the ALI/ARDS and cardiogenic edema patients. A PVPI value of 2.6 to 2.85 provided a definitive diagnosis of ALI/ARDS (specificity, 0.90 to 0.95), and a value < 1.7 ruled out an ALI/ARDS diagnosis (specificity, 0.95). CONCLUSION: PVPI may be a useful quantitative diagnostic tool for ARDS in patients with hypoxemic respiratory failure and radiographic infiltrates. TRIAL REGISTRATION: UMIN-CTR ID UMIN000003627.