The dynamics of the pulmonary microbiome during mechanical ventilation in the intensive care unit and the association with occurrence of pneumonia.

RATIONALE: Ventilator-associated pneumonia (VAP) is the most common nosocomial infections in patients admitted to the ICU. The adapted island model predicts several changes in the respiratory microbiome during intubation and mechanical ventilation. OBJECTIVES: We hypothesised that mechanical ventilation and antibiotic administration decrease the diversity of the respiratory microbiome and that these changes are more profound in patients who develop VAP. METHODS: Intubated and mechanically ventilated ICU-patients were included. Tracheal aspirates were obtained three times a week. 16S rRNA gene sequencing with the Roche 454 platform was used to measure the composition of the respiratory microbiome. Associations were tested with linear mixed model analysis and principal coordinate analysis. MEASUREMENTS AND MAIN RESULTS: 111 tracheal aspirates were obtained from 35 patients; 11 had VAP, 18 did not have VAP. Six additional patients developed pneumonia within the first 48 hours after intubation. Duration of mechanical ventilation was associated with a decrease in α diversity (Shannon index; fixed-effect regression coefficient (ß): -0.03 (95% CI -0.05 to -0.005)), but the administration of antibiotic therapy was not (fixed-effect ß: 0.06; 95% CI -0.17 to 0.30). There was a significant difference in change of ß diversity between patients who developed VAP and control patients for Bray-Curtis distances (p=0.03) and for Manhattan distances (p=0.04). Burkholderia, Bacillales and, to a lesser extent, Pseudomonadales positively correlated with the change in ß diversity. CONCLUSION: Mechanical ventilation, but not antibiotic administration, was associated with changes in the respiratory microbiome. Dysbiosis of microbial communities in the respiratory tract was most profound in patients who developed VAP.

The incidence, risk factors, and outcome of transfusion-related acute lung injury in a cohort of cardiac surgery patients: a prospective nested case-control study.

Transfusion-related acute lung injury (TRALI) is the leading cause of transfusion-related morbidity and mortality. Both antibodies and bioactive lipids that have accumulated during storage of blood have been implicated in TRALI pathogenesis. In a single-center, nested, case-control study, patients were prospectively observed for onset of TRALI according to the consensus definition. Of 668 patients, 16 patients (2.4%) developed TRALI. Patient-related risk factors for onset of TRALI were age and time on the cardiopulmonary bypass. Transfusion-related risk factors were total amount of blood products (odds ratio [OR] = 1.2; 95% confidence interval [CI], 1.03-1.44), number of red blood cells stored more than 14 days (OR = 1.6; 95% CI, 1.04-2.37), total amount of plasma (OR = 1.2; 95% CI, 1.03-1.44), presence of antibodies in donor plasma (OR = 8.8; 95% CI, 1.8-44), and total amount of transfused bioactive lipids (OR = 1.0; 95% CI, 1.00-1.07). When adjusted for patient risk factors, only the presence of antibodies in the associated blood products remained a risk factor for TRALI (OR = 14.2; 95% CI, 1.5-132). In-hospital mortality of TRALI was 13% compared with 0% and 3% in transfused and nontransfused patients, respectively (P < .05). In conclusion, the incidence of TRALI is high in cardiac surgery patients and associated with adverse outcome. Our results suggest that cardiac surgery patients may benefit from exclusion of blood products containing HLA/HNA antibodies.

In the critically ill patient, diabetes predicts mortality independent of statin therapy but is not associated with acute lung injury: a cohort study.

OBJECTIVES: Patients with diabetes mellitus form 23%-30% of published cohorts of critically ill patients. Conflicting published evidence links diabetes mellitus to both higher and lower mortality. Other cohort studies suggest that diabetes mellitus protects against acute lung injury. We hypothesized that diabetes mellitus is an independent risk factor for mortality. We further hypothesized that diabetes mellitus is a risk factor for cardiac overload and not for acute lung injury. DESIGN: Retrospective cohort study. SETTING: The intensive care unit of a tertiary referral hospital. PATIENTS: From November 1, 2004, to October 1, 2007, a cohort of patients admitted ≥48 hrs to the intensive care unit. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Of 2,013 patients, 317 had diabetes mellitus. Ninety-day mortality was higher in the diabetes mellitus patients compared to patients without diabetes mellitus (hazard ratio 1.53, 95% confidence interval 1.29-1.80). This association strengthened after adjusting for confounders and for medication (hazard ratio 1.53, 95% confidence interval 1.07-2.17).We found no association between diabetes mellitus and acute lung injury (relative risk ratio 1.01, 95% confidence interval 0.78-1.32; adjusted relative risk ratio 0.99, 95% confidence interval 0.75-1.31), but diabetes mellitus was a risk factor for cardiac overload (relative risk ratio 1.91, 95% confidence interval 1.30-2.81; adjusted relative risk ratio 1.45, 95% confidence interval 0.97-2.18). Statins were associated with both a reduced risk of mortality (hazard ratio 0.74, 95% confidence interval 0.63-0.87; adjusted hazard ratio 0.53, 95% confidence interval 0.44-0.64) and a decreased risk of developing acute lung injury (relative risk ratio 0.71, 95% confidence interval 0.56-0.89; adjusted relative risk ratio 0.61, 95% confidence interval 0.47-0.79). CONCLUSIONS: Diabetes mellitus is an independent risk factor for mortality in critically ill patients and failure to adjust for statins underestimates the size of this association. Diabetes mellitus is not associated with acute lung injury but is associated with cardiac overload. A diagnosis of cardiac overload excludes a diagnosis of acute lung injury. Investigators who do not account for cardiac overload as a competing alternative outcome may therefore falsely conclude that diabetes mellitus protects from acute lung injury.

Transfusion-related acute lung injury in cardiac surgery patients is characterized by pulmonary inflammation and coagulopathy: a prospective nested case-control study.

OBJECTIVE: Transfusion-related acute lung injury is the leading cause of transfusion-related morbidity and mortality. Clinical data on the pathogenesis of transfusion-related acute lung injury are sparse. The objective of the present study was to determine inflammation and coagulation pathways involved in the onset of transfusion-related acute lung injury. DESIGN: Nested case-control study. SETTING: Operating theatre and intensive care department of a tertiary referral hospital. PATIENTS: Elective cardiac surgery patients requiring postsurgery intensive care admission. INTERVENTIONS: None. MEASUREMENTS: Cardiac surgery patients (n=668) were prospectively screened for the onset of transfusion-related acute lung injury. Transfusion-related acute lung injury cases (n=16) were randomly assigned to transfused and nontransfused cardiac surgery controls in a 1:2 ratio. Blood samples were taken pre- and postoperatively and at onset of transfusion-related acute lung injury. In addition, at onset of transfusion-related acute lung injury, bronchoalveolar lavage fluid was obtained. In plasma and bronchoalveolar lavage fluid, levels of interleukin-6, interleukin-8, elastase-α1-antitrypsin complexes, thrombin-antithrombin complexes, plasminogen activator activity, and plasminogen activator inhibitor-1 were determined by means of enzyme-linked immunosorbent assay. MAIN RESULTS: In all patients, cardiac surgery was associated with systemic inflammation, evidenced by an increase in plasma levels of interleukin-6, interleukin-8, and elastase-α1-antitrypsin complexes compared with presurgery levels (p<.001). Prior to onset of transfusion-related acute lung injury, systemic interleukin-8 and interleukin-6 levels were higher compared with nontransfused controls (p<.01). In transfusion-related acute lung injury cases, bronchoalveolar lavage fluid levels of interleukin-8, interleukin-6, and elastase-α1-antitrypsin complexes were elevated compared with control groups (p<.05). Both plasma and bronchoalveolar lavage fluid levels of thrombin-antithrombin complexes were enhanced in transfusion-related acute lung injury cases compared with control groups (p<.01). Bronchoalveolar lavage fluid levels of plasminogen activator activity were decreased due to an increase in plasminogen activator inhibitor-1 levels in transfusion-related acute lung injury cases compared with control groups (p<.01), indicating suppressed fibrinolysis. CONCLUSIONS: Prior to onset of transfusion-related acute lung injury, there is systemic inflammation and neutrophil sequestration. Transfusion-related acute lung injury is characterized by both systemic and pulmonary inflammation and activation of neutrophils, as well as enhanced coagulation and suppressed fibrinolysis.

Supernatant of stored platelets causes lung inflammation and coagulopathy in a novel in vivo transfusion model.

Transfusion-related acute lung injury is suggested to be a "2-hit" event resulting from priming and activation of pulmonary neutrophils. Activation may result from infusion of lysophosphatidylcholines (LysoPCs), which accumulate during storage of blood products. In the present study, we developed a syngeneic in vivo transfusion model to test whether storage of platelet concentrates (PLTs) results in lung injury in healthy rats as well as in a "2-hit" model using lipopolysaccharide-pretreated rats. In addition, the effect of washing of platelets was studied. In healthy rats, transfusion of aged PLTs caused mild lung inflammation. In LPS-pretreated rats, transfusion of aged PLTs, but not fresh PLTs, augmented pulmonary systemic coagulopathy. When PLTs components were transfused separately, supernatant of aged PLTs, but not washed aged platelets, induced pulmonary injury in the "2-hit" model. Supernatants of aged PLTs contained increased concentrations of LysoPCs compared with fresh PLTs, which enhanced neutrophil priming activity in vitro. We conclude that transfusion of aged PLTs induces lung inflammation in healthy rats. In a "2-hit" model, aged PLTs contribute to pulmonary and systemic coagulopathy, which may be mediated by LysoPCs, which accumulate in the supernatant of PLTs during storage.

The effect of blood transfusion on pulmonary permeability in cardiac surgery patients: a prospective multicenter cohort study.

BACKGROUND: There is an association between blood transfusion and pulmonary complications in cardiac surgery. Mediators of increased pulmonary vascular leakage after transfusion are unknown. We hypothesized that factors may include antibodies or bioactive lipids, which have been implicated in transfusion-related acute lung injury. STUDY DESIGN AND METHODS: We performed a prospective cohort study in two university hospital intensive care units in the Netherlands. Pulmonary vascular permeability was measured in cardiac surgery patients after receiving no, restrictive (one or two transfusions), or multiple (five or more transfusions) transfusions (n=20 per group). The pulmonary leak index (PLI), using (67) Ga-labeled transferrin, was determined within 3 hours postoperatively. Blood products were screened for bioactive lipid accumulation and the presence of antibodies. RESULTS: The PLI was elevated in all groups after cardiac surgery. Transfused patients had a higher PLI compared to nontransfused patients (33×10(-3) ± 20×10(-3) vs. 23×10(-3) ± 11×10(-3)/min, p<0.01). The amount of red blood cell (RBC) products, but not of fresh-frozen plasma or platelets, was associated with an increase in PLI (ß, 1.6 [0.2-3.0]). Concerning causative factors in the blood product, neither the level of bioactive lipids nor the presence of antibodies was associated with an increase in PLI. Patient factors such as surgery risk and time on cardiopulmonary bypass did not influence the risk of pulmonary leakage after blood transfusion. CONCLUSIONS: Transfusion in cardiothoracic surgery patients is associated with an increase in pulmonary capillary permeability, an effect that was dose dependent for RBC products. The level of bioactive lipids or the presence of HLA or HNA antibodies in the transfused products were not associated with increased pulmonary capillary permeability.

Early intravenous unfractionated heparin and outcome in acute lung injury and acute respiratory distress syndrome: a retrospective propensity matched cohort study.

BACKGROUND: Acute lung injury (ALI) is characterized by a pro-coagulant state. Heparin is an anticoagulant with anti-inflammatory properties. Unfractionated heparin has been found to be protective in experimental models of ALI. We hypothesized that an intravenous therapeutic dose of unfractionated heparin would favorably influence outcome of critically ill patients diagnosed with ALI. METHODS: Patients admitted to the Intensive Care Unit (ICU) of a tertiary referral center in the Netherlands between November 2004 and October 2007 were screened. Patients who developed ALI (consensus definition) were included. In this cohort, the impact of heparin use on mortality was assessed by logistic regression analysis in a propensity matched case-control design. RESULTS: Of 5,561 admitted patients, 2,138 patients had a length of stay > 48 hours, of whom 723 were diagnosed with ALI (34%), of whom 164 received intravenous heparin. In a propensity score adjusted logistic regression analysis, heparin use did not influence 28-day mortality (odds ratio 1.23 [confidence interval 95% 0.80-1.89], nor did it affect ICU length of stay. CONCLUSIONS: Administration of therapeutic doses of intravenous unfractionated heparin was not associated with reduced mortality in critically ill patients diagnosed with ALI. Heparin treatment did not increase transfusion requirements. These results may help in the design of prospective trials evaluating the use of heparin as adjunctive treatment for ALI.

Blood transfusion during cardiac surgery is associated with inflammation and coagulation in the lung: a case control study.

INTRODUCTION: Blood transfusion is associated with increased morbidity and mortality in cardiac surgery patients, but cause-and-effect relations remain unknown. We hypothesized that blood transfusion is associated with changes in pulmonary and systemic inflammation and coagulation occurring in patients who do not meet the clinical diagnosis of transfusion-related acute lung injury (TRALI). METHODS: We performed a case control study in a mixed medical-surgical intensive care unit of a university hospital in the Netherlands. Cardiac surgery patients (n = 45) were grouped as follows: those who received no transfusion, those who received a restrictive transfusion (one two units of blood) or those who received multiple transfusions (at least five units of blood). Nondirected bronchoalveolar lavage fluid (BALF) and blood were obtained within 3 hours postoperatively. Normal distributed data were analyzed using analysis of variance and Dunnett's post hoc test. Nonparametric data were analyzed using the Kruskal-Wallis and Mann-Whitney U tests. RESULTS: Restrictive transfusion increased BALF levels of interleukin (IL)-1ß and D-dimer compared to nontransfused controls (P < 0.05 for all), and IL-1ß levels were further enhanced by multiple transfusions (P < 0.01). BALF levels of IL-8, tumor necrosis factor α (TNFα) and thrombin-antithrombin complex (TATc) were increased after multiple transfusions (P < 0.01, P < 0.001 and P < 0.01, respectively) compared to nontransfused controls, but not after restrictive transfusions. Restrictive transfusions were associated with increased pulmonary levels of plasminogen activator inhibitor 1 compared to nontransfused controls with a further increase after multiple transfusions (P < 0.001). Concomitantly, levels of plasminogen activator activity (PAA%) were lower (P < 0.001), indicating impaired fibrinolysis. In the systemic compartment, transfusion was associated with a significant increase in levels of TNFα, TATc and PAA% (P < 0.05). CONCLUSIONS: Transfusion during cardiac surgery is associated with activation of inflammation and coagulation in the pulmonary compartment of patients who do not meet TRALI criteria, an effect that was partly dose-dependent, suggesting transfusion as a mediator of acute lung injury. These pulmonary changes were accompanied by systemic derangement of coagulation.

Pulmonary activation of coagulation and inhibition of fibrinolysis after burn injuries and inhalation trauma.

BACKGROUND: Pulmonary coagulopathy is intrinsic to pneumonia and other forms of acute lung injury. We hypothesized patients with burn injuries and inhalation trauma to have similar alterations in pulmonary coagulation and fibrinolysis. METHODS: We performed a prospective study on changes in pulmonary and systemic thrombin generation and fibrinolytic activity in patients with burn injuries and inhalation trauma requiring mechanical ventilation. Nondirected bronchial lavage was performed on alternate days. Patients requiring mechanical ventilation for nonpulmonary reasons who did not meet the North American European Consensus Conference criteria for acute lung injury functioned as control patients. RESULTS: We studied 13 patients with burn injuries and inhalation trauma and 15 control patients. On admission, patients with burn injuries and inhalation trauma showed a significant increase in thrombin generation in the airways compared with control patients, as reflected by increased lavage fluid levels of thrombin-antithrombin complexes and fibrin degradation products, and decreased lavage fluid levels of activated protein C and antithrombin. Simultaneously, burn patients showed a significant decrease in fibrinolytic activity, as reflected by decreased lavage fluid levels of plasminogen activator activity. Pulmonary coagulopathy persisted throughout the period of mechanical ventilation and was accompanied by similar changes in systemic coagulation and fibrinolysis. There was no significant correlation between changes in coagulation and fibrinolysis and the extent of burn injury. CONCLUSIONS: Patients with burn injuries and inhalation trauma requiring mechanical ventilation show a distinct and sustained procoagulant and antifibrinolytic shift in the pulmonary compartment. Pulmonary coagulopathy could be an important therapeutic target in these patients.

Head-to-head validation of six immunoassays for SARS-CoV-2 in hospitalized patients.

BACKGROUND: Detecting SARS-CoV-2 antibodies may help to diagnose COVID-19. Head-to-head validation of different types of immunoassays in well-characterized cohorts of hospitalized patients remains needed. METHODS: We validated three chemiluminescence immunoassays (CLIAs) (Liaison, Elecsys, and Abbott) and one single molecule array assay (SIMOA) (Quanterix) for automated analyzers, one rapid immunoassay RIA (AllTest), and one ELISA (Wantai) in parallel in first samples from 126 PCR confirmed COVID-19 hospitalized patients and 158 pre-COVID-19 patients. Specificity of the AllTest was also tested in 106 patients with confirmed parasitic and dengue virus infections. Specificity of the Wantai assay was not tested due to limitations in sample volumes. RESULTS: Overall sensitivity in first samples was 70.6 % for the Liaison, 71.4 % for the Elecsys, 75.4 % for the Abbott, 70.6 % for the Quanterix, 77.8 % for the AllTest, and 88.9 % for the Wantai assay, respectively. Sensitivity was between 77.4 % (Liaison) and 94.0 % (Wantai) after 10 dpso. No false positive results were observed for the Elecsys and Abbott assays. Specificity was 91.1 % for the Quanterix, 96.2 % for the Liaison, and 98.1 % for the AllTest assay, respectively. CONCLUSION: We conclude that low sensitivity of all immunoassays limits their use early after onset of illness in diagnosing COVID-19 in hospitalized patients. After 10 dpso, the Wantai ELISA has a relatively high sensitivity, followed by the point-of-care AllTest RIA that compares favorably with automated analyzer immunoassays.

Risk factors and outcome of transfusion-related acute lung injury in the critically ill: a nested case-control study.

OBJECTIVES: To determine the incidence, risk factors, and outcome of transfusion-related acute lung injury in a cohort of critically ill patients. DESIGN: In a retrospective cohort study, patients with transfusion-related acute lung injury were identified using the consensus criteria of acute lung injury within 6 hrs after transfusion. Inclusion criterion was a length of intensive care unit admission >48 hrs. Patients developing transfusion-related acute lung injury were matched (on age, sex, and admission diagnosis) to transfused control subjects and patients developing acute lung injury from another origin. SETTING: Tertiary referral hospital. PATIENTS: All first-admitted patients from November 1, 2004, until October 1, 2007, to the intensive care unit. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Of 5208 admitted patients, 2024 patients had a length of stay >48 hrs, of whom 109 were suspected transfusion-related acute lung injury cases. Compared with transfused control subjects, risk factors for transfusion-related acute lung injury were emergency cardiac surgery (odds ratio, 17.6 [1.8-168.5]), hematologic malignancy (odds ratio, 13.1 [2.7-63.8]), massive transfusion (odds ratio, 4.5 [2.1-9.8]), sepsis (odds ratio, 2.5 [1.2-5.2]), mechanical ventilation (odds ratio, 3.0 [1.3-7.1], and high Acute Physiology and Chronic Health Evaluation II score (odds ratio, 1.1 [1.0-1.1]; p < .03 for all). The volume of platelets and plasma transfused was associated with transfusion-related acute lung injury in the univariate analysis. However, this association disappeared in the multivariate analysis. Compared with acute lung injury control subjects, risk factors for transfusion-related acute lung injury were sepsis (odds ratio, 2.4 [1.1-5.3]) and high Acute Physiology and Chronic Health Evaluation II score (odds ratio, 1.1 [1.0-1.1]), whereas pneumonia (odds ratio, 0.4 [0.2-0.7]) was a negative predictive factor. Patients with transfusion-related acute lung injury had a longer duration of mechanical ventilation compared with transfused control subjects and acute lung injury control subjects (231 [138-472] vs. 71 [46-163] and 70 [42-121] hrs, p < .001). Also, 90-day survival of patients with transfusion-related acute lung injury was lower compared with transfused control subjects and acute lung injury control subjects (53% vs. 75% and 83%, p < .02). CONCLUSIONS: Transfusion-related acute lung injury is common in critically ill patients. Transfusion-related acute lung injury may contribute to an adverse outcome associated with transfusion. This study identifies transfusion-related acute lung injury risk factors, which may aid in assessing the risks and benefits of transfusion in critically ill patients.

Supernatant of aged erythrocytes causes lung inflammation and coagulopathy in a "two-hit" in vivo syngeneic transfusion model.

BACKGROUND: Transfusion of erythrocytes is associated with increased morbidity in certain patient groups. Storage time of erythrocytes may contribute to respiratory complications. Using a syngeneic in vivo transfusion model, we investigated whether transfusion of stored rat erythrocytes causes lung injury in healthy and in lipopolysaccharide-primed rats in a "two-hit" model of lung injury. METHODS: Rats were infused with aged rat erythrocytes (14 days of storage) and washed aged erythrocytes or supernatant of aged erythrocytes. Controls received fresh rat erythrocytes (0 days of storage) or saline. In the "two-hit" model of lung injury, lipopolysaccharide was used as a "first hit" before transfusion. Rat and control human erythrocyte products were analyzed for lysophosphatidylcholine accumulation. RESULTS: In healthy rats, transfusion of aged erythrocytes caused mild pulmonary inflammation but no coagulopathy. In lipopolysaccharide-pretreated rats, transfusion of aged erythrocytes augmented lung injury by inducing coagulopathy, both in the pulmonary and systemic compartment, when compared with transfusion with fresh erythrocytes. When transfused separately, supernatant of aged erythrocytes, but not washed aged erythrocytes, mediated coagulopathy in the "two-hit" model. Analysis of the supernatant of aged erythrocytes (rat and human) showed no lysophosphatidylcholine accumulation. CONCLUSIONS: Transfusion of aged erythrocytes induces lung injury in healthy rats. In a "two-hit" model, injury induced by aged erythrocytes was characterized by coagulopathy and was abrogated by washing. Washing of aged erythrocytes may decrease pulmonary complications in patients with an inflammatory condition who are exposed to a blood transfusion.

Nebulized antithrombin limits bacterial outgrowth and lung injury in Streptococcus pneumoniae pneumonia in rats.

INTRODUCTION: Disturbed alveolar fibrin turnover is a cardinal feature of severe pneumonia. Clinical studies suggest that natural inhibitors of coagulation exert lung-protective effects via anticoagulant and possibly also anti-inflammatory pathways. Intravenous infusion of the natural anticoagulants increases the risk of bleeding. Local administration may allow for higher treatment dosages and increased local efficacy while at the same time reducing the risk of bleeding. We evaluated the effect of nebulized anticoagulants on pulmonary coagulopathy and inflammation in a rat model of Streptococcus pneumoniae pneumonia. METHODS: In this randomized controlled in vivo laboratory study rats were challenged intratracheally with S. pneumoniae, inducing pneumonia, and randomized to treatment with normal saline (placebo), recombinant human activated protein C (rh-APC), plasma-derived antithrombin (AT), heparin or danaparoid, by means of nebulization. RESULTS: S. pneumoniae infection increased pulmonary levels of thrombin-antithrombin complexes and fibrin degradation products. All nebulized anticoagulants significantly limited pulmonary coagulopathy. None of the agents except danaparoid resulted in changes in systemic coagulopathy. Treatment with plasma-derived AT reduced outgrowth of S. pneumoniae and histopathologic damage in lungs. In vitro experiments confirmed outgrowth was reduced in bronchoalveolar lavage fluid (BALF) from rats treated with plasma-derived AT compared with placebo. Neutralizing of cationic components in BALF diminished the inhibitory effects on bacterial outgrowth of BALF, suggesting a role for cationic antimicrobial proteins. CONCLUSIONS: Nebulization of anticoagulants attenuates pulmonary coagulopathy during S. pneumoniae pneumonia in rats while only danaparoid affects systemic coagulation. Nebulized plasma-derived AT reduces bacterial outgrowth and exerts significant lung-protective effects.

Cumulative fluid balance predicts mortality and increases time on mechanical ventilation in ARDS patients: An observational cohort study.

INTRODUCTION: Acute respiratory distress syndrome (ARDS) is characterized by acute, diffuse, inflammatory lung injury leading to increased pulmonary vascular permeability, pulmonary oedema and loss of aerated tissue. Previous literature showed that restrictive fluid therapy in ARDS shortens time on mechanical ventilation and length of ICU-stay. However, the effect of intravenous fluid use on mortality remains uncertain. We investigated the relationship between cumulative fluid balance (FB), time on mechanical ventilation and mortality in ARDS patients. MATERIALS AND METHODS: Retrospective observational study. Patients were divided in four cohorts based on cumulative FB on day 7 of ICU-admission: ≤0 L (Group I); 0-3.5 L (Group II); 3.5-8 L (Group III) and ≥8 L (Group IV). In addition, we used cumulative FB on day 7 as continuum as a predictor of mortality. Primary outcomes were 28-day mortality and ventilator-free days. Secondary outcomes were 90-day mortality and ICU length of stay. RESULTS: Six hundred ARDS patients were included, of whom 156 (26%) died within 28 days. Patients with a higher cumulative FB on day 7 had a longer length of ICU-stay and fewer ventilator-free days on day 28. Furthermore, after adjusting for severity of illness, a higher cumulative FB was associated with 28-day mortality (Group II, adjusted OR (aOR) 2.1 [1.0-4.6], p = 0.045; Group III, aOR 3.3 [1.7-7.2], p = 0.001; Group IV, aOR 7.9 [4.0-16.8], p<0.001). Using restricted cubic splines, a non-linear dose-response relationship between cumulative FB and probability of death at day 28 was found; where a more positive FB predicted mortality and a negative FB showed a trend towards survival. CONCLUSIONS: A higher cumulative fluid balance is independently associated with increased risk of death, longer time on mechanical ventilation and longer length of ICU-stay in patients with ARDS. This underlines the importance of implementing restrictive fluid therapy in ARDS patients.

The incidence of low venous oxygen saturation on admission to the intensive care unit: a multi-center observational study in The Netherlands.

BACKGROUND: Low mixed or central venous saturation (S(c)vO2) can reveal global tissue hypoxia and therefore can predict poor prognosis in critically ill patients. Early goal directed therapy (EGDT), aiming at an ScvO2 >/= 70%, has been shown to be a valuable strategy in patients with sepsis or septic shock and is incorporated in the Surviving Sepsis Campaign guidelines. METHODS: In this prospective observational multi-center study, we determined central venous pressure (CVP), hematocrit, pH, lactate and ScvO2 or SvO2 in a heterogeneous group of critically ill patients early after admission to the intensive care units (ICUs) in three Dutch hospitals. RESULTS: Data of 340 acutely admitted critically ill patients were collected. The mean SvO2 value was > 65% and the mean ScvO2 value was > 70%. With mean CVP of 10.3 +/- 5.5 mmHg, lactate plasma levels of 3.6 +/- 3.6 and acute physiology, age and chronic health evaluation (APACHE II) scores of 21.5 +/- 8.3, the in-hospital mortality of the total heterogeneous population was 32.0%. A subgroup of septic patients (n = 125) showed a CVP of 9.8 +/- 5.4 mmHg, mean ScvO2 values of 74.0 +/- 10.2%, where only 1% in this subgroup revealed a ScvO2 value < 50%, and lactate plasma levels of 2.7 +/- 2.2 mmol/l with APACHE II scores 20.9 +/- 7.3. Hospital mortality of this subgroup was 26%. CONCLUSION: The incidence of low ScvO2 values for acutely admitted critically ill patients is low in Dutch ICUs. This is especially true for patients with sepsis/septic shock.

Nebulized Recombinant Human Tissue Factor Pathway Inhibitor Attenuates Coagulation and Exerts Modest Anti-inflammatory Effects in Rat Models of Lung Injury.

BACKGROUND: Critically ill patients are at a constant risk of direct (e.g., by pneumonia) or indirect lung injury (e.g., by sepsis). Excessive alveolar fibrin deposition is a prominent feature of lung injury, undermining pulmonary integrity and function. METHODS: We examined the effect of local administration of recombinant human tissue factor pathway inhibitor (rh-TFPI), a natural anticoagulant, in two well-established models of lung injury in rats. Rats received intratracheal instillation of Pseudomonas aeruginosa, causing direct lung injury, or they received an intravenous injection of Escherichia coli lipopolysaccharide (LPS), causing indirect lung injury. Rats were randomized to local treatment with rh-TFPI or placebo through repeated nebulization. RESULTS: Challenge with P. aeruginosa or LPS was associated with increased coagulation and decreased fibrinolysis in bronchoalveolar lavage fluid (BALF) and plasma. Rh-TFPI levels in BALF increased after nebulization, whereas plasma rh-TFPI levels remained low and systemic TFPI activity was not affected. Nebulization of rh-TFPI attenuated pulmonary and systemic coagulation in both models, without affecting fibrinolysis. Nebulization of rh-TFPI modestly reduced the inflammatory response and bacterial growth of P. aeruginosa in the alveolar compartment. CONCLUSIONS: Local treatment with rh-TFPI does not alter systemic TFPI activity; however, it attenuates both pulmonary and systemic coagulopathy. Furthermore, nebulized rh-TFPI modestly reduces the pulmonary inflammatory response and allows increased bacterial clearance in rats with direct lung injury caused by P. aeruginosa.

Feasibility and Safety of Local Treatment with Recombinant Human Tissue Factor Pathway Inhibitor in a Rat Model of Streptococcus pneumoniae Pneumonia.

Pulmonary coagulopathy is intrinsic to pulmonary injury including pneumonia. Anticoagulant strategies could benefit patients with pneumonia, but systemic administration of anticoagulant agents may lead to suboptimal local levels and may cause systemic hemorrhage. We hypothesized nebulization to provide a safer and more effective route for local administration of anticoagulants. Therefore, we aimed to examine feasibility and safety of nebulization of recombinant human tissue factor pathway inhibitor (rh-TFPI) in a well-established rat model of Streptococcus (S.) pneumoniae pneumonia. Thirty minutes before and every 6 hours after intratracheal instillation of S. pneumonia causing pneumonia, rats were subjected to local treatment with rh-TFPI or placebo, and sacrificed after 42 hours. Pneumonia was associated with local as well as systemic activation of coagulation. Nebulization of rh-TFPI resulted in high levels of rh-TFPI in bronchoalveolar lavage fluid, which was accompanied by an attenuation of pulmonary coagulation. Systemic rh-TFPI levels remained undetectable, and systemic TFPI activity and systemic coagulation were not affected. Histopathology revealed no bleeding in the lungs. We conclude that nebulization of rh-TFPI seems feasible and safe; local anticoagulant treatment with rh-TFPI attenuates pulmonary coagulation, while not affecting systemic coagulation in a rat model of S. pneumoniae pneumonia.

Recombinant human activated protein C in the treatment of acute respiratory distress syndrome: a randomized clinical trial.

RATIONALE: Pulmonary coagulopathy may play a pathogenetic role in acute respiratory distress syndrome (ARDS), by contributing to alveolocapillary inflammation and increased permeability. Recombinant human activated protein C (rh-APC) may inhibit this process and thereby improve patient outcome. METHODS: A prospective randomized, saline-controlled, single-blinded clinical trial was performed in the intensive care units of two university hospitals, and patients with ARDS were included within 24 h after meeting inclusion criteria. INTERVENTION: A 4-day course of intravenous rh-APC (24 mcg/kg/h) (n = 33) versus saline (n = 38). OUTCOMES: The primary outcome parameter was the pulmonary leak index (PLI) of 67Gallium-transferrin as a measure of alveolocapillary permeability and secondary outcomes were disease severity scores and ventilator-free days, among others. RESULTS: Baseline characteristics were similar; in 87% of patients the PLI was above normal and in 90% mechanical or non-invasive ventilation was instituted at a median lung injury score of 2.5. There was no evidence that Rh-APC treatment affected the PLI or attenuated lung injury and sequential organ failure assessment scores. Mean ventilator-free days amounted to 14 (rh-APC) and 12 days (saline, P = 0.35). 28-day mortality was 6% in rh-APC- and 18% in saline-treated patients (P = 0.12). There was no difference in bleeding events. The study was prematurely discontinued because rh-APC was withdrawn from the market. CONCLUSION: There is no evidence that treatment with intravenous rh-APC during 4 days for infectious or inflammatory ARDS ameliorates increased alveolocapillary permeability or the clinical course of ARDS patients. We cannot exclude underpowering. TRIAL REGISTRATION: Nederlands Trial Register ISRCTN 52566874.