American-European Consensus Conference Definition Research Articles

Development of acute lung injury or acute respiratory distress syndrome after subarachnoid hemorrhage, predictive factors, and impact on prognosis

Acute lung injury or acute respiratory distress syndrome (ALI/ARDS) is a common complication after aneurysmal subarachnoid hemorrhage (aSAH), and is associated with worse neurologic outcomes and longer hospitalization. However, the effect of ALI/ARDS in SAH has not been well elucidated. The purpose of this study was to determine the incidence of ALI/ARDS in a cohort of patients with SAH and to determine the risk factors for ALI/ARDS and their impact on patient prognosis. We performed a retrospective analysis of 167 consecutive patients with aSAH enrolled. ALI/ARDS patients were rigorously adjudicated using North American-European Consensus Conference definition. Regression analyses were used to test the risk factors for ALI/ARDS in patients with SAH. A total of 167 patients fulfilled the inclusion criteria, and 27% patients (45 of 167) developed ALI. Among all 45 ALI patients, 33 (20%, 33 of 167) patients met criteria for ARDS. On multivariate analysis, elderly patients, lower glasgow coma scale (GCS), higher Hunt-Hess grade, higher simplified acute physiology score (SAPS) II score, pre-existing pneumonia, gastric aspiration, hypoxemia, and tachypnea were the strongest risk factor for ALI/ARDS. Patients with ALI/ARDS showed worse clinical outcomes measured at 30 days. Development of ALI/ARDS was associated with a statistically significant increasing the odds of tracheostomy and hospital complications, and increasing duration of mechanical ventilation, intensive care unit (ICU) length and hospitalization stay. Development of ALI/ARDS is a severe complication of SAH and is associated with a poor clinical outcome, and further studies should focus on both prevention and management strategies specific to SAH-associated ALI/ARDS.

Newly Proposed Diagnostic Criteria for Acute Respiratory Distress Syndrome: Does Inclusion of High Flow Nasal Cannula Solve the Problem?

Acute respiratory distress syndrome (ARDS) is a common life-threatening clinical syndrome which accounts for 10% of intensive care unit admissions. Since the Berlin definition was developed, the clinical diagnosis and therapy have changed dramatically by adding a minimum positive end-expiratory pressure (PEEP) to the assessment of hypoxemia compared to the American-European Consensus Conference (AECC) definition in 1994. High-flow nasal cannulas (HFNC) have become widely used as an effective respiratory support for hypoxemia to the extent that their use was proposed in the expansion of the ARDS criteria. However, there would be problems if the diagnosis of a specific disease or clinical syndrome occurred, based on therapeutic strategies.

Prognostic factors for development of acute respiratory distress syndrome following traumatic injury: a systematic review and meta-analysis.

Our purpose was to summarise the prognostic associations between various clinical risk factors and development of acute respiratory distress syndrome (ARDS) following traumatic injury. We conducted this review in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) and CHARMS (Critical Appraisal and Data Extraction for Systematic Reviews of Prediction Modeling Studies) guidelines. We searched six databases from inception through December 2020. We included English language studies describing the clinical risk factors associated with development of post-traumatic ARDS, as defined by either the American-European Consensus Conference or Berlin definition. We pooled adjusted odds ratios for prognostic factors using the random effects method. We assessed risk of bias using the QUIPS (Quality in Prognosis Studies) tool and certainty of findings using GRADE (Grading of Recommendations Assessment, Development and Evaluation) methodology. We included 39 studies involving 5 350 927 patients. We identified the amount of crystalloid resuscitation as a potentially modifiable prognostic factor associated with development of post-traumatic ARDS (adjusted OR 1.19, 95% CI 1.15-1.24 for each additional litre of crystalloid administered within the first 6 h after injury; high certainty). Non-modifiable prognostic factors with a moderate or high certainty of association with post-traumatic ARDS included increasing age, non-Hispanic White race, blunt mechanism of injury, presence of head injury, pulmonary contusion or rib fracture and increasing chest injury severity. We identified one important modifiable factor, the amount of crystalloid resuscitation within the first 24 h of injury, and several non-modifiable factors associated with development of post-traumatic ARDS. This information should support the judicious use of crystalloid resuscitation in trauma patients and may inform development of risk stratification tools.

Mortality of Adult Respiratory Distress Syndrome in Trauma Patients: A Systematic Review over a Period of Four Decades.

Acute respiratory distress syndrome (ARDS) is associated with high morbidity and mortality. In addition, its aetiologies are heterogeneous, and the outcome depends on the underlying cause. In trauma care, changes in diagnostics, management and treatment may influence the outcome of posttraumatic ARDS over time, which are attributable to geographic distribution, relate to the definition used and depend on the injury severity. We selected studies by searching PubMed using the MeSH terms "acute respiratory distress syndrome", "mortality" and "trauma" and all their combinations. Studies that reported mortality rates for polytrauma patients with ARDS were included. We excluded studies with selected population collectives (e.g. burn patients, isolated thoracic trauma and paediatric trauma) and non-trauma studies. Studies were stratified according to the recruitment year of patients into Decade 1 (prior 1990), Decade 2(1990-1999), Decade 3 (2000-2009) and Decade 4 (later 2009); geographic location (North America or Europe), the definition used in the different studies (American European Consensus Conference (AECC) definition or Berlin definition) and the mean injury severity of the patient populations, respectively. Twenty-three studies between 1 January 1980 and 30 June 2018 were included in the analysis (486,861 patients, 52,561 with posttraumatic ARDS). There was a wide variation in mortality rates among the studies (4-39%). The overall pooled mean mortality rate for all studies was 21.8%, SD ± 8.3%. The mean mortality over the last four decades was similar between decade 1 (25.8%), decade 2 (20.6%), decade 3 (20.7%) and decade 4 (22.5%). Geographical observations comparing Europe and North America revealed no difference [Europe (22.1%) and North America (21.7%)]. The ARDS mortality in publications using the Berlin definition (23%) was comparable to the mortality rate in publications using the AECC definition (22.9%). The mortality rate based on the injury severity showed no alteration (ISS ≤ 25 points, 22.6%, ISS > 25 points, 22.6%). In this systematic review, there was no change in the mortality rate over the last four decades, no geographical difference within Western societies, no dependence on the ARDS definition used and no association with injury severity, respectively.

A Scoring System with High-Resolution Computed Tomography to Predict Drug-Associated Acute Respiratory Distress Syndrome: Development and Internal Validation

Drugs can cause acute respiratory distress syndrome (ARDS). However, there is no established clinical prediction rule for drug-associated ARDS (DARDS). We aimed to develop and validate a scoring system for DARDS prediction. We analysed data collected from a prospective, single-centre, cohort study that included ARDS patients. The ARDS diagnosis was based on the American-European Consensus Conference or Berlin definition. Drug-associated acute lung injury (DALI) was defined as previous exposure to drugs which cause ALI and presence of traditional risk factors for ALI. High-resolution computed tomography (HRCT; indicating extent of lung damage with fibroproliferation), Acute Physiology and Chronic Health Evaluation (APACHE) II, and disseminated intravascular coagulation (DIC; indicating multiorgan failure) scores and PaO2/FiO2 were evaluated for their ability to predict DARDS. Twenty-nine of 229 patients had DARDS. The HRCT, APACHE II, and DIC scores and PaO2/FiO2 were assessed. The model-based predicted probability of DARDS fitted well with the observed data, and discrimination ability, assessed through bootstrap with an area under the receiver-operating curve, improved from 0.816 to 0.875 by adding the HRCT score. A simple clinical scoring system consisting of the APACHE II score, PaO2/FiO2, and DIC and HRCT scores can predict DARDS. This model may facilitate more appropriate clinical decision-making.

Practice of diagnosis and management of acute respiratory distress syndrome in mainland China: a cross-sectional study.

Although acute respiratory distress syndrome (ARDS) has been recognized for more than 50 years, limited information exists about the incidence and management of ARDS in mainland China. To evaluate the potential for improvement in management of patients with ARDS, this study was designed to describe the incidence and management of ARDS in mainland China. National prospective multicenter observational study over one month (August 31st to September 30th, 2012) of all patients who fulfilled the Berlin or American European Consensus Conference (AECC) definition of ARDS in 20 intensive care units, with data collection related to the management of ARDS, patient characteristics and outcomes. Of the 1,814 patients admitted during the enrollment period, 149 (8.2%) and 147 (8.1%) patients were diagnosed by AECC and Berlin definition, respectively. Lung protective strategy with low tidal volume (Vt) (≤8 mL/kg) and limitation of the plateau pressure (Pplat) (≤30 cmH2O) was performed in 75.2% patients. And, 36%, 21.1% and 4.1% patients with severe, moderate and mild ARDS had the driving pressure more than 14 cmH2O (P<0.05). Pplat and driving pressure increased significantly in patients with a higher degree of ARDS severity (P=0.002 and P<0.001, respectively), but Vt were comparable in the three groups (P>0.05). In severe ARDS, patient median positive end expiratory pressure (PEEP) was 10.0 (8.0-11.3) cmH2O and median FiO2 was 90%. A recruitment maneuver was performed in 35.5% of the patients, and 8.7% of patients with severe ARDS received prone position. Overall hospital mortality was 34.0%. Hospital mortality was 21.8% for mild, 31.1% for moderate, and 60.0% for patients with severe ARDS (P=0.004). Despite general acceptance of low Vt and limited Pplat, high driving pressure, low PEEP and low use of adjunctive measures may still be a concern in mainland China, especially in patients with severe ARDS. ClinicalTrials.gov NCT01666834; date of registration release: August 14th 2012.

Recent advances in understanding and treating acute respiratory distress syndrome.

Acute respiratory distress syndrome (ARDS) is a clinically and biologically heterogeneous disorder associated with many disease processes that injure the lung, culminating in increased non-hydrostatic extravascular lung water, reduced compliance, and severe hypoxemia. Despite enhanced understanding of molecular mechanisms, advances in ventilatory strategies, and general care of the critically ill patient, mortality remains unacceptably high. The Berlin definition of ARDS has now replaced the American-European Consensus Conference definition. The recently concluded Large Observational Study to Understand the Global Impact of Severe Acute Respiratory Failure (LUNG-SAFE) provided worldwide epidemiological data of ARDS including prevalence, geographic variability, mortality, and patterns of mechanical ventilation use. Failure of clinical therapeutic trials prompted the investigation and subsequent discovery of two distinct phenotypes of ARDS (hyper-inflammatory and hypo-inflammatory) that have different biomarker profiles and clinical courses and respond differently to the random application of positive end expiratory pressure (PEEP) and fluid management strategies. Low tidal volume ventilation remains the predominant mainstay of the ventilatory strategy in ARDS. High-frequency oscillatory ventilation, application of recruitment maneuvers, higher PEEP, extracorporeal membrane oxygenation, and alternate modes of mechanical ventilation have failed to show benefit. Similarly, most pharmacological therapies including keratinocyte growth factor, beta-2 agonists, and aspirin did not improve outcomes. Prone positioning and early neuromuscular blockade have demonstrated mortality benefit, and clinical guidelines now recommend their use. Current ongoing trials include the use of mesenchymal stem cells, vitamin C, re-evaluation of neuromuscular blockade, and extracorporeal carbon dioxide removal. In this article, we describe advances in the diagnosis, epidemiology, and treatment of ARDS over the past decade.

Keratinocyte growth factor for the treatment of the acute respiratory distress syndrome (KARE): a randomised, double-blind, placebo-controlled phase 2 trial

Data from in-vitro, animal, and human lung injury models suggest that keratinocyte growth factor (KGF) might be beneficial in acute respiratory distress syndrome (ARDS). The objective of this trial was to investigate the effect of KGF in patients with ARDS. We did a double-blind, allocation concealed, randomised, placebo-controlled phase 2 trial in two intensive care units in the UK, involving patients fulfilling the American-European Consensus Conference Definition of ARDS. Patients were randomly assigned (1:1) by computer-generated randomisation schedule with variable block size stratified by site and presence of severe sepsis requiring vasopressors to receive either recombinant human KGF (palifermin 60 μg/kg) or placebo (0·9% sodium chloride solution) daily for a maximum of 6 days. Both patients and investigators were masked to treatment. The primary endpoint was oxygenation index (OI) at day 7. Analyses were by intention to treat. The trial is registered with International Standard Randomised Controlled Trial Registry, number ISRCTN95690673. Between Feb 23, 2011, and Feb 26, 2014, 368 patients were assessed for eligibility for inclusion in the trial. Of the 60 patients recruited, 29 patients were randomly assigned to receive KGF and 31 to placebo; all were included in the analysis of the primary outcome. There was no significant difference between the two groups in OI at day 7 (mean 62·3 [SD 57·8] in the KGF group, 43·1 [33·5] in the placebo group; mean difference 19·2, 95% CI -5·6 to 44·0, p=0·13). Of interest, although not defined as outcome measures a priori, the KGF group, compared with placebo, had fewer median ventilator-free days (1 day [IQR 0 to 17] in the KGF group vs 20 days [13-22] in the placebo group; difference -8 days, 95% CI -17 to -2; p=0·0002), a longer median duration of ventilation in survivors to day 90 (16 days [IQR 13-30] in the KGF group vs 11 days [8-16] in the placebo group; difference 6 days, 95% CI 2 to 14; p=0·002), and a higher mortality at 28 days (nine [31%] vs three [10%] deaths; risk ratio 3·2, 95% CI 1·0 to 10·7, p=0·054). Adverse events were more frequent in the KGF group than the placebo group (14 vs 5 events; odds ratio 4·9, 95% CI 1·3 to 20·3, p=0·008). The two adverse events assessed as related to KGF were due to pyrexia. KGF did not improve physiological or clinical outcomes in ARDS and might be harmful to patient health. The Northern Ireland Public Health Agency Research and Development Division.

Incorporating Inflammation into Mortality Risk in Pediatric Acute Respiratory Distress Syndrome.

In pediatric acute respiratory distress syndrome, lung injury is mediated by immune activation and severe inflammation. Therefore, we hypothesized that patients with elevated pro- and anti-inflammatory cytokines would have higher mortality rates and that these biomarkers could improve risk stratification of poor outcomes. Multicenter prospective observational study. We enrolled patients from five academic PICUs between 2008 and 2015. Patients were 1 month to 18 years old, used noninvasive or invasive ventilation, and met the American European Consensus Conference definition of acute respiratory distress syndrome. Eight proinflammatory and anti-inflammatory cytokines were measured on acute respiratory distress syndrome day 1 and correlated with mortality, ICU morbidity as measured by survivor Pediatric Logistic Organ Dysfunction score, and biomarkers of endothelial injury, including angiopoietin-2, von Willebrand Factor, and soluble thrombomodulin. We measured biomarker levels in 194 patients, including 38 acute respiratory distress syndrome nonsurvivors. Interleukin-6, interleukin-8, interleukin-10, interleukin-18, and tumor necrosis factor-R2 were each strongly associated with all-cause mortality, multiple markers of ICU morbidity, and endothelial injury. A multiple logistic regression model incorporating oxygenation index, interleukin-8, and tumor necrosis factor-R2 was superior to a model of oxygenation index alone in predicting the composite outcome of mortality or severe morbidity (area under the receiver operating characteristic, 0.77 [0.70-0.83] vs 0.70 [0.62-0.77]; p = 0.042). In pediatric acute respiratory distress syndrome, pro- and anti-inflammatory cytokines are strongly associated with mortality, ICU morbidity, and biochemical evidence of endothelial injury. These cytokines significantly improve the ability of the oxygenation index to discriminate risk of mortality or severe morbidity and may allow for identification and enrollment of high-risk subgroups for future studies.

OP58 - Incidence of ARDS following cardiac surgery: comparison between American-European Consensus Conference Definition and Berlin Definition

OP58 - Incidence of ARDS following cardiac surgery: comparison between American-European Consensus Conference Definition and Berlin Definition

Evaluating the Performance of the Pediatric Acute Lung Injury Consensus Conference Definition of Acute Respiratory Distress Syndrome.

The Pediatric Acute Lung Injury Consensus Conference has developed a pediatric-specific definition of acute respiratory distress syndrome, which is a significant departure from both the Berlin and American European Consensus Conference definitions. We sought to test the external validity and potential impact of the Pediatric Acute Lung Injury Consensus Conference definition by comparing the number of cases of acute respiratory distress syndrome and mortality rates among children admitted to a multidisciplinary PICU when classified by Pediatric Acute Lung Injury Consensus Conference, Berlin, and American European Consensus Conference criteria. Retrospective cohort study. Tertiary care, university-affiliated PICU. All patients admitted between March 2009 and April 2013 who met inclusion criteria for acute respiratory distress syndrome. None. Of 4,764 patients admitted to the ICU, 278 (5.8%) met Pediatric Acute Lung Injury Consensus Conference pediatric acute respiratory distress syndrome criteria with a mortality rate of 22.7%. One hundred forty-three (32.2% mortality) met Berlin criteria, and 134 (30.6% mortality) met American European Consensus Conference criteria. All patients who met American European Consensus Conference criteria and 141 (98.6%) patients who met Berlin criteria also met Pediatric Acute Lung Injury Consensus Conference criteria. The 137 patients who met Pediatric Acute Lung Injury Consensus Conference but not Berlin criteria had an overall mortality rate of 13.1%, but 29 had severe acute respiratory distress syndrome with 31.0% mortality. At acute respiratory distress syndrome onset, there was minimal difference in mortality between mild or moderate acute respiratory distress syndrome by both Berlin (32.4% vs 25.0%, respectively) and Pediatric Acute Lung Injury Consensus Conference (16.7% vs 18.6%, respectively) criteria, but higher mortality for severe acute respiratory distress syndrome (Berlin, 43.6%; Pediatric Acute Lung Injury Consensus Conference, 37.0%). Twenty-four hours after acute respiratory distress syndrome onset, the presence of severe acute respiratory distress syndrome (using either Berlin or Pediatric Acute Lung Injury Consensus Conference) was associated with nearly 50% mortality. Applying the Pediatric Acute Lung Injury Consensus Conference definition of acute respiratory distress syndrome has the potential to significantly increase the number of acute respiratory distress syndrome patients identified, with a lower overall mortality rate. However, severe acute respiratory distress syndrome is associated with extremely high mortality, particularly if present at 24 hours after initial diagnosis.

Infection site is predictive of outcome in acute lung injury associated with severe sepsis and septic shock.

Sepsis is a leading cause of acute lung injury (ALI); however, the characteristics and outcome of sepsis-associated ALI are poorly understood. We aimed to elucidate factors that predict patient outcome in sepsis-associated ALI. Secondary analysis of a multicenter, prospective, observational study was performed. Among 624 patients with severe sepsis and septic shock, 251 (40.2%) fulfilled the definition of American-European Consensus Conference definition of ALI. All-cause 28-day and in-hospital mortalities were 30.7% and 38.6%, respectively. More than 40% of ALI patients had neurological, cardiovascular and haematological dysfunctions or disseminated intravascular coagulation, all of which were associated with higher mortality. We report a significant correlation between infection site and mortality in patients with ALI, but not in those without ALI. The proportion of ALI was significantly higher in pulmonary sepsis; further, a complication of ALI was associated with higher mortality in sepsis from pulmonary and other sources, but not in abdominal sepsis. Among the other sepsis sites, urinary tract, central nervous system, catheter-related and undetermined foci of infection had worse outcomes when associated with ALI. None of the individual severe sepsis bundles, including fluid resuscitation and early antibiotic administration, correlated with mortality. Compliance with a set of sepsis management bundles was associated with better outcomes. In severe sepsis and septic shock, the proportion and effect on outcome was not uniform among infection sites. The infection site was predictive of outcome in patients with ALI but not in those without ALI.

The incidence of ARDS and associated mortality in severe TBI using the Berlin definition.

The incidence of adult respiratory distress syndrome (ARDS) in severe traumatic brain injury (TBI) is poorly reported. Recently, a new definition for ARDS was proposed, the Berlin definition. The percentage of patients represented by TBI in the Berlin criteria study is limited. This study describes the incidence and associated mortality of ARDS in TBI patients. The study was an analysis of the safety of erythropoietin administration and transfusion threshold on the incidence of ARDS in severe TBI patients. Three reviewers independently assessed all patients enrolled in the study for acute lung injury/ARDS using the Berlin and the American-European Consensus Conference (AECC) definitions. A Cox proportional hazards model was used to assess the relationship between ARDS and mortality and 6-month Glasgow Outcome Scale (GOS) score. Two hundred patients were enrolled in the study. Of the patients, 21% (41 of 200) and 26% (52 of 200) developed ARDS using the AECC and Berlin definitions, respectively, with a median time of 3 days (interquartile range, 3) after injury. ARDS by either definition was associated with increased mortality (p = 0.04) but not with differences in functional outcome as measured by the GOS score at 6 months. Adjusted analysis using the Berlin criteria showed an increased mortality associated with ADS (p = 0.01). Severe TBI is associated with an incidence of ARDS ranging from 20% to 25%. The incidence is comparable between the Berlin and AECC definitions. ARDS is associated with increased mortality in severe TBI patients, but further studies are needed to validate these findings. Epidemiologic study, level II.

Application of the Berlin definition in children with acute respiratory distress syndrome

Purpose: The revised Berlin definition (BD) showed better predictive validity for mortality in adults with acute respiratory distress syndrome (ARDS). We examined the validity of BD for pediatric ARDS as compared to the American-European Consensus Conference definition (AECCD). Methods: This single-center, retrospective study included 127 patients aged 1 month to 19 years who were admitted to the medical intensive care unit due to acute lung injury (ALI, n=31) or ARDS (n=96) using the AECCD. All patient characteristics and mortality rates were compared between the individual severity groups according to the BD and AECCD. Results: Sixty-four patients (50%) died. Mortality rates increased across the severity groups according to both definitions (26% in mild, 42% in moderate, and 75% in severe by the BD [P<0.001]; 26% in ALI non-ARDS and 58% in ARDS by the AECCD [P=0.002]). The mortality risk increased only for ‘severe ARDS’ (hazard radio for mortality, 2.56; 95% confidence intervals [CI], 1.14-5.78; P=0.023) after adjusting for confounding factors. The BD better predicted mortality, with an integrated area under the receiver operating characteristic curve (iAUC) of 0.651 (95% CI, 0.571-0.725), than the AECCD, with an iAUC of 0.584 (95% CI, 0.523-0.637). The pediatric risk of mortality (PRISM) III and pediatric index of mortality 3 scores were significantly different across BD severity groups, whereas only PRISM III scores were different according to the AECCD. Conclusion: The BD applied to children with ARDS. It could be adopted to severity classifications and predict pediatric ARDS mortality better than the AECCD. (Allergy Asthma Respir Dis 2016:4:257-263)

Aetiology, outcomes & predictors of mortality in acute respiratory distress syndrome from a tertiary care centre in north India.

Background & objectives:Acute respiratory distress syndrome (ARDS) is a common disorder in critically ill patients and is associated with high mortality. There is a paucity of literature on this condition from developing countries. This prospective observational study was designed to find out the aetiology, outcomes and predictors of mortality in ARDS.Methods:Sixty four consecutive patients who satisfied American-European Consensus Conference (AECC) definition of ARDS from medical Intensive Care Unit (ICU) of a tertiary care centre in New Delhi, India, were enrolled in the study. Demographic, biochemical and ventilatory variables were recorded for each patient. Baseline measurements of serum interleukin (IL)-1β, IL-6, tumour necrosis factor-alpha (TNF-α), procalcitonin (PCT) and high sensitivity C-reactive protein (hsCRP) were performed.Results:Common causes of ARDS included pneumonia [44/64 (68.7%)], malaria [9/64 (14.1%)] and sepsis [8/64 (12.5%]. Eight of the 64 (12.5%) patients had ARDS due to viral pneumonia. The 28-day mortality was 36/64 (56.2%). Independent predictors of mortality included non-pulmonary organ failure, [Hazard ratio (HR) 7.65; 95% CI 0.98-59.7, P=0.05], Simplified Acute Physiology Score (SAPS-II) [HR 2.36; 95% CI 1.14-4.85, P=0.02] and peak pressure (Ppeak) [HR 1.13; 95% CI 1.00-1.30, P = 0.04] at admission.Interpretation & conclusions:Bacterial and viral pneumonia, malaria and tuberculosis resulted in ARDS in a considerable number of patients. Independent predictors of mortality included non-pulmonary organ failure, SAPS II score and Ppeak at baseline. Elevated levels of biomarkers such as TNF-α, PCT and hsCRP at admission might help in identifying patients at a higher risk of mortality.

Open Lung Approach for the Acute Respiratory Distress Syndrome: A Pilot, Randomized Controlled Trial.

The open lung approach is a mechanical ventilation strategy involving lung recruitment and a decremental positive end-expiratory pressure trial. We compared the Acute Respiratory Distress Syndrome network protocol using low levels of positive end-expiratory pressure with open lung approach resulting in moderate to high levels of positive end-expiratory pressure for the management of established moderate/severe acute respiratory distress syndrome. A prospective, multicenter, pilot, randomized controlled trial. A network of 20 multidisciplinary ICUs. Patients meeting the American-European Consensus Conference definition for acute respiratory distress syndrome were considered for the study. At 12-36 hours after acute respiratory distress syndrome onset, patients were assessed under standardized ventilator settings (FIO2≥0.5, positive end-expiratory pressure ≥10 cm H2O). If Pao2/FIO2 ratio remained less than or equal to 200 mm Hg, patients were randomized to open lung approach or Acute Respiratory Distress Syndrome network protocol. All patients were ventilated with a tidal volume of 4 to 8 ml/kg predicted body weight. From 1,874 screened patients with acute respiratory distress syndrome, 200 were randomized: 99 to open lung approach and 101 to Acute Respiratory Distress Syndrome network protocol. Main outcome measures were 60-day and ICU mortalities, and ventilator-free days. Mortality at day-60 (29% open lung approach vs. 33% Acute Respiratory Distress Syndrome Network protocol, p = 0.18, log rank test), ICU mortality (25% open lung approach vs. 30% Acute Respiratory Distress Syndrome network protocol, p = 0.53 Fisher's exact test), and ventilator-free days (8 [0-20] open lung approach vs. 7 [0-20] d Acute Respiratory Distress Syndrome network protocol, p = 0.53 Wilcoxon rank test) were not significantly different. Airway driving pressure (plateau pressure - positive end-expiratory pressure) and PaO2/FIO2 improved significantly at 24, 48 and 72 hours in patients in open lung approach compared with patients in Acute Respiratory Distress Syndrome network protocol. Barotrauma rate was similar in both groups. In patients with established acute respiratory distress syndrome, open lung approach improved oxygenation and driving pressure, without detrimental effects on mortality, ventilator-free days, or barotrauma. This pilot study supports the need for a large, multicenter trial using recruitment maneuvers and a decremental positive end-expiratory pressure trial in persistent acute respiratory distress syndrome.

Acute Respiratory Distress Syndrome: Mortality in a Single Center According to Different Definitions.

Mortality in acute lung injury (ALI) remains high, with outcome data arising mostly from multicenter studies. We undertook this investigation to determine hospital mortality in patients with ALI in a single center. We studied patients admitted between 2005 and 2012 with ALI and acute respiratory distress syndrome (ARDS) according to the American European Consensus Conference (AECC) criteria and recorded clinical variables. Thereafter, patients were classified as subgroups according to the AECC and Berlin definition in order to compare the clinical characteristics and outcomes. In the 93 patients comprising the study, hospital mortality was 38%. Mortality at 28 days was 36%. Multivariate analysis associated hospital mortality with age and Pao2/Fio2 on day 1 ( P < .001). Differences resulted between the subgroups of AECC (ALI vs ARDS) and Berlin (mild vs moderate vs severe ARDS) in the lung injury score, Pao2/Fio2, Pao2/PAo2, PaCo2 on day 1, and hospital mortality. The overall hospital mortality (38%) was similar to that of other studies and according to the presence of ARDS (Pao2/Fio2 ≤ 200), we found significant differences between ALI and ARDS (AECC) and between mild and moderate or severe ARDS (Berlin) in baseline respiratory variables and mortality.

Epidemiology and outcomes of acute respiratory distress syndrome in children according to the Berlin definition: a multicenter prospective study.

In 2012, a new acute respiratory distress syndrome definition was proposed for adult patients. It was later validated for infants and toddlers. Our objective was to evaluate the prevalence, outcomes, and risk factors associated with acute respiratory distress syndrome in children up to 15 years according to the Berlin definition. A prospective, multicenter observational study from March to September 2013. Seventy-seven PICU beds in eight centers: two private hospitals and six public academic hospitals in Brazil. All children aged 1 month to 15 years admitted to the participating PICUs in the study period. None. All children admitted to the PICUs were daily evaluated for the presence of acute respiratory distress syndrome according to the American-European Consensus Conference and Berlin definitions. Of the 562 patients included, acute respiratory distress syndrome developed in 57 patients (10%) and 58 patients (10.3%) according to the Berlin definition and the American-European Consensus Conference definition, respectively. Among patients with acute respiratory distress syndrome according to the Berlin definition, nine patients (16%) were mild, 21 (37%) were moderate, and 27 (47%) were severe. Compared with patients without acute respiratory distress syndrome, patients with acute respiratory distress syndrome had significantly higher severity scores, longer PICU and hospital length of stay, longer duration of mechanical ventilation, and higher mortality (p < 0.001). The presence of two or more comorbidities and admission for medical reasons were associated with development of acute respiratory distress syndrome. Comparisons across the three the Berlin categories showed significant differences in the number of ventilator-free days (21, 20, and 5 d, p = 0.001) and mortality for severe acute respiratory distress syndrome (41%) in comparison with mild (0) and moderate (15%) acute respiratory distress syndrome(p = 0.02). No differences in PICU or hospital stay were observed across the groups. The Berlin definition can identify a subgroup of patients with distinctly worse outcomes, as shown by the increased mortality and reduced number of ventilator-free days in pediatric patients with severe acute respiratory distress syndrome.

Epidemiology of pediatric acute respiratory distress syndrome in singapore: risk factors and predictive respiratory indices for mortality.

Aim: Acute respiratory distress syndrome (ARDS) represents the most severe form of acute lung injury. The aim of our study is to describe the epidemiology of pediatric ARDS in Singapore and compare the outcomes of ARDS using the following respiratory indices: PaO2/FiO2 ratio (P/F ratio), SpO2/FiO2 ratio (S/F ratio), oxygenation index (OI), and oxygen saturation index (OSI).Methods: We examined medical records of patients admitted to the Children’s Intensive Care Unit in KK Women’s and Children’s Hospital from 2009 to 2012. Those who fulfilled criteria for the American-European Consensus Conference definition for ARDS were identified. Demographic, clinical, and radiographic information were extracted and analyzed.Results: We identified 70 patients with ARDS. Median age (interquartile range) was 6.2 (1.4, 10.4) years. The most common risk factor was pneumonia [50 (71%)]. Overall mortality was 44 (63%) patients. Thirty-two (56%) patients had an underlying chronic comorbidity; 18 (46%) were hematology–oncology conditions. Fifty-six (80%) patients had multiorgan dysfunction. Adjunct therapies used in our patients included inhaled nitric oxide [5 (7%)], prone position [22 (31%)], steroids [26 (37%)], and neuromuscular blockade [26 (37%)]. A high OI and low PF ratio after 24 h of diagnosis of ARDS were associated with mortality. From day 3 onward, all four respiratory indices appropriately differentiated survivors from non-survivors. Severity based on the S/F ratio and OSI demonstrated association with decreased ventilator free days and ICU free days.Conclusion: Risk factors for mortality included having an underlying comorbidity, multiorgan dysfunction, a low PF ratio, and high OI at 24 h of ARDS. Abnormal SpO2-based measurements were reliable markers of poor outcomes in pediatric ARDS.

ABSTRACT 45

Background: The anatomical feature of ARDS is to diffuse alveolar damage (DAD) but the correlation between the American European Consensus Conference (AECC) definition of ARDS and DAD has not been studied in Pediatrics. Aim: To compare the AECC definition of ARDS to autopsy findings. Methods: Retrospective matching study of autopsies conducted at Hospital La Misericordia between 2000 - 2010 (n 355). The findings of the histopathological and clinical history was processed by calculating sensitivity, specificity and likelihood ratio considering the pulmonary and extrapulmonary risk factors. Results: The sensitivity of clinical criteria is 64.4 (95 % CI) and specificity 71 (95 % CI), with (LR)+=2.2 and LR (-) 0.5 . With intrapulmonary risk factors, the sensitivity is 80 (95 % CI) and specificity 50 (95 %) with an LR (+) of 1.6 and an LR (-) of 0.4. With extrapulmonary risk factors, the sensitivity is 55 (95 % CI) and specificity 84 (95 %) with LR + of 3.43 and LR- of 0.53. Conclusions: The clinical AECC criteria adequately discriminate patients with DAD and extrapulmonary risk factors, but not in the case where the factor is pulmonary. An adequate contribution of this study is that stratification is done based on the risk factors. Despite the limitations of the AECC definition, they are still valuable since patients will benefit from the proposed treatments even if they do not have DAD.