Pediatric Acute Respiratory Distress Syndrome Research Articles

Time Course of Mechanical Ventilation Driving Pressure Levels in Pediatric Acute Respiratory Distress Syndrome: Outcomes in a Prospective, Multicenter Cohort Study From Colombia, 2018-2022.

High driving pressure (DP, ratio of tidal volume (V t ) over respiratory system compliance) is a risk for poor outcomes in patients with pediatric acute respiratory distress syndrome (PARDS). We therefore assessed the time course in level of DP (i.e., 24, 48, and 72 hr) after starting mechanical ventilation (MV), and its association with 28-day mortality. Multicenter, prospective study conducted between February 2018 and December 2022. Twelve tertiary care PICUs in Colombia. One hundred eighty-four intubated children with moderate to severe PARDS. None. The median (interquartile range [IQR]) age of the PARDS cohort was 11 (IQR 3-24) months. A total of 129 of 184 patients (70.2%) had a pulmonary etiology leading to PARDS, and 31 of 184 patients (16.8%) died. In the first 24 hours after admission, the plateau pressure in the nonsurvivor group, compared with the survivor group, differed (28.24 [IQR 24.14-32.11] vs. 23.18 [IQR 20.72-27.13] cm H 2 O, p < 0.01). Of note, children with a V t less than 8 mL/kg of ideal body weight had lower adjusted odds ratio (aOR [95% CI]) of 28-day mortality (aOR 0.69, [95% CI, 0.55-0.87]; p = 0.02). However, we failed to identify an association between DP level and the oxygenation index (aOR 0.58; 95% CI, 0.21-1.58) at each of time point. In a diagnostic exploratory analysis, we found that DP greater than 15 cm H 2 O at 72 hours was an explanatory variable for mortality, with area under the receiver operating characteristic curve of 0.83 (95% CI, 0.74-0.89); there was also increased hazard for death with hazard ratio 2.5 (95% CI, 1.07-5.92). DP greater than 15 cm H 2 O at 72 hours was also associated with longer duration of MV (10 [IQR 7-14] vs. 7 [IQR 5-10] d; p = 0.02). In children with moderate to severe PARDS, a DP greater than 15 cm H 2 O at 72 hours after the initiation of MV is associated with greater odds of 28-day mortality and a longer duration of MV. DP should be considered a variable worth monitoring during protective ventilation for PARDS.

Lung behavior during a staircase high-frequency oscillatory ventilation recruitment maneuver

BackgroundLung volume optimization maneuvers (LVOM) are necessary to make physiologic use of high-frequency oscillatory ventilation (HFOV), but lung behavior during such maneuvers has not been studied to determine lung volume changes after initiation of HFOV, to quantify recruitment versus derecruitment during the LVOM and to calculate the time to stabilization after a pressure change.MethodsWe performed a secondary analysis of prospectively collected data in subjects < 18 years on HFOV. Uncalibrated respiratory inductance plethysmography (RIP) tracings were used to quantify lung recruitment and derecruitment during the LVOM inflation and deflation. The time constant was calculated according to the Niemann model.ResultsRIP data of 51 subjects (median age 3.5 [1.7–13.3] months) with moderate-to-severe pediatric acute respiratory distress syndrome (PARDS) in 85.4% were analyzed. Lung recruitment and derecruitment occurred during the LVOM inflation phase upon start of HFOV and between and within pressure changes. At 90% of maximum inflation pressure, lung derecruitment already started during the deflation phase. Time to stable lung volume (time constant) could only be calculated in 26.2% of all pressure changes during the inflation and in 21.4% during the deflation phase, independent of continuous distending pressure (CDP). Inability to calculate the time constant was due to lack of stabilization of the RIP signal or no change in any direction.ConclusionsSignificant heterogeneity in lung behavior during a staircase incremental–decremental LVOM occurred, underscoring the need for higher initial inflation pressures when transitioning from conventional mechanical ventilation (CMV) and a longer time between pressure changes to allow for equilibration.

Paediatric acute respiratory distress syndrome (PARDS)

Paediatric acute respiratory distress syndrome (PARDS)

Biomarker-Based Risk Stratification Tool in Pediatric Acute Respiratory Distress Syndrome: Single-Center, Longitudinal Validation in a 2014-2019 Cohort.

The Pediatric Acute Respiratory Distress Syndrome Biomarker Risk Model (PARDSEVERE) used age and three plasma biomarkers measured within 24 hours of pediatric acute respiratory distress syndrome (ARDS) onset to predict mortality in a pilot cohort of 152 patients. However, longitudinal performance of PARDSEVERE has not been evaluated, and it is unclear whether the risk model can be used to prognosticate after day 0. We, therefore, sought to determine the test characteristics of PARDSEVERE model and population over the first 7 days after ARDS onset. Secondary unplanned post hoc analysis of data from a prospective observational cohort study carried out 2014-2019. University-affiliated PICU. Mechanically ventilated children with ARDS. None. Between July 2014 and December 2019, 279 patients with ARDS had plasma collected at day 0, 266 at day 3 (11 nonsurvivors, two discharged between days 0 and 3), and 207 at day 7 (27 nonsurvivors, 45 discharged between days 3 and 7). The actual prevalence of mortality on days 0, 3, and 7, was 23% (64/279), 14% (38/266), and 13% (27/207), respectively. The PARDSEVERE risk model for mortality on days 0, 3, and 7 had area under the receiver operating characteristic curve (AUROC [95% CI]) of 0.76 (0.69-0.82), 0.68 (0.60-0.76), and 0.74 (0.65-0.83), respectively. The AUROC data translate into prevalence thresholds for the PARDSEVERE model for mortality (i.e., using the sensitivity and specificity values) of 37%, 27%, and 24% on days 0, 3, and 7, respectively. Negative predictive value (NPV) was high throughout (0.87-0.90 for all three-time points). In this exploratory analysis of the PARDSEVERE model of mortality risk prediction in a population longitudinal series of data from days 0, 3, and 7 after ARDS diagnosis, the diagnostic performance is in the "acceptable" category. NPV was good. A major limitation is that actual mortality is far below the prevalence threshold for such testing. The model may, therefore, be more useful in cohorts with higher mortality rates (e.g., immunocompromised, other countries), and future enhancements to the model should be explored.

Inflammatory and tissue injury marker dynamics in pediatric acute respiratory distress syndrome.

BACKGROUNDThe molecular signature of pediatric acute respiratory distress syndrome (ARDS) is poorly described, and the degree to which hyperinflammation or specific tissue injury contributes to outcomes is unknown. Therefore, we profiled inflammation and tissue injury dynamics over the first 7 days of ARDS, and associated specific biomarkers with mortality, persistent ARDS, and persistent multiple organ dysfunction syndrome (MODS).METHODSIn a single-center prospective cohort of intubated pediatric patients with ARDS, we collected plasma on days 0, 3, and 7. Nineteen biomarkers reflecting inflammation, tissue injury, and damage-associated molecular patterns (DAMPs) were measured. We assessed the relationship between biomarkers and trajectories with mortality, persistent ARDS, or persistent MODS using multivariable mixed effect models.RESULTSIn 279 patients (64 [23%] nonsurvivors), hyperinflammatory cytokines, tissue injury markers, and DAMPs were higher in nonsurvivors. Survivors and nonsurvivors showed different biomarker trajectories. IL-1α, soluble tumor necrosis factor receptor 1, angiopoietin 2 (ANG2), and surfactant protein D increased in nonsurvivors, while DAMPs remained persistently elevated. ANG2 and procollagen type III N-terminal peptide were associated with persistent ARDS, whereas multiple cytokines, tissue injury markers, and DAMPs were associated with persistent MODS. Corticosteroid use did not impact the association of biomarker levels or trajectory with mortality.CONCLUSIONSPediatric ARDS survivors and nonsurvivors had distinct biomarker trajectories, with cytokines, endothelial and alveolar epithelial injury, and DAMPs elevated in nonsurvivors. Mortality markers overlapped with markers associated with persistent MODS, rather than persistent ARDS.FUNDINGNIH (K23HL-136688, R01-HL148054).

Healthcare Burden and Resource Utilization After Pediatric Acute Respiratory Distress Syndrome: A Secondary Analysis of the Collaborative Pediatric Critical Care Research Network Acute Respiratory Distress Syndrome Study.

To describe family healthcare burden and health resource utilization in pediatric survivors of acute respiratory distress syndrome (ARDS) at 3 and 9 months. Secondary analysis of a prospective multisite cohort study. Eight academic PICUs in the United States (2019-2020). Critically ill children with ARDS and follow-up survey data collected at 3 and/or 9 months after the event. None. We evaluated family healthcare burden, a measure of healthcare provided by families at home, and child health resource use including medication use and emergency department (ED) and hospital readmissions during the initial 3- and 9-month post-ARDS using proxy-report. Using multivariable logistic regression, we evaluated patient characteristics associated with family healthcare burden at 3 months. Of 109 eligible patients, 74 (68%) and 63 patients (58%) had follow-up at 3- and 9-month post-ARDS. At 3 months, 46 families (62%) reported healthcare burden including (22%) with unmet care coordination needs. At 9 months, 33 families (52%) reported healthcare burden including 10 families (16%) with unmet care coordination needs. At month 3, 61 patients (82%) required prescription medications, 13 patients (18%) had ED visits and 16 patients (22%) required hospital readmission. At month 9, 41 patients (65%) required prescription medications, 19 patients (30%) had ED visits, and 16 (25%) required hospital readmission were reported. Medication use was associated with family healthcare burden at both 3 and 9 months. In a multivariable analysis, preillness functional status and chronic conditions were associated with healthcare burden at month 3 but illness characteristics were not. Pediatric ARDS survivors report high rates of healthcare burden and health resource utilization at 3- and 9-month post-ARDS. Future studies should assess the impact of improved care coordination to simplify care (e.g., medication management) and improve family burden.

About the Second International Guidelines for the Diagnosis and Management of Pediatric Acute Respiratory Distress Syndrome.

About the Second International Guidelines for the Diagnosis and Management of Pediatric Acute Respiratory Distress Syndrome.

Executive Summary of the Second International Guidelines for the Diagnosis and Management of Pediatric Acute Respiratory Distress Syndrome (PALICC-2): Erratum.

Executive Summary of the Second International Guidelines for the Diagnosis and Management of Pediatric Acute Respiratory Distress Syndrome (PALICC-2): Erratum.

Definition, Incidence, and Epidemiology of Pediatric Acute Respiratory Distress Syndrome: From the Second Pediatric Acute Lung Injury Consensus Conference: Erratum.

Definition, Incidence, and Epidemiology of Pediatric Acute Respiratory Distress Syndrome: From the Second Pediatric Acute Lung Injury Consensus Conference: Erratum.

Deep learning model performance for identifying pediatric acute respiratory distress syndrome on chest radiographs

PurposePediatric acute respiratory distress syndrome (PARDS) is underrecognized in the pediatric intensive care unit and the interpretation of chest radiographs is a key step in identification. We sought to test the performance of a machine learning model to detect PARDS in a cohort of children with respiratory failure.Materials and methodsA convolutional neural network (CNN) model previously developed to detect ARDS on adult chest radiographs was applied to a cohort of children age 7 days to 18 years, admitted to the PICU, and mechanically ventilated through a tracheostomy, endotracheal tube or full-face non-invasive positive pressure mask between May 2016 and January 2017. Two pediatric critical care physicians and a pediatric radiologist reviewed chest radiographs to evaluate if the chest radiographs were consistent with ARDS (bilateral airspace disease) and PARDS (any airspace disease) and the CNN model was tested against clinicians.ResultsA total of 328 chest radiographs were evaluated from 66 patients. Clinicians identified 84% (276/328) of the radiographs as potentially consistent with PARDS. Inter-rater reliability between individual clinicians and between the model and clinicians was similar (Cohen’s kappa 0.48 [95% CI 0.37–0.59] and 0.45 [95% CI 0.33–0.57], respectively). The model was better at identifying PARDS (AUC 0.882, F1 0.897) than ARDS (AUC 0.842, F1 0.742) and had equivalent or better performance to individual clinicians.ConclusionsAn ARDS detection model trained on adults performed well in detecting PARDS in children. Computer-assisted identification of PARDS on chest radiographs could improve the diagnosis of PARDS for enrollment in clinical trials and application of PARDS guidelines through improved diagnosis.

Airway opening pressure maneuver to detect airway closure in mechanically ventilated pediatric patients.

Airway closure, which refers to the complete collapse of the airway, has been described under mechanical ventilation during anesthesia and more recently in adult patients with acute respiratory distress syndrome (ARDS). A ventilator maneuver can be used to identify airway closure and measure the pressure required for the airway to reopen, known as the airway opening pressure (AOP). Without that maneuver, AOP is unknown to clinicians. This study aims to demonstrate the technical adaptation of the adult maneuver for children and illustrate its application in two cases of pediatric ARDS (p-ARDS). A bench study was performed to adapt the maneuver for 3-50 kg patients. Four maneuvers were performed for each simulated patient, with 1, 2, 3, and 4 s of insufflation time to deliver a tidal volume (Vt) of 6 ml/kg by a continuous flow. Airway closure was simulated, and AOP was visible at 15 cmH2O with a clear inflection point, except for the 3 kg simulated patient. Regarding insufflation time, a 4 s maneuver exhibited a better performance in 30 and 50 kg simulated patients since shorter insufflation times had excessive flowrates (>10 L/min). Below 20 kg, the difference in resistive pressure between a 3 s and a 4 sec maneuver was negligible; therefore, prolonging the maneuver beyond 3 s was not useful. Airway closure was identified in two p-ARDS patients, with the pediatric maneuver being employed in the 28 kg patient. We propose a pediatric AOP maneuver delivering 6 ml/kg of Vt at a continuous low-flow inflation for 3 s for patients weighing up to 20 kg and for 4 s for patients weighing beyond 20 kg.

Association between Age and Mortality in Pediatric and Adult Acute Respiratory Distress Syndrome.

Rationale: The epidemiology, management, and outcomes of acute respiratory distress syndrome (ARDS) differ between children and adults, with lower mortality rates in children despite comparable severity of hypoxemia. However, the relationship between age and mortality is unclear.Objective: We aimed to define the association between age and mortality in ARDS, hypothesizing that it would be nonlinear.Methods: We performed a retrospective cohort study using data from two pediatric ARDS observational cohorts (n = 1,236), multiple adult ARDS trials (n = 5,547), and an adult observational ARDS cohort (n = 1,079). We aligned all datasets to meet Berlin criteria. We performed unadjusted and adjusted logistic regression using fractional polynomials to assess the potentially nonlinear relationship between age and 90-day mortality, adjusting for sex, PaO2/FiO2, immunosuppressed status, year of study, and observational versus randomized controlled trial, treating each individual study as a fixed effect.Measurements and Main Results: There were 7,862 subjects with median ages of 4 years in the pediatric cohorts, 52 years in the adult trials, and 61 years in the adult observational cohort. Most subjects (43%) had moderate ARDS by Berlin criteria. Ninety-day mortality was 19% in the pediatric cohorts, 33% in the adult trials, and 67% in the adult observational cohort. We found a nonlinear relationship between age and mortality, with mortality risk increasing at an accelerating rate between 11 and 65 years of age, after which mortality risk increased more slowly.Conclusions: There was a nonlinear relationship between age and mortality in pediatric and adult ARDS.

Imaging of Acute Complications of Community-Acquired Pneumonia in the Paediatric Population-From Chest Radiography to MRI.

The most common acute infection and leading cause of death in children worldwide is pneumonia. Clinical and laboratory tests essentially diagnose community-acquired pneumonia (CAP). CAP can be caused by bacteria, viruses, or atypical microorganisms. Imaging is usually reserved for children who do not respond to treatment, need hospitalisation, or have hospital-acquired pneumonia. This review discusses the imaging findings for acute CAP complications and the diagnostic role of each imaging modality. Pleural effusion, empyema, necrotizing pneumonia, abscess, pneumatocele, pleural fistulas, and paediatric acute respiratory distress syndrome (PARDS) are acute CAP complications. When evaluating complicated CAP patients, chest radiography, lung ultrasonography, computed tomography (CT), and magnetic resonance imaging (MRI) can be used, with each having their own pros and cons. Imaging is usually not needed for CAP diagnosis, but it is essential for complicated cases and follow-ups. Lung ultrasound can supplement chest radiography (CR), which starts the diagnostic algorithm. Contrast-enhanced computed tomography (CECT) is used for complex cases. Advances in MRI protocols make it a viable alternative for diagnosing CAP and its complications.

Mechanical power and normalized mechanical power in pediatric acute respiratory distress syndrome.

Mechanical power (MP) refers to the energy transmitted over time to the respiratory system and serves as a unifying determinant of ventilator-induced lung injury. MP normalization is required to account for developmental changes in children. We sought to examine the relationship between mechanical energy (MEBW), MP normalized to body weight (MPBW), and MP normalized to respiratory compliance (MPCRS) concerning the severity and outcomes of pediatric acute respiratory distress syndrome (pARDS). In this retrospective study, children aged 1 month to 18 years diagnosed with pARDS who underwent pressure-control ventilation for at least 24 h between January 2017 and September 2020 were enrolled. We calculated MP using Becher's equation. Multivariable logistic regression analysis adjusted for age, pediatric organ dysfunction score, and oxygenation index (OI) was performed to determine the independent association of MP and its derivatives 24 h after diagnosing pARDS with 28-day mortality. The association was also studied for 28 ventilator-free days (VFD-28) and the severity of pARDS in terms of OI. Out of 246 admitted with pARDS, 185 were eligible, with an overall mortality of 43.7%. Non-survivors exhibited higher severity of illness, as evidenced by higher values of MP, MPBW, and MEBW. Multivariable logistic regression analysis showed that only MEBW but not MP, MPBW, or MPCRS at 24 h was independently associated with mortality [adjusted OR: 1.072 (1.002-1.147), p = 0.044]. However, after adjusting for the type of pARDS, MEBW was not independently associated with mortality [adjusted OR: 1.061 (0.992-1.136), p = 0.085]. After adjusting for malnutrition, only MP at 24 h was found to be independently associated. Only MPCRS at 1-4 and 24 h but not MP, MPBW, or MEBW at 24 h of diagnosing pARDS was significantly correlated with VFD-28. Normalization of MP is better related to outcomes and severity of pARDS than non-normalized MP. Malnutrition can be a significant confounding factor in resource-limited settings.

So, You Say You Want a Revolution? You Tell Me That It's Evolution: Associating Temporal Changes in Pediatric Acute Respiratory Distress Syndrome Plasma Biomarkers With Lung Injury Severity.

So, You Say You Want a Revolution? You Tell Me That It's Evolution: Associating Temporal Changes in Pediatric Acute Respiratory Distress Syndrome Plasma Biomarkers With Lung Injury Severity.

ОСТРЫЙ РЕСПИРАТОРНЫЙ ДИСТРЕСС-СИНДРОМ У ДЕТЕЙ: АСПЕКТЫ ИНТЕНСИВНОЙ ТЕРАПИИ

A literature review on the intensive care of pediatric acute respiratory distress syndrome (pARDS) was conducted. Information was collected by searching in ScienceDirect, PubMed, and eLibrary databases. Keywords such as "acute respiratory syndrome," "children," "intensive care," and "mechanical ventilation" were used as search terms. The review included full-text publication with statistical data analysis. Publications on the treatment of ARDS in adult patients were excluded. There are currently no proven pharmacological treatments for pARDS, and there is a lack of randomized clinical trials. Treatment mainly involves respiratory support, infusion therapy, sedation, administration of glucocorticoids (GCs), and enteral nutrition. If necessary, non-invasive ventilation with positive end-expiratory pressure is performed as the initial respiratory support method. If it is ineffective and accompanied by evidence of increasing respiratory failure, tracheal intubation and artificial ventilation are utilized. No substantial evidence supports the use of GCs for this condition. Despite the high prevalence and mortality rates of pARDS, there is still a need to optimize intensive care algorithms and the quality of care for this condition based on more extensive randomized clinical trials. Keywords: Children, acute respiratory distress syndrome, intensive care, mechanical ventilation, glucocorticosteroids.

Clinical Profile and Outcome of Moderate to Severe Acute Respiratory Distress Syndrome in a Paediatric Intensive Care Unit of Eastern India: A Prospective Cohort Study

Introduction: Paediatric Acute Respiratory Distress Syndrome (PARDS) remains a major cause of mortality and morbidity in Paediatric Intensive Care Units (PICU) despite various advanced management strategies. The management and outcome of PARDS depend on the severity of the disease. Aim: To study the clinical profile in terms of aetiology and outcome of paediatric patients with moderate to severe Acute Respiratory Distress Syndrome (ARDS) in the PICU. Materials and Methods: A prospective cohort study was conducted at the PICU in Dr. BC Roy Postgraduate Institute of Paediatric Sciences, Kolkata, West Bengal, India, from July 2018 to June 2019. A total of 120 children aged between two months and 12 years who developed moderate to severe ARDS according to Paediatric Acute Lung Injury Consensus Conference (PALICC) criteria were included. Demographic details, different risk factors, morbidity patterns, and outcomes were recorded. Patients were categorised into three groups based on Positive End Expiratory Pressure (PEEP): 5-8 cm of H2 O, 9-12 cm of H2 O, and &gt;12 cm of H2 O. Based on Peak Inspiratory Pressure (PIP), patients were divided into two groups: &lt;30 cm of H2 O and 30-35 cm of H2 O. Data were statistically analysed using the Chisquare test, Fisher’s test, and t-tests where applicable. Results: Out of a total of 120 children with moderate to severe ARDS, there were 75 males and 45 females. Direct lung injury accounted for 79 cases (65.5%), while indirect lung injury occurred in 41 cases (34.5%). Pneumonia and sepsis were the most common causes of direct and indirect lung injury, respectively. Among 75 cases of pneumonia, 40 deaths were reported (53.3%), and out of 37 cases of sepsis, 31 resulted in death (83%). On the day of admission, 38.3% of cases were classified as moderate ARDS and 61.7% as severe ARDS. The mortality rate for severe ARDS was 77%, compared to 43.5% for moderate ARDS. The mortality rate was 100% in the PEEP max &gt;12 cm of H2 O group and 84.4% in the PIP 30-35 cm of H2 O group. Conclusion: The majority of ARDS cases are due to direct lung injury caused by pneumonia, and the outcome is better than in cases of indirect lung injury. Mortality is nearly twice as high in severe ARDS as in moderate ARDS.

Evaluation of the classifications of severity in acute respiratory distress syndrome in childhood by the Berlin Consensus and the Pediatric Acute Lung Injury Consensus Conference.

To compare two methods for defining and classifying the severity of pediatric acute respiratory distress syndrome: the Berlin classification, which uses the relationship between the partial pressure of oxygen and the fraction of inspired oxygen, and the classification of the Pediatric Acute Lung Injury Consensus Conference, which uses the oxygenation index. This was a prospective study of patients aged 0 - 18 years with a diagnosis of acute respiratory distress syndrome who were invasively mechanically ventilated and provided one to three arterial blood gas samples, totaling 140 valid measurements. These measures were evaluated for correlation using the Spearman test and agreement using the kappa coefficient between the two classifications, initially using the general population of the study and then subdividing it into patients with and without bronchospasm and those with and without the use of neuromuscular blockers. The effect of these two factors (bronchospasm and neuromuscular blocking agent) separately and together on both classifications was also assessed using two-way analysis of variance. In the general population, who were 54 patients aged 0 - 18 years a strong negative correlation was found by Spearman's test (ρ -0.91; p < 0.001), and strong agreement was found by the kappa coefficient (0.62; p < 0.001) in the comparison between Berlin and Pediatric Acute Lung Injury Consensus Conference. In the populations with and without bronchospasm and who did and did not use neuromuscular blockers, the correlation coefficients were similar to those of the general population, though among patients not using neuromuscular blockers, there was greater agreement between the classifications than for patients using neuromuscular blockers (kappa 0.67 versus 0.56, p < 0.001 for both). Neuromuscular blockers had a significant effect on the relationship between the partial pressure of oxygen and the fraction of inspired oxygen (analysis of variance; F: 12.9; p < 0.001) and the oxygenation index (analysis of variance; F: 8.3; p = 0.004). There was a strong correlation and agreement between the two classifications in the general population and in the subgroups studied. Use of neuromuscular blockers had a significant effect on the severity of acute respiratory distress syndrome.

Pediatric Acute Respiratory Distress Syndrome and Sepsis in Children with Dravet Syndrome Following Upper Respiratory Tract Infections

Pediatric Acute Respiratory Distress Syndrome and Sepsis in Children with Dravet Syndrome Following Upper Respiratory Tract Infections

Categorizing Acute Respiratory Distress Syndrome with Different Severities by Oxygen Saturation Index.

The oxygen saturation index (OSI), defined by FIO2/SpO2 multiplied by the mean airway pressure, has been reported to exceed the Berlin definition in predicting the mortality of acute respiratory distress syndrome (ARDS). The OSI has served as an alternative to the Berlin definition in categorizing pediatric ARDS. However, the use of the OSI for the stratification of adult ARDS has not been reported. A total of 379 invasively ventilated adult ARDS patients were retrospectively studied. The ARDS patients were classified into three groups by their incidence rate of mortality: mild (OSI < 14.69), moderate (14.69 < OSI < 23.08) and severe (OSI > 23.08). OSI-based categorization was highly correlated with the Berlin definition by a Kendall's tau of 0.578 (p < 0.001). The Kaplan-Meier curves of the three OSI-based groups were significantly different (p < 0.001). By the Berlin definition, the hazard ratio for 28-day mortality was 0.58 (0.33-1.05) and 0.95 (0.55-1.67) for the moderate and severe groups, respectively (compared to the mild group). In contrast, the corresponding hazard ratio was 1.01 (0.69-1.47) and 2.39 (1.71-3.35) for the moderate and severe groups defined by the OSI. By multivariate analysis, OSI-based severe ARDS was independently associated with 28-D or 90-D mortality. In conclusion, we report the first OSI-based stratification for adult ARDS and find that it serves well as an alternative to the Berlin definition.