Acute Respiratory Distress Syndrome

The 2024 global definition retains the core construct of acute hypoxemic respiratory failure with bilateral pulmonary opacities and edema not fully explained by cardiac failure or fluid overload. It accommodates intubated and nonintubated patients and permits chest radiography, CT, or lung ultrasound for imaging assessment. BMJBMJAcute respiratory distress syndrome (ARDS) - Symptoms, diagnosis and treatment | BMJ Best Practice US

At the bedside, diagnosis requires integration of timing, imaging, oxygenation, and the edema mechanism. Pneumonia, aspiration, pulmonary contusion, inhalational injury, drowning, and pulmonary vasculitis are direct insults; nonpulmonary sepsis, pancreatitis, major trauma, burns, shock, drug overdose, transfusion, and transfusion-related acute lung injury are indirect insults. fda+1fdaA Structured Review of Electronic Coding Algorithms for ...The LancetAcute respiratory distress syndrome: causes, pathophysiology, and phenotypes

When no clear ARDS risk factor is present, actively evaluate hydrostatic edema rather than assuming ARDS. The Berlin-derived framework calls for objective assessment when needed to exclude cardiac failure or fluid overload. fda+1fdaA Structured Review of Electronic Coding Algorithms for ...BMJAcute respiratory distress syndrome (ARDS) - Symptoms, diagnosis and treatment | BMJ Best Practice US

SpO2/FiO2 is a validated noninvasive surrogate for hypoxemia assessment and is incorporated into the global ARDS definition at a threshold of 315. BMJBMJAcute respiratory distress syndrome (ARDS) - Symptoms, diagnosis and treatment | BMJ Best Practice US The relationship is most useful when SpO2 is 97% or less; above that level, the oxyhemoglobin dissociation curve is flat and PaO2 cannot be reliably inferred. The LancetThe LancetPulse oximetry for the diagnosis and management of acute respiratory distress syndrome

For screening or longitudinal monitoring, calculate SpO2/FiO2 only with a stable oxygen delivery setting and a high-quality oximetry waveform. Confirm with arterial blood gas analysis when the estimate is near a management threshold, the clinical picture and oximetry are discordant, or pulse-oximeter reliability is impaired. The LancetThe LancetPulse oximetry for the diagnosis and management of acute respiratory distress syndrome

ARDS produces a reduced functional lung volume, regional heterogeneity, alveolar flooding, surfactant dysfunction, and increased susceptibility to ventilator-induced lung injury. High tidal volumes or inspiratory pressures can worsen epithelial and endothelial injury, inflammation, and extra-pulmonary organ dysfunction. The LancetThe LancetAcute respiratory distress syndrome: causes, pathophysiology, and phenotypes

Low-tidal-volume, plateau-pressure-limited ventilation is the foundation of treatment. Formal ARDS guidelines identify low tidal volume and plateau-pressure limitation as high-certainty recommendations. ScienceDirectScienceDirectFormal guidelines: management of acute respiratory distress syndrome Contemporary observational data show that this evidence-based strategy remains underused in practice. ScienceDirectScienceDirectManagement of severe acute respiratory distress syndrome in Australia and New Zealand (SAGE-ANZ): An observational study

Prone positioning improves oxygenation by redistributing lung density and ventilation-perfusion matching and by making stress distribution more homogeneous. In severe ARDS, prolonged prone sessions reduced mortality in randomized evidence, and formal guidelines identify prone positioning as a high-certainty recommendation. The Lancet+1The LancetPulse oximetry for the diagnosis and management of acute respiratory distress syndromeScienceDirectFormal guidelines: management of acute respiratory distress syndrome

Use prone positioning in intubated patients with severe hypoxemia after lung-protective ventilation is established. The supplied literature identifies PaO2/FiO2 persistently below 150 mm Hg as the severity range in which prone positioning should be strongly considered, absent contraindications. The Lancet+1The LancetPulse oximetry for the diagnosis and management of acute respiratory distress syndromeNatureAdvances in acute respiratory distress syndrome: focusing on heterogeneity, pathophysiology, and therapeutic strategies | Signal Transduction and Targeted Therapy

For severe ARDS that remains refractory despite optimized conventional ventilation and appropriate adjuncts, discuss venovenous ECMO early with a capable referral center. Trial and meta-analytic evidence support ECMO as a rescue strategy in selected severe ARDS, whereas extracorporeal carbon dioxide removal has not improved mortality and has increased serious adverse events in a randomized trial. Nature+1NatureAdvances in acute respiratory distress syndrome: focusing on heterogeneity, pathophysiology, and therapeutic strategies | Signal Transduction and Targeted TherapyScienceDirectFormal guidelines: management of acute respiratory distress syndrome

After initial shock management, avoid ongoing positive fluid balance when possible. Increased hydrostatic pressure worsens edema formation across an injured alveolar-capillary barrier, whereas restrictive fluid management is an established supportive strategy in ARDS. The LancetThe LancetAcute respiratory distress syndrome: causes, pathophysiology, and phenotypes

Corticosteroid evidence differs by cause and timing. In COVID-19-associated respiratory failure, dexamethasone and selected immunomodulators have demonstrated benefit in defined hospitalized populations; these results should not be generalized to every non-COVID ARDS phenotype. fda+2fdafact sheet for healthcare providers: emergency use ...fdaNovember 9, 2022 Meeting of the Pulmonary-Allergy Drugs ...The LancetAcute respiratory distress syndrome: causes, pathophysiology, and phenotypes

There is no validated routine role for statins, cell therapy, convalescent plasma, IV immunoglobulin, or broad biomarker-directed therapies in unselected ARDS based on the supplied evidence. ARDS subphenotypes are promising for research but are not yet a standard basis for routine bedside drug selection. The Lancet+1The LancetAcute respiratory distress syndrome: causes, pathophysiology, and phenotypesNatureAdvances in acute respiratory distress syndrome: focusing on heterogeneity, pathophysiology, and therapeutic strategies | Signal Transduction and Targeted Therapy

ARDS results from epithelial and endothelial barrier injury, producing protein-rich alveolar edema, shunt, surfactant dysfunction, atelectasis, decreased compliance, and, in some patients, microvascular thrombosis with increased dead space and right-ventricular stress. The LancetThe LancetAcute respiratory distress syndrome: causes, pathophysiology, and phenotypes These mechanisms explain why oxygenation severity alone is an incomplete marker of clinical trajectory.

Hyperinflammatory and hypoinflammatory subphenotypes have been replicated in research cohorts. The hyperinflammatory phenotype is associated with more vasopressor use, higher inflammatory biomarker concentrations, fewer ventilator-free days, and greater mortality; post-hoc analyses suggest heterogeneous treatment effects with PEEP, fluid strategy, and simvastatin. The LancetThe LancetAcute respiratory distress syndrome: causes, pathophysiology, and phenotypes These observations should guide trial interpretation rather than trigger off-label phenotype-directed prescribing.

Radiologic focal and nonfocal patterns may have different responses to recruitment and prone positioning, but classification error can cause harm. In the LIVE trial, 20% of patients were misclassified, and those exposed to a mismatched personalized ventilatory strategy had worse outcomes. The LancetThe LancetAcute respiratory distress syndrome: causes, pathophysiology, and phenotypes