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Acute respiratory distress syndrome
Background
Overview
Definition
ARDS is an acute inflammatory disease of the lungs that develops secondary to pulmonary or extrapulmonary damage to the alveolar-capillary membrane, leading to interstitial and alveolar edema. Clinically, ARDS is characterized by acute hypoxemic respiratory failure, decreased lung compliance, and bilateral radiographic infiltrates in the absence of cardiogenic pulmonary edema.
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Pathophysiology
An acute injury to the lungs (direct or indirect) is the most common cause of ARDS, with pneumonia, aspiration of gastric contents, and sepsis accounting for > 85% of all cases.
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Epidemiology
In the US, the incidence of ARDS is estimated at 64.2-78.9 cases per 100,000 person-years.
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Disease course
Classically, an initial exudative phase with interstitial and alveolar edema is followed by a proliferative phase, which may further progress to a fibrotic phase. The latter is associated with collagen deposition, along with interstitial and alveolar fibrosis, causing decreased lung compliance, respiratory dysfunction, multisystem organ failure, and death.
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Prognosis and risk of recurrence
ARDS is associated with an in-hospital mortality of 27%, 32%, and 45% for mild, moderate, and severe disease, respectively.
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Guidelines
Key sources
The following summarized guidelines for the evaluation and management of acute respiratory distress syndrome are prepared by our editorial team based on guidelines from the Society of Critical Care Medicine (SCCM 2025,2024,2016), the American Thoracic Society (ATS 2024), the European Society of Intensive Care Medicine (ESICM 2024,2023), the International Collaboration for Transfusion Medicine Guidelines (ICTMG 2024), the Japanese Society of ...
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Screening and diagnosis
Classification and risk stratification
Diagnostic investigations
Cardiac biomarkers: as per JSICM/JSRCM 2022 guidelines, consider measuring BNP or NT-proBNP levels to identify cardiogenic pulmonary edema in patients with acute respiratory failure.
C
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Infectious workup
Critical care ultrasound
Respiratory support
High-flow nasal oxygen therapy
As per ESICM 2023 guidelines:
Initiate high-flow nasal oxygen therapy over conventional oxygen therapy to reduce the risk of intubation in non-mechanically ventilated patients with acute hypoxemic respiratory failure (including patients with COVID-19) not due to cardiogenic pulmonary edema or acute exacerbation of COPD.
B
Insufficient evidence to recommend for or against the use of high-flow nasal oxygen compared to CPAP/noninvasive ventilation to reduce intubation
I
or mortality in unselected patients with acute hypoxemic respiratory failure not due to cardiogenic pulmonary edema or acute exacerbation of COPD. I
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Noninvasive ventilation
Mechanical ventilation (early tracheostomy)
Mechanical ventilation (tidal volume targets)
Mechanical ventilation (plateau pressure targets)
Mechanical ventilation (PEEP targets)
Mechanical ventilation (recruitment maneuvers)
Mechanical ventilation (prone positioning)
Mechanical ventilation (high-frequency oscillatory ventilation)
Mechanical ventilation (oxygen targets)
Mechanical ventilation (weaning)
Medical management
Fluid management
As per ESICM 2024 guidelines:
Consider administering crystalloids rather than albumin for volume expansion in critically ill patients in general
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and in patients with acute respiratory failure. C
Consider administering balanced crystalloids rather than isotonic saline in critically ill patients in general. C
Consider administering isotonic crystalloids rather than small-volume hypertonic crystalloids in critically ill patients in general.
C
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Sedation
Corticosteroids
Neuromuscular blockade
Inhaled nitric oxide
Thrombomodulin
Sivelestat
Nonpharmacologic interventions
Therapeutic procedures
Pulmonary artery catheterization: as per SSC 2017 guidelines, do not perform pulmonary artery catheterization routinely in patients with sepsis-induced ARDS.
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ECMO
Extracorporeal CO2 removal
Surgical interventions
Lung transplantation: as per ISHLT 2021 guidelines, refer and list patients with ARDS with a persistent requirement for mechanical ventilatory support and/or extracorporeal life support without expectation of clinical recovery and with evidence of irreversible lung destruction for lung transplantation.
E