From the Guidelines
The diagnostic criteria for Acute Respiratory Distress Syndrome (ARDS) are clearly defined and include specific requirements.
Key Diagnostic Criteria
- Onset within one week of a known clinical insult or new or worsening respiratory symptoms.
- Bilateral opacities on chest imaging, not fully explained by effusions, lobar/lung collapse, or nodules.
- Respiratory failure not fully explained by cardiac failure or fluid overload, with an objective assessment (e.g., echocardiography) to exclude hydrostatic pulmonary edema if no ARDS risk factor is present.
- Impaired oxygenation as indicated by a ratio of partial pressure of arterial oxygen to fraction of inspired oxygen (PaO2/FiO2) of 300 mmHg or less, with a positive end-expiratory pressure (PEEP) or continuous positive airway pressure (CPAP) of 5 cmH2O or more, as stated in the Berlin Definition 1.
Classification of ARDS
The severity of ARDS can be classified into mild, moderate, and severe based on the PaO2/FiO2 ratio, with thresholds of 201-300 mmHg, 101-200 mmHg, and less than 100 mmHg, respectively 1.
Importance of Accurate Diagnosis
Accurate diagnosis of ARDS is crucial, as it is associated with substantial morbidity and mortality, and evidence-based interventions can improve outcomes 1.
From the Research
Diagnostic Criteria for Acute Respiratory Distress Syndrome (ARDS)
The diagnostic criteria for ARDS include:
- Onset within one week of a known insult or new or worsening respiratory symptoms 2
- Profound hypoxemia 2, 3
- Bilateral pulmonary opacities on radiography 2, 4, 3
- Inability to explain respiratory failure by cardiac failure or fluid overload 2, 4, 3
- Acute onset 3
- Absence of left atrial hypertension 3
Berlin Criteria
The Berlin criteria are also used to define ARDS, which includes acute hypoxaemic respiratory failure with bilateral infiltrates on chest imaging, not fully explained by cardiac failure or fluid overload 4
Clinical Diagnostic Criteria
Clinical diagnostic criteria used by intensive care physicians include:
- Bilateral infiltrates on chest radiograph 5
- PaO2/FIO2 ratio 5
- Pulmonary artery occlusion pressure 5
- Shunt fraction 5
- Alveolar-arterial oxygen tension gradient 5
- FIO2 5
- PaO2 5
- Respiratory system compliance 5
- Minute ventilation 5
Limitations of Current Definition
There are limitations to the current definition of ARDS, and some studies suggest that a change in definition is needed to better identify patients with different severities of pulmonary dysfunction 6