Acute Respiratory Distress Syndrome (ARDS)¶
Judd Heideman
Background¶
- A syndrome of diffuse inflammation and injury of the alveoli and capillary endothelium leading to fluid and protein accumulation in the interstitium and alveoli, pulmonary edema, and hypoxemic respiratory failure; 30-50% mortality rate
- Triggers:
- Pulmonary
- Pneumonia (viral and bacterial) • Lung contusion
- Direct inhalation injury • Aspiration
- Primary graft dysfunction of pulmonary transplant
- Extra-pulmonary
- Sepsis (most common cause) • HSCT
- Trauma • Burns
- Massive blood transfusions/TRALI • Pancreatitis
- Drugs (amiodarone, chemotherapy, cocaine, opioids)
Evaluation¶
- Diagnosis: Berlin Criteria
- New or worsening respiratory symptoms beginning within one week of diagnosis
- New bilateral opacities present on chest radiograph or CT chest
- Not explained by effusions, collapse of lobe/lung, or nodules
- Absence of left heart failure or volume overload
- Severity: based on PaO2/FiO2 ratio with a PEEP ≥ 5 cm H2O
- PaO2 = arterial partial pressure of O2 (requires ABG)
- FiO2 = fraction of inspired oxygen (expressed as a decimal between 0.21 and 1.0)
PaO2/FiO2 ratio | PEEP | |
---|---|---|
Mild | 201-300 | ≥5 |
Moderate | 101-200 | ≥5 |
Severe | \<100 | ≥5 |
Management¶
- Frequently requires intubation; non-invasive ventilation not a great treatment
- Low tidal volume (Vt) ventilation mortality benefit
- Goal Vt = 4-8 mL/kg of predicted body weight (obese patients don’t have bigger lungs)
- Plateau pressure goal: ≤30 cm H2O
- Oxygenation goal: PaO2 55-80 or SpO2 88-95%
- pH goal: ≥7.20, “permissive hypercapnia”
- Treat the underlying cause (see “Triggers” above)
Last update:
2022-06-02 13:28:55