From the Guidelines
I strongly recommend immediately reassessing and adjusting the ventilator settings for your deteriorating ARDS patient to prioritize lung-protective ventilation and improve oxygenation. The most recent and highest quality study, 1, suggests using mechanical ventilation strategies that limit tidal volume (4–8 mL/kg predicted body weight) and inspiratory pressures (plateau pressure < 30 cm H2O) in patients with ARDS.
Key Ventilator Settings
- Tidal volume: 4-6 ml/kg of predicted body weight
- Plateau pressure: ≤30 cmH2O
- PEEP: 10-15 cmH2O (titrated based on oxygenation response)
- Target SpO2: 88-95% with FiO2 ≤60% if possible
Additional Considerations
- Consider prone positioning for 16+ hours if PaO2/FiO2 ratio is <150 mmHg despite optimal ventilation, as recommended by 1
- If refractory hypoxemia persists, neuromuscular blockade with cisatracurium (37.5 mg/hr after 15 mg loading dose) for 48 hours may help, as suggested by 1
- For severe cases with persistent hypoxemia, consider ECMO evaluation, as recommended by 1
Monitoring and Adjustments
- Reassess for pneumothorax, mucus plugging, or ventilator dyssynchrony
- Adjust sedation as needed with propofol (25-75 mcg/kg/min) or midazolam (1-4 mg/hr) plus fentanyl (25-100 mcg/hr) to improve patient-ventilator synchrony while monitoring hemodynamics closely, as suggested by 1 and 1
From the Research
Optimal Ventilator Settings for ARDS Patients
The optimal ventilator setting for a patient with acute respiratory distress syndrome (ARDS) who has deteriorated involves several key considerations:
- Lung-protective ventilator strategies are considered standard practice in the care of patients with ARDS 2
- The lowest possible plateau pressure and tidal volume (V(T)) should be selected, with a reasonable target V(T) of 6 mL/kg 2
- Positive end-expiratory pressure (PEEP) should be set to maximize alveolar recruitment while avoiding overdistention 2, 3, 4
PEEP Settings
- Results of a meta-analysis suggest that higher PEEP should be used for moderate and severe ARDS, whereas lower PEEP may be more appropriate in patients with mild ARDS 2
- A study found that clinical outcomes are similar whether lower or higher PEEP levels are used in patients with acute lung injury and ARDS who receive mechanical ventilation with a tidal-volume goal of 6 ml per kilogram of predicted body weight and an end-inspiratory plateau-pressure limit of 30 cm of water 3
- Another study found that a ventilatory strategy based on PEEP above the lower inflection point of the pressure volume curve of the respiratory system (Pflex) set on day 1 with a low tidal volume resulted in improved outcome in patients with severe and persistent ARDS 5
Tidal Volume and Plateau Pressure
- The lowest possible tidal volume and plateau pressure should be selected to minimize ventilator-induced lung injury 2
- A tidal volume of 6 mL/kg is considered a reasonable target 2
- The end-inspiratory plateau-pressure limit should be set at 30 cm of water 3
Fraction of Inspired Oxygen (Fio2)
- Fio2 and PEEP are typically titrated to maintain arterial oxygen saturation (Spo2) of 88 to 95% (Pao2 55-80 mm Hg) 2