What are the interventions used in the PReVENT (Prevention) trial?

The PREVENT Trial: Interventions and Strategies

The PREVENT trial compared two different tidal volume ventilation strategies in patients without ARDS: 6 mL/kg predicted body weight versus 10 mL/kg predicted body weight, both with goal plateau pressures <25 cm H2O. 1

Key Interventions in the PREVENT Trial

The PREVENT (PREVENTion) trial was a clinical trial focused on mechanical ventilation strategies for critically ill patients without Acute Respiratory Distress Syndrome (ARDS). The trial specifically evaluated:

1. Low tidal volume strategy:

   • 6 mL/kg predicted body weight (PBW)
   • Goal plateau pressure <25 cm H2O

2. Conventional tidal volume strategy:

   • 10 mL/kg predicted body weight (PBW)
   • Goal plateau pressure <25 cm H2O

Clinical Context and Significance

The PREVENT trial addressed an important clinical question about optimal ventilation strategies for non-ARDS patients. This is particularly relevant because:

• Most ventilation research has focused on ARDS patients, where low tidal volume strategies (6 mL/kg PBW) with plateau pressures <30 cm H2O have shown mortality benefits 1
• There was uncertainty whether non-ARDS patients would benefit from the same low tidal volume approach
• The trial results showed no significant difference in outcomes between the two ventilation strategies for non-ARDS patients 1

Application to Patients with Cirrhosis and ACLF

For patients with cirrhosis and acute-on-chronic liver failure (ACLF) requiring mechanical ventilation:

• Recommendations are derived from general critical care literature due to limited specific data for this population 1
• Lung protective ventilation with low plateau pressures is advocated to prevent ventilator-induced lung injury
• Spontaneous breathing should be encouraged when possible 1

Important Considerations for Ventilation in Cirrhosis

When applying ventilation strategies to patients with cirrhosis:

• Hemodynamic effects: Lower tidal volume strategies may have beneficial effects on hemodynamic status by minimizing negative effects of positive pressure ventilation on preload in patients with systemic vasodilation 1
• PEEP strategy: For mild ARDS (PaO2/FiO2 200-300 mm Hg), a low PEEP strategy (<10 cm H2O) should be considered to avoid impeding venous return and cardiac preload 1
• Monitoring: Close monitoring is essential as high PEEP can induce or exacerbate hypotension in patients with baseline vasodilated state 1

Common Pitfalls to Avoid

1. Delayed intubation: When using non-invasive ventilation methods like high-flow nasal cannula (HFNC), closely monitor respiratory status to avoid delaying necessary intubation 1

2. Inappropriate PEEP levels: High PEEP strategies can worsen hemodynamics in cirrhosis patients who already have systemic vasodilation 1

3. Overlooking coexisting pulmonary comorbidities: Investigate and treat conditions like hydrothorax, ascites, and hepatopulmonary syndrome in patients with cirrhosis and respiratory failure 1

The PREVENT trial provides important evidence that informs ventilation strategies for critically ill patients, highlighting that a one-size-fits-all approach to tidal volumes may not be necessary for all mechanically ventilated patients without ARDS.