Study Reference

Phoophiboon V, Rodrigues A, Vieira F, et al. Ventilation distribution during spontaneous breathing trials predicts liberation from mechanical ventilation: the VISION study. Crit Care 2025;29(1):11.

Brief Summary for Clinicians

What This Study Found

This study from Toronto used Electrical Impedance Tomography (EIT) to monitor 98 mechanically ventilated patients during spontaneous breathing trials (SBTs). The researchers measured how evenly ventilation was distributed between the front (ventral) and back (dorsal) regions of the lungs to predict successful liberation from mechanical ventilation.

Key Findings

The “Goldilocks Zone” for ventilation distribution: Patients had better outcomes when ventilation was evenly distributed between front and back lung regions:

• Successful liberation: Absolute ventral-to-dorsal difference <20%
• Liberation failure: Absolute ventral-to-dorsal difference >20%

Early prediction capability: This difference could be detected as early as 5 minutes into the SBT and remained consistent throughout the trial.

Clinical outcomes measured:

• Liberation success: 40/98 patients (41%) – passed SBT + successfully extubated same/next day + no reintubation for 7 days
• Liberation failure: 58/98 patients (59%) – including rescue therapy, reintubation, tracheostomy, or delayed extubation

Validation results: Using a 20% cutoff in the validation cohort showed:

• Sensitivity: 71%
• Specificity: 78%
• Positive predictive value: 81%

Clinical Implications

1. EIT may provide additional prognostic information beyond traditional weaning parameters (RSBI, P0.1, ΔPocc) which showed no significant differences between groups
2. Real-time bedside assessment: The ventral-to-dorsal difference can be viewed directly on the EIT screen during SBTs, requiring no complex offline analysis
3. Early risk identification: Clinicians may be able to identify patients at risk for liberation failure within the first few minutes of an SBT
4. Complementary tool: This measurement appeared to work regardless of neurological vs. respiratory causes of respiratory failure
5. Simple parameter: Unlike complex EIT measurements, this is a straightforward percentage that can be easily interpreted

Important limitations: This was an observational study from a single center with a high proportion of neurological patients (49%). EIT technology is not yet widely available, and the findings need validation in larger, multicenter studies before clinical implementation can be recommended.

The research suggests that monitoring ventilation distribution patterns during SBTs may help optimize timing of extubation decisions, though causation cannot be established from this observational data.

Reference

Phoophiboon V, Rodrigues A, Vieira F, et al. Ventilation distribution during spontaneous breathing trials predicts liberation from mechanical ventilation: the VISION study. Crit Care 2025;29(1):11.