Ventilator settings for fiberoptic bronchoscopy during mechanical ventilation: a randomized adjudicator-blinded...

During bronchoscopy in mechanically ventilated patients, bronchoscope insertion markedly increases airway resistance, elevating peak airway pressure and reducing delivered tidal volume. We sought to determine whether specific ventilator settings (assist volume-controlled with reduced inspiratory flow and tidal volume) lower serious adverse events during flexible fiberoptic bronchoscopy compared with conventional ventilator settings.

Single-center randomized adjudicator-blinded controlled trial in intubated adult patients undergoing fiberoptic bronchoscopy. Patients were assigned (1:1) to bronchoscopy-optimized settings (inspiratory flow ≤ 25L/min, tidal volume = 5mL/Kg, 1s ≤ inspiratory time ≤ 1.3s, respiratory frequency = 16 breaths/min, positive end-expiratory pressure = 5cmH₂O) or to conventional ventilator settings. The primary endpoint was a composite of serious adverse events requiring premature termination (inability to deliver ventilatory support, significant arterial desaturation, or hemodynamic instability), adjudicated by blinded experts. All analyses were performed on an intention-to-treat basis.

The primary composite endpoint occurred in 1/23 (4%) with optimized settings compared with 22/23 (96%) with conventional settings (risk difference -91.3%; risk ratio 0.05; p < 0.001). Events were driven by ventilatory failure due to pressure-alarm limitation, with lower delivered tidal volume (median 160 vs 400 mL; p < 0.001) and minute ventilation (3.2 vs 7.2 L/min; p < 0.001) under conventional settings. Respiratory and circulatory events were rare and similar between groups (each 1/23 [4%]). Among 19 crossover patients, switching to optimized settings reduced peak airway pressure and restored adequate ventilation.

A bronchoscopy-optimized ventilation strategy substantially reduces pressure-alarm-limited ventilation events and enables the delivery of adequate ventilatory support during fiberoptic bronchoscopy.