Airway microbial compartmentalization under mechanical ventilation: a randomized pilot study comparing an endotracheal tube with suction and continuous cuff pressure control (Venner PneuX®) to standard intubation.

Abstract

Objectives: Ventilator-associated pneumonia (VAP) is driven in part by microaspiration along the endotracheal tube cuff, a process difficult to measure directly in ventilated patients. Because microbial communities differ between airway compartments, changes in their similarity over time may serve as an indirect readout of microaspiration. We assessed whether the Venner PneuX^® Tube (VT) system, combining cuff-pressure monitoring, subglottic suction, and a biofilm-resistant coating, reduces microbial exchange between airway compartments compared with a standard endotracheal tube (ST).

Methods: In a prospective, randomized, single-center pilot study, 50 adults with acute respiratory failure received an ST or VT intubation. Microbial communities from five airway niches (throat, tracheal secretions, right upper, right lower, and left lower lung lobes) were sampled by 16 S rRNA sequencing at intubation (T1), after four days of ventilation (T2) and, for the tube tip, at extubation (T3). The primary outcome was the change in beta diversity (Morisita-Horn distances) between tube-associated, upper-airway, and lower-airway communities from T1 to T2.

Results: Twenty-one of 50 randomized patients had complete microbiota data sets (9 ST, 12 VT) and were comparable in demographics, comorbidities, severity, and ventilation duration. In the ST group, tube-associated communities became more similar to tracheal and lower-airway communities from T1 to T2 (e.g. TS-Tube Morisita-Horn 0.55 → 0.30, p = 0.001), while lung regions diverged from each other and from the throat (LLL-LRL 0.08 → 0.31, p = 0.003; LLL-Throat 0.30 → 0.61, p < 0.001). None of these distances changed significantly in the VT group. Lower-airway Shannon diversity declined in both groups, more in the VT group.

Conclusions: Standard intubation produced progressive microbial convergence between airway compartments, while the VT system did not. The findings provide biological plausibility for previously reported VAP reductions with the VT system and show that microbiota sampling can detect device-related differences in airway community structure, warranting further investigation as an endpoint for evaluating airway devices.

Trial registration: The study is registered in the German Clinical Trials Register (DRKS- Deutsches Register für klinische Studien) under the clinical trial number: DRKS00029176. The Date of Trial Registration was 07.07.2022.