Bench evaluation of commercially available and newly developed interfaces for mouthpiece ventilation

Mouthpiece ventilation represents a valuable treatment for patients needing daytime non-invasive ventilation. This modality is however underused, in part because of limitations in the available equipment.

To develop a new flexible and moldable mouthpiece, aiming to address some of the issues of the currently available interfaces.

We compared two commercially available and the newly developed mouthpieces in a bench test using four life-support home ventilators and three settings per ventilator.

The three interfaces showed marked differences in their resistive characteristics. In the volume-controlled setting (VC-CMV) with 500 mL tidal volume (V_T ), the delivered V_T , ranged between 459 ± 7 mL (-8%) and 501 ± 4 mL (+0.2%), according to the used ventilator. In the VC-CMV setting with V_T 1000 mL, one of the ventilators did not assure the set V_T with the new mouthpiece, because of the high-pressure limitation. In the pressure-controlled setting (PC-CMV at 20 cmH₂ O), the effective pressure differed between the tested interfaces according to their resistance, resulting in a decrease in the delivered V_T .

They found measurable differences in the ventilation's performances comparing the interfaces for mouthpiece ventilation, which seem to have a minor clinical relevance in the most settings, but should be systematically checked. They validated in-vitro the newly developed mouthpiece with respect to the ventilation performances; a clinical study is needed to investigate the potential advantages we expect from the new mouthpiece.