An improved Bussignac device for the delivery of noninvasive continuous positive airway pressure: the SUPER-Bussignac

Introduction

The purpose of this work was to test, in a bench study, the performance of a modified Boussignac continuous positive airway pressure (CPAP) system, aimed at avoiding the drop in inspired oxygen fraction (FiO₂) during high inspiratory patient peak flows.

Methods

We modified a Boussignac system (Bssc), inserting between the valve and the face mask a T-piece, connected with a 1.5 l reservoir balloon, supplemented with oxygen independently from the valve itself. During inspiration, the patient inhales oxygen from the reservoir, diminishing the blending with atmospheric air and keeping the FiO₂ higher. The performance of the system was evaluated in a bench study, applying a CPAP face mask to a plexiglass cylinder connected with an active lung simulator (ASL 5000; IngMar Medical, USA) generating tidal volumes with increasing inspiratory peak flow rates (V'_insp). Two positive end-expiratory pressure (PEEP) levels were tested for the Bssc, SUPER-Boussignac with 10 l/min (SB10) and 30 l/min (SB30) supplementary oxygen flows. The FiO₂ was continuously recorded and the lowest value reached during each tidal volume (FiO₂) was averaged over 20 breaths.

Results

With all systems the FiO₂ increased with increasing PEEP levels and decreased at higher V'_insp. SB10 and, to a greater extent, SB30 allowed one to reach greater FiO₂ values, and decreased the drop in FiO₂ due to increasing V'_insp. See Tables 1 and 2.

Table 1 FiO₂ values at PEEP 7 cmH₂O

Table 2 FiO₂ values at PEEP 13 cmH₂O

Conclusion

The SUPER-Boussignac is simple and effective in increasing (up to 30%) the FiO₂, and limiting the drop related to V'_insp during noninvasive CPAP.