An improved Boussignac device for the delivery of non-invasive CPAP: the SUPER-Boussignac.

Abstract

The purpose of this study is to describe and test a modified Boussignac system for non-invasive continuous positive airway pressure, aimed at reducing the decrease in inspiratory oxygen fraction (FiO(2)) with higher inspiratory peak flow rates. We modified a Boussignac circuit by inserting a T-piece between the Boussignac valve and the face mask. The T-piece was connected to a reservoir balloon receiving oxygen by an independent source. The system was tested in a bench study, consisting of five steps, with increasing inspiratory peak flow rates (V(insp)) Three levels of PEEP were tested: 7, 10 and 13 cmH(2)O. The following devices were tested: Boussignac, Boussignac with reservoir but without supplementary oxygen, Boussignac with reservoir and 10 (SUPER-Boussignac(10)) and 30 l/min (SUPER-Boussignac(30)) of supplementary oxygen. In each step we measured FiO(2), tidal volumes, and airway pressure. FiO(2) increased with PEEP and decreased at increasing V(insp) with all the systems. However, FiO(2) increased with SUPER-Boussignac(10) (7-10%) and with SUPER-Boussignac(30) (10-30%). Moreover, in the latter case, for V(insp) values up to 60 l/min, FiO(2) became independent of V(insp). The SUPER-Boussignac allowed also smaller drop in airway pressure during inspiration and higher tidal volumes. The SUPER-Boussignac represents a simple way to significantly improve the performance of the Boussignac device.