Respiratory assist device for spontaneously ventilating patients. This device allows to maintain a higher pressure in the airways than atmospheric pressure throughout the respiratory cycle. The CPAP ventilation mode allows: – Recruit collapsed alveoli; – Restore a satisfactory level of functional residual capacity; – Improve the exchange of gases at the level of the capillary alveolus membrane – Decrease pulmonary resistance; – Reduce the effort to breathe; – Redistribute the alveolar fluid to the interstitial space in case of acute pulmonary edema The Boussignac CPAP device and its connector for manometer constitute a device that is connects to a face mask via a 22mm male connector, ribbed top open to air