This study aimed to assess the short-term respiratory effects of a new portable device that delivers a continuous positive airway pressure via a face mask (Boussignac-CPAP) in patients with severe acute cardiogenic pulmonary oedema, and the feasibility of using this technique in an emergency department. We prospectively studied 30 consecutive patients with acute cardiogenic pulmonary oedema. They were randomly assigned either to the Boussignac-CPAP valve, which delivered oxygen, or to standard oxygen delivery for a duration of 30 min. The end-expiratory pressure reached 9.3+/-0.3 cm H2O with the Boussignac-CPAP valve. At the end of the 30 min period, the decreases in respiratory rate and muscular activity were significantly greater among patients assigned to the Boussignac-CPAP valve compared with those on standard oxygen delivery [24+/-1.6 breaths/min, median 24 (15-37) versus 28.5+/-1.9, median 27 (16-38) and 1.3+/-0.2, median 1 (0-4) versus 2.7+/-0.3, median 2 (0-4), respectively]. Moreover, the arterial oxygen tension to inspired oxygen concentration ratio and tidal volume were improved at the end of the 30 min Boussignac-CPAP period compared with baseline. Boussignac-CPAP was easily implemented and no side-effects were reported. Continuous positive pressure delivered using the Boussignac-CPAP device is feasible in an emergency care setting. It can quickly improve respiratory distress in acute cardiogenic pulmonary oedema patients. A larger trial should be initiated in such an emergency care setting to demonstrate the effectiveness of the Boussignac-CPAP device.