A face mask (10) for a patient undergoing a sedated endoscopic procedure. The face mask (10) includes means (16, 17) to provide positive airway pressure to the nose, a bite block (18) with an opening therein (20) and a one-way valve (22). The one-way valve (22) has an open position, adapted to allow passage of an endoscopic device therethrough and into the opening (20), and a closed position substantially sealing the opening (20).