Fig. 2.

Fig. 2 shows five photographs, the left hand shows a patient with a nasal mask (Dreamwear, Phillips Respironics, Murrysville, PA, USA). The second left photograph shows the patient using a nasal mask (AirFit N30i ResMed, San Diego, CA, USA) The centre photograph shows the patient using a nasal pillows interface (Swift Lt, ResMed, San Diego, CA, USA). The two right hand photographs show the same patient using mouthpiece ventilation with a mouthpiece (left) and straw (right) (Phillips Respironics, Murrysville, PA, USA).