A new nasal oxygen mask

Recent interest in the benefits of long-term oxygen therapy for patients with chronic airflow obstruction and hypoxaemia should lead to an increased use of nasal prongs for prolonged (15 hours/day) oxygen administration. Because some patients find nasal prongs uncomfortable and since they may slip out of position during use, we have devised a new nasal oxygen mask and compared both its performance and comfort with conventional nasal prongs. Changes in end-tidal oxygen concentration were measured after administering oxygen at 2 litres/min through each device for 10 minutes in 15 normal subjects and for 1 hour in patients with chronic airflow obstruction and hypoxaemia. Although the prongs produced larger increases in end-tidal oxygen concentration in normal subjects, there were no significant differences between the two devices in the patients. There was also no difference in the improvement in arteriolized capillary oxygen tensions (mask 3.5 kPa; prongs 4.0 kPa). In a separate study of prolonged (22 hours) use there was no difference in reported comfort. The new mask is a useful alternative to conventional nasal prongs.