NASAL CPAP IN SLEEP-APNEA - PATIENT PROFI LE, COMPLIANCE AND INFLUENCE ON GAS-EXCHANGE AND PULMONARY-FUNCTION

A survey performed in 100 CPAP users indicated that irritation of the face, a painful nose and nasal obstruction were among the most frequen tly mentionned complaints in chronic CPAP users. In 132 normocapnic SA S patients a significant improvement of PaO2 was shown, with a decreas e of the alveolo-arterial oxygen difference. This improved gas exchang e was parallelled by a significant increase in the FRC and TLC. Maybe a modulation in force of the respiratory muscles may be involved. Thes e data were more pronounced in obstructive sleep apnea than in central sleep apnea. In 50 chronic CPAP users we could show a lower AHI immed iately after CPAP withdrawal after a previous prolonged treatment. The se findings may support the insufflation theory as a mechanism of acti on of CPAP. Traditionnally, mechanical splinting of the upper airway h as been considered as the dominant mechanism of action. Other mechanis ms like changes in regulation of breathing and decrease of the pharyng eal edema may be involved as well.