Long-term effects nasal continuous positive airway pressure on daytime sleepiness, mood and traffic accidents in patients with obstructive sleep apnoea

To describe the long-term effects of nasal continuous positive airway pressure (CPAP) on the rate of traffic car accidents, excessive daytime sleepiness (EDS) and mood in patients with obstructive sleep apnoea syndrome (OSAS), we investigated the changes of these parameters before and after nasal CPAP treatment using a questionnaire. Seventy-five male patients who were diagnosed with severe OSAS by polysomnography were evaluated for driving competence, by looking at their driving history for 2 yr, for EDS by the Epwarth Sleepiness Scale (ESS) and for mood by the Self-related Depression Scale (SDS), and then underwent nasal CPAP treatment. After 2 yr of treatment, questionnaires inquiring about the patients' use of CPAP, their ESS, SDS and driving history during treatment were sent to the patients. A total of 47 patients (63%) responded to these questionnaires. Forty-six of the 47 responders had continued to use the nasal CPAP and completed the questionnaire. No traffic car accidents were observed among the 39 routine car users during treatment, while 13 of 39 patients (33%) had had car accidents before treatment. Although near-miss accidents had been reported by 32 of 39 patients (82%) before treatment, only four patients reported near-miss accidents during nasal CPAP treatment. The mean score of ESS was significantly (P<0.01) reduced in 46 patients after nasal CPAP. The mean score of SDS was also decreased (P<0.01) after nasal CPAP in 46 patients. Although 26 of 41 patients had been depressive on SDS before treatment, the mood was improved in 13 patients after nasal CPAP. These results suggest that long-term nasal CPAP treatment reduces the rate of traffic car accidents and improves the EDS and the mood in patients with OSAS.