Effect of continuous positive airway pressure therapy on infectious complications in patients with obstructive sleep apnea syndrome

Background: Nasal continuous positive airway pressure (CPAP) is a well-established, widely used and effective treatment of obstructive sleep apnea syndrome (OSAS). Unfortunately, side effects are frequent during CPAP treatment.

Objectives: Little is known about the effects of CPAP on infectious complications in patients with OSAS.

Methods: We retrospectively analyzed the kinds and rate of infections of the upper airway in 246 consecutive patients (mean age, 59.7 years) with polysomnographically verified OSAS using CPAP with or without a heated humidifier and compared them with OSAS patients who received non-CPAP therapy.

Results: Of the 246 patients, 40 received conservative therapy and 206 CPAP treatment, 36 of them with a heated humidifier. The mean follow-up period of the study group was 165.4 +/- 92.1 weeks and did not differ between the three groups. Infectious diseases were frequent in all three groups, but patients using CPAP without humidifier suffered from upper airway infections significantly more frequently than controls (42.9 vs. 25%; p < 0.05), and more patients on CPAP therapy with humidifier than controls (22.2 vs. 2.5%; p < 0.01) reported an increased rate of upper airway infections since initiation of CPAP therapy or diagnosis of OSAS. Especially patients using a hot water bath humidifier who cleaned their devices inadequately had significantly more upper airway infections since diagnosis (57.1 vs. 20%; p < 0.05) or during the past 6 months (52.4 vs. 13.3%; p < 0.05) than patients who regularly cleaned CPAP machines, humidifiers and ventilatory circuits.

Conclusions: Our results suggest that patients using CPAP therapy either with or without heated humidity seem to be at an increased risk of upper airway infections compared to conservatively treated patients.