Predictive factors for the need for additional humidification during nasal continuous positive airway pressure...

To identify potential risk factors for the need for an additional cold or heated humidifier in nasal continuous positive airway pressure (nCPAP) circuitry.

A prospective cohort study.

University hospital sleep-disorders center.

Eighty-two consecutive patients with obstructive sleep apnea syndrome were followed up for a median of 347 days (range, 3 to 530 days) after the initiation of nCPAP therapy.

In 46 patients (56%), the occurrence of upper-airway symptoms led to the addition of a cold humidifier after a median time of 39 days (range, 2 to 94 days). In 23 of the 46 patients, the persistence of the symptoms indicated the secondary use of a heated humidifier after a median time of 28 days (range, 5 to 70 days). nCPAP use (mean +/- SD) was not influenced by cold humidification (4.58 +/- 2.05 h/d vs 4.7 +/- 2.48 h/d; p = 0.75), but it increased significantly with heated humidification (5.38 +/- 2.26 h/d vs 3.51 +/- 2.53 h/d; p < 0.01). Anthropometric characteristics, drying medications, clinical findings such as deformity of the nasal septum, symptoms of a chronic mucosa disease (CMD), a previous uvulopalatopharyngoplasty (UPPP), and polysomnographic parameters had no significant effect on the need for a cold humidifier. Age > 60 years (odds ratio [OR], 5.58; 95% confidence interval [CI], 1.69 to 18.43), drying medications (OR, 6.59; 95% CI, 1.29 to 33.51), presence of CMD (OR, 4.11; 95% CI, 1.24 to 13.58), and previous UPPP (OR, 4.56; 95% CI, 1.18 to 17.6) were found as significant risk factors for the addition of a heated humidifier.

Our results demonstrate that heated humidification significantly improves the nCPAP daily rate of use and that its need may be predicted.