Introduction It has been hypothesized that increasing the interstitial hydrostatic pressure within the sinonasal mucosa of patients with nasal polyposis (NP) might decrease the size of nasal polyps.

Objective To evaluate the effects of positive airway pressure, delivered by a continuous positive airway pressure (CPAP) device, in patients with NP and in control subjects.

Methods Twelve patients with NP and 27 healthy subjects were exposed to CPAP (20 cm H2O) for 2 hours. Visual analog scale (VAS), Nasal Obstruction Symptom Evaluation (NOSE) scale, acoustic rhinometry (AR), peak nasal inspiratory flow (PNIF) and nasal endoscopy (NE-Meltzer polyp grading system) were performed before and after the intervention, for all patients.

Results The control group showed a significant worsening in nasal obstruction symptoms, as measured by VAS and NOSE (p < 0.01), and a significant decrease in nasal patency, as measured by the PNIF and AR (p < 0.01). For the NP group, VAS, NOSE, and AR did not differ significantly (p = 0.72, p = 0.73, and p = 0.17, respectively), but PNIF values worsened (p = 0.04) after exposure to CPAP. There was a statistically significant reduction in the nasal polyps' size (p = 0.04).

Conclusions Positive pressure worsened the nasal obstruction symptoms and decreased objective parameters of nasal patency in control subjects. In patients with NP, exposure to CPAP reduced the nasal polyps' size, and the nasal patency, as measured by PNIF. However, it had no significant effects in AR and in nasal obstruction symptoms.