Effects of left-to-right ratio of nasal resistance in rinomanometry and subjective nasal obstruction on continuous positive airway pressure (CPAP) therapy adherence

Abstract

In obstructive sleep apnea syndrome (OSAS), continuous positive airway pressure (CPAP) therapy is a symptomatic therapy and requires good adherence. Nasal obstruction is one of the causes of difficulty in continuing treatment. Rhinomanometry can be used to objectively assess nasal resistance, which has also been used for the diagnosis of OSAS, but there are only a few reports of its usefulness in improving thrapy adherence. Therefore, this study was conducted to evaluate the relationship between the left-to-right ratio of nasal resistance in rhinomanometry and CPAP therapy adherence in 105 patients who were treated at our hospital. Although bilateral nasal resistance was not associated with subjective nasal obstruction and CPAP therapy adherence, the left-to-right ratio of nasal resistance with subjective nasal obstruction was significantly higher than without (p < 0.01). On the basis of the ROC curve, the optimal cut-off value of the left-to-right ratio of nasal resistance indicating subjective nasal obstruction was 1.88, discontinuation of CPAP therapy was 3.37. CPAP therapy adherence was significantly lower in patients with a left-to-right ratio ≥ 3.37 (p < 0.05). Furthermore, there was a significant tendency to drop out of the therapy (p < 0.05).The subjective nasal obstruction and the left-to-right ratio of nasal resistance may be useful for determining adherence of patients to CPAP therapy.