Nasal resistance for determinant factor of nasal surgery in CPAP failure patients with obstructive sleep apnea syndrome.

Objectives: Given that criteria for nasal surgery in individuals with obstructive sleep apnea syndrome (OSAS) have not been proposed, we investigated the effectiveness of nasal surgery for CPAP failure in patients with both severe OSAS and nasal obstruction.

Patients And Methods: Conventional nasal surgery was performed in 12 patients who were refractory to treatment by CPAP. The subject group consisted of 12 males (mean age, 54.2 +/- 9.2 years; range 39-66 years). The effect of nasal surgery was evaluated with data from preoperative and postoperative polysomunography. The nasal resistance value was first deduced to determine which OSAS patients with CPAP failure should undergo nasal surgery, compared to control values.

Results: Nasal surgery resulted in a significant decrease in nasal resistance, as measured by rhinomanometry, from 0.57 +/- 0.31 Pa/cm3 /sec to 0.16 +/- 0.03 Pa/cm3/sec and rendered all patients tolerant to CPAP. In addition, the lowest nocturnal oxygen saturation significantly increased from 68.3 +/- 12.1% to 75.3 +/- 7.1% after surgery. Subjectively, Epworth sleepiness scale (ESS) significantly decreased from 11.7 +/- 4.1 to 3.3 +/- 1.3 after surgery, but the number of apnea and hypopnea episodes per hour did not change significantly. In five patients, for whom it was possible to perform a CPAP titration before nasal surgery, the value decreased significantly from 16.8 +/- 1.1 to 12.0 +/- 1.9 cmH2O. The bilateral nasal resistance of the 410SAS patients with CPAP therapy (control group) was 0.24 +/- 0.11 Pa/cm3/sec. The cut off value for differentiation between CPAP failure patients and control group was determined as 0.38 Pa/cm3 /sec.

Conclusion: Increased nasal resistance is a determinant of CPAP failure, and the surgical correction of severe nasal obstruction should thus be considered to facilitate treatment of OSAS patients with CPAP.