Change in Nasal Continuous Positive Airway Pressure (NCPAP) requirement in obstructive sleep apnea syndrome

Purpose: Few studies have evaluated the need to re-titrate nCPAP after several months of successful treatment. The American Sleep Disorders Association recommends that follow-up polysomnography should not be routinely obtained in those whose symptoms continue to be resolved with nCPAP treatment. To our knowledge this recommendation is not based on published studies. The purpose of this study is to evaluate the change, if any, in the pressure requirement over time. Methods: Thirty patients with OSA who had a baseline nCPAP titration and who were deriving continued benefit from nCPAP treatment, were asked to return to the Sleep Laboratory for a repeat titration. The same nCPAP titration protocol was followed, using a Respironics® BiPAP system. The adequacy of the pressures attained at the baseline and repeat titrations were reviewed by the same two sleep specialists. The change in either the inspiratory pressure (IPAP) or the expiratory pressure (EPAP) were analyzed with the Student t test for paired data. Correlation with weight change and time interval of the repeat titration was done using Pearson's correlation coefficient. Results: n= 30 mean interval = 23 months (range 10 - 72) Baseline titration Repeat titration p Weight (kg) 104.7 106.5 0.15 BMI (kg m ^-2) 34.2 34.9 0.14 IPAP (cm H₂O) 13.5 13.8 0.34 EPAP (cm H₂O) 11.7 13.3 <0.001 The change in the pressure requirement, which ranged between 2 and 8 cm H₂O did not correlate with the change in weight (Pearson's r = -0.07; p = 0.72) nor with the interval between the initial and repeat titrations (Pearson's r = -0.31; p = 0.1). A change in pressure of ≥ 4 cm H₂O occurred in 8 patients (27%). Conclusions: In our group of 30 patients with OSA treated with nCPAP, a statistically significant increase in the pressure requirement is noted, after a mean of 23 months. Clinical Implications: We conclude that a repeat nCPAP titration may be routinely indicated at approximately 2 years, even in the absence of significant weight change. Further evaluation of the clinical benefit of this pressure adjustment is needed.