Comparison of respiratory polysomnographic parameters in matched cohorts of upper airway resistance and obstructive sleep apnea syndrome patients

Objective: To compare respiratory nocturnal polysomnography (NPSG) characteristics between matched cohorts of upper airway resistance syndrome (UARS) and obstructive sleep apnea syndrome (OSAS) patients, Methods: All patients received 13-channel NPSG, including esophageal pressure (Pes) manometry. By definition, OSAS patients had an apnea-hypopnea index (AHI, number of apneas/ hypopneas per hour total sleep time) greater than or equal to 15, and UARS patients had an AHI < 5, Respiratory effort-related arousal (RERA) was defined as the absence of apnea/hypopnea with greater than or equal to 10 s duration of progressive negative Pes, culminating in an arousal or microarousal. UARS patients, by definition, had greater than or equal to 15 RERAs per hour. Fifteen consecutively diagnosed UARS patients were matched with OSAS patients on the basis of bod, mass index (BMI) and gender. Results: Respiratory disturbance index (sum of the AHI and RERA per hour) was the same for both cohorts: UARS, 36 +/- 4; OSAS, 42 +/- 6 (p = 0.34). There were no differences between cohorts for mean inspiratory Pes nadirs for each 30-s epoch of sleep compared for each sleep stage ol er an entire night. For randomly selected breaths from supine stage 2 sleep, the mean inspiratory Pes nadir was the same for the cohorts: UARS, -16.6 +/- 2 cm H2O; OSAS, -16.1 +/- 3 cm H2O (p = 0.30), Differences between cohorts for each parameter fell within respective 95% confidence intervals. Conclusion: With the exception of AHI, respiratory NPSG parameters were the same for UARS and OSAS patients when BMI and gender were controlled for.