Content area
Full Text
Accuracy of Respiratory Inductive Plethysmography for the Diagnosis of Upper Airway Resistance Syndrome*
Objective: To determine the sensitivity and specificity of quantitative respiratory inductive plethysmography (RIP) compared with the "gold standard," nocturnal esophageal pressure (Pes) measurement, in the diagnosis of upper airway resistance syndrome (UARS) in adults.
Methods: Fourteen consecutive patients without obstructive sleep apnea and suspected of having UARS underwent simultaneous measurement of Pes with a catheter and standard nocturnal polysomnography along with RIP. UARS events (RERAs, respiratory effort-related arousals) were identified by observing crescendo changes in Pes with a Pes nadir <= -12 cm H2O, followed by an arousal or microarousal. UARS was defined as >= 10 RERAs per hour. For each patient, the ratio of peak inspiratory flow to mean inspiratory flow (PIFMF) measured by RIP was performed during quiet wakefulness and with 40 randomly selected breaths in the supine position for two
conditions: stage 2 sleep, immediately prior to arousals in any sleep stage. The mean PIFMF (wake-sleep) was calculated for each condition.
Results: The sensitivities and specificities, respectively, of RIP to distinguish UARS patients from non-UARS patients are from stage 2 sleep (67%, 80%), immediately prior to arousals (100%, 100%). For breaths occurring immediately prior to arousals, the mean PIFMF (wake-sleep) is >= 0.13 for UARS patients and < 0.13 for non-UARS patients.
Conclusion: The PIFMF measured by RIP allows for the most accurate identification of UARS patients when breaths are selected for analysis immediately prior to arousals.
Key words: obstructive sleep apnea; polysomnography; respiratory inductive plethysmography; upper airway resistance syndrome
Abbreviations: AHI = apnea-hypopnea index; BMI = body mass index; NPSG = nocturnal polysomnography; OSA = obstructive sleep apnea; Pes = esophageal pressure; PIFMF = peak inspiratory flow to mean flow ratio; RERA = respiratory effort-related arousal; RIP = respiratory inductive plethysmography; UARS = upper airway resistance syndrome
Upper airway resistance syndrome (UARS) patients present with complaints of excessive daytime sleepiness and do not have obstructive sleep apnea (OSA) on evaluation by standard nocturnal polysomnography (NPSG).1 The diagnosis of UARS is made when nocturnal esophageal pressure (Pes) monitoring demonstrates crescendo changes in intrathoracic pressures followed by frequent arousals or microarousals.2 Alternative methods to Pes monitoring that have been studied for use in the diagnosis of UARS include semiquantitative...