Overnight home oximetry: can it identify patients with obstructive sleep apnea–hypopnea who have minimal daytime sleepiness?

Abstract

Background: Overnight home oximetry is being widely used as a case selection technique for patients with suspected obstructive sleep apnea–hypopnea (OSAH). In the absence of excessive daytime sleepiness (EDS), patients with snoring and/or witnessed apnea are considered to have low probability of OSAH. Methods: Patients suspected to have OSAH, who denied EDS, and had a normal overnight home oximetry were studied by polysomnography for presence of significant OSAH (apnea/hypopnea index (AHI) >15/h). Results: Twelve (40%) of the 30 patients studied had significant OSAH. All had a 2% oxygen desaturation index of less than 10/h. The sensitivity of oximetry increased at lower desaturation indices but this was associated with decreased specificity. Review of oximetry waveform pattern, by experienced physicians, did not improve the diagnostic accuracy. Combining oximetry with a clinical prediction rule would have reduced the need for polysomnography by 30%. Conclusion: Many patients, who present with snoring and/or witnessed apnea and are referred to a sleep disorder clinic for suspected OSAH, may have significant OSAH even if they deny EDS. Overnight home oximetry did not help discriminate between those patients with or without OSAH.