Abstract

Background: A portable monitor for the automated analysis of episodic nocturnal oxygen saturation or Spo₂ (the Remmers Sleep Recorder, RSR) has been proposed for the diagnosis of obstructive sleep apnoea-hypopnoea (OSAH). A study was undertaken to compare the diagnostic performance of automated analysis with the manual scoring of polygraphic data by a more comprehensive respiratory monitor (the Suzanne recorder) used simultaneously in their intended home environment.

Methods: The respiratory disturbance indexes of the two monitors were compared in 94 consecutive adult patients suspected of having OSAH and who were deemed eligible for home-based investigation.

Results: The RSR overestimated the number of respiratory events associated with a ⩾4% fall in Spo₂ by 13% (p<0.005) but underestimated the number of apnoeas and hypopnoeas defined on the basis of respiratory variables alone or their association with a ⩾4% fall in Spo₂ or autonomic arousals by 38–48% (p<0.0001). In addition to these significant biases, the limits of agreement in all instances were wide, indicating a poor concurrence between the two monitors.

Conclusion: The automated analysis of Spo₂ with the RSR cannot be substituted for the manual scoring of polygraphic data with the more comprehensive respiratory monitor in the diagnosis of OSAH in an ambulatory home-based setting.