Respiration monitorring of sleep apnea syndrome using a pressure sensor bed

Abstract

Monitoring of respiration under unrestrained and noninvasive conditions is indispensable to determine natural respiration during sleep.A pressure sensor bed capable of detecting a decrease in electric resistance with compression was prepared (Denso Corp.) and used to observe respiration during sleep.
Subjects included four healthy adult volunteers (two males and two females, 25 to 31 years old) and 13 subjects with chief complaints of sleep apnea or snoring at night (8 males and 5 females, 25 to 62 years old and an average BMI 26.3). Apnea, blood oxygen saturation and movement of thoracoabdominal wall with respiration were monitored with the Microsleep.Respiration waveform during nightlong sleep was monitored by using the pressure sensor bed. Respiration during sleep was investigated comparatively by using the bed and the Microsleep.
Healthy subjects with normal respiration showed a regular respiratory waveform with the Microsleep and normal oxygen saturation and regular respiration with constant amplitude in respiration waveform. with the pressure sensor. Subjects who complained of snoring recorded constant amplitude and regular respiratory waveform with the Microsleep and the pressure sensor regardless of the sound of snoring as well as subjects with normal respiration. Subjects diagnosed as having a obstructive apnea recorded similar periodic respiration waveforms (Cheyne-Stokes-like breathing waveform) with that of apnea both with the Microsleep and the pressure sensor. These waveforms were observed in all eight cases diagnosed with obstructive apnea.
A correlation was obtained between Cheyne-Stokes-like respiration waveforms, apnea index (AI) and oxygen desaturation 4% index (ODI4) in the measured results with the Microsleep in an hour. Sleep apnea could be detected by using a thoracoabdominal spirogram during sleep.