Significance of a screening device (Apnomonitor 5) for sleep apnea syndrome.

OBJECTIVES: The objective was to evaluate the significance of a portable sleep-monitoring device (Apnomonitor 5, Chest Co., Tokyo, Japan) to diagnose sleep apnea syndrome (SAS). METHODS: The Apnomonitor 5 comprised an oronasal thermistor, a pulse oximeter, chest and abdominal belts to monitor the circumferences of the chest and abdomen, a microphone to monitor tracheal sound, a position detector, and an integrative unit. This screening device was commercially available and it had been used to diagnose SAS in our country. Twenty-two consecutive adults who attended Inazawa City Hospital who were suspected for SAS were prospectively enrolled and they undertook the standard polysomnography (PSG) and Apnomonitor 5 simultaneously. The designated polysomnographers analyzed the records of the PSG and Apnomonitor 5. These sleep and respiratory parameters of the devices were compared, the results of which were double-checked by the designated sleep specialist. RESULTS: The apnea-hypopnea index (AHI), apnea index, total number of apnea, and oxygen desaturation index obtained by the PSG and Apnomonitor 5 correlated significantly, whereas the averaged sleep time, total number of hypopnea, hypopnea index, and nadir oxygen saturation differed between the devices. The sensitivity of the Apnomonitor 5 versus PSG was 95% in the SAS patients with the AHI> or =15. CONCLUSIONS: The Apnomonitor 5 can be a sensitive and useful screening device for SAS especially in patients with the AHI> or =15.

Assessment of continuous positive airway pressure treatment in obstructive sleep apnea syndrome using 24-hour urinary catecholamines.

BACKGROUND: Obstructive sleep apnea syndrome (OSAS) is related to diurnal sympathetic hyperactivity and increased blood pressure, both factors that are likely to lead to the development of cardiovascular disease. HYPOTHESIS: The study investigated whether 24-h urinary catecholamines would reflect the effect of obstructive sleep apnea on autonomic activity. METHODS: Standard polysomnography was performed in 17 patients with OSAS (age 53.7 +/- 13.5 years, mean +/- standard deviation). The number of apnea/hypopnea episodes per hour of sleep (apnea/hypopnea index [AHI]); number of oxygen desaturation episodes per hour (desaturation index [DSI]); arousals per hour (arousal index); lowest oxygen saturation (lowest SpO2); and percentages of stages 1, 2, 3/4, and rapid eye movement sleep (% stage 1, -2, and -3/4, and % REM, respectively) were measured. Overnight continuous positive airway pressure (CPAP) titration was performed the night after the baseline sleep measurements had been taken. Twenty-four-hour urinary adrenaline and noradrenaline were also examined. RESULTS: During the CPAP treatment, both 24-h urinary adrenaline and noradrenaline were significantly lower compared with natural sleep. Continuous positive airway pressure significantly decreased the AHI, DSI, % stage 1, and arousal index and significantly increased the lowest SpO2. There were no significant differences in % stage 2, % stage 3/4, and % REM between before and during CPAP treatment. Multiple analysis of covariance tests revealed that lowest SpO2 was the most important factor for increasing 24-h urinary noradrenaline levels (F = 4.75, p = 0.048). CONCLUSIONS: One night CPAP treatment could improve autonomic dysfunction. The assessment of 24-h urinary noradrenaline would provide important information for evaluating the effect of CPAP treatment.