PURPOSE: Continuous positive airway pressure (CPAP) has established as an effective alternatives for treating obstructive sleep apnea-hypopnea syndrome (OSAHS). Recently, several autotitrating CPAP devices which were able to detect apnea or hypopnea events and provide information about residual obstructive events on CPAP come into clinical use. However, there were few data showed the validity of event detection by such devices.
METHODS: Consecutive patient who were diagnosed as having OSAHS and performed polysomnograpy (PSG) on CPAP using S8 system (ResMed Inc., Sydney, Australia) from May to November, 2006 were assessed. Correlation between manually determined apnea-hypopnea index (AHI) and it determined by device (AHI-S8) during standard clinical PSG on CPAP were evaluated. In addition, apnea index (AI) and hypopnea index (HI) were also evaluated separately.
RESULTS: Finally, 74 patients including 95 % male were enrolled (mean age: 52.3 ± 11.3 years old, mean BMI: 28.6 ± 4.7 kg/m2). Mean AHI on diagnostic PSG was 51.9 ± 19.5 events/h (AI: 41.6 ± 23.2 events/h, HI: 10.5 ± 8.8 events/h). During CPAP titration, the device markedly suppressed apnea and hypopnea events, such as manually determined AHI 4.4±3.7 events/h (AI: 2.1 ± 2.5 events/h, HI: 2.3 ± 2.3 events/h). On the other hand, AHI-S8 revealed 10.8 ± 6.3 events/h (AI-S8: 2.6 ± 2.6 events/h, HI-S8: 8.2 ± 4.6/h). There was strong correlation between manually determined AHI and AHI-S8 (r=0.808, p<0.0001). Focused on the AI and HI, there was stronger correlation between manually determined AI and AI-S8 (r=0.934, p<0.0001), whereas there was weaker correlation between manually determined HI and HI-S8 (r=0.611, P<0.0001).
CONCLUSION: Strong correlation between manually determined AHI and AHI-S8 was observed. However, the correlation was weakened when the analysis was limited to the HI.
CLINICAL IMPLICATIONS: The information about residual AHI by CPAP device was validated. However, this result should be interpreted with caution in patients with more number of residual hypopnea events on CPAP.
DISCLOSURE: Kanako Ueno, No Financial Disclosure Information; No Product/Research Disclosure Information