[Validation of the Sleep-Doc-Porti system for ambulatory sleep apnea diagnosis]

The aim of our study was to validate the Sleep-Doc-Porti-System (SDPS), a simple device to monitor patients suspected of suffering from obstructive sleep apnea syndrome (OSAS). This digital recording system measures nasal flow, oxygen saturation, heart rate, and body position. To assess the reliability of results obtained by the SDPS, cardiorespiratory polygraphy and SDPS were performed simultaneously on 48 patients with OSAS (apnea/hypopnea index (AHI) 26 +/- 25) and 10 habitual snorers (AHI = 0.6 +/- 0.7). There was a strong correlation between the apnea index (AI) recorded by the SDPS and the AI (r = 98; p < 0.001) and AHI (r = 97; p < 0.001) obtained by polygraphy. However, the SDPS significantly underestimated the respiratory disturbance index, because hypopneas were not detected by the recorder (AI by SDPS vs. AHI by polygraphy: 19.6 +/- 24.4 vs. 26.7 +/- 25.3; p < 0.01). With the cardiorespiratory polygraphy as standard, the sensitivity of the SDPS in detecting OSAS ranged between 71 and 72%, and the specificity between 91 and 100%, depending on the AHI values of 5, 10, 15 and 20 chosen to define severity of the disease. Reproducibility was assessed in 23 patients who underwent in-home monitoring in two consecutive nights and yielded no evidence of a "first night effect" (AI: 30.9 +/- 24.3 vs. 33.4 +/- 23.3; p = n.s.). In 18 OSAS patients in-home monitoring was able to demonstrate the worsening effect of alcohol on the disease by a significant increase in the AI comparing the night with and without alcohol (AI: 23.1 +/- 11.9 vs. 35.2 +/- 14.8; p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)