Comparison of AutoSetä and polysomnography for the detection of apnea-hypopnea events

Abstract

The use of the flow vs time relationship obtained with the nasal prongs of the AutoSet (AS) system (diagnosis mode) has been proposed to detect apneas and hypopneas in patients with reasonable nasal patency. Our aim was to compare the accuracy of AS to that of a computerized polysomnographic (PSG) system. The study was conducted on 56 individuals (45 men) with clinical characteristics of obstructive sleep apnea (OSA). Their mean (± SD) age was 44.6 ± 12 years and their body mass index was 31.3 ± 7 kg/m 2 . Data were submitted to parametric analysis to determine the agreement between methods and the intraclass correlation coefficient was calculated. The Student t-test and Bland and Altman plots were also used. Twelve patients had an apnea-hypopnea index (AHI) <10 in bed and 20 had values >40. The mean (± SD) AHI PSG index of 37.6 (28.8) was significantly lower (P = 0.0003) than AHI AS (41.8 (25.3)), but there was a high intraclass correlation coefficient (0.93), with 0.016 variance. For a threshold of AHI of 20, AS showed 73.0% accuracy, 97% sensitivity and 60% specificity, with positive and negative predictive values of 78% and 93%, respectively. Sensitivity, specificity and negative predictive values increased in parallel to the increase in AHI threshold for detecting OSA. However, when the differences of AHI PSG-AS were plotted against their means, the limits of agreement between the methods (95% of the differences) were +13 and -22, showing the discrepancy between the AHI values obtained with PSG and AS. Finally, cubic regression analysis was used to better predict the result of AHI PSG as a function of the method proposed, i.e., AHI AS . We conclude that, despite these differences, AHI measured by AutoSet can be useful for the assessment of patients with high pre-test clinical probability of OSA, for whom standard PSG is not possible as an initial step in diagnosis.

A novel device (SD‐101) with high accuracy for screening sleep apnoea‐hypopnoea syndrome

“…Previous portable level‐four devices have not shown good correlations with PSG data, and the sensitivity and specificity have not been particularly high 21–23 . However, newly developed portable level‐four devices have shown higher correlation coefficients with PSG and increased accuracy 24,26 . SD‐101 corresponds to a level‐four measurement device, and the time‐matched comparison with RDI measured by SD‐101 and AHI calculated from PSG were closely correlated in the present study (with correlation coefficients of 0.88 in the suspected SAHS group and 0.92 in the screening group).…”

“…The same measurements without monitoring by a laboratory technician and with online paper and monitor form level two, measurement of cardiorespiratory items without sleep parameters is level three and measurement of one or two items is classified as level four (which has been recognized as unable to diagnose SDB accurately). Time‐matched comparisons between RDI measured by portable devices without EEG and AHI measured by PSG reportedly show a good correlation of 0.7–0.94 21–25 . Previous portable level‐four devices have not shown good correlations with PSG data, and the sensitivity and specificity have not been particularly high 21–23 .…”

Home Diagnosis of Sleep Apnea: A Systematic Review of the Literature

“…There were 25 studies (level I evidence, 2 studies; level II evidence, 14 studies; level IV evidence, 9 studies) performed on type 4 monitors (Tables 4 and 7). There were 13 studies that used oximetry alone, 34 -37,45,46,48 -52,54,55 8 studies that used airflow (nasal pressure alone, 6 studies [11][12][13][14]16,17 ; nasal pressure and oxygen desaturation, 1 study 15 ; thermistor with oxygen desaturation, 1 study 33 ), 1 study that used snoring with oximetry, 57 2 studies that used oximetry plus heart rate and snoring, 43,44 and 1 study that used heart rate alone. 58 One other study did not report sensitivity in an interpretable fashion, 59 and three other studies did not report sensitivities and specificities.…”

Nasal pressure recordings to detect obstructive sleep apnea

“…No electroencephalography signals are monitored. Many of these devices use different methodologies to evaluate sleep apnea severity, which include oximetry alone; [5][6][7] oximetry and nasal airflow [8][9][10][11]; peripheral arterial tonometry, oximetry, and actigraphy [12,13]; airflow, body position, wrist actimetry, pulse rate, and oxygen desaturation [14]; oral and nasal thermistor [15]; microphone and nasal airflow [16]; or tracheal sound analysis [17]. These modalities are feasible for an ambulatory setting in which physicians treat sleep-related breathing disorders.…”