Automated Screening of Children With Obstructive Sleep Apnea Using Nocturnal Oximetry: An Alternative to Respiratory Polygraphy in Unattended Settings

Abstract

Study Objectives: Nocturnal oximetry has become known as a simple, readily available, and potentially useful diagnostic tool of childhood obstructive sleep apnea (OSA). However, at-home respiratory polygraphy (HRP) remains the preferred alternative to polysomnography (PSG) in unattended settings. The aim of this study was twofold: (1) to design and assess a novel methodology for pediatric OSA screening based on automated analysis of at-home oxyhemoglobin saturation (SpO2), and (2) to compare its diagnostic performance with HRP. Methods: SpO2 recordings were parameterized by means of time, frequency, and conventional oximetric measures. Logistic regression models were optimized using genetic algorithms (GAs) for three cutoffs for OSA: 1, 3, and 5 events/h. The diagnostic performance of logistic regression models, manual obstructive apnea-hypopnea index (OAHI) from HRP, and the conventional oxygen desaturation index ≥ 3% (ODI3) were assessed. Results: For a cutoff of 1 event/h, the optimal logistic regression model significantly outperformed both conventional HRP-derived ODI3 and OAHI: 85.5% accuracy (HRP 74.6%; ODI3 65.9%) and 0.97 area under the receiver operating characteristics curve (AUC) (HRP 0.78; ODI3 0.75) were reached. For a cutoff of 3 events/h, the logistic regression model achieved 83.4% accuracy (HRP 85.0%; ODI3 74.5%) and 0.96 AUC (HRP 0.93; ODI3 0.85) whereas using a cutoff of 5 events/h, oximetry reached 82.8% accuracy (HRP 85.1%; ODI3 76.7) and 0.97 AUC (HRP 0.95; ODI3 0.84). Conclusions: Automated analysis of at-home SpO2 recordings provide accurate detection of children with high pretest probability of OSA. Thus, unsupervised nocturnal oximetry may enable a simple and effective alternative to HRP and PSG in unattended settings. Keywords: at-home respiratory polygraphy, automated pattern recognition, blood oxygen saturation, genetic algorithms, nocturnal oximetry Citation: Álvarez D, Alonso-Álvarez ML, Gutiérrez-Tobal GC, Crespo A, Kheirandish-Gozal L, Hornero R, Gozal D, Terán-Santos J, Del Campo F. Automated screening of children with obstructive sleep apnea using nocturnal oximetry: an alternative to respiratory polygraphy in unattended settings. J Clin Sleep Med. 2017;13(5):693-702.

Multiscale Entropy Analysis of Unattended Oximetric Recordings to Assist in the Screening of Paediatric Sleep Apnoea at Home

“…There is a great controversy regarding the clinical cut-off used to confirm childhood OSAS [2,4,10,15]. In order to address this issue, a common OAHI cut-off point of 3 events/h was used in the present study [11,18,19]. According to this clinical threshold, a positive diagnosis was confirmed in 26 children (OSAS prevalence 52%).…”

“…Regarding the input parameters of SampEn, the values of m and r are critical in the estimation of entropy and thus in the performance of MSE analyses. In the present study, we used m = 1 and r = 0.25 times the standard deviation (SD) of the original recording, which have demonstrated to be optimal in previous analysis of oximetry by means of SampEn [19,27,31]. As recommended by Costa et al [33], r was not normalised for time scales τ > 1 because changes of variance in the coarse-grained versions of the signal have information about the whole original time series.…”

“…Among these complementary approaches, nonlinear methods have been marginally explored. Approximate entropy (ApEn) [22], sample entropy (SampEn) [23], central tendency measure [24], and Lempel-Ziv complexity [25] have demonstrated their usefulness to characterise desaturations linked to apnoeic events both in adults [26][27][28][29][30][31][32] and children [16,19]. Nevertheless, we hypothesise that different nonlinear metrics could gain insight into the dynamics of oximetry leading to additional and essential information.…”

“…In this regard, recording of single-channel SpO 2 from overnight oximetry has been also proposed as a highly simple as well as effective screening technique for paediatric OSAS due to its suitability for children [10,14,15]. Moreover, automated processing of oximetric recordings has been proposed to enhance the diagnostic performance of overnight oximetry as a single screening test for childhood OSAS [16][17][18][19].…”

“…Previous studies in the framework of paediatric OSAS detection by means of oximetry assessed conventional desaturation indexes [16][17][18][19][20][21], common statistics in the time domain [16,17,19], spectral features in the frequency domain [16,19] and nonlinear measures [16,19]. Among these complementary approaches, nonlinear methods have been marginally explored.…”