Usefulness of Home Overnight Pulse Oximetry in Patients with Suspected Sleep-Disordered Breathing

Background and Objective. To determine the diagnostic yield of nocturnal oximetry versus polygraphy for the diagnosis and classification of sleep apnea hypopnea syndrome (SAHS). Methods. Prospective study conducted in a university hospital. Subjects with a clinical suspicion of SAHS were included. All of them underwent home polygraphy and oximetry on the same night. A correlation was made between the apnea-hypopnea index (AHI) and the oximetry variables. The variable with the highest diagnostic value was calculated using the area under the curve (AUC), and the best cut-off point for discriminating between patients with SAHS and severe SAHS was identified. Results. One hundred and four subjects were included; 73 were men (70%); mean age was 52 ± 10.1 years; body mass index was 30 ± 4.1, and AHI = 29 ± 23.2/h. A correlation was observed between the AHI and oximetry variables, particularly ODI3 (r = 0.850; P < 0.001 ) and ODI4 (r = 0.912; P < 0.001 ). For an AHI ≥ 10/h, the ODI3 had an AUC = 0.941 (95% confidence interval (CI) = 0.899–0.982) and the ODI4, an AUC = 0.984 (95% CI = 0.964–1), with the ODI4 having the best cut-off point (5.4/h). Similarly, for an AHI ≥ 30/h, the ODI4 had an AUC = 0.922 (95% CI = 0.859–0.986), with the best cut-off point being 10.5/h. Conclusion. Nocturnal oximetry is useful for diagnosing and evaluating the severity of SAHS. The ODI4 variable was most closely correlated with AHI for both diagnosis.

Use of oximetry to screen for paediatric obstructive sleep apnoea: is one night enough and is 6 hours too much?

IntroductionNocturnal pulse oximetry can be used to screen for obstructive sleep apnoea (OSA) using the McGill Oximetry Score (MOS). The MOS has a time threshold for a technically adequate study of 6 hours. It has been suggested that one night of oximetry is sufficient to screen for OSA using the MOS.Aims(1) To evaluate night-to-night variation of the MOS. (2) To determine the impact of recording three nights of oximetry on the screening yield for OSA. (3) To explore whether useful MOS data are discarded when a threshold of 6 hours of oximetry recording is used.MethodsA retrospective study of nocturnal pulse oximetry done at home over three consecutive nights in paediatric patients with suspected OSA. Studies were scored (MOS) using thresholds of ≥6 and ≥4 hours of recording.ResultsA total of 329 patients were studied. MOS scores over three nights showed only fair to moderate agreement. On the first night 126 patients (38%) screened positive for OSA. When three nights of oximetry were done 195 patients (59%) screened positive on at least one of the nights. There were 48 patients with studies of between 4 and 6 hours duration on one or more nights. If these studies are scored 20 patients (42%) would screen positive for OSA on at least one night based on scoring these studies alone.ConclusionOne night of oximetry screening may not be sufficient to screen for OSA. Lowering the time threshold to ≥4 hours may increase the screening capability of nocturnal oximetry.