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Abstract
Introduction Inpatient full polysomnography (PSG) is the gold standard diagnostic to identify obstructive sleep apnoea syndrome (OSAS)1. Due to healthcare resources and utilisation many sleep centres employ limited multichannel sleep testing (MC) at the patient’s home. Both diagnostic tests provide measurements of oxygen desaturation index (ODI), apnoea-hypopnoea index (AHI) and oxygen saturation (Sp02). The sleep studies however are subject to factors that may influence sleep quality, including environmental effects (location of performance and staff versus patient setup) that may influence overall sleep study scoring.
Methods All patients referred to the CSU for investigation of OSAS who subsequently performed a PSG were included in this observational study. Patients who were symptomatic (Epworth score ≥11) and received a diagnosis of mild OSAS (AHI 5–14/hr) continued to PSG. MC were performed using NOX T3 and PSG using NOX A1 (Nox Medical, Katrínartún, Iceland). Sleep scoring was in accordance with AASM guidelines version 2.3. Comparisons of data sets was performed using SPSS statistical software.
Results Patient demographics are shown in table 1. In total 8 patients were included. All patients scored a higher AHI on PSG compared to MC. Mean PSG AHI and ODI were significantly higher than MC (18.48/hr; 8.1/hr and 17.68/hr; 7.08/hr, p≤0.001 respectively). Sp02 was comparable between PSG and MC (92% and 94%, p=0.0135, respectively). [Figure 1].
A Graph to show the AHI’s gathered from a Nox T3 and a Nox A1
Discussion Data from this single centre, small sample study shows higher AHI and ODI from PSG compared to MC in symptomatic mild OSAS patients. Reasons may include location of sleep and clinical support with sleep study setup. In this patient group it may be advised that PSG is required in order to confirm a diagnosis of OSAS and severity in order to select the most appropriate treatment modality and optimisation of treatment selections. Larger multicentre studies are required to substantiate the results from this study.