O009 Are there Differences in SpO2 Recordings from Two Oximeters on the same hand during an Overnight Sleep Study Significant?

BACKGROUND: Accurate non-invasive oxygen saturation (SpO2) measurement is crucial in healthcare, however is challenged by numerous devices using variable algorithms1. We compared two commonly used oximeter devices worn simultaneously in patients during an overnight polysomnogram. AIM: To assess (1) differences between two SpO2 recording devices and (2) SpO2 accuracy against SaO2. METHODS: SpO2 data of two devices were recorded, downloaded and analysed with corresponding software: device 1 (Rad7 [Masimo, Irvine, CA, USA] set at 2-4sec averaging time) with software 1 (PSG 4 [Compumedics, Melbourne, Australia]) and device 2 (Wrist-Ox2® [Nonin Medical Inc, Plymouth, MN, USA] set at 3 sec averaging time) with software 2 (Noxturnal [Nox Medical Inc, Reykjavik, Iceland]). Responsiveness of each oximeter to changes in the patients’ desaturations associated with apnoeas and hypopnoeas overnight was assessed. In addition, both device SpO2 values were compared with SaO2 from simultaneous arterial blood gas sampling. PRELIMINARY RESULTS: 7 patients (age 56.4±7.1 years, BMI 31.6±2.2 kg/m2, 100% male, 87% light skinned) were studied. The mean SpO2 with RAD7 was higher than the Nonin (95.9±1.6 vs 94.2±1.4%, mean difference 1.6±1.0%). Differences in the responsiveness of the oximeters during overnight desaturations were also observed. However, both device SpO2 values were found to be within ±2% of SaO2. CONCLUSIONS: Discrepancies in SpO2 measurement do occur between devices and may have important clinical implications especially when it comes to the measurement of hypoxemic burden during sleep. 1.Blanchet MA et al. Accuracy of Multiple Pulse Oximeters in Stable Critically Ill Patients. Respir Care. 2023 May;68(5):565-574.