Performance validation of a new finger-root-adapted ring-shaped oximeter sensor during stepwise steady-state inspired hypoxia

Peripheral pulse oxygen saturation (SpO 2 ) is a widely applied substitute parameter to arterial oxygen saturation (SaO 2 ). Optimized morphological design and geometrical arrangement of the light-source and photodetector without compromising their precision, can maximize the clinical utility of the SpO 2 sensors. We analyzed data of 36 participants collected from two multicenter trials that examined the performances of 3 transmittance oximeter sensors. A finger-root-adapted ring-shaped sensor with light-source and detector located on the sides of the finger, was compared with 2 fingertip-adapted designs (finger-clip and finger-case), whose light-sources and detectors were located on the antero-posterior axis of the finger. A stepwise steady-state inspired hypoxia protocol according to ISO 80,601 2–61: 2017 were adopted to examine the SpO 2 measurements of all the sensors obtained at 5 different SaO 2 levels (100%-97%, 92% − 96%, 85% ~ 91%, 78% ~ 84%, 70% ~ 77) under either quiescent or motion condition as well as in darkly or lightly pigmented populations. Under each tested condition, all the sensors presented an accuracy root mean square (Arms) within 2%. Bland-Altman analysis of all the sensors demonstrated narrow limits of agreement. Paired SaO₂ and SpO₂ values were fitted to linear regression lines and yielded high coefficients of determination (R² > 0.97) for all sensors, indicating excellent distribution matches. The finger-ring sensor was rated by the participants to offer higher finger-movement flexibility, attachment stability and more comfortable experiences to users. The finger-root-adapted ring-shaped oximetry sensor demonstrated high precision and is more user-friendly for SpO 2 monitoring.