0946 CIRCUL: VALIDATION OF A SMART RING FORM OXIMETER IN INDIVIDUALS WITH DARK SKIN PIGMENT

Abstract

Abstract Introduction The potential impact of skin pigmentation on the accuracy of oximetric assessment has long been known to be a clinically relevant matter. During the COVID pandemic it became apparent that oximeters may underestimate oxyhemoglobin saturation in darkly pigmented individuals. Validation data for SaO2 is not generally available for the many consumer wearable oximeter devices. Circul® (Bodimetrics Corp, Los Angeles, CA), a wearable oximeter with a form factor of a ring, measures several variables for cardiorespiratory assessment (SpO2, movement, heart rate). We aimed to evaluate the accuracy this device in the measurement of SaO2 compared to a simultaneous values obtained by measurement of SaO2 by arterial blood gases. Methods 24 subjects (8 Black, 16 Non-Black) participated in the validation of the Circul device. In an operating suite they had catheters inserted into their radial arteries. They were administered nitrogen rich air which made them hypoxic in steps to an SaO2 of 70%. Arterial blood was sampled at various levels of hypoxia and simultaneous readings were obtained from the Circul device. We compared SaO2 obtained by Circul vs measurement of ABGs by a medical grade blood gas analyzer. Results There was excellent correlation between SaO2 measured by the ring oximeter and ABGs in both Black (y = 1.0174x - 1.573; R² = 0.9414) and Non-Black (y = 1.0209x - 2.5607; R² = 0.9207) subjects. No significant differences were found in comparing the intercept and slopes of the regressions. At ABG of 70% and 100% the SaO2 measured by the ring was calculated to be 69.6% and 100.2% for the Black subjects and 68.9% and 99.5% for the non-Black subjects. Conclusion Results from this study confirmed that Circul oximetry accuracy seems to be independent of the skin tone. Support (if any)