P81. The Evaluation of Skin Pigmentation Effects on Pulse Oximetry Monitoring Using a Novel Porcine Deoxygenation Model

PURPOSE: The purpose of this study was to investigate the impact of skin pigmentation on the accuracy of pulse oximetry using a modified porcine model with controlled systemic deoxygenation and alternately pigmented ears. METHODS: Two Hampshire pigs with naturally occurring oppositely pigmented ears were utilized. Pulse-oximetry (SpO2) data was continuously and simultaneously collected from each ear using research grade open data stream (Maxim-86171 pulseoximeter) and clinical standard proprietary pulse oximeters (Masimo-K181956). Starting from normoxemia, progressive hypoxemia (SaO2 60-100%) was induced by decreasing the fraction of inhaled oxygen in a stepwise manner. Arterial blood gas samples were intermittentlydrawn from an indwelling catheter, and co-oximetry was used to define the gold standard SaO2. RESULTS: During normoxemia, pulse oximetry readings were similar for both pigmented and non-pigmented ears. During hypoxemia, oximeters overestimated oxygen saturation in pigmented ears by +16% at 70% SaO2, while non-pigmented skin showed only a +1% discrepancy.This discrepancy was recapitulated in the Maxim oximetry data, where the slope of the modulation ratio (R)-vs SaO2 curve was 5.9% steeper in the non-pigmented compared to the pigmented ear. CONCLUSION: This study provides the first internally controlled animal model showing that skin pigmentation affects the accuracy of pulse oximetry, with comparable estimation of oxygen saturation between pigmented and non-pigmented skin, but overestimation in pigmented skin during hypoxemia.