Evaluation of Transmittance and Reflectance Pulse Oximetry in a Canine Model of Hypotension and Desaturation

Abstract

Summary Ten, anesthetized dogs were instrumented with three pulse oximeter probes; two lingual transmittance probes and one rectal reflective probe. Arterial oxygen desaturation was produced by decreasing the inspired oxygen concentration. Hypotension was produced with an infusion of nitroprusside. Simultaneous pulse oximeter readings (SpO 2 ) were compared to co‐oximeter measured arterial saturation (SaO 2 ) collected over a range of SaO 2 (50–100%) and mean arterial pressures (40–100mmHg). Each of the monitors and means of evaluating SpO 2 studied provided accurate SpO 2 measurements over a range of mean arterial pressure from 40–100mmHg. All of the monitors tested tended to overestimate the SaO 2 when the arterial saturation was less than 70%.