Clinical Evaluation of the Biox IIA Ear Oximeter in the Critical Care Environment

Abstract

We evaluated the Biox IIA Ear Oximeter for accuracy of intermittent measurement of arterial oxygen saturation (SaO2) in the critically ill patient. Arterial blood was sampled simultaneously with ear oximetry in 79 patients from three critical care units in our institution. Acceptable data were obtained in 173 of 187 oximeter measurements (92.5%). The blood-sample SaO2 ranged from 75.1 to 98.5% (94.5 ± 4.08%), and the Biox IIA SaO2 ranged from 72.0 to 100.0% (94.9 ± 4.41%), yielding a mean difference of +0.34% (P<0.005). The correlation coefficient (r) resulting from linear regression analysis of all pairs of measurements (173) was high (0.913), and there was also a significant correlation in the subset of data in which blood SaO2 was < 90% (r = 0.875, P < 0.005). The Biox IIA has a small, clinically insignificant positive bias. These data demonstrate that the Biox IIA can accurately monitor SaO2 in patients in an intensive care unit. (Respir Care 1985;30:179-183.)