Ear oximetry in clinical practice

Abstract

The arterial blood O2 saturation measurement obtained by the Hewlett-Packard ear oximeter was compared to that derived from the arterial PO2 in 41 patients with various pulmonary diseases and in 11 jaundiced patients with serum bilirubin concentrations between 2.7 and 35 mg per 100 ml. There was a good correlation between results obtained with the 2 methods in the jaundiced group (r = + 0.85, n = 19) and in the patients with pulmonary disease (r = + 0.90, n = 57); however, in the jaundiced patients, the ear oximeter arterial O2 saturation was significantly lower (-6.06 per cent, n = 19, P less than 0.01) than the arterial O2 saturation derived from the arterial PO2. There was a significant correlation between the serum bilirubin concentration and the magnitude of difference between the oximeter arterial O2 saturation and the arterial PO2-derived arterial O2 saturation (r = + 0.848, n = 16, P less than 0.001). In the nonjaundiced patients, the difference between the 2 measurements was small when the arterial P(02) was greater than 61 mm Hg; the variation increased with lower arterial PO2 concentrations, but the difference was not significant.