Use of the Ear Oximeter for Assay of Pulmonary Disability

¹ Pulmonary Physiology Research Labthe Department of Medicine and the Department of Physiology, University of Cincinnati College of Medicine

An oximetric method for assessing pulmonary impairment has been devised. The decrease in arterial oxygen saturation, measured by an ear oximeter, and the work performed by stepping up and down on an 8-inch step 30 times per minute not to exceed five minutes are correlated. An index of disability is calculated as follows:

[See equation in pdf file]

Fifteen normal subjects had scores ranging from +14 to -20 (median=-1) and 14 patients with pulmonary diseases not expected to interfere with pulmonary function had scores ranging from +142 to -12 (median=+9). Thirty-six of the 51 patients with diseases expected to interfere with function and who were receiving therapy had scores from -24 to -1112 (median=-126). The remaining 15 had scores in the range of the normal subjects. Had these 51 patients not been receiving treatment, the number of patients responding to the test would probably have been nearer 100 per cent. Studies in another 16 patients showed that changes in arterial blood saturation by oximetry agreed well with changes obtained by arterial blood gas analysis. The correlation coefficient r=0.994.

The method is easy, simple, rapid and causes little or no anxiety in the subject tested. The testing equipment can be easily set up in a plant dispensary or in a field location.