Journal of Applied Physiology, Vol 44, Issue 3 483-487, Copyright © 1978 by American Physiological Society
Calibration of a new ear oximeter in humans during exposure to centrifugation
E. L. Besch, F. W. Baumgardner, R. R. Burton, K. K. Gillingham, R. F. McPherson and S. D. Leverett Jr
An optoelectronic ear oximeter (Hewlett-Packard, model 47201A) was
evaluated as a noninvasive method for determining arterial oxygen
saturation (SaO2) in human subjects during exposure to various levels of
accelerative forces. This physiological calibration involved exposing five
subjects, while breathing air and wearing the ear oximeter for 60 s to each
of three levels of accelerative forces (3, 5, and 7 G); arterial blood
samples were withdrawn concurrently. SaO2 was calculated indirectly from
the oxygen tensions (PaO2) measured from the sampled arterial blood with a
blood gas analyzer and corrected for pH and base excess. These data were
compared, as were similar data taken from the same subjects breathing three
different hypoxic gas mixtures while resitng at earth's gravity (1 G).
Regression analyses of these data for both experimental groups (a, G
exposure, or b, hypoxic exposure), comparing the ear-oximeter SaO2 with the
calculated SaO2, showed the ear oximeter to be accurate with correlation
coefficients of 0.95 and 0.98, respectively.
