Use of dichromatic earpiece densitometry for determination of cardiac output.

Publisher Website
Google Scholar
Abstract
Simultaneous dilution curves after injection of 5 mg of indocyanine green into the superior vena cava of 14 subjects during rest and exercise were recorded by a dichromatic ear densitometer, a conventional ear oximeter used as a monochromatic densitometer, and a cuvette coupled to the radial artery. Calibration of earpieces assumed linearity for extrapolation of the deflection at 90 sec. after injection on the basis of dye concentration estimated from hematocrit and spectrophotometry of plasma samples from the radial artery and arm vein. With the cuvette as a reference, cardiac output values gave no systematic variation when calibrated from arterial blood. The standard deviation of differences by ear oximeter was 31% and by dichromatic ear densitometer 14%. The dichromatic ear densitometer showed a linear relationship between its calibration factor for dye (cm deflection/mg dye/liter of blood) and the relative blood content of the ear determined by inflating its pressure capsule so that by the use of previously calibrated earpiece, values for cardiac output can be obtained without sampling blood.

This publication has 0 references indexed in Scilit: