Use of Dichromatic Earpiece Densitometry for Determination of Cardiac Output

Item

Title
Use of Dichromatic Earpiece Densitometry for Determination of Cardiac Output
Date
1964
Index Abstract
Not Available
Photo Quality
Not Needed
Report Number
AMRL TR 64-134
Creator
Reed, John H., Jr.
Wood, Earl H.
Corporate Author
The Mayo Clinic and Mayo Graduate School of Medicine
Laboratory
Biophysics Laboratory
Extent
20
Identifier
AD0613335
Access Rights
CFSTI
Distribution Classification
1
Contract
AF 33(657)-8899
DoD Project
7222
DTIC Record Exists
No
Distribution Change Authority Correspondence
None
Distribution Conflict
No
Abstract
Dye-dilution curves were recorded simultaneously by a monochromatic earpiece densitometer, a dichromatic earpiece densitometer and a cuvette densitometer through which blood was sampled continuously from a radial artery. Comparison of cardiac output values were made using the direct coupled arterial cuvette as a standard in nine healthy subjects during three periods of rest and during two periods of pedalling a bicycle ergometer at different levels of work output. Data are also included from similar studies carried out in five cardiac patients in whom no great vessel or intracardiac shunts could be demonstrated. The results showed a high degree of variability for the monochromatic earpiece densitometer values (standard deviation of differences: =31%) because of baseline variations due to changing conditions in the ear. The dichromatic earpiece densitometer which compensates for dynamic changes in the ear showed satisfactory comparison with arterial cuvette densitometer (standard deviation of differences: =14%). The dichromatic earpiece densitometer showed a linear relationship between its calibration factor for dye (centimeters deflection/milligrams dye/liter of blood) and the relative blood content of the ear. A dichromatic ear densitometer appears feasible for estimating cardiac output where use of more direct methods is precluded.
Report Availability
Full text available
Is Referenced By
Button, Vera Lucia da Silveira Nantes, "Principles of measurement and transduction of biomedical variables" in Flow Transducers, p. 271-323, 2015
Date Issued
1964-12
Provenance
RAF Centre of Aviation Medicine
Type
report
Format
1 online resource
Media
AMRLTR64-134.pdf