Use of the Lambert-Beer Transmission Law determines blood oxygen saturation of hemolyzed blood samples. This simplified method is based on the difference in optical absorption properties of hemoglobin and oxyhemoglobin

Malik, W. M.

English

NASA Technical Reports Server

1967August 
	
Brief 67-10252 
•Cop	 NASA TECH BRIEF 
NASA Tech Briefs are issued to summarize specific innovations derived from the U.S. space program, 
to encourage their commercial application. Copies are available to the public at 15 cents each 
from the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Blood Oxygen Saturation Determined by Transmission Spectrophotometry

of Hemolyzed Blood Samples 
The problem: 
To develop a simplified method of determining 
blood oxygen saturation of hemolyzed blood samples. 
It is well known that the attenuation of light caused by 
a real sample of an absorbing material is a function 
not only of its extinction coefficient at the wavelength 
used, but is also a function of the concentration of the 
material in the sample and the thickness of the sample. 
The method should use as its basis the difference in 
optical absorption properties of hemoglobin and 
oxyhemoglobin. 
The solution: 
Base the method on the Lambert-Beer Transmis-
sion Law which states that light traversing an absorb-
ing medium suffers an exponential (logarithmic) 
reduction in its intensity. Use the differences in the 
absorption spectra of the samples to make the de-
termination. 
How it's-done: 
To convert highly turbid whole blood samples to 
nonturbid hemoglobin solutions which obey the 
Lambert-Beer Transmission Law, it is first necessary 
to break apart the red blood cells, liberating the 
hemoglobin contained therein (a procedure referred to 
as hemolysis), thereby converting the suspension of 
red blood cells in plasma to a uniform solution of 
hemoglobin pigments. This hemoglobin solution 
consists of a mixture of oxygenated hemoglobin 
(oxyhemoglobin, Hb02) and nonoxygenated hemo-
globin (reduced hemoglobin, Hb). The oxygen satura-
tion of the solution is defined as that fraction of the
Note: 
Inquiries concerning this invention may be di-
rected to:
Technology Utilization Officer 
Manned Spacecraft Center 
Houston, Texas 77058 
Reference: B67-10252 
total hemoglobin present in the oxygenated form. 
Nonturbid hemoglobin solutions are absorbing 
media that follow the Lambert-Beer Transmission 
Law. The propensity of an absorbing material to 
produce "extinction" of the light traversing it is quan-
tified in spectrophotometric notation as its "extinction 
coefficient." The extinction coefficients are wave-
length dependent. The differences in the absorption '\ 
spectra of the reduced and oxygenated form of
	 N 
hemoglobin form the basis upon which the spectro-
photometric determination of oxygen saturation is 
made. 
In practice, the transmission of light through a 
hemolyzed-blood sample is measured at an isosbestic 
wavelength and nonisosbestic (signal) wavelength. 
(An isosbestic wavelength is defined as a wavelength 
at which the extinction coefficients for Hb and Hb02 
are identical.) These two measurements are also per-
formed with a cuvette filled with water rather than 
hemolyzed blood. The differences between the in-
tensity measurements performed upon the hemolyzed-
blood-filled cuvettes and the water-filled cuvettes 
establish the optical densities of the samples. The 
percent hemoglobin oxygen saturation can be found 
from the ratio of the two optical-density measure-
ments. 
Idalk	 (continued ovcrlcaf) 
Now
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19670000252 2020-03-11T20:34:17+00:00Z
Patent status: 
Inquiries about obtaining rights for the commercial 
use of this invention may be made to NASA, Code 
GP, Washington, D.C. 20546.
Source: W. M. Malik 
of the Institute of Medical Sciences 
under contract to 
Manned Spacecraft Center 
(MSC-1 1018 
I 
/
Brief 67-10252	 Category 04


Blood oxygen saturation determined by transmission spectrophotometry of hemolyzed blood samples

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server