Method for noninvasive intermittent and/or continuous hemoglobin, arterial oxygen content, and hematocrit determination
Noninvasive measurement of hematocrit and hemoglobin content by differential optical analysis
System and method for noninvasive hematocrit monitoring Patent #: 5372136
ApplicationNo. 623862 filed on 03/29/1996
US Classes:600/322, Determining blood constituent600/309Measuring or detecting nonradioactive constituent of body liquid by means placed against or in body throughout test
ExaminersPrimary: Bahr, Jennifer
Assistant: Winakur, Eric F.
Attorney, Agent or Firm
Foreign Patent References
International ClassA61B 005/00
Foreign Application Priority Data1995-03-31 JP
AbstractLight of various wavelengths emitted from light sources and transmitted through vital tissues is converted by light sensors and current/voltage transducers, into electric signals. The signals are converted into digital values by an A/D converter. The light source emits light of a wavelength which can be optically absorbed by water. A computer obtains a ratio of variations of the digital values for each wavelength, and calculates the values of tissue terms and the hemoglobin concentration on the basis of the ratios. In the calculation, since tissue terms of the wavelengths have mutual constant relationships, an equation which is prepared so that there exists only one unknown in the tissue terms is used.