Method of optical measurement for determing various parameters of the patient's blood

A method of optical measurements of at least one desired parameter of blood of a specific patient extracted from optical characteristics associated with erythrocytes aggregation process during a state of the blood flow cessation, the method comprising the steps of:

• providing reference data in the form of a function describing diffraction effects on particles, K(x(nHb−nH2O), wherein x=2πa/λ;
• a is the size of erythrocyte, nHb is the refraction index of hemoglobin and npl is the refraction index of water, λ is the wavelength of incident radiation;
• providing the state of the blood flow cessation and maintaining said state during a predetermined period of time;
• performing measurement sessions within said predetermined time period, each measurement session including several measurements with different wavelengths of incident radiation, and obtaining measured data representative of the time dependence of light response signals;
• analyzing the measured data for determining a Rouleaux Geometry Factor (RGF) for the specific patient, the RGF characterizing the changes of the light response of blood at the state of the blood flow cessation as a function of time and wavelengths of the incident radiation, associated with the erythrocytes' aggregation.

A method of optical measurements of at least one desired parameter of blood of a specific patient extracted from optical characteristics associated with erythrocytes aggregation process during the state of the blood flow cessation, the method comprising the steps of:

• providing reference data in the form of at least one calibration curve corresponding to a parametric slope as a function of values of said desired parameter;
• providing the state of the blood flow cessation within a measurement region, and maintaining the blood-flow cessation state during a predetermined time period;
• performing timely separated measurement sessions within said predetermined time period, each measurement session including at least two measurements with different wavelengths of incident light, and obtaining the time dependence of transmission signals, wherein the at least two wavelengths are selected in accordance with the desired parameter to be determined;
• analyzing the obtained data for determining the parametric slope value for said specific patient;
• using said calibration curve for determining the value of said desired parameter for said specific patient.

A measurement apparatus for performing optical measurements of at least one desired parameter of the patient's blood, the apparatus comprising:

• an occlusion assembly operable to apply pressure to a location on a blood containing medium and maintain said pressure for a predetermined time period;
• illumination/detection assembly operable for applying optical measurements with at least two different wavelengths of incident radiation to a measurement region in the medium, and generating data representative of light response signals from the measurement region;
• and
• a control unit for operating the occlusion and illumination/detection assemblies to allow application of the optical measurements during said predetermined time period, for processing the generated data to determine measured data in the form of at least two time variations of the light response signals corresponding to said at least two wavelengths, respectively, and for analyzing the measured data to determine the at least one desired parameter of the patient's blood;
• the apparatus being characterized in that:
• the occlusion assembly is applicable to a first location on the medium upstream of a second location that contains said measurement region, with respect to the blood flow direction in the medium, the application of the pressure to the first location resulting in creation of a state of temporary blood flow cessation in the measurement region thereby causing a Rouleaux effect at the state of blood flow cessation;
• the control unit comprises:
• a memory for storing reference data in the form of a calibration curve of a value of a certain parameter associated with the Rouleaux effect as a function of values of the desired blood parameter;
• a processor operable to analyze the measured data in the form of the two time variations to calculate a value of said parameter associated with the Rouleaux effect, and to utilize the reference data to determine the value of the desired parameter of the patient's blood, the analyzing of the measured data from within a preset time interval of said predetermined period of time utilizing optical characteristics of blood associated with the erythrocytes aggregation process during the state of the blood flow cessation.

A method of optical measurements of at least one desired parameter of a patient's blood, the method comprising the steps of:

• providing a flow of the patient's blood sample into a cuvette;
• applying a pressure to a location upstream of the cuvette with respect to the direction of the blood flow, to create a state of blood flow cessation in a measurement region inside the cuvette, and maintaining the blood-flow cessation state during a predetermined time period, the creation of the state of the blood flow cessation in the measurement region causing a Rouleaux effect;
• applying optical measurement sessions to said measurement region within said predetermine time period, each measurement session including at least two measurements with different wavelengths of incident light, detecting light response signals from the measurement region, and obtaining measured data in the form of at least two time variations of the light response signals corresponding to said at least two wavelengths, respectively, said variation being caused by the Rouleaux effect;
• analyzing the measured data to calculate a value of a certain parameter associated with the Rouleaux effect as a function of time and wavelength of the incident radiation;
• utilizing the calculated value of said parameter associated with the Rouleaux effect and utilizing predetermined reference data in the form of a calibration curve of a value of said parameter associated with the Rouleaux effect as a function of values of the desired blood parameter, and determining the desired parameter of the patient's blood.