Method and device for non-invasive measurements of blood parameters

A device for use in non-invasive measurements in a patient's body, the device comprising:

• (a) a measurement unit comprising a light source assembly configured and operable for applying an external electromagnetic field to a measurement location on the body, and a light detector arrangement configured and operable for detecting a response of the measurement location to the applied field and generating data indicative thereof;
• (b) a pressure applying assembly configured and operable for applying over-systolic pressure to the body portion so as to create a condition of artificial kinetics in the measurement location characterized by a blood flow cessation;
• (c) a control unit connectable to the measurement unit and to the pressure applying assembly for operating them so as to enable several measurement sessions on the measurement location, each measurement session carried out with at least two different values of a controllable parameter, such that the measurement sessions include at least two measurement sessions carried out at a first condition of normal blood flow in the measurement location with no application of pressure and at least two measurement sessions carried out at the second condition of artificial kinetics in the measurement location;
• the control unit being configured for receiving and processing said data indicative of the response of the measurement location to the applied field to determine first measured data indicative of a first time variation of the response for each of said at least two parameter values while at the normal blood flow condition and second measured data indicative of a second time variation of the response for each of said at least two parameter values while at the artificial kinetics condition, thereby enabling determination of a first relation between the first time variations for the different parameter values and a second relation between the second time variations for said different parameter values, the control unit being programmed to determine each of the first and second relations as a parametric slope of the respective time functions of the responses and utilizing said first and second relations to determine at least one blood related parameter BP as follows
• BP
• =
• ∑
• i
• =
• 1
• N
• ⁢
• A
• i
• ·
• (
• PS
• 1
• )
• i
• +
• ∑
• i
• =
• 1
• M
• ⁢
• B
• i
• ·
• (
• PS
• 2
• )
• i
• wherein Ai and Bi are calibrated coefficients;
• (PS1)i and (PS2)1 are first and second parametric slopes obtained for the same pair of wavelengths;
• and i is a number of wavelengths.