CONCENTRATION-MEASUREMENT DEVICE AND CONCENTRATION-MEASUREMENT METHOD

• US 20140058233A1
• Filed: 04/06/2012
• Published: 02/27/2014
• Est. Priority Date: 04/21/2011
• Status: Active Grant

• Current Assignee: Hamamatsu Photonics KK, Stmarianna University School of Medicine
• Original Assignee: Hamamatsu Photonics KK, Stmarianna University School of Medicine
• Inventors: Koyama, Yasuaki, Ozaki, Takeo, Suzuki, Susumu
• Granted Patent: US 9,808,189 B2
• Time in Patent Office: Days
• US Class Current: 600/328
• CPC Class Codes: A61B 5/0261 using optical means, e.g. infrared light
• CPC Class Codes: A61B 5/0295 using plethysmography, i.e. measuring the variations in the volume of a body part as modified by the circulation of blood therethrough, e.g. impedance plethysmography
• CPC Class Codes: A61B 5/14535 for measuring haematocrit
• CPC Class Codes: A61B 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/14553 specially adapted for cerebral tissue
• CPC Class Codes: A61B 5/6814 Head
• CPC Class Codes: A61B 5/72 Signal processing specially adapted for physiological signals or for diagnostic purposes character recognition, recognising digital ink, document-oriented image-based pattern recognition G06V30/00; recognition or understanding of postal images G06V30/424
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence
• CPC Class Codes: A61H 2201/5092 Optical sensor
• CPC Class Codes: A61H 2230/201 used as a control parameter for the apparatus
• CPC Class Codes: A61H 2230/208 used as a control parameter for the apparatus
• CPC Class Codes: A61H 31/005 with feedback for the user

Abstract

A concentration measurement apparatus measures a temporal relative change amount (ΔcHb, ΔO₂Hb) of either or both of total hemoglobin concentration and oxygenated hemoglobin concentration in the head that vary due to repetition of chest compression, and includes a light incidence section making measurement light incident on the head, a light detection section detecting the measurement light propagated through the interior of the head and generating a detection signal in accordance with the intensity of the measurement light, and a CPU determining, based on the detection signal, the relative change amount (ΔcHb, ΔO₂Hb) and performing a filtering process of removing frequency components less than a predetermined frequency from frequency components contained in the relative change amount (ΔcHb, ΔO₂Hb).

Claims

1. A concentration measurement apparatus measuring a temporal relative change amount of at least one of total hemoglobin concentration, oxygenated hemoglobin concentration, and deoxygenated hemoglobin concentration in the head that vary due to repetition of chest compression, comprising:

a light incidence section making measurement light incident on the head;

a light detection section detecting the measurement light that has propagated through the interior of the head and generating a detection signal in accordance with an intensity of the measurement light; and

a calculation section determining, based on the detection signal, the temporal relative change amount of at least one of the total hemoglobin concentration, the oxygenated hemoglobin concentration, and the deoxygenated hemoglobin concentration, wherein

the calculation section determines the temporal relative change amount from which frequency components less than a predetermined frequency are removed by a filtering process.

2. The concentration measurement apparatus according to claim 1, wherein a calculation cycle of the relative change amount is not more than 0.2 seconds.

3. The concentration measurement apparatus according to claim 1, wherein the predetermined frequency is not more than 1.66 Hz.

4. The concentration measurement apparatus according to claim 1, further comprising a display section displaying the calculation result by the calculation section, and wherein

the calculation section determines the temporal relative change amount of the total hemoglobin concentration and the temporal relative change amount of the oxygenated hemoglobin concentration, and determines first information related to a ratio (A2/A1) of an amplitude (A1) of the temporal variation of the temporal relative change amount of the total hemoglobin concentration and an amplitude (A2) of the temporal variation of the temporal relative change amount of the oxygenated hemoglobin concentration, after the filtering process, and

the display section displays the first information.

5. The concentration measurement apparatus according to claim 1, further comprising a display section displaying the calculation result by the calculation section, and wherein

the calculation section determines the temporal relative change amount of the total hemoglobin concentration and the temporal relative change amount of the oxygenated hemoglobin concentration, and determines at least one of an integrated value (I1) of the temporal variation of the temporal relative change amount of the total hemoglobin concentration and an integrated value (I2) of the temporal variation of the temporal relative change amount of the oxygenated hemoglobin concentration, after the filtering process, and

the display section displays at least one of the integrated value (I1) and the integrated value (I2).

6. The concentration measurement apparatus according to claim 5, wherein the calculation section determines both the integrated value (I1) and the integrated value (I2), and thereafter, further determines second information related to a ratio (I2/I1) of the integrated value (I1) and the integrated value (I2), and

the display section further displays the second information.

7. The concentration measurement apparatus according to claim 1, further comprising a display section displaying the calculation result by the calculation section, and wherein

the calculation section determines an amplitude (A1) of the temporal variation of the temporal relative change amount of the total hemoglobin concentration after the filtering process, and

the display section displays the numerical value of the amplitude (A1).

8. The concentration measurement apparatus according to claim 1, further comprising a display section displaying the calculation result by the calculation section, and wherein

the calculation section determines the temporal relative change amount of the total hemoglobin concentration and the temporal relative change amount of the oxygenated hemoglobin concentration, and

the display section displays graphs of the temporal relative change amount of the oxygenated hemoglobin concentration and the temporal relative change amount of the deoxygenated hemoglobin concentration contained in the total hemoglobin concentration, after the filtering process, in a color-coded manner.

9. The concentration measurement apparatus according to claim 1, wherein the calculation section removes the frequency components less than the predetermined frequency from the frequency components contained in the relative change amount by a digital filter.

10. The concentration measurement apparatus according to claim 1, wherein the calculation section calculates data resulting from smoothing of the temporal variation of the relative change amount, and subtracts the data from the relative change amount to remove the frequency components less than the predetermined frequency from the frequency components contained in the relative change amount.

11. The concentration measurement apparatus according to claim 1, wherein the calculation section determines at least one of a maximal value and a minimal value in the temporal variation of the relative change amount, and removes the frequency components less than the predetermined frequency from the frequency components contained in the relative change amount based on at least one of the maximal value and the minimal value.

13. The concentration measurement apparatus according to claim 1, further comprising a display section displaying the calculation result by the calculation section, and wherein

the calculation section calculates information related to a variation frequency of the relative change amount, and

the display section displays the information.

14. The concentration measurement apparatus according to claim 1, further comprising a display section displaying the calculation result by the calculation section, and wherein

the calculation section calculates hemoglobin oxygen saturation, and

the display section displays the hemoglobin oxygen saturation.

12. A concentration measurement method of measuring a temporal relative change amount of at least one of total hemoglobin concentration, oxygenated hemoglobin concentration, and deoxygenated hemoglobin concentration in the head that vary due to repetition of chest compression, the method comprising:

a light incidence step of making measurement light incident on the head;

a light detection step of detecting the measurement light that has propagated through the interior of the head and generating a detection signal in accordance with an intensity of the measurement light; and

a calculation step of determining, based on the detection signal, the temporal relative change amount of at least one of the total hemoglobin concentration, the oxygenated hemoglobin concentration, and the deoxygenated hemoglobin concentration, wherein

the calculation step determines the temporal relative change amount from which frequency components less than a predetermined frequency are removed by a filtering process.