Multiple wavelength sensor emitters

• US 8,385,996 B2
• Filed: 04/13/2009
• Issued: 02/26/2013
• Est. Priority Date: 03/01/2005
• Status: Active Grant

• Current Assignee: Cercacor Laboratories
• Original Assignee: Cercacor Laboratories
• Inventors: Smith, Robert, Dalke, David, Al-Ali, Ammar, Diab, Mohamed, Lamego, Marcelo
• Primary Examiner(s): WINAKUR, ERIC FRANK
• Application Number:
  US12/422,915
• Publication Number:
  US 20100049020A1
• Time in Patent Office: 1,415 Days
• Field of Search: 600/310, 600/316, 356/39, 356/40, 356/41, 356/451
• US Class Current: 600/310
• CPC Class Codes: A61B 1/00 Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes examination of body cavities or body tracts using ultrasonic, sonic or infrasonic waves A61B8/12; endoscopic instruments for taking cell samples or for biopsy A61B10/04; for surgical purposes A61B17/00; endoscopic surgical cutting instruments A61B17/32; surgical instruments using a laser beam being directed along or through a flexible conduit A61B18/22; Illuminating arrangements therefor for the eyes A61B3/00
• CPC Class Codes: A61B 2562/08 Sensors provided with means for identification, e.g. barcodes or memory chips
• CPC Class Codes: A61B 2562/085 combined with means for recording calibration data
• CPC Class Codes: A61B 2562/185 Optical shielding, e.g. baffles
• CPC Class Codes: A61B 2562/222 Electrical cables or leads therefor, e.g. coaxial cables or ribbon cables
• CPC Class Codes: A61B 5/0022 Monitoring a patient using a global network, e.g. telephone networks, internet
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/02427 Details of sensor
• 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 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• 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 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/1495 Calibrating or testing of in-vivo probes
• CPC Class Codes: A61B 5/6815 Ear
• CPC Class Codes: A61B 5/6826 Finger
• CPC Class Codes: A61B 5/6829 Foot or ankle
• CPC Class Codes: A61B 5/6832 : using adhesives A61B5/259 takes precedence
• CPC Class Codes: A61B 5/6838 : Clamps or clips
• CPC Class Codes: A61B 5/7221 : Determining signal validity, reliability or quality A61B5/7207 and A61B5/7217 take precedence
• CPC Class Codes: A61B 5/7246 : using correlation, e.g. template matching or determination of similarity
• CPC Class Codes: A61B 5/7275 : Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor
• CPC Class Codes: A61B 5/7278 : Artificial waveform generation or derivation, e.g. synthesising signals from measured signals A61B5/327 takes precedence
• CPC Class Codes: A61B 5/7405 : using sound
• CPC Class Codes: A61B 5/742 : using visual displays A61B5/339 takes precedence
• CPC Class Codes: A61B 5/746 : Alarms related to a physiological condition, e.g. details of setting alarm thresholds or avoiding false alarms alarms per se G08B
• CPC Class Codes: A61B 5/7475 : User input or interface means, e.g. keyboard, pointing device, joystick
• CPC Class Codes: G16H 10/40 : for data related to laboratory analysis, e.g. patient specimen analysis
• CPC Class Codes: G16H 40/67 : for remote operation
• CPC Class Codes: Y10S 439/909 : Medical use or attached to human body

Abstract

A physiological sensor is adapted to removably attach an emitter assembly and a detector assembly to a fingertip. The emitter assembly is adapted to transmit optical radiation having multiple wavelengths into fingertip tissue. The detector assembly is adapted to receive the optical radiation after attenuation by the fingertip tissue. The sensor has a first shell and a second shell hinged to the first shell. A spring is disposed between the shells and urges the shells together. An emitter pad is fixedly attached to the first shell and configured to retain the emitter assembly. A detector pad is fixedly attached to the second shell and configured to retain the detector assembly. A detector aperture is defined within the detector pad and adapted to pass optical radiation to the detector assembly. A contour is defined along the detector pad and generally shaped to conform to a fingertip positioned over the detector aperture.

Claims

1. A physiological sensor configured to measure an indication of a physiological characteristic of a living patient, the physiological sensor comprising:

a plurality of light emitting sources arranged to impinge light on body tissue of a living patient including at least eight light emitting sources, each of the at least eight light emitting sources emitting light at a different wavelength,

wherein at least a subset of the plurality of light emitting sources are further arranged in two or more clusters, each cluster comprising at least two light emitting sources that emit light within a wavelength range that is different from and does not overlap with the wavelength range of the at least two light emitting sources of other clusters,

wherein for each cluster, light emitting sources that emit light at proximate wavelengths are adjacent to each other,

wherein each light emitting source is activated by addressing at least one of a plurality of rows and at least one of a plurality of columns of an electrical grid and the plurality of light emitting sources are arranged to minimize optical pathlength differences;

a detector responsive to transmitted light after attenuation by body tissue of the living patient, the body tissue including pulsating blood, wherein the detector is configured to generate a signal indicative of a physiological characteristic of the living patient; and

a sensor housing configured to position the plurality of light emitting sources and the detector with respect to the body tissue of the living patient.

2. The physiological sensor according to claim 1, wherein multiple ones of the plurality of light emitting sources are capable of transmitting light of the same wavelength, the multiple ones simultaneously activated by addressing one of the rows or columns.

3. The physiological sensor according to claim 2, wherein:

the plurality of light emitting sources are LEDs, and

each of the LEDs have an anode in common with one of the rows and a cathode in common with one of the columns so that driving one of the rows and one of the columns activates a unique one of the LEDs.

4. The physiological sensor according to claim 3, further comprising:

a plurality of row drivers in communication with the rows; and

a plurality of column drivers in communication with the columns, wherein a selected row driver sources current to a corresponding row and selected column driver sinks current from a corresponding column so as to activate an addressed one of the LEDs.

5. The physiological sensor according to claim 4, wherein deselected ones of the row drivers pull corresponding rows to a low voltage via a functional switch configured to operably connect deselected rows to a low voltage source and deselected ones of the column drivers pull corresponding columns to a high voltage via a functional switch configured to operably connect deselected columns to a high voltage source so as to substantially block parasitic current from unaddressed ones of the LEDs.

6. The physiological sensor according to claim 5, wherein the electrical grid comprises at least three rows or at least three columns.

7. The physiological sensor according to claim 5, wherein the electrical grid comprises four rows and four columns in communication with up to sixteen of LEDs.

8. The physiological sensor of claim 1, wherein the plurality of light emitting sources and the detector are coupled to a flex circuit.

9. The physiological sensor of claim 1, wherein the plurality of light emitting sources are further arranged to facilitate equalization.

10. The physiological sensor of claim 1, wherein the electrical grid is arranged so as to prevent parasitic currents from unwanted activation of the plurality of light emitting sources.

11. The physiological sensor of claim 1, wherein the at least two light emitting sources of each cluster are arranged on the same row or column.

12. The physiological sensor of claim 1, wherein the light emitting sources are further configured to comprise wavelengths usable to measure two or more of HbCO, METHb, and SpO₂.

13. A method for measuring a physiological characteristic of a living patient, the method comprising:

positioning a sensor with respect to body tissue of a living patient, the sensor comprising a detector and a plurality of light emitting sources arranged in an electrical grid comprising rows and columns, the plurality of light emitting sources arranged to minimize path-length errors and to impinge light on the body tissue, the plurality of light emitting sources including at least eight light emitting sources, each of the at least eight light emitting sources emitting light at a different wavelength,

wherein at least a subset of the plurality of light emitting sources are further arranged in two or more clusters, each cluster comprising at least two light emitting sources that emit light within a wavelength range that is different from and does not overlap with the wavelength range of the at least two light emitting sources of other clusters,

wherein for each cluster, light emitting sources that emit light at proximate wavelengths are adjacent to each other;

activating at least one of the plurality of light emitting sources, said activating comprising addressing at least one of the rows and at least one of the columns of the electrical grid;

detecting transmitted light with the detector after attenuation by the body tissue of the living patient, the body tissue comprising pulsating blood; and

generating a signal reflecting a physiological characteristic of the living patient responsive to the detected light.

14. The method of claim 13, wherein the electrical grid is arranged so as to prevent parasitic currents from unwanted activation of the light emitting sources.

15. The method of claim 13, further comprising connecting deselected columns to a voltage source to substantially block parasitic current from unaddressed ones of the light emitting sources.

16. The method of claim 13, wherein the light emitting sources are further configured to emit wavelengths adapted to measure two or more of HbCO, METHb, and SpO₂.