CA2260928C - Direct to digital oximeter - Google Patents
Direct to digital oximeter Download PDFInfo
- Publication number
- CA2260928C CA2260928C CA002260928A CA2260928A CA2260928C CA 2260928 C CA2260928 C CA 2260928C CA 002260928 A CA002260928 A CA 002260928A CA 2260928 A CA2260928 A CA 2260928A CA 2260928 C CA2260928 C CA 2260928C
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- CA
- Canada
- Prior art keywords
- analog
- oximeter
- light
- oxygen saturation
- voltage signal
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Classifications
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/145—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue
- A61B5/1455—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters
- A61B5/14551—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters for measuring blood gases
Abstract
This invention is an oximeter for non-invasive measure of the oxygen saturation in blood with increased speed and accuracy. The device includes a sensor unit (20) which can be attached to a patient, and a n oximeter (10) which determines the oxygen saturation in the blood based on signals received from the sensor (20). In the present invention, the detected signal is immediately converted to a digital value (30).
Description
Direct to Digital Oximeter The present invention is concerned generally with an improved oximeter for non=lnvasivel~ measuring arterial oxygen saturation. More particularly, this invention is concerned with an improved method for direct digital signal formation from input signals produced by a sensor device which is connected to the oximeter.
In all oximeters, input signals are received from a sensor device which is directly connected to the blood-carrying tissue of a patient, such as a finger or ear lobe. The sensor device generally consists of a red LED, an infrared LED, and one or two photodetectors. Light from each LED is transmitted through the tissue, and the photodetectors detect the amount of light which passes through the tissue. The detected light consists of two components for each bandwidth. An AC component represents the amount of pulsating blood detected, while the DC component represents the amount of non-pulsating blood. Therefore, four separate components of detected light are examined in order to determine the arterial oxygen saturation: red DC, red AC, infrared DC and infrared AC. The amount of light detected is then used to determine the oxygen saturation in the blood of the patient based on the following equation:
(IR(AC) / IR(DC)) / (Red(AC) / Red(DC)) In a traditional oximeter, the sensor output signal is converted to an analog voltage and then separated into infrared and red components. Some oximeters further separate the AC and DC components. Separate analog circuits are then used to sample, demultiplex, and filter these signals. In these systems, therefore, it is necessary to carefully match the analog components to minimize errors which can result from differences in gain or frequency response in the two circuits.
The instant invention improves on this method by receiving input current signals from at least two and preferably three LED's of different wavelengths and converting these input signals directly to digital voltage values, without first converting to analog voltages or separating the signals. This is accomplished by using a charge digitizing analog to digital converter with suff cient range to represent the large DC
signals and sufficient resolution to represent the small AC signals. This charge digitizing converter employs a current integrator as the front stage, which tends to average and filter input noise.
This is an improvement over the analog current to voltage conversion used in traditional oximeters, which tend to amplify noise.
Once the input current is converted to a digital voltage value, all input signals are processed along the same digital hardware path, instead of the separate analog hardware paths required by the traditional method. This system eliminates the need to match analog hardware components, and therefore further reduces potential errors. Furthermore, once the signals are digitized, a microprocessor can perform all of the signal processing, demultiplexing, and filtering steps required by traditional oximeters. This reduction in the analog signal processing stage increases both the speed and accuracy of the oximeter, decreases cost by eliminating expensive analog components, and reduces the size of the oximeter by eliminating physically large analog components.
Accordingly, this invention seeks to provide an improved method for non-invasively measuring fluid parameters.
Further, this invention seeks to provide an improved method for measuring arterial blood saturation.
Still further, the invention seeks to provide improved speed and accuracy in the measurements provided by oximeters.
Further still, the invention seeks to provide a direct analog to digital conversion of the input current signal with sufficient range to measure large DC signals and enough resolution to represent small AC signals so that accurate measurements can be made with reduced analog signal processing.
Moreover, the invention seeks to provide a reduction in potential errors by directly converting the input current signal to a digital voltage signal, thereby bypassing the current to voltage conversion step which can amplify noise.
In all oximeters, input signals are received from a sensor device which is directly connected to the blood-carrying tissue of a patient, such as a finger or ear lobe. The sensor device generally consists of a red LED, an infrared LED, and one or two photodetectors. Light from each LED is transmitted through the tissue, and the photodetectors detect the amount of light which passes through the tissue. The detected light consists of two components for each bandwidth. An AC component represents the amount of pulsating blood detected, while the DC component represents the amount of non-pulsating blood. Therefore, four separate components of detected light are examined in order to determine the arterial oxygen saturation: red DC, red AC, infrared DC and infrared AC. The amount of light detected is then used to determine the oxygen saturation in the blood of the patient based on the following equation:
(IR(AC) / IR(DC)) / (Red(AC) / Red(DC)) In a traditional oximeter, the sensor output signal is converted to an analog voltage and then separated into infrared and red components. Some oximeters further separate the AC and DC components. Separate analog circuits are then used to sample, demultiplex, and filter these signals. In these systems, therefore, it is necessary to carefully match the analog components to minimize errors which can result from differences in gain or frequency response in the two circuits.
The instant invention improves on this method by receiving input current signals from at least two and preferably three LED's of different wavelengths and converting these input signals directly to digital voltage values, without first converting to analog voltages or separating the signals. This is accomplished by using a charge digitizing analog to digital converter with suff cient range to represent the large DC
signals and sufficient resolution to represent the small AC signals. This charge digitizing converter employs a current integrator as the front stage, which tends to average and filter input noise.
This is an improvement over the analog current to voltage conversion used in traditional oximeters, which tend to amplify noise.
Once the input current is converted to a digital voltage value, all input signals are processed along the same digital hardware path, instead of the separate analog hardware paths required by the traditional method. This system eliminates the need to match analog hardware components, and therefore further reduces potential errors. Furthermore, once the signals are digitized, a microprocessor can perform all of the signal processing, demultiplexing, and filtering steps required by traditional oximeters. This reduction in the analog signal processing stage increases both the speed and accuracy of the oximeter, decreases cost by eliminating expensive analog components, and reduces the size of the oximeter by eliminating physically large analog components.
Accordingly, this invention seeks to provide an improved method for non-invasively measuring fluid parameters.
Further, this invention seeks to provide an improved method for measuring arterial blood saturation.
Still further, the invention seeks to provide improved speed and accuracy in the measurements provided by oximeters.
Further still, the invention seeks to provide a direct analog to digital conversion of the input current signal with sufficient range to measure large DC signals and enough resolution to represent small AC signals so that accurate measurements can be made with reduced analog signal processing.
Moreover, the invention seeks to provide a reduction in potential errors by directly converting the input current signal to a digital voltage signal, thereby bypassing the current to voltage conversion step which can amplify noise.
Yet further, the invention seeks to provide a reduction in potential errors by processing all signals along one digital hardware path, thereby eliminating the need for matched analog components.
The invention in another aspect seeks to provide an improved oximeter having a reduced number of electronic circuit components.
Therefore, the invention in one broad aspect pertains to a method for non-invasively measuring arterial oxygen saturation, comprising the steps of: producing light of at least first:
and second wavelengths; directing the light at a tissue sample containing a pulsating blood supply; detecting the light, after passing through the tissue sample, and producing an analog electrical current signal representing the absorption rate of each wavelength of the light; then directly converting the analog electrical current signal to a digital voltage signal; and then processing the digital voltage signal to calculate an arterial oxygen saturation.
The invention in another broad aspect provides an oximeter for non-invasively measuring arterial oxygen saturation, comprising a sensor including at least first and second light emitting devices for producing light in at least two wavelengths, and at least one photodetector for detecting the light, after passing through a tissue sample containing a pulsating blood supply, and for producing an analog electrical current signal representing the absorption of each wavelength of the light. An analog to digital converter is provided for directly converting the analog electrical current signal to a digital voltage signal, and a processing unit processes the digital voltage signal to calculate an arterial oxygen saturation.
More particularly, the analog to digital converter directly receives the analog electrical current signal produced by the photodetectors for directly converting the analog electrical signal to a digital voltage signal without first converting the analog electrical current to an analog voltage signal.
These and other aspects and advantages of the invention, together with the organization and manner of operation thereof, will become apparent from the following detailed description when taken in conjunction with the accompanying drawings described below.
Brief Description of the Drawings FIGURE 1 illustrates a block diagram of the direct to digital oximeter as connected to a sensor device; and FIGURE 2 illustrates the sensor device and direct to digital oximeter connected to a patient.
Detailed Description of the Preferred Embodiment , A block diagram of a direct to digital oximeter 10 constructed in accordance with the invention, along with an external sensor device 20 is shown in FIG. 1. The direct to digital oximeter 10 comprises a charge digitizing analog to digital converter 30, a microprocessor 40, a digital to analog converter/LED driver 50, and a flash EPROM 60. In order to achieve sufficient accuracy, the charge digitizing analog to digital converter 30 preferably converts the input analog signal to a digital signal of at least 20 bits.
In a preferred embodiment (see FIG. 2) the sensor 20 is attached to a blood-carrying tissue sample, such as the finger or ear lobe of a patient. Here, the sensor 20 is shown to consist of a red LED 70, an infrared LED 80, and a single photodetectar 90, but the sensor device 20 can include three or more LED's of different wavelengths and an associated plurality of photodetectors. The LED's 70 and 80 are driven by digital signals from the microprocessor 40. These digital signals are converted to analog voltages by means of the digital to analog converter/LED driver 50. Light from the LED's 70 and 80 is transmitted through the tissue sample, and is detected by the photodetector 90, which produces an analog current signal with an amplitude proportional to the amount of light detected in each bandwidth. The current signal from the photodetector 90 is then digitized with 20 bits of resolution by the charge digitizing analog to digital converter 30, and is sent to the microprocessor 40. Demultiplexing, ambient interference identification and elimination, and signal filtering are performed by means of digital signal processing software routines in the microprocessor 40. Once the signals are processed, the microprocessor 40 calculates the value of the ratio (IR(AC) / IR(DC)) / (Red(AC) / Red(DC)) where the DC component represents the non-pulsating blood flow, and the AC
component indicates the pulsatile blood flow. The microprocessor 40 then determines the absolute arterial oxygen saturation by comparing the result to the value stored in a look-up table in flash EPROM 60.
While preferred embodiments of the invention have been shown and described, it will be clear to those skilled in the art that various changes and modifications can be made without departing from the invention in its broader aspects as set forth in the claims provided hereinafter.
The invention in another aspect seeks to provide an improved oximeter having a reduced number of electronic circuit components.
Therefore, the invention in one broad aspect pertains to a method for non-invasively measuring arterial oxygen saturation, comprising the steps of: producing light of at least first:
and second wavelengths; directing the light at a tissue sample containing a pulsating blood supply; detecting the light, after passing through the tissue sample, and producing an analog electrical current signal representing the absorption rate of each wavelength of the light; then directly converting the analog electrical current signal to a digital voltage signal; and then processing the digital voltage signal to calculate an arterial oxygen saturation.
The invention in another broad aspect provides an oximeter for non-invasively measuring arterial oxygen saturation, comprising a sensor including at least first and second light emitting devices for producing light in at least two wavelengths, and at least one photodetector for detecting the light, after passing through a tissue sample containing a pulsating blood supply, and for producing an analog electrical current signal representing the absorption of each wavelength of the light. An analog to digital converter is provided for directly converting the analog electrical current signal to a digital voltage signal, and a processing unit processes the digital voltage signal to calculate an arterial oxygen saturation.
More particularly, the analog to digital converter directly receives the analog electrical current signal produced by the photodetectors for directly converting the analog electrical signal to a digital voltage signal without first converting the analog electrical current to an analog voltage signal.
These and other aspects and advantages of the invention, together with the organization and manner of operation thereof, will become apparent from the following detailed description when taken in conjunction with the accompanying drawings described below.
Brief Description of the Drawings FIGURE 1 illustrates a block diagram of the direct to digital oximeter as connected to a sensor device; and FIGURE 2 illustrates the sensor device and direct to digital oximeter connected to a patient.
Detailed Description of the Preferred Embodiment , A block diagram of a direct to digital oximeter 10 constructed in accordance with the invention, along with an external sensor device 20 is shown in FIG. 1. The direct to digital oximeter 10 comprises a charge digitizing analog to digital converter 30, a microprocessor 40, a digital to analog converter/LED driver 50, and a flash EPROM 60. In order to achieve sufficient accuracy, the charge digitizing analog to digital converter 30 preferably converts the input analog signal to a digital signal of at least 20 bits.
In a preferred embodiment (see FIG. 2) the sensor 20 is attached to a blood-carrying tissue sample, such as the finger or ear lobe of a patient. Here, the sensor 20 is shown to consist of a red LED 70, an infrared LED 80, and a single photodetectar 90, but the sensor device 20 can include three or more LED's of different wavelengths and an associated plurality of photodetectors. The LED's 70 and 80 are driven by digital signals from the microprocessor 40. These digital signals are converted to analog voltages by means of the digital to analog converter/LED driver 50. Light from the LED's 70 and 80 is transmitted through the tissue sample, and is detected by the photodetector 90, which produces an analog current signal with an amplitude proportional to the amount of light detected in each bandwidth. The current signal from the photodetector 90 is then digitized with 20 bits of resolution by the charge digitizing analog to digital converter 30, and is sent to the microprocessor 40. Demultiplexing, ambient interference identification and elimination, and signal filtering are performed by means of digital signal processing software routines in the microprocessor 40. Once the signals are processed, the microprocessor 40 calculates the value of the ratio (IR(AC) / IR(DC)) / (Red(AC) / Red(DC)) where the DC component represents the non-pulsating blood flow, and the AC
component indicates the pulsatile blood flow. The microprocessor 40 then determines the absolute arterial oxygen saturation by comparing the result to the value stored in a look-up table in flash EPROM 60.
While preferred embodiments of the invention have been shown and described, it will be clear to those skilled in the art that various changes and modifications can be made without departing from the invention in its broader aspects as set forth in the claims provided hereinafter.
Claims (15)
- WHAT IS CLAIMED IS:
An oximeter for non-invasively measuring arterial oxygen saturation, comprising:
a sensor including at least first and second light emitting devices for producing light in at least two wavelengths;
at least one photodetector for detecting said light, after passing through a tissue sample containing a pulsating blood supply, and for producing an analog electrical current signal representing the absorption of each wavelength of said light;
an analog to digital converter for directly converting said analog electrical current signal to a digital voltage signal; and a processing unit for processing said digital voltage signal to calculate an arterial oxygen saturation. - 2. The oximeter of claim 1 wherein said sensor comprises LED's which produce light in three wavelengths.
- 3. The oximeter of claim 1 wherein said analog to digital converter comprises a charge digitizing analog to digital converter.
- 4. The oximeter of claim 1 wherein said analog to digital converter has sufficient range to measure large DC signals and sufficient resolution to represent small AC
signals modulated on the DC signals. - 5. The oximeter of claim 1 wherein said analog to digital converter includes a current integrator in the first stage.
- 6. The oximeter of claim 1 wherein said processing unit comprises a computer executing software routines.
- 7. The oximeter of claim 1 further comprising a stored look-up table for calculating oxygen saturation.
- 8. The oximeter of claim 1 further comprising a stored look-up table stored in flash EPROM for calculating oxygen saturation.
- 9. A method for non-invasively measuring arterial oxygen saturation, comprising the steps of:
producing light of at least first and second wavelengths;
directing said light at a tissue sample containing a pulsating blood supply;
detecting said light, after passing through said tissue sample, and producing an analog electrical current signal representing the absorption rate of each wavelength of said light;
then directly converting said analog electrical current signal to a digital voltage signal;
and then processing the digital voltage signal to calculate an arterial oxygen saturation. - 10. The method as defined in claim 9 further including the step of utilizing a stored look-up table to calculate the oxygen saturation.
- 11. The method as defined in claim 9 further including the steps of storing a look-up table in a flash EPROM and utilizing this look-up table to calculate the oxygen saturation.
- 12. The method as defined in claim 9 further including the steps of identifying and filtering ambient noise from the digital voltage signal.
- 13. The method as defined in claim 9 further including the step of mathematically integrating the analog electrical current signal before converting the analog current signal to the digital voltage signal.
- 14. The method as defined in claim 9 further including the step of demultiplexing the digital voltage signal to provide a first value representative of light detected of the first wavelength and a second value representative of light detected of the second wavelength.
- 15. The method as defined in claim 14 further including the step of digitally filtering the first and second values of the digital voltage signal.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08/683,617 US5842981A (en) | 1996-07-17 | 1996-07-17 | Direct to digital oximeter |
| US08/683,617 | 1996-07-17 | ||
| PCT/US1997/012484 WO1998002087A1 (en) | 1996-07-17 | 1997-07-17 | Direct to digital oximeter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2260928A1 CA2260928A1 (en) | 1998-01-22 |
| CA2260928C true CA2260928C (en) | 2005-05-24 |
Family
ID=24744795
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002260928A Expired - Fee Related CA2260928C (en) | 1996-07-17 | 1997-07-17 | Direct to digital oximeter |
Country Status (10)
| Country | Link |
|---|---|
| US (1) | US5842981A (en) |
| EP (1) | EP0955869B1 (en) |
| JP (1) | JP2000514683A (en) |
| CN (1) | CN1160021C (en) |
| AU (1) | AU720111B2 (en) |
| BR (1) | BR9710330A (en) |
| CA (1) | CA2260928C (en) |
| DE (1) | DE69724822T2 (en) |
| ES (1) | ES2206740T3 (en) |
| WO (1) | WO1998002087A1 (en) |
Families Citing this family (172)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5490505A (en) | 1991-03-07 | 1996-02-13 | Masimo Corporation | Signal processing apparatus |
| MX9702434A (en) | 1991-03-07 | 1998-05-31 | Masimo Corp | Signal processing apparatus. |
| WO1992015955A1 (en) | 1991-03-07 | 1992-09-17 | Vital Signals, Inc. | Signal processing apparatus and method |
| US5632272A (en) | 1991-03-07 | 1997-05-27 | Masimo Corporation | Signal processing apparatus |
| US8019400B2 (en) | 1994-10-07 | 2011-09-13 | Masimo Corporation | Signal processing apparatus |
| EP1905352B1 (en) | 1994-10-07 | 2014-07-16 | Masimo Corporation | Signal processing method |
| US6163715A (en) * | 1996-07-17 | 2000-12-19 | Criticare Systems, Inc. | Direct to digital oximeter and method for calculating oxygenation levels |
| US6018673A (en) | 1996-10-10 | 2000-01-25 | Nellcor Puritan Bennett Incorporated | Motion compatible sensor for non-invasive optical blood analysis |
| US5855550A (en) | 1996-11-13 | 1999-01-05 | Lai; Joseph | Method and system for remotely monitoring multiple medical parameters |
| US8932227B2 (en) | 2000-07-28 | 2015-01-13 | Lawrence A. Lynn | System and method for CO2 and oximetry integration |
| US9468378B2 (en) | 1997-01-27 | 2016-10-18 | Lawrence A. Lynn | Airway instability detection system and method |
| US9042952B2 (en) | 1997-01-27 | 2015-05-26 | Lawrence A. Lynn | System and method for automatic detection of a plurality of SPO2 time series pattern types |
| WO1998037473A2 (en) | 1997-02-07 | 1998-08-27 | General Internet, Inc. | Collaborative internet data mining system |
| US20030208535A1 (en) | 2001-12-28 | 2003-11-06 | Appleman Kenneth H. | Collaborative internet data mining system |
| US6002952A (en) | 1997-04-14 | 1999-12-14 | Masimo Corporation | Signal processing apparatus and method |
| US9521971B2 (en) | 1997-07-14 | 2016-12-20 | Lawrence A. Lynn | System and method for automatic detection of a plurality of SPO2 time series pattern types |
| US20070191697A1 (en) | 2006-02-10 | 2007-08-16 | Lynn Lawrence A | System and method for SPO2 instability detection and quantification |
| EP1083822A4 (en) * | 1998-06-11 | 2005-10-12 | S P O Medical Equipment Ltd | Physiological stress detector device and method |
| US6990365B1 (en) * | 1998-07-04 | 2006-01-24 | Edwards Lifesciences | Apparatus for measurement of blood analytes |
| US6842635B1 (en) | 1998-08-13 | 2005-01-11 | Edwards Lifesciences Llc | Optical device |
| US7400918B2 (en) * | 1998-07-04 | 2008-07-15 | Edwards Lifesciences | Measurement of blood oxygen saturation |
| US6675031B1 (en) | 1999-04-14 | 2004-01-06 | Mallinckrodt Inc. | Method and circuit for indicating quality and accuracy of physiological measurements |
| US6339715B1 (en) | 1999-09-30 | 2002-01-15 | Ob Scientific | Method and apparatus for processing a physiological signal |
| US6433696B1 (en) | 1999-11-05 | 2002-08-13 | Alto U.S., Inc. | Carbon monoxide emitting apparatus, carbon monoxide monitor shutoff, and circuit therefor |
| US8224412B2 (en) | 2000-04-17 | 2012-07-17 | Nellcor Puritan Bennett Llc | Pulse oximeter sensor with piece-wise function |
| ES2392818T3 (en) | 2000-04-17 | 2012-12-14 | Nellcor Puritan Bennett Llc | Pulse oximeter sensor with section function |
| US6889153B2 (en) | 2001-08-09 | 2005-05-03 | Thomas Dietiker | System and method for a self-calibrating non-invasive sensor |
| IL138884A (en) | 2000-10-05 | 2006-07-05 | Conmed Corp | Pulse oximeter and a method of its operation |
| US20060195041A1 (en) | 2002-05-17 | 2006-08-31 | Lynn Lawrence A | Centralized hospital monitoring system for automatically detecting upper airway instability and for preventing and aborting adverse drug reactions |
| US9053222B2 (en) | 2002-05-17 | 2015-06-09 | Lawrence A. Lynn | Patient safety processor |
| JP4642279B2 (en) * | 2001-06-28 | 2011-03-02 | 株式会社日立メディコ | Biological light measurement device |
| US6754516B2 (en) | 2001-07-19 | 2004-06-22 | Nellcor Puritan Bennett Incorporated | Nuisance alarm reductions in a physiological monitor |
| US6654621B2 (en) | 2001-08-29 | 2003-11-25 | Bci, Inc. | Finger oximeter with finger grip suspension system |
| IL145445A (en) * | 2001-09-13 | 2006-12-31 | Conmed Corp | Signal processing method and device for signal-to-noise improvement |
| US6748254B2 (en) | 2001-10-12 | 2004-06-08 | Nellcor Puritan Bennett Incorporated | Stacked adhesive optical sensor |
| US7698909B2 (en) | 2002-10-01 | 2010-04-20 | Nellcor Puritan Bennett Llc | Headband with tension indicator |
| US7810359B2 (en) | 2002-10-01 | 2010-10-12 | Nellcor Puritan Bennett Llc | Headband with tension indicator |
| US7190986B1 (en) | 2002-10-18 | 2007-03-13 | Nellcor Puritan Bennett Inc. | Non-adhesive oximeter sensor for sensitive skin |
| US7006856B2 (en) | 2003-01-10 | 2006-02-28 | Nellcor Puritan Bennett Incorporated | Signal quality metrics design for qualifying data for a physiological monitor |
| US7016715B2 (en) | 2003-01-13 | 2006-03-21 | Nellcorpuritan Bennett Incorporated | Selection of preset filter parameters based on signal quality |
| US7047056B2 (en) | 2003-06-25 | 2006-05-16 | Nellcor Puritan Bennett Incorporated | Hat-based oximeter sensor |
| US8412297B2 (en) | 2003-10-01 | 2013-04-02 | Covidien Lp | Forehead sensor placement |
| EP1520514A1 (en) | 2003-10-02 | 2005-04-06 | Matsushita Electric Industrial Co., Ltd. | Optical biological information measuring apparatus and method |
| US7190985B2 (en) | 2004-02-25 | 2007-03-13 | Nellcor Puritan Bennett Inc. | Oximeter ambient light cancellation |
| US7120479B2 (en) | 2004-02-25 | 2006-10-10 | Nellcor Puritan Bennett Inc. | Switch-mode oximeter LED drive with a single inductor |
| US7534212B2 (en) | 2004-03-08 | 2009-05-19 | Nellcor Puritan Bennett Llc | Pulse oximeter with alternate heart-rate determination |
| US7194293B2 (en) | 2004-03-08 | 2007-03-20 | Nellcor Puritan Bennett Incorporated | Selection of ensemble averaging weights for a pulse oximeter based on signal quality metrics |
| US7277741B2 (en) * | 2004-03-09 | 2007-10-02 | Nellcor Puritan Bennett Incorporated | Pulse oximetry motion artifact rejection using near infrared absorption by water |
| US9143572B2 (en) | 2004-09-17 | 2015-09-22 | About, Inc. | Method and system for providing content to users based on frequency of interaction |
| US20080281298A1 (en) * | 2005-02-07 | 2008-11-13 | Andersen David R | Electronic support system for biological data sensor |
| US7392075B2 (en) | 2005-03-03 | 2008-06-24 | Nellcor Puritan Bennett Incorporated | Method for enhancing pulse oximetry calculations in the presence of correlated artifacts |
| US8204565B2 (en) * | 2005-04-04 | 2012-06-19 | University Of Iowa Research Foundation | Reagentless optical analyte detection system |
| US7657295B2 (en) | 2005-08-08 | 2010-02-02 | Nellcor Puritan Bennett Llc | Medical sensor and technique for using the same |
| US7590439B2 (en) | 2005-08-08 | 2009-09-15 | Nellcor Puritan Bennett Llc | Bi-stable medical sensor and technique for using the same |
| US7657294B2 (en) | 2005-08-08 | 2010-02-02 | Nellcor Puritan Bennett Llc | Compliant diaphragm medical sensor and technique for using the same |
| US20070060808A1 (en) | 2005-09-12 | 2007-03-15 | Carine Hoarau | Medical sensor for reducing motion artifacts and technique for using the same |
| US8092379B2 (en) | 2005-09-29 | 2012-01-10 | Nellcor Puritan Bennett Llc | Method and system for determining when to reposition a physiological sensor |
| US7904130B2 (en) | 2005-09-29 | 2011-03-08 | Nellcor Puritan Bennett Llc | Medical sensor and technique for using the same |
| US7869850B2 (en) | 2005-09-29 | 2011-01-11 | Nellcor Puritan Bennett Llc | Medical sensor for reducing motion artifacts and technique for using the same |
| US7725147B2 (en) | 2005-09-29 | 2010-05-25 | Nellcor Puritan Bennett Llc | System and method for removing artifacts from waveforms |
| US7899510B2 (en) | 2005-09-29 | 2011-03-01 | Nellcor Puritan Bennett Llc | Medical sensor and technique for using the same |
| US7725146B2 (en) | 2005-09-29 | 2010-05-25 | Nellcor Puritan Bennett Llc | System and method for pre-processing waveforms |
| US20070106126A1 (en) | 2005-09-30 | 2007-05-10 | Mannheimer Paul D | Patient monitoring alarm escalation system and method |
| US8062221B2 (en) | 2005-09-30 | 2011-11-22 | Nellcor Puritan Bennett Llc | Sensor for tissue gas detection and technique for using the same |
| US7486979B2 (en) | 2005-09-30 | 2009-02-03 | Nellcor Puritan Bennett Llc | Optically aligned pulse oximetry sensor and technique for using the same |
| US8233954B2 (en) | 2005-09-30 | 2012-07-31 | Nellcor Puritan Bennett Llc | Mucosal sensor for the assessment of tissue and blood constituents and technique for using the same |
| US7555327B2 (en) | 2005-09-30 | 2009-06-30 | Nellcor Puritan Bennett Llc | Folding medical sensor and technique for using the same |
| US7881762B2 (en) | 2005-09-30 | 2011-02-01 | Nellcor Puritan Bennett Llc | Clip-style medical sensor and technique for using the same |
| US7483731B2 (en) | 2005-09-30 | 2009-01-27 | Nellcor Puritan Bennett Llc | Medical sensor and technique for using the same |
| US20070100220A1 (en) | 2005-10-28 | 2007-05-03 | Baker Clark R Jr | Adjusting parameters used in pulse oximetry analysis |
| US7668579B2 (en) | 2006-02-10 | 2010-02-23 | Lynn Lawrence A | System and method for the detection of physiologic response to stimulation |
| US8702606B2 (en) | 2006-03-21 | 2014-04-22 | Covidien Lp | Patient monitoring help video system and method |
| US8073518B2 (en) | 2006-05-02 | 2011-12-06 | Nellcor Puritan Bennett Llc | Clip-style medical sensor and technique for using the same |
| US8380271B2 (en) | 2006-06-15 | 2013-02-19 | Covidien Lp | System and method for generating customizable audible beep tones and alarms |
| EP2043522A4 (en) * | 2006-06-16 | 2010-01-06 | Medtor Llc | System and method for a non-invasive medical sensor |
| US20070299323A1 (en) * | 2006-06-27 | 2007-12-27 | Martijn Wilco Arns | Apparatus for measuring one or more physiological functions of a body and a method using the same |
| US8145288B2 (en) | 2006-08-22 | 2012-03-27 | Nellcor Puritan Bennett Llc | Medical sensor for reducing signal artifacts and technique for using the same |
| US8064975B2 (en) | 2006-09-20 | 2011-11-22 | Nellcor Puritan Bennett Llc | System and method for probability based determination of estimated oxygen saturation |
| US8219170B2 (en) | 2006-09-20 | 2012-07-10 | Nellcor Puritan Bennett Llc | System and method for practicing spectrophotometry using light emitting nanostructure devices |
| US8190224B2 (en) | 2006-09-22 | 2012-05-29 | Nellcor Puritan Bennett Llc | Medical sensor for reducing signal artifacts and technique for using the same |
| US8175671B2 (en) | 2006-09-22 | 2012-05-08 | Nellcor Puritan Bennett Llc | Medical sensor for reducing signal artifacts and technique for using the same |
| US8396527B2 (en) | 2006-09-22 | 2013-03-12 | Covidien Lp | Medical sensor for reducing signal artifacts and technique for using the same |
| US7869849B2 (en) | 2006-09-26 | 2011-01-11 | Nellcor Puritan Bennett Llc | Opaque, electrically nonconductive region on a medical sensor |
| US8696593B2 (en) | 2006-09-27 | 2014-04-15 | Covidien Lp | Method and system for monitoring intracranial pressure |
| US7574245B2 (en) | 2006-09-27 | 2009-08-11 | Nellcor Puritan Bennett Llc | Flexible medical sensor enclosure |
| US7922665B2 (en) | 2006-09-28 | 2011-04-12 | Nellcor Puritan Bennett Llc | System and method for pulse rate calculation using a scheme for alternate weighting |
| US7796403B2 (en) | 2006-09-28 | 2010-09-14 | Nellcor Puritan Bennett Llc | Means for mechanical registration and mechanical-electrical coupling of a faraday shield to a photodetector and an electrical circuit |
| US7890153B2 (en) | 2006-09-28 | 2011-02-15 | Nellcor Puritan Bennett Llc | System and method for mitigating interference in pulse oximetry |
| US7925511B2 (en) | 2006-09-29 | 2011-04-12 | Nellcor Puritan Bennett Llc | System and method for secure voice identification in a medical device |
| US7706896B2 (en) | 2006-09-29 | 2010-04-27 | Nellcor Puritan Bennett Llc | User interface and identification in a medical device system and method |
| US8116852B2 (en) | 2006-09-29 | 2012-02-14 | Nellcor Puritan Bennett Llc | System and method for detection of skin wounds and compartment syndromes |
| US7698002B2 (en) | 2006-09-29 | 2010-04-13 | Nellcor Puritan Bennett Llc | Systems and methods for user interface and identification in a medical device |
| US20080081956A1 (en) | 2006-09-29 | 2008-04-03 | Jayesh Shah | System and method for integrating voice with a medical device |
| US8068891B2 (en) | 2006-09-29 | 2011-11-29 | Nellcor Puritan Bennett Llc | Symmetric LED array for pulse oximetry |
| US8160668B2 (en) | 2006-09-29 | 2012-04-17 | Nellcor Puritan Bennett Llc | Pathological condition detector using kernel methods and oximeters |
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| US8175667B2 (en) | 2006-09-29 | 2012-05-08 | Nellcor Puritan Bennett Llc | Symmetric LED array for pulse oximetry |
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| US8032528B2 (en) | 2007-01-12 | 2011-10-04 | About Inc. | Method and system for managing content submission and publication of content |
| US7894869B2 (en) | 2007-03-09 | 2011-02-22 | Nellcor Puritan Bennett Llc | Multiple configuration medical sensor and technique for using the same |
| US8265724B2 (en) | 2007-03-09 | 2012-09-11 | Nellcor Puritan Bennett Llc | Cancellation of light shunting |
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| AU2008322541A1 (en) * | 2007-11-14 | 2009-05-22 | Conmed Corporation | Method and apparatus for processing a pulsatile biometric signal |
| US8204567B2 (en) | 2007-12-13 | 2012-06-19 | Nellcor Puritan Bennett Llc | Signal demodulation |
| US8352004B2 (en) | 2007-12-21 | 2013-01-08 | Covidien Lp | Medical sensor and technique for using the same |
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| US8577434B2 (en) | 2007-12-27 | 2013-11-05 | Covidien Lp | Coaxial LED light sources |
| US8452364B2 (en) | 2007-12-28 | 2013-05-28 | Covidien LLP | System and method for attaching a sensor to a patient's skin |
| US8442608B2 (en) | 2007-12-28 | 2013-05-14 | Covidien Lp | System and method for estimating physiological parameters by deconvolving artifacts |
| US8070508B2 (en) | 2007-12-31 | 2011-12-06 | Nellcor Puritan Bennett Llc | Method and apparatus for aligning and securing a cable strain relief |
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| US8092993B2 (en) | 2007-12-31 | 2012-01-10 | Nellcor Puritan Bennett Llc | Hydrogel thin film for use as a biosensor |
| US8199007B2 (en) | 2007-12-31 | 2012-06-12 | Nellcor Puritan Bennett Llc | Flex circuit snap track for a biometric sensor |
| US8750953B2 (en) | 2008-02-19 | 2014-06-10 | Covidien Lp | Methods and systems for alerting practitioners to physiological conditions |
| US8275553B2 (en) | 2008-02-19 | 2012-09-25 | Nellcor Puritan Bennett Llc | System and method for evaluating physiological parameter data |
| US8140272B2 (en) | 2008-03-27 | 2012-03-20 | Nellcor Puritan Bennett Llc | System and method for unmixing spectroscopic observations with nonnegative matrix factorization |
| US8437822B2 (en) | 2008-03-28 | 2013-05-07 | Covidien Lp | System and method for estimating blood analyte concentration |
| US8364224B2 (en) | 2008-03-31 | 2013-01-29 | Covidien Lp | System and method for facilitating sensor and monitor communication |
| US8292809B2 (en) | 2008-03-31 | 2012-10-23 | Nellcor Puritan Bennett Llc | Detecting chemical components from spectroscopic observations |
| US8112375B2 (en) | 2008-03-31 | 2012-02-07 | Nellcor Puritan Bennett Llc | Wavelength selection and outlier detection in reduced rank linear models |
| WO2009137682A1 (en) | 2008-05-07 | 2009-11-12 | Lynn Lawrence A | Medical failure pattern search engine |
| US8071935B2 (en) | 2008-06-30 | 2011-12-06 | Nellcor Puritan Bennett Llc | Optical detector with an overmolded faraday shield |
| USD626562S1 (en) | 2008-06-30 | 2010-11-02 | Nellcor Puritan Bennett Llc | Triangular saturation pattern detection indicator for a patient monitor display panel |
| USD626561S1 (en) | 2008-06-30 | 2010-11-02 | Nellcor Puritan Bennett Llc | Circular satseconds indicator and triangular saturation pattern detection indicator for a patient monitor display panel |
| US7887345B2 (en) | 2008-06-30 | 2011-02-15 | Nellcor Puritan Bennett Llc | Single use connector for pulse oximetry sensors |
| US9895068B2 (en) | 2008-06-30 | 2018-02-20 | Covidien Lp | Pulse oximeter with wait-time indication |
| US7880884B2 (en) | 2008-06-30 | 2011-02-01 | Nellcor Puritan Bennett Llc | System and method for coating and shielding electronic sensor components |
| US8257274B2 (en) | 2008-09-25 | 2012-09-04 | Nellcor Puritan Bennett Llc | Medical sensor and technique for using the same |
| US8364220B2 (en) | 2008-09-25 | 2013-01-29 | Covidien Lp | Medical sensor and technique for using the same |
| US8423112B2 (en) | 2008-09-30 | 2013-04-16 | Covidien Lp | Medical sensor and technique for using the same |
| US8386000B2 (en) | 2008-09-30 | 2013-02-26 | Covidien Lp | System and method for photon density wave pulse oximetry and pulse hemometry |
| US20100081904A1 (en) * | 2008-09-30 | 2010-04-01 | Nellcor Puritan Bennett Llc | Device And Method For Securing A Medical Sensor to An Infant's Head |
| US8417309B2 (en) | 2008-09-30 | 2013-04-09 | Covidien Lp | Medical sensor |
| US8914088B2 (en) | 2008-09-30 | 2014-12-16 | Covidien Lp | Medical sensor and technique for using the same |
| US8968193B2 (en) | 2008-09-30 | 2015-03-03 | Covidien Lp | System and method for enabling a research mode on physiological monitors |
| US8433382B2 (en) | 2008-09-30 | 2013-04-30 | Covidien Lp | Transmission mode photon density wave system and method |
| US8452366B2 (en) | 2009-03-16 | 2013-05-28 | Covidien Lp | Medical monitoring device with flexible circuitry |
| US8515515B2 (en) | 2009-03-25 | 2013-08-20 | Covidien Lp | Medical sensor with compressible light barrier and technique for using the same |
| US8221319B2 (en) | 2009-03-25 | 2012-07-17 | Nellcor Puritan Bennett Llc | Medical device for assessing intravascular blood volume and technique for using the same |
| US8781548B2 (en) | 2009-03-31 | 2014-07-15 | Covidien Lp | Medical sensor with flexible components and technique for using the same |
| US8509869B2 (en) | 2009-05-15 | 2013-08-13 | Covidien Lp | Method and apparatus for detecting and analyzing variations in a physiologic parameter |
| US8634891B2 (en) | 2009-05-20 | 2014-01-21 | Covidien Lp | Method and system for self regulation of sensor component contact pressure |
| US8505821B2 (en) | 2009-06-30 | 2013-08-13 | Covidien Lp | System and method for providing sensor quality assurance |
| US8311601B2 (en) | 2009-06-30 | 2012-11-13 | Nellcor Puritan Bennett Llc | Reflectance and/or transmissive pulse oximeter |
| US9010634B2 (en) | 2009-06-30 | 2015-04-21 | Covidien Lp | System and method for linking patient data to a patient and providing sensor quality assurance |
| US8391941B2 (en) | 2009-07-17 | 2013-03-05 | Covidien Lp | System and method for memory switching for multiple configuration medical sensor |
| US8494786B2 (en) | 2009-07-30 | 2013-07-23 | Covidien Lp | Exponential sampling of red and infrared signals |
| US8417310B2 (en) | 2009-08-10 | 2013-04-09 | Covidien Lp | Digital switching in multi-site sensor |
| US8428675B2 (en) | 2009-08-19 | 2013-04-23 | Covidien Lp | Nanofiber adhesives used in medical devices |
| US8494606B2 (en) | 2009-08-19 | 2013-07-23 | Covidien Lp | Photoplethysmography with controlled application of sensor pressure |
| US8788001B2 (en) | 2009-09-21 | 2014-07-22 | Covidien Lp | Time-division multiplexing in a multi-wavelength photon density wave system |
| US8704666B2 (en) | 2009-09-21 | 2014-04-22 | Covidien Lp | Medical device interface customization systems and methods |
| US8494604B2 (en) | 2009-09-21 | 2013-07-23 | Covidien Lp | Wavelength-division multiplexing in a multi-wavelength photon density wave system |
| US8798704B2 (en) | 2009-09-24 | 2014-08-05 | Covidien Lp | Photoacoustic spectroscopy method and system to discern sepsis from shock |
| US8376955B2 (en) | 2009-09-29 | 2013-02-19 | Covidien Lp | Spectroscopic method and system for assessing tissue temperature |
| US8515511B2 (en) | 2009-09-29 | 2013-08-20 | Covidien Lp | Sensor with an optical coupling material to improve plethysmographic measurements and method of using the same |
| US9554739B2 (en) | 2009-09-29 | 2017-01-31 | Covidien Lp | Smart cable for coupling a medical sensor to an electronic patient monitor |
| US8930145B2 (en) | 2010-07-28 | 2015-01-06 | Covidien Lp | Light focusing continuous wave photoacoustic spectroscopy and its applications to patient monitoring |
| CN102846323A (en) * | 2011-07-01 | 2013-01-02 | 中国计量学院 | LED-based noninvasive blood oxygen saturation tester |
| DE102012007417A1 (en) | 2012-04-16 | 2013-10-17 | Festo Ag & Co. Kg | sensor module |
| US9833146B2 (en) | 2012-04-17 | 2017-12-05 | Covidien Lp | Surgical system and method of use of the same |
| US20160066863A1 (en) * | 2013-04-05 | 2016-03-10 | Nitto Denko Corporation | METHOD AND APPARATUS FOR DETERMINING SpO2 OF A SUBJECT FROM AN OPTICAL MEASUREMENT |
| US10485463B2 (en) | 2014-10-10 | 2019-11-26 | Medtor Llc | System and method for a non-invasive medical sensor |
| DE102014117879A1 (en) | 2014-12-04 | 2016-06-09 | Osram Opto Semiconductors Gmbh | A pulse oximetry device and method of operating a pulse oximetry device |
| GB201608781D0 (en) * | 2016-05-19 | 2016-07-06 | Leman Micro Devices Sa | Non-invasive blood analysis |
| EP3531912B1 (en) | 2016-12-05 | 2020-11-11 | Medipines Corporation | Method and device for respiratory measurements using breathing gas samples |
| CN109596552B (en) * | 2018-12-24 | 2021-07-16 | 中北大学 | Method for measuring tissue blood oxygen saturation using single range light source-detector pair |
Family Cites Families (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3638640A (en) * | 1967-11-01 | 1972-02-01 | Robert F Shaw | Oximeter and method for in vivo determination of oxygen saturation in blood using three or more different wavelengths |
| CA971768A (en) * | 1972-02-01 | 1975-07-29 | Robert F. Shaw | Oximeter and method |
| US3799672A (en) * | 1972-09-15 | 1974-03-26 | Us Health Education & Welfare | Oximeter for monitoring oxygen saturation in blood |
| JPS5725217B2 (en) * | 1974-10-14 | 1982-05-28 | ||
| CA1037285A (en) * | 1975-04-30 | 1978-08-29 | Glenfield Warner | Ear oximetry process and apparatus |
| US4167331A (en) * | 1976-12-20 | 1979-09-11 | Hewlett-Packard Company | Multi-wavelength incremental absorbence oximeter |
| JPS5524004A (en) * | 1978-06-22 | 1980-02-20 | Minolta Camera Kk | Oxymeter |
| JPS56104646A (en) * | 1980-01-25 | 1981-08-20 | Minolta Camera Kk | Optical analyzer for forming ratio of element contained in organism |
| US4357105A (en) * | 1980-08-06 | 1982-11-02 | Buffalo Medical Specialties Mfg., Inc. | Blood diagnostic spectrophotometer |
| US4407290A (en) * | 1981-04-01 | 1983-10-04 | Biox Technology, Inc. | Blood constituent measuring device and method |
| US4740080A (en) * | 1985-03-21 | 1988-04-26 | Abbott Laboratories | Analog to digital converter for fluid analyzing apparatus |
| US4819646A (en) * | 1986-08-18 | 1989-04-11 | Physio-Control Corporation | Feedback-controlled method and apparatus for processing signals used in oximetry |
| US4773422A (en) * | 1987-04-30 | 1988-09-27 | Nonin Medical, Inc. | Single channel pulse oximeter |
| US4807631A (en) * | 1987-10-09 | 1989-02-28 | Critikon, Inc. | Pulse oximetry system |
| US4854699A (en) * | 1987-11-02 | 1989-08-08 | Nippon Colin Co., Ltd. | Backscatter oximeter |
| US5299120A (en) * | 1989-09-15 | 1994-03-29 | Hewlett-Packard Company | Method for digitally processing signals containing information regarding arterial blood flow |
| US5190038A (en) * | 1989-11-01 | 1993-03-02 | Novametrix Medical Systems, Inc. | Pulse oximeter with improved accuracy and response time |
| US5348004A (en) * | 1993-03-31 | 1994-09-20 | Nellcor Incorporated | Electronic processor for pulse oximeter |
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1996
- 1996-07-17 US US08/683,617 patent/US5842981A/en not_active Expired - Lifetime
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- 1997-07-17 ES ES97934987T patent/ES2206740T3/en not_active Expired - Lifetime
- 1997-07-17 CN CNB971965226A patent/CN1160021C/en not_active Expired - Fee Related
- 1997-07-17 CA CA002260928A patent/CA2260928C/en not_active Expired - Fee Related
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- 1997-07-17 AU AU38029/97A patent/AU720111B2/en not_active Ceased
- 1997-07-17 DE DE69724822T patent/DE69724822T2/en not_active Expired - Lifetime
- 1997-07-17 JP JP10506296A patent/JP2000514683A/en active Pending
- 1997-07-17 BR BR9710330-6A patent/BR9710330A/en not_active IP Right Cessation
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| EP0955869B1 (en) | 2003-09-10 |
| US5842981A (en) | 1998-12-01 |
| WO1998002087A1 (en) | 1998-01-22 |
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| DE69724822T2 (en) | 2004-07-01 |
| DE69724822D1 (en) | 2003-10-16 |
| BR9710330A (en) | 2000-01-11 |
| CN1225562A (en) | 1999-08-11 |
| ES2206740T3 (en) | 2004-05-16 |
| JP2000514683A (en) | 2000-11-07 |
| EP0955869A4 (en) | 2001-03-14 |
| EP0955869A1 (en) | 1999-11-17 |
| AU720111B2 (en) | 2000-05-25 |
| CN1160021C (en) | 2004-08-04 |
| CA2260928A1 (en) | 1998-01-22 |
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