CA2556724C - Techniques for detecting heart pulses and reducing power consumption in sensors - Google Patents
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- 238000000034 method Methods 0.000 title claims abstract description 37
- 238000001514 detection method Methods 0.000 claims abstract description 23
- 230000007704 transition Effects 0.000 claims abstract description 16
- 238000012935 Averaging Methods 0.000 claims abstract description 6
- 238000012797 qualification Methods 0.000 claims description 26
- 229910052760 oxygen Inorganic materials 0.000 claims description 25
- 239000001301 oxygen Substances 0.000 claims description 25
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 24
- 238000012360 testing method Methods 0.000 claims description 16
- 238000004364 calculation method Methods 0.000 claims description 15
- 238000005259 measurement Methods 0.000 claims description 11
- 230000003205 diastolic effect Effects 0.000 claims description 7
- 230000007423 decrease Effects 0.000 claims description 6
- 238000009532 heart rate measurement Methods 0.000 claims description 4
- 230000003247 decreasing effect Effects 0.000 claims description 3
- 238000002496 oximetry Methods 0.000 claims description 2
- 238000001914 filtration Methods 0.000 claims 1
- 230000000747 cardiac effect Effects 0.000 abstract description 7
- 239000008280 blood Substances 0.000 description 17
- 210000004369 blood Anatomy 0.000 description 17
- 230000008901 benefit Effects 0.000 description 3
- 239000000470 constituent Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 230000004044 response Effects 0.000 description 3
- 230000008859 change Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000031700 light absorption Effects 0.000 description 2
- 230000010349 pulsation Effects 0.000 description 2
- 102000001554 Hemoglobins Human genes 0.000 description 1
- 108010054147 Hemoglobins Proteins 0.000 description 1
- 238000010420 art technique Methods 0.000 description 1
- 210000005242 cardiac chamber Anatomy 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000002106 pulse oximetry Methods 0.000 description 1
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
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/72—Signal processing specially adapted for physiological signals or for diagnostic purposes
- A61B5/7203—Signal processing specially adapted for physiological signals or for diagnostic purposes for noise prevention, reduction or removal
- A61B5/7207—Signal processing specially adapted for physiological signals or for diagnostic purposes for noise prevention, reduction or removal of noise induced by motion artifacts
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B2560/00—Constructional details of operational features of apparatus; Accessories for medical measuring apparatus
- A61B2560/02—Operational features
- A61B2560/0204—Operational features of power management
- A61B2560/0209—Operational features of power management adapted for power saving
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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
- A61B5/02—Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
- A61B5/024—Detecting, measuring or recording pulse rate or heart rate
- A61B5/02416—Detecting, measuring or recording pulse rate or heart rate using photoplethysmograph signals, e.g. generated by infrared radiation
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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
- A61B5/72—Signal processing specially adapted for physiological signals or for diagnostic purposes
- A61B5/7235—Details of waveform analysis
- A61B5/7239—Details of waveform analysis using differentiation including higher order derivatives
Abstract
Low power techniques for sensing cardiac pulses in a signal from a sensor (101) are provided. A pulse detection block (102) senses the sensor signal and determines its signal-to-noise ratio. After comparing the signal-to-noise ratio to a threshold, the drive current of light emitting elements in the sensor is dynamically adjusted to reduce power consumption while maintaining the signal-to-noise ratio at an adequate level. The signal component of the sensor signal can be measured by identifying systolic transitions. The systolic transitions are detected using a maximum and minimum derivative averaging scheme. The moving minimum (301) and the moving maximum (304) are compared to the scaled sum (312, 313) of the moving minimum and moving maximum to identify the systolic transitions. Once the signal component has been identified, the signal component is compared to a noise component to calculate the signal-to-noise ratio.
Description
TECHNIQUES FOR DETECTING HEART PULSES AND REDUCING
POWER CONSUMPTION IN SENSORS
BACKGROUND OF THE INVENTION
[0001] The present invention relates to techniques for detecting heart pulses and reducing power consumption in sensors and oximeter systems, and more particularly, to techniques for distinguishing heart pulses in a sensor signal from noise and adjusting drive current provided to light emitting elements in response to a signal-to-noise ratio of the pulse in order to reduce power consumption.
POWER CONSUMPTION IN SENSORS
BACKGROUND OF THE INVENTION
[0001] The present invention relates to techniques for detecting heart pulses and reducing power consumption in sensors and oximeter systems, and more particularly, to techniques for distinguishing heart pulses in a sensor signal from noise and adjusting drive current provided to light emitting elements in response to a signal-to-noise ratio of the pulse in order to reduce power consumption.
[0002] Pulse oximetry is a technology that is typically used to measure various blood chemistry characteristics including, but not limited to, the blood-oxygen saturation of hemoglobin in arterial blood, the volume of individual blood pulsations supplying the tissue, and the rate of blood pulsations corresponding to each heartbeat of a patient.
[0003] Measurement of these characteristics has been accomplished by use of a non-invasive sensor. The sensor has a light source such as a light emitting diode (LED) that scatters light through a portion of the patient's tissue where blood perfuses the tissue. The sensor also has a photodetector that photoelectrically senses the absorption of light at various wavelengths in the tissue. The photodetector generates a pulse oximeter signal that indicates the amount of light absorbed by the blood. The amount of light absorbed is then used to calculate the amount of blood constituent being measured.
[0004] The light scattered through the tissue is selected to be of one or more wavelengths that are absorbed by the blood in an amount representative of the amount of the blood constituent present in the blood. The amount of transmitted light scattered through the tissue will vary in accordance with the changing amount of blood constituent in the tissue and the related light absorption.
[0005] For measuring blood oxygen level, oximeter sensors typically have a light source that is adapted to generate light of at least two different wavelengths, and with photodetectors sensitive to these wavelengths, in accordance with known techniques for measuring blood oxygen saturation. A typical pulse oximeter will alternately illuminate the patient with red and infrared light using two LEDs to obtain two different detector signals.
[0006] The pulse oximeter signal generated by the photodetector usually contains components of noise introduced by the electronics of the oximeter, by the patient, and by the environment. Noisy signals have a low signal-to-noise ratio. A pulse oximeter cannot accurately identify the blood oxygen saturation when the signal-to-noise ratio of the pulse oximeter signal is too low.
[0007] To improve the signal-to-noise ratio of the pulse oximeter signal, a pulse oximeter system will typically drive the LEDs with a large amount of current. A servo in the pulse oximeter will typically drive as much current as possible through the LEDs without causing the oximeter to be over-ranged (i.e., driven to full rail). The large drive current causes the LEDs to generate more light and to consume more power. Because the photodetector is able to sense more of the light from the LEDs, the signal-to-noise ratio of the pulse oximeter signal is higher.
[0008] Increasing the drive current of the LEDs to improve the signal-to-noise ratio of the pulse oximeter signal causes the system to consume an undesirably large amount of power.
The large amount of power consumption can be a problem for oximeter systems that are battery operated.
The large amount of power consumption can be a problem for oximeter systems that are battery operated.
[0009] It would therefore be desirable to provide pulse oximeter systems that consume less power without negatively compromising the signal-to-noise ratio of the pulse oximeter signal.
BRIEF SUMMARY OF THE INVENTION
BRIEF SUMMARY OF THE INVENTION
[0010] The present invention provides CPU cycle efficient techniques for sensing heart pulses in a signal from a sensor. The sensor signal can be, for example, a pulse oximeter signal generated by a photodetector in a pulse oximeter sensor. The signal component of the sensor signal is measured by identifying potential systolic transitions of the cardiac cycle.
The systolic transitions are detected using a derivative averaging scheme. The moving minimum and the moving maximum of the average derivative are compared to a scaled sum of the minimum and maximum to identify the systolic transitions. The systolic transitions correspond to a signal component of the sensor signal. The signal component is compared to a noise component to determine the signal-to-noise ratio of the signal.
The systolic transitions are detected using a derivative averaging scheme. The moving minimum and the moving maximum of the average derivative are compared to a scaled sum of the minimum and maximum to identify the systolic transitions. The systolic transitions correspond to a signal component of the sensor signal. The signal component is compared to a noise component to determine the signal-to-noise ratio of the signal.
[0011] The present invention also provides techniques for reducing power consumption in a sensor. After the signal-to-noise ratio of the pulse oximeter has been determined, the signal-to-noise ratio is compared to a threshold. In response to the output of the comparison, the drive current of light emitting elements in the sensor is dynamically adjusted to reduce power consumption and to maintain the signal-to-noise ratio at an adequate level for signal processing.
[0012] Accordingly, there is provided a pulse oximeter system comprising: a drive interface that controls drive current of light emitting elements in a pulse oximeter sensor; a feedback loop coupled around the pulse oximeter sensor and the drive interface that dynamically adjusts the drive current of the light emitting elements based on results of a comparison between a signal-to-noise ratio of a pulse oximeter signal and a threshold, a pulse detection block that calculates the signal-to-noise ratio of the pulse oximeter signal, wherein the pulse detection block calculates a moving average of a derivative of the pulse oximeter signal to generate a first output, calculates a moving average of the first output to generate a second output, calculates a moving average of the second output to generate a third output, and identifies a moving minimum and a moving maximum of the third output; and a comparator that performs the comparison of the signal-to-noise ratio of the pulse oximeter signal to the threshold; wherein the feedback loop comprises the pulse detection block and the comparator;
and wherein the pulse oximeter signal is generated by a photodetector in the pulse oximeter sensor.
[0012a] There is also provided a pulse oximeter system comprising: a drive interface that controls drive current of light emitting elements in a pulse oximeter sensor;
and a feedback loop coupled around the pulse oximeter sensor and the drive interface that is capable of dynamically adjusting the drive current of the light emitting elements based at least in part upon results of a comparison between a signal-to-noise ratio of a pulse oximeter signal and a threshold, wherein the feedback loop is capable of detecting systolic transitions based at least in part upon a multi-step averaging scheme, wherein the pulse oximeter signal is generated by a photodetector in the pulse oximeter sensor.
10012b] There is also provided a monitor for controlling drive current of light emitting elements in a pulse oximeter sensor, comprising: an identification module capable of identifying a systolic period of a pulse oximeter signal; a qualification module capable of performing multiple stages of pulse qualification tests to qualify the systolic period for oxygen saturation calculations; a strength determination module capable of determining a strength of the systolic period if the systolic period is qualified for oxygen saturation calculations; a ratio module capable of identifying a signal-to-noise ratio by comparing the strength of the systolic period to a measured value of a noise component of the pulse oximeter signal stored in a memory; and a controller capable of controlling the drive current based at least in part upon a comparison of the signal-to-noise ratio to a threshold.
[0012c] In a further aspect, there is provided a method for reducing power consumption in a pulse oximeter sensor, the method comprising: providing drive current to light emitting elements in the pulse oximeter sensor; and dynamically determining a signal-to-noise ratio of a pulse oximeter signal generated by a photodetector in the pulse oximeter sensor, wherein determining the signal-to-noise ratio comprises measuring and storing the noise at each of a plurality of gain stages; and dynamically adjusting the drive current of the light emitting elements based at least in part upon results of a comparison between the signal-to-noise ratio of the pulse oximeter signal and a threshold.
[0012d] There is also provided a method for controlling drive current of light emitting elements in a pulse oximeter sensor, comprising: using a pulse oximeter;
measuring a noise component of a pulse oximeter signal; identifying a systolic period of the pulse oximeter signal; performing first pulse qualification tests to qualify a systolic period for pulse rate measurement; performing second pulse qualification tests to qualify the systolic period for 3a oxygen saturation calculations, if the systolic period is qualified for pulse rate measurement;
determining a strength of the systolic period if the systolic period is qualified for oxygen saturation calculations; identifying a signal-to-noise ratio by comparing the strength of the systolic period to the noise component; and controlling the drive current based at least in part upon a comparison of the signal-to-noise ratio to a threshold.
and wherein the pulse oximeter signal is generated by a photodetector in the pulse oximeter sensor.
[0012a] There is also provided a pulse oximeter system comprising: a drive interface that controls drive current of light emitting elements in a pulse oximeter sensor;
and a feedback loop coupled around the pulse oximeter sensor and the drive interface that is capable of dynamically adjusting the drive current of the light emitting elements based at least in part upon results of a comparison between a signal-to-noise ratio of a pulse oximeter signal and a threshold, wherein the feedback loop is capable of detecting systolic transitions based at least in part upon a multi-step averaging scheme, wherein the pulse oximeter signal is generated by a photodetector in the pulse oximeter sensor.
10012b] There is also provided a monitor for controlling drive current of light emitting elements in a pulse oximeter sensor, comprising: an identification module capable of identifying a systolic period of a pulse oximeter signal; a qualification module capable of performing multiple stages of pulse qualification tests to qualify the systolic period for oxygen saturation calculations; a strength determination module capable of determining a strength of the systolic period if the systolic period is qualified for oxygen saturation calculations; a ratio module capable of identifying a signal-to-noise ratio by comparing the strength of the systolic period to a measured value of a noise component of the pulse oximeter signal stored in a memory; and a controller capable of controlling the drive current based at least in part upon a comparison of the signal-to-noise ratio to a threshold.
[0012c] In a further aspect, there is provided a method for reducing power consumption in a pulse oximeter sensor, the method comprising: providing drive current to light emitting elements in the pulse oximeter sensor; and dynamically determining a signal-to-noise ratio of a pulse oximeter signal generated by a photodetector in the pulse oximeter sensor, wherein determining the signal-to-noise ratio comprises measuring and storing the noise at each of a plurality of gain stages; and dynamically adjusting the drive current of the light emitting elements based at least in part upon results of a comparison between the signal-to-noise ratio of the pulse oximeter signal and a threshold.
[0012d] There is also provided a method for controlling drive current of light emitting elements in a pulse oximeter sensor, comprising: using a pulse oximeter;
measuring a noise component of a pulse oximeter signal; identifying a systolic period of the pulse oximeter signal; performing first pulse qualification tests to qualify a systolic period for pulse rate measurement; performing second pulse qualification tests to qualify the systolic period for 3a oxygen saturation calculations, if the systolic period is qualified for pulse rate measurement;
determining a strength of the systolic period if the systolic period is qualified for oxygen saturation calculations; identifying a signal-to-noise ratio by comparing the strength of the systolic period to the noise component; and controlling the drive current based at least in part upon a comparison of the signal-to-noise ratio to a threshold.
[0013] For a further understanding of the nature and advantages of the invention, reference should be made to the following description taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 illustrates a block diagram of a pulse oximeter system with reduced power consumption according to an embodiment of the present invention;
0015] Figure 2 is a flow chart that illustrates a process for identifying the systolic period of a pulse oximeter signal according to an embodiment of the present invention;
[0016] Figures 3A-3C are graphs that illustrates how systolic transitions are identified in pulse oximeter signals according to embodiments of the present invention; and [0017] Figure 4 illustrates a portion of a pulse oximeter system with a transimpedance amplifier, a sigma-delta modulator, an analog-to-digital converter, and a gain control feedback loop according to an embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
DETAILED DESCRIPTION OF THE INVENTION
[0018] The techniques of the present invention can be used in the context of a pulse oximeter system. A pulse oximeter system receives a pulse oximeter signal from a photodetector in a pulse oximeter sensor. Figure 1 illustrates a block diagram of pulse oximeter system according to an embodiment of the present invention. The pulse oximeter system includes an oximeter sensor 101.
3b [0019] An oximeter sensor of the present invention can utilize any suitable number of light emitting elements. For example, a sensor of the present invention can have 1, 2, 3, or 4 light emitting elements. In the example of Figure 1, sensor 101 has two LEDs 110 and 111 that emit two different wavelengths of light.
3b [0019] An oximeter sensor of the present invention can utilize any suitable number of light emitting elements. For example, a sensor of the present invention can have 1, 2, 3, or 4 light emitting elements. In the example of Figure 1, sensor 101 has two LEDs 110 and 111 that emit two different wavelengths of light.
[0020] Sensor 101 also includes photodetector 112 that senses light from LEDs 110 and 111 after the light has passed through the patient's tissue. The pulse oximeter system also includes feedback loop circuitry 110 and LED drive interface 104. Feedback loop circuitry 110 includes pulse detection block 102 and threshold comparison block 103.
[0021] Photodetector 112 transmits the pulse oximeter signal to pulse detection block 102.
Pulse detection block 102 has a servo that measures the signal component of the pulse oximeter signal by identifying the systolic transitions. The pulse detection block 102 and the threshold comparison block 103 form a feedback loop 110 around the sensor to control the drive current of the LEDs and the signal-to-noise ratio of the pulse oximeter signal, as will be discussed in detail below.
Pulse detection block 102 has a servo that measures the signal component of the pulse oximeter signal by identifying the systolic transitions. The pulse detection block 102 and the threshold comparison block 103 form a feedback loop 110 around the sensor to control the drive current of the LEDs and the signal-to-noise ratio of the pulse oximeter signal, as will be discussed in detail below.
[0022] A cardiac pulse can be divided into a diastolic and systolic period.
The systolic period is typically characterized by a rapid change in value due to the contraction of the heart.
The diastolic period is typically characterized by a gradual change in value, due to the relaxation and refilling of the heart chambers.
The systolic period is typically characterized by a rapid change in value due to the contraction of the heart.
The diastolic period is typically characterized by a gradual change in value, due to the relaxation and refilling of the heart chambers.
[0023] Systolic transitions in the pulse oximeter signal are detected using a three step maximum and minimum derivative averaging scheme, which is discussed in further detail below. Qualification routines are then used to filter out false positives. The resulting data contains the systolic transitions separated from the non-systolic periods in the pulse oximeter signal.
[0024] Pulse detection block 102 then compares the amplitude of the systolic portion of the pulse oximeter signal to a noise component to generate a value for the signal-to-noise ratio of the pulse oximeter signal. Subsequently, threshold comparison block 103 compares this signal-to-noise ratio to a threshold level to determine whether the signal-to-noise ratio is high enough such that the pulse oximeter signal can be used to accurately calculate pulse rate and oxygen saturation. Too much noise obscures the pulse rate and oxygen saturation information in the signal. Noise can degrade the signal to the point that it cannot be used to accurately calculate pulse rate or oxygen saturation.
[0025] Threshold comparison block 103 preferably contains two hysteretic threshold levels.
In this embodiment, threshold comparison block 103 senses whether the signal-to-noise ratio is greater than a maximum threshold level or less than a minimum threshold level. As an example, the maximum threshold level can represent a signal-to-noise ratio of 128:1, and the minimum threshold level can represent a signal-to-noise ratio of 8:1. These are merely two examples of thresholds levels. They are not intended to limit the scope of the present invention. Prior art oximeter systems, for example, operate at a signal-to-noise ratio of 10,000:1 or higher, because they drive the LEDs as bright as possible.
In this embodiment, threshold comparison block 103 senses whether the signal-to-noise ratio is greater than a maximum threshold level or less than a minimum threshold level. As an example, the maximum threshold level can represent a signal-to-noise ratio of 128:1, and the minimum threshold level can represent a signal-to-noise ratio of 8:1. These are merely two examples of thresholds levels. They are not intended to limit the scope of the present invention. Prior art oximeter systems, for example, operate at a signal-to-noise ratio of 10,000:1 or higher, because they drive the LEDs as bright as possible.
[0026] If the signal-to-noise ratio is greater than the maximum threshold level, threshold comparison block 103 sends a signal to LED drive interface 104 to reduce the LED current.
Based on the value of the signal-to-noise ratio, threshold comparison block 103 can determine how much the LED drive current needs to be reduced to decrease the signal-to-noise ratio while maintaining the signal level within the minimum and maximum threshold levels. LED drive interface 104 responds by decreasing the LED drive current to the value indicated by threshold comparison block 103.
Based on the value of the signal-to-noise ratio, threshold comparison block 103 can determine how much the LED drive current needs to be reduced to decrease the signal-to-noise ratio while maintaining the signal level within the minimum and maximum threshold levels. LED drive interface 104 responds by decreasing the LED drive current to the value indicated by threshold comparison block 103.
[0027] The feedback loop continuously monitors the signal-to-noise ratio of the pulse oximeter signal and dynamically adjusts the LED drive current and subsequent system gain until the signal-to-noise ratio is less than the maximum threshold. The oximeter system saves power by substantially reducing the LED drive current (relative to prior art systems), while maintaining the signal-to-noise ratio of the pulse oximeter signal within an acceptable range.
[0028] The signal-to-noise ratio can also drop too low for a number of reasons. For example, the noise in the pulse oximeter may increase, or the strength of the signal component may decrease if the blood oxygen saturation of the patient decreases. In any event, the system of Figure 1 senses when the magnitude of the pulse oximeter signal is too low and increases the LED drive current accordingly.
[0029] If the signal-to-noise ratio is less than the minimum threshold level, threshold comparison block 103 sends a signal to LED drive interface 104 to increase the LED current.
Based on the value of the signal-to-noise ratio, the threshold comparison can determine how much the LED drive current needs to be increased to increase the signal-to-noise ratio while maintaining the signal within the minimum and maximum threshold levels. LED
drive interface 104 responds by increasing the LED drive current to the value indicated by the threshold comparison system.
Based on the value of the signal-to-noise ratio, the threshold comparison can determine how much the LED drive current needs to be increased to increase the signal-to-noise ratio while maintaining the signal within the minimum and maximum threshold levels. LED
drive interface 104 responds by increasing the LED drive current to the value indicated by the threshold comparison system.
[0030] The feedback loop continuously monitors the signal-to-noise ratio of the pulse oximeter signal and dynamically adjusts the LED drive current until the signal-to-noise ratio is greater than the minimum threshold level. The minimum threshold indicates a minimum allowable value for the signal-to-noise ratio for which the pulse rate and the oxygen saturation can be accurately calculated.
[0031] If the signal-to-noise ratio falls between the maximum and minimum threshold levels, the oximeter system maintains the LED drive current at a stable value.
The oximeter system maintains equilibrium until the signal-to-noise ratio of the pulse oximeter signal moves outside the range of the thresholds. Thus, an oximeter system of the present invention contains a dynamic feedback loop as shown in Figure 1. The dynamic feedback loop automatically adjusts the drive current of the LEDs to reduce power consumption in the sensor and to maintain the signal-to-noise ratio at an acceptable level for the purpose of accurately calculating blood oxygen saturation levels.
The oximeter system maintains equilibrium until the signal-to-noise ratio of the pulse oximeter signal moves outside the range of the thresholds. Thus, an oximeter system of the present invention contains a dynamic feedback loop as shown in Figure 1. The dynamic feedback loop automatically adjusts the drive current of the LEDs to reduce power consumption in the sensor and to maintain the signal-to-noise ratio at an acceptable level for the purpose of accurately calculating blood oxygen saturation levels.
[0032] According to a preferred embodiment of the present invention, the hardware for the servo in pulse detection block 102 maintains a predictable relationship between the power that LED drive 104 attempts to the drive the LEDs at and the radiated output power actually generated by the LEDs. By providing a predictable relationship between the input and output power, the feedback loop is more likely to acquire the oxygen saturation from the pulse oximeter signal in significantly less time, requiring less executions of the servo.
[0033] As the gain of the pulse oximeter signal is increased, the signal component generally increases faster than the noise component (at least to a point below the highest gain settings). The effect that increasing the gain of the pulse oximeter signal has on the signal-to-noise ratio in a particular system should be understood. Certain combinations of gain may cause more noise to be present in the pulse oximeter signal. Therefore, the gain stages in the pulse detection block preferably take advantage of characteristics of the gain-to-noise variability.
[0034] For example, the signal from the photodetector that is sampled using an analog-to-digital converter is fed into a gain block. The gain block includes several gain stages to achieve a known response. The noise is measured at each of the gain stages, and then stored for later use to calculate the signal-to-noise ratio.
[0035] Techniques for identifying the systolic portions of a pulse oximeter signal generated by an oximeter sensor are now discussed. The systole identification of the present invention uses a three step maximum and minimum derivative averaging scheme in order to detect cardiac systolic events.
[0036] Figure 2 illustrates one method for identifying the systolic period of a pulse .
oximeter signal. In the first step 201, the moving average of the derivative of the pulse oximeter signal is found. In the second step 202, the moving average of the output of the first step 201 is found. In the third step 203, the moving average of the output of the second step 202 is found.
oximeter signal. In the first step 201, the moving average of the derivative of the pulse oximeter signal is found. In the second step 202, the moving average of the output of the first step 201 is found. In the third step 203, the moving average of the output of the second step 202 is found.
[0037] Next, the moving maximum and the moving minimum of the output of the third step is found at step 204. At step 205, systole transitions are detected by comparing this moving minimum and moving maximum to a scaled sum of the moving minimum and maximum.
For example, the scaled sum of the moving minimum and maximum values can be a fractional sum of the minimum and maximum moving averages.
For example, the scaled sum of the moving minimum and maximum values can be a fractional sum of the minimum and maximum moving averages.
[0038] When the minimum output of step 204 becomes less than a fractional sum of the maximum and minimum moving averages, the system determines that the pulse oximeter signal is entering systole. When the minimum output of step 204 becomes more than a fractional sum of the maximum and minimum moving averages, the system determines that pulse oximeter signal is exiting systole.
[0039] The two predetermined fractional sums can be selected to be any suitable values.
As a specific example, the system can determine that the pulse oximeter signal is entering systole when the minimum derivative output becomes less than 1/16 the sum of the minimum and maximum moving averages of the third stage. As another example, the system can determine that the pulse oximeter signal is exiting systole when the minimum derivative output becomes more than 1/8 the sum of the maximum and minimum moving averages of the third stage. These two examples are not intended to limit the scope of the present invention. Many other fractional values can also be used to identify systole transitions.
As a specific example, the system can determine that the pulse oximeter signal is entering systole when the minimum derivative output becomes less than 1/16 the sum of the minimum and maximum moving averages of the third stage. As another example, the system can determine that the pulse oximeter signal is exiting systole when the minimum derivative output becomes more than 1/8 the sum of the maximum and minimum moving averages of the third stage. These two examples are not intended to limit the scope of the present invention. Many other fractional values can also be used to identify systole transitions.
[0040] These techniques of the present invention can detect and qualify pulses using CPU, RAM, and ROM efficient algorithms. Minimal processor resources are required to perform oximetry calculations with a comparable level of saturation and pulse rate performance as prior art oximeter technology.
[0041] Example waveforms for the results of these calculations are shown in Figure 3A.
Waveform 303 is an example of the derivative of a pulse oximeter signal.
Waveforms 301 and 304 are examples of the minimum and maximum moving average of the pulse oximeter signal, respectively. Waveform 302 is an example of the output signal of the three-step moving average.
Waveform 303 is an example of the derivative of a pulse oximeter signal.
Waveforms 301 and 304 are examples of the minimum and maximum moving average of the pulse oximeter signal, respectively. Waveform 302 is an example of the output signal of the three-step moving average.
[0042] The output of the moving average is a smoothed and delayed version of the derivative of the pulse oximeter signal. The minimum output tracks the negative-going trends and lags the positive-going trends. The maximum output tracks the positive-going trends and lags the negative-going trends. These relationships are key to detecting potential systolic cardiac periods.
[0043] Figure 3B shows examples of the minimum moving average 301 with a waveform 313 that represents 1/16 of the sum of the minimum and maximum moving averages of the third stage. Figure 3B also shows an example of waveform 312 that represents 1/8 of the sum of the minimum and maximum moving averages of the third stage.
[0044] According to one embodiment of the present invention, waveforms 312 and 313 are compared to the minimum moving average waveform 301 at step 205 to identify the systolic period of the pulse oximeter signal. Alternatively, other scaled sums for the minimum and/or maximum moving averages can be used to identify systolic periods in the pulse oximeter signal. The beginning and the end of a systole in signal 301 are identified in Figure 3B. The period between crossing points of signal 301 and signals 312/313 defines the systolic period.
[0045] When applied to the original pulse oximeter signal 320, the systolic period identification is shown in Figure 3C. The systolic period includes the time between the peak (i.e. maximum value) and the subsequent valley (i.e. minimum value) of pulse oximeter signal 320. The actual systolic period is identified in Figure 3C as well as the dichrotic notch of the next pulse.
[0046] After the systolic period has been identified, unique pulse qualification tests based upon typical physiological pulse characteristics are applied to the systole pulse at step 206.
The full pulse qualification tests remove false positive systolic detections (e.g., the dichrotic notch) and pulses that have an inadequate signal-to-noise ratio. False positives are portions of the signal that are falsely identified as systolic transitions in step 205.
Pulse qualifications are used in step 206 to filter out false positives identified in step 205. The steps of Figure 2 can be implemented in software or hardware.
The full pulse qualification tests remove false positive systolic detections (e.g., the dichrotic notch) and pulses that have an inadequate signal-to-noise ratio. False positives are portions of the signal that are falsely identified as systolic transitions in step 205.
Pulse qualifications are used in step 206 to filter out false positives identified in step 205. The steps of Figure 2 can be implemented in software or hardware.
[0047] Pulse qualification tests qualify cardiac pulses in the pulse oximeter signal. The pulse qualification tests are designed to identify cardiac pulses that have adequate signal-to-noise ratio for use in measuring pulse rate and blood oxygen saturation. The pulse qualification tests can include any number techniques including traditional pulse qualification techniques.
[0048] Some examples of pulse qualification tests according to particular embodiments of the present invention are now discussed. The qualifications are comparisons of special pulse characteristics to determined threshold values. For example, the pulse qualifications compare systolic area, width, and number of sub-peaks to fixed thresholds. Diastolic area, width, and number of sub-peaks are compared to thresholds. Systolic area and width are compared to diastolic area and width. Pulse area and width are compared to thresholds. All of the above individually are compared to the last N pulses detected.
[0049] Pulses that pass these qualifications can be used to measure pulse rate. To qualify the systolic periods for oxygen saturation calculations, the following additional qualifications are used. The lag/lead time between the infrared and red pulse detection are compared. The pulse size is compared to the N pulses qualified. The statistically significant coefficient of the best-fit line plot of the moving average between the infrared and the red signals is compared to fixed thresholds. The saturation rate-of-change is compared to fixed thresholds.
Pulses that pass these additional qualifications can be used to measure oxygen saturation.
Pulses that pass these additional qualifications can be used to measure oxygen saturation.
[0050] After the pulse qualification tests have filtered out false positives, the systolic periods are identified. The systolic periods represent a signal component of the pulse oximeter signal. The signal-to-noise ratio of the pulse oximeter signal is calculated by comparing the strength of the systolic period to the noise component of the pulse oximeter signal.
[0051] According to one embodiment, the noise component of a pulse oximeter sensor is calculated in advance using a separate instrument that measures noise in the pulse oximeter signal at various gain values. The measured noise component is then stored in memory for later use. The stored noise component is subsequently compared to the size of the systolic pulse for a particular gain value to determine the signal-to-noise ratio of the pulse oximeter signal.
[0052] According to another embodiment, dynamic measurements of the noise of the pulse oximeter system are made. These noise measurements can include electrical noise, ambient noise caused by ambient light, and/or noise (e.g. motion) caused by the patient. The dynamic noise measurement is updated continuously throughout the operation of the pulse oximeter sensor. An updated noise component is continuously compared to the pulse to calculate a more accurate signal-to-noise ratio of the pulse oximeter signal.
[0053] Once the signal-to-noise ratio of the pulse oximeter signal has been calculated, a determination is made as whether the signal-to-noise ratio falls within an acceptable range.
The acceptable range is selected based on the relative noise component for accurately calculating oxygen saturation and pulse rate. If the ratio is outside the acceptable range, the feedback loop discussed above with respect to Figure 1 adjusts the LED drive current to bring the signal-to-noise ratio within the acceptable range.
The acceptable range is selected based on the relative noise component for accurately calculating oxygen saturation and pulse rate. If the ratio is outside the acceptable range, the feedback loop discussed above with respect to Figure 1 adjusts the LED drive current to bring the signal-to-noise ratio within the acceptable range.
[0054] The present invention has the advantage of requiring fewer servo executions to acquire and maintain the oxygen saturation of the signal than many prior art techniques, particularly in the presence of patient motion interference. In many prior art oximeter systems, the LEDs are driven with a large current, and the pulse oximeter signal fills up its entire system dynamic range. The oximeter signal exceeds the system's current dynamic range as soon as the patient starts moving, and the signal is effectively lost (i.e., flat-line, invalid signal). Additional servo executions are required to re-acquire the signal. While the servo is executing, the sensor signal is not available; therefore, the oximeter cannot calculate pulse rate or oxygen saturation data from the pulse oximeter signal.
[0055] On the other hand, the LED drive current is substantially reduced in the present invention. The dynamic range is greatly increased relative to the size of the pulse oximeter signal, because the signal has been greatly reduced by cutting back on the LED
drive current.
The oximeter signal can now move around more within the dynamic range without requiring additional servo executions or changes to the LED settings. In the present invention, the patient can move around vigorously without causing the servo to execute in an attempt to re-acquire the signal. The techniques of the present invention can allow an oximeter system to be much more tolerant of patient motion.
drive current.
The oximeter signal can now move around more within the dynamic range without requiring additional servo executions or changes to the LED settings. In the present invention, the patient can move around vigorously without causing the servo to execute in an attempt to re-acquire the signal. The techniques of the present invention can allow an oximeter system to be much more tolerant of patient motion.
[0056] Pulse detection block 102 can include a transimpedance (I-V) amplifier or converter 401 that converts a current signal from photodetector 112 to a voltage signal as shown in Figure 4. Ambient light in the environment adds a component of DC bias into the pulse oximeter signal. This DC bias shifts the pulse oximeter signal higher, closer to the rail of the dynamic range of the transimpedance amplifier.
[0057] According to an embodiment of the present invention, an analog-to-digital (A-to-D) converter 402 samples the output signal of transimpedance amplifier 401 during a time when either LED 110-111 is on or off to provide a continuous, real-time measurement of the ambient light and or noise that gets into sensor 101. This feature can also be used to provide information on the magnitude of the signal at the output of A-to-D converter 402.
[0058] The information about the signal magnitude from A-to-D converter 402 is fed back through gain control feedback loop 403 and used to choose an appropriate gain for transimpedance amplifier 401. For example, gain control feedback loop 403 causes the transimpedance gain of transimpedance amplifier 401 to increase or decrease to reduce and/or accommodate the effect of the environmental DC bias on the signal. This real-time measurement can also be used for determining a sensor-off condition, measuring electrical and optical noise, detecting transients in the signal, and detecting patient motion.
100591 During the normal operation of the sensor, the LEDs can be pulsed on and off in any desired manner to provide the continuous (multiplexed), real-time measurement of the ambient light and other noise sources. For example, one red and one infrared LED can be alternately turned on and off in the following manner: red LED on and infrared LED off, then red LED off and infrared LED on, then both LEDs off, then red LED on and infrared LED
off, etc, repeating in this sequence. As another example, one red and one infrared LED can be alternately turned on and off as follows: red LED on and infrared LED off, then both LEDs off, then red LED off and infrared LED on, then both LEDs off, then red LED on and infrared LED off, etc. repeating in this sequence. These patterns are examples that are not intended to limit the scope of the present invention.
[0060] Sigma-delta modulator 410 also receives the output signal of the transimpedance amplifier 402. Modulator 410 demodulates the signal from the photodetector into separate red and infrared components. The demodulation function can be performed in the digital domain using a software or firmware program run by a microcontroller. Further details of a Multi-Bit ADC With Sigma-Delta Modulation are discussed in commonly assigned, US
Published Patent Application No. 2005/0184895 to Ethan Petersen et al.
[0061] As will be understood by those of skill in the art, the present invention could be embodied in other specific forms without departing from the essential characteristic thereof.
Accordingly, the foregoing description is intended to be illustrative, but not limiting.
[0062] For example, the components in pulse detection block 102 that are shown in Figure 4 can be implemented in systems other than pulse oximeter systems. These components can reduce the effect of noise in signals from other types of sensors as well. The scope of the claims should not be limited by the preferred embodiments set forth in the examples, but should be given the broadest interpretation consistent with the description as a whole.
100591 During the normal operation of the sensor, the LEDs can be pulsed on and off in any desired manner to provide the continuous (multiplexed), real-time measurement of the ambient light and other noise sources. For example, one red and one infrared LED can be alternately turned on and off in the following manner: red LED on and infrared LED off, then red LED off and infrared LED on, then both LEDs off, then red LED on and infrared LED
off, etc, repeating in this sequence. As another example, one red and one infrared LED can be alternately turned on and off as follows: red LED on and infrared LED off, then both LEDs off, then red LED off and infrared LED on, then both LEDs off, then red LED on and infrared LED off, etc. repeating in this sequence. These patterns are examples that are not intended to limit the scope of the present invention.
[0060] Sigma-delta modulator 410 also receives the output signal of the transimpedance amplifier 402. Modulator 410 demodulates the signal from the photodetector into separate red and infrared components. The demodulation function can be performed in the digital domain using a software or firmware program run by a microcontroller. Further details of a Multi-Bit ADC With Sigma-Delta Modulation are discussed in commonly assigned, US
Published Patent Application No. 2005/0184895 to Ethan Petersen et al.
[0061] As will be understood by those of skill in the art, the present invention could be embodied in other specific forms without departing from the essential characteristic thereof.
Accordingly, the foregoing description is intended to be illustrative, but not limiting.
[0062] For example, the components in pulse detection block 102 that are shown in Figure 4 can be implemented in systems other than pulse oximeter systems. These components can reduce the effect of noise in signals from other types of sensors as well. The scope of the claims should not be limited by the preferred embodiments set forth in the examples, but should be given the broadest interpretation consistent with the description as a whole.
Claims (39)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A pulse oximeter system comprising:
a drive interface that controls drive current of light emitting elements in a pulse oximeter sensor;
a feedback loop coupled around the pulse oximeter sensor and the drive interface that dynamically adjusts the drive current of the light emitting elements based on results of a comparison between a signal-to-noise ratio of a pulse oximeter signal and a threshold, a pulse detection block that calculates the signal-to-noise ratio of the pulse oximeter signal, wherein the pulse detection block calculates a moving average of a derivative of the pulse oximeter signal to generate a first output, calculates a moving average of the first output to generate a second output, calculates a moving average of the second output to generate a third output, and identifies a moving minimum and a moving maximum of the third output; and a comparator that performs the comparison of the signal-to-noise ratio of the pulse oximeter signal to the threshold;
wherein the feedback loop comprises the pulse detection block and the comparator;
and wherein the pulse oximeter signal is generated by a photodetector in the pulse oximeter sensor.
a drive interface that controls drive current of light emitting elements in a pulse oximeter sensor;
a feedback loop coupled around the pulse oximeter sensor and the drive interface that dynamically adjusts the drive current of the light emitting elements based on results of a comparison between a signal-to-noise ratio of a pulse oximeter signal and a threshold, a pulse detection block that calculates the signal-to-noise ratio of the pulse oximeter signal, wherein the pulse detection block calculates a moving average of a derivative of the pulse oximeter signal to generate a first output, calculates a moving average of the first output to generate a second output, calculates a moving average of the second output to generate a third output, and identifies a moving minimum and a moving maximum of the third output; and a comparator that performs the comparison of the signal-to-noise ratio of the pulse oximeter signal to the threshold;
wherein the feedback loop comprises the pulse detection block and the comparator;
and wherein the pulse oximeter signal is generated by a photodetector in the pulse oximeter sensor.
2. The pulse oximeter system as defined in claim 1 wherein the feedback loop causes the drive current of the light emitting elements to decrease if the signal-to-noise ratio of the pulse oximeter signal is greater than a maximum threshold, and the feedback loop causes the drive current of the light emitting elements to increase of the signal-to-noise ratio of the pulse oximeter signal is less than a minimum threshold.
3. The pulse oximeter system as defined in claim 1, wherein the pulse detection block compares the moving minimum and the moving maximum of the third output to a scaled sum of the moving minimum and the moving maximum of the third output to generate a fourth output that identifies a systolic period.
4. The pulse oximeter system as defined in claim 3, wherein the pulse oximeter system filters out false positives from the fourth output using pulse qualification tests to generate a signal component of the pulse oximeter signal.
5. The pulse oximeter system as defined in claim 4, wherein the pulse oximeter system compares systolic area, width, and number of sub-peaks in the fourth output to first thresholds; compares diastolic area, width, and number of sub-peaks in the fourth output to second thresholds; compares systolic area and width to diastolic area and width; compares pulse area and width to third thresholds.
6. The pulse oximeter system as defined in claim 4, wherein the pulse oximeter system compares systolic area, width, and number of sub-peaks in the fourth output;
diastolic area, width, and number of sub-peaks in the fourth output; and pulse area and width to N detected heart pulses.
diastolic area, width, and number of sub-peaks in the fourth output; and pulse area and width to N detected heart pulses.
7. The pulse oximeter system as defined in claim 4, wherein the pulse oximeter system performs additional qualification tests to generate the signal component by comparing the lag/lead time between infrared pulse detection and red pulse detection, comparing pulse size to N qualified pulses, comparing a statistically significant coefficient of a best-fit line plot of a moving average between the infrared and the red signals to thresholds, and comparing a saturation rate-of-change to thresholds.
8. The pulse oximeter system as defined in claim 4, wherein the pulse oximeter system compares the signal component to a determined noise component to calculate the signal-to-noise ratio.
9. The pulse oximeter system as defined in claim 4, wherein the pulse oximeter system compares the signal component to a noise component, the noise component being obtained by a continuously updated measurement of noise in the pulse oximeter signal.
10. The pulse oximeter system as defined in claim 1, wherein a reduced amount of processor resources are required to perform oximetry calculations on the pulse oximeter signal.
11. The pulse oximeter system as defined in claim 4, wherein the pulse detection block detects and qualifies pulses using CPU, RAM, and ROM efficient algorithms.
12. A method for reducing power consumption in a pulse oximeter sensor, the method comprising:
providing drive current to light emitting elements in the pulse oximeter sensor; and determining a signal-to-noise ratio of a pulse oximeter signal generated by a photo detector in the pulse oximeter sensor, wherein determining the signal-to-noise ratio of the pulse oximeter signal further comprises:
calculating a moving average of a derivative of the pulse oximeter signal to generate a first output; and calculating a moving average of the first output to generate a second output;
calculating a moving average of the second output to generate a third output;
and identifying a moving minimum and a moving maximum of the third output; and dynamically adjusting the drive current of the light emitting elements based on results of a comparison between the signal-to-noise ratio of the pulse oximeter signal and a threshold, wherein dynamically adjusting the drive current of the light emitting elements further comprises:
increasing the drive current provided to the light emitting elements if the signal-to-noise ratio of the pulse oximeter signal is less than a minimum threshold; and decreasing the drive current provided to the light emitting elements if the signal-to-noise ratio of the pulse oximeter signal is greater than a maximum threshold.
providing drive current to light emitting elements in the pulse oximeter sensor; and determining a signal-to-noise ratio of a pulse oximeter signal generated by a photo detector in the pulse oximeter sensor, wherein determining the signal-to-noise ratio of the pulse oximeter signal further comprises:
calculating a moving average of a derivative of the pulse oximeter signal to generate a first output; and calculating a moving average of the first output to generate a second output;
calculating a moving average of the second output to generate a third output;
and identifying a moving minimum and a moving maximum of the third output; and dynamically adjusting the drive current of the light emitting elements based on results of a comparison between the signal-to-noise ratio of the pulse oximeter signal and a threshold, wherein dynamically adjusting the drive current of the light emitting elements further comprises:
increasing the drive current provided to the light emitting elements if the signal-to-noise ratio of the pulse oximeter signal is less than a minimum threshold; and decreasing the drive current provided to the light emitting elements if the signal-to-noise ratio of the pulse oximeter signal is greater than a maximum threshold.
13. The method as defined in claim 12, wherein determining the signal-to-noise ratio of the pulse oximeter signal further comprises:
comparing the moving minimum and the moving maximum of the third output to a scaled sum of the moving minimum and the moving maximum of the third output to generate a fourth output that identifies a systolic period.
comparing the moving minimum and the moving maximum of the third output to a scaled sum of the moving minimum and the moving maximum of the third output to generate a fourth output that identifies a systolic period.
14. The method as defined in claim 13, wherein determining the signal-to-noise ratio of the pulse oximeter signal further comprises:
filtering out false positives from the fourth output using pulse qualification tests to generate a signal component of the pulse oximeter signal.
filtering out false positives from the fourth output using pulse qualification tests to generate a signal component of the pulse oximeter signal.
15. The method as defined in claim 14, wherein determining the signal-to-noise ratio of the pulse oximeter signal further comprises:
comparing the signal component to a determined, noise component to calculate the signal-to-noise ratio.
comparing the signal component to a determined, noise component to calculate the signal-to-noise ratio.
16. The method as defined in claim 14, wherein determining the signal-to-noise ratio of the pulse oximeter signal further comprises:
comparing the signal component to a noise component, wherein the noise component is obtained by a continuously updated measurement of noise in the pulse oximeter signal.
comparing the signal component to a noise component, wherein the noise component is obtained by a continuously updated measurement of noise in the pulse oximeter signal.
17. A pulse oximeter system comprising:
a drive interface that controls drive current of light emitting elements in a pulse oximeter sensor; and a feedback loop coupled around the pulse oximeter sensor and the drive interface that is capable of dynamically adjusting the drive current of the light emitting elements based at least in part upon results of a comparison between a signal-to-noise ratio of a pulse oximeter signal and a threshold, wherein the feedback loop is capable of detecting systolic transitions based at least in part upon a multi-step averaging scheme, wherein the pulse oximeter signal is generated by a photodetector in the pulse oximeter sensor.
a drive interface that controls drive current of light emitting elements in a pulse oximeter sensor; and a feedback loop coupled around the pulse oximeter sensor and the drive interface that is capable of dynamically adjusting the drive current of the light emitting elements based at least in part upon results of a comparison between a signal-to-noise ratio of a pulse oximeter signal and a threshold, wherein the feedback loop is capable of detecting systolic transitions based at least in part upon a multi-step averaging scheme, wherein the pulse oximeter signal is generated by a photodetector in the pulse oximeter sensor.
18. The pulse oximeter system as defined in claim 17 wherein the feedback loop causes the drive current of the light emitting elements to decrease if the signal-to-noise ratio of the pulse oximeter signal is greater than a maximum threshold, and the feedback loop causes the drive current of the light emitting elements to increase if the signal-to-noise ratio of the pulse oximeter signal is less than a minimum threshold.
19. The pulse oximeter system as defined in claim 17 wherein the feedback loop further comprises: a pulse detection block that is capable of calculating the signal-to-noise ratio of the pulse oximeter signal; and a comparator that is capable of performing the comparison of the signal-to-noise ratio of the pulse oximeter signal to the threshold.
20. A method for reducing power consumption in a pulse oximeter sensor, the method comprising:
providing drive current to light emitting elements in the pulse oximeter sensor; and dynamically determining a signal-to-noise ratio of a pulse oximeter signal generated by a photodetector in the pulse oximeter sensor, wherein determining the signal-to-noise ratio comprises measuring and storing the noise at each of a plurality of gain stages; and dynamically adjusting the drive current of the light emitting elements based at least in part upon results of a comparison between the signal-to-noise ratio of the pulse oximeter signal and a threshold.
providing drive current to light emitting elements in the pulse oximeter sensor; and dynamically determining a signal-to-noise ratio of a pulse oximeter signal generated by a photodetector in the pulse oximeter sensor, wherein determining the signal-to-noise ratio comprises measuring and storing the noise at each of a plurality of gain stages; and dynamically adjusting the drive current of the light emitting elements based at least in part upon results of a comparison between the signal-to-noise ratio of the pulse oximeter signal and a threshold.
21. The method as defined in claim 20 wherein dynamically adjusting the drive current of the light emitting elements further comprises: increasing the drive current provided to the light emitting elements if the signal-to-noise ratio of the pulse oximeter signal is less than a minimum threshold; and decreasing the drive current provided to the light emitting elements if the signal-to-noise ratio of the pulse oximeter signal is greater than a maximum threshold.
22. A method for controlling drive current of light emitting elements in a pulse oximeter sensor, comprising:
using a pulse oximeter:
measuring a noise component of a pulse oximeter signal;
identifying a systolic period of the pulse oximeter signal;
performing first pulse qualification tests to qualify a systolic period for pulse rate measurement;
performing second pulse qualification tests to qualify the systolic period for oxygen saturation calculations, if the systolic period is qualified for pulse rate measurement;
determining a strength of the systolic period if the systolic period is qualified for oxygen saturation calculations;
identifying a signal-to-noise ratio by comparing the strength of the systolic period to the noise component; and controlling the drive current based at least in part upon a comparison of the signal-to-noise ratio to a threshold.
using a pulse oximeter:
measuring a noise component of a pulse oximeter signal;
identifying a systolic period of the pulse oximeter signal;
performing first pulse qualification tests to qualify a systolic period for pulse rate measurement;
performing second pulse qualification tests to qualify the systolic period for oxygen saturation calculations, if the systolic period is qualified for pulse rate measurement;
determining a strength of the systolic period if the systolic period is qualified for oxygen saturation calculations;
identifying a signal-to-noise ratio by comparing the strength of the systolic period to the noise component; and controlling the drive current based at least in part upon a comparison of the signal-to-noise ratio to a threshold.
23. The method of claim 22, comprising measuring the noise component before determining the strength of the systolic period and storing the measured noise component in memory for comparison with the strength of the systolic period.
24. The method of claim 22, comprising measuring the noise in the pulse oximeter signal at various gain values.
25. The method of claim 22, wherein the threshold comprises a maximum signal-to-noise ratio value of 128:1.
26. The method of claim 22, wherein the threshold comprises a minimum signal-to-noise ratio value of 8:1.
27. The method of claim 22, comprising calculating a series of moving averages based at least in part upon a derivative of the pulse oximeter signal to identify the systolic period.
28. The method of claim 27, comprising identifying a moving minimum and moving maximum of a last moving average of the series of moving averages to identify the systolic period.
29. The method of claim 22, comprising calculating a moving average of a derivative of the pulse oximeter signal to generate a first output, calculating a moving average of the first output to generate a second output, calculating a moving average of the second output to generate a third output, and identifying a moving minimum and a moving maximum of the third output to identify the systolic period.
30. The method of claim 29, comprising comparing the moving minimum and the moving maximum to a scaled sum of the moving minimum and the moving maximum to determine the systolic period.
31. A monitor for controlling drive current of light emitting elements in a pulse oximeter sensor, comprising:
an identification module capable of identifying a systolic period of a pulse oximeter signal;
a qualification module capable of performing multiple stages of pulse qualification tests to qualify the systolic period for oxygen saturation calculations;
a strength determination module capable of determining a strength of the systolic period if the systolic period is qualified for oxygen saturation calculations;
a ratio module capable of identifying a signal-to-noise ratio by comparing the strength of the systolic period to a measured value of a noise component of the pulse oximeter signal stored in a memory; and a controller capable of controlling the drive current based at least in part upon a comparison of the signal-to-noise ratio to a threshold.
an identification module capable of identifying a systolic period of a pulse oximeter signal;
a qualification module capable of performing multiple stages of pulse qualification tests to qualify the systolic period for oxygen saturation calculations;
a strength determination module capable of determining a strength of the systolic period if the systolic period is qualified for oxygen saturation calculations;
a ratio module capable of identifying a signal-to-noise ratio by comparing the strength of the systolic period to a measured value of a noise component of the pulse oximeter signal stored in a memory; and a controller capable of controlling the drive current based at least in part upon a comparison of the signal-to-noise ratio to a threshold.
32. The monitor of claim 31, comprising a measurement module capable of measuring the noise component.
33. The monitor of claim 32, wherein the measurement module is capable of measuring the noise component at various gain values.
34. The monitor of claim 31, wherein the threshold comprises a maximum signal-to-noise ratio value of 128:1.
35. The monitor of claim 31, wherein the threshold comprises a minimum signal-to-noise ratio value of 8:1.
36. The monitor of claim 31, comprising a calculation module capable of calculating a series of moving averages based at least in part upon a derivative of the pulse oximeter signal to identify the systolic period.
37. The monitor of claim 36, wherein the calculation module is capable of identifying a moving minimum and moving maximum of a last moving average of the series of moving averages to identify the systolic period.
38. The monitor of claim 31, comprising a calculation module capable of calculating a moving average of a derivative of the pulse oximeter signal to generate a first output, calculating a moving average of the first output to generate a second output, calculating a moving average of the second output to generate a third output, and identifying a moving minimum and a moving maximum of the third output to identify the systolic period.
39. The monitor of claim 38, comprising a comparison module capable of comparing the moving minimum and the moving maximum to a scaled sum of the moving minimum and the moving maximum to determine the systolic period.
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Families Citing this family (159)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6675031B1 (en) * | 1999-04-14 | 2004-01-06 | Mallinckrodt Inc. | Method and circuit for indicating quality and accuracy of physiological measurements |
US7190986B1 (en) | 2002-10-18 | 2007-03-13 | Nellcor Puritan Bennett Inc. | Non-adhesive oximeter sensor for sensitive skin |
JP3784766B2 (en) * | 2002-11-01 | 2006-06-14 | 株式会社半導体理工学研究センター | Multi-port unified cache |
US7198604B2 (en) * | 2003-03-18 | 2007-04-03 | Ge Medical Systems Information Technologies | Method and system for determination of pulse rate |
US7534212B2 (en) * | 2004-03-08 | 2009-05-19 | Nellcor Puritan Bennett Llc | Pulse oximeter with alternate heart-rate determination |
US7892178B1 (en) * | 2009-09-28 | 2011-02-22 | Impact Sports Technologies, Inc. | Monitoring device for an interactive game |
FR2877948B1 (en) * | 2004-11-12 | 2007-01-05 | Arkema Sa | PROCESS FOR SYNTHESIZING POLYAMIDE POWDERS |
WO2006094171A1 (en) | 2005-03-01 | 2006-09-08 | Masimo Laboratories, Inc. | Multiple wavelength sensor drivers |
US7657294B2 (en) | 2005-08-08 | 2010-02-02 | Nellcor Puritan Bennett Llc | Compliant diaphragm medical sensor and technique for using the same |
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 |
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 |
US7899510B2 (en) * | 2005-09-29 | 2011-03-01 | 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 |
US7555327B2 (en) * | 2005-09-30 | 2009-06-30 | Nellcor Puritan Bennett Llc | Folding medical sensor and technique for using the same |
US8062221B2 (en) * | 2005-09-30 | 2011-11-22 | Nellcor Puritan Bennett Llc | Sensor for tissue gas detection 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 |
US7881762B2 (en) * | 2005-09-30 | 2011-02-01 | Nellcor Puritan Bennett Llc | Clip-style 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 |
US20070149870A1 (en) * | 2005-12-28 | 2007-06-28 | Futrex, Inc. | Systems and methods for determining an organism's pathology |
US8073518B2 (en) | 2006-05-02 | 2011-12-06 | Nellcor Puritan Bennett Llc | Clip-style medical sensor and technique for using the same |
US20070282181A1 (en) * | 2006-06-01 | 2007-12-06 | Carol Findlay | Visual medical sensor indicator |
US8145288B2 (en) * | 2006-08-22 | 2012-03-27 | Nellcor Puritan Bennett Llc | Medical sensor for reducing signal artifacts and technique for using the same |
US20080064940A1 (en) * | 2006-09-12 | 2008-03-13 | Raridan William B | Sensor cable design for use with spectrophotometric sensors and method of using the same |
US8219170B2 (en) * | 2006-09-20 | 2012-07-10 | Nellcor Puritan Bennett Llc | System and method for practicing spectrophotometry using light emitting nanostructure devices |
US8190225B2 (en) * | 2006-09-22 | 2012-05-29 | 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 |
US8175671B2 (en) * | 2006-09-22 | 2012-05-08 | Nellcor Puritan Bennett Llc | 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 |
US7574245B2 (en) * | 2006-09-27 | 2009-08-11 | Nellcor Puritan Bennett Llc | Flexible medical sensor enclosure |
US7890153B2 (en) * | 2006-09-28 | 2011-02-15 | Nellcor Puritan Bennett Llc | System and method for mitigating interference in pulse oximetry |
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 |
US8068891B2 (en) | 2006-09-29 | 2011-11-29 | Nellcor Puritan Bennett Llc | Symmetric LED array for pulse oximetry |
US8068890B2 (en) * | 2006-09-29 | 2011-11-29 | Nellcor Puritan Bennett Llc | Pulse oximetry sensor switchover |
US7680522B2 (en) * | 2006-09-29 | 2010-03-16 | Nellcor Puritan Bennett Llc | Method and apparatus for detecting misapplied sensors |
US8175667B2 (en) | 2006-09-29 | 2012-05-08 | Nellcor Puritan Bennett Llc | Symmetric LED array for pulse oximetry |
US7476131B2 (en) | 2006-09-29 | 2009-01-13 | Nellcor Puritan Bennett Llc | Device for reducing crosstalk |
US7684842B2 (en) | 2006-09-29 | 2010-03-23 | Nellcor Puritan Bennett Llc | System and method for preventing sensor misuse |
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 |
US8280469B2 (en) * | 2007-03-09 | 2012-10-02 | Nellcor Puritan Bennett Llc | Method for detection of aberrant tissue spectra |
US8374665B2 (en) | 2007-04-21 | 2013-02-12 | Cercacor Laboratories, Inc. | Tissue profile wellness monitor |
US8376952B2 (en) * | 2007-09-07 | 2013-02-19 | The Nielsen Company (Us), Llc. | Method and apparatus for sensing blood oxygen |
US8352004B2 (en) | 2007-12-21 | 2013-01-08 | Covidien Lp | Medical sensor and technique for using the same |
US8346328B2 (en) | 2007-12-21 | 2013-01-01 | Covidien Lp | Medical sensor and technique for using the same |
CN101467882B (en) * | 2007-12-24 | 2011-04-20 | 北京超思电子技术有限责任公司 | Oximeter and working method thereof |
US8366613B2 (en) | 2007-12-26 | 2013-02-05 | Covidien Lp | LED drive circuit for pulse oximetry and method for using same |
US8577434B2 (en) | 2007-12-27 | 2013-11-05 | Covidien Lp | Coaxial LED light sources |
US20090168050A1 (en) * | 2007-12-27 | 2009-07-02 | Nellcor Puritan Bennett Llc | Optical Sensor System And Method |
US8442608B2 (en) * | 2007-12-28 | 2013-05-14 | Covidien Lp | System and method for estimating physiological parameters by deconvolving artifacts |
US8452364B2 (en) | 2007-12-28 | 2013-05-28 | Covidien LLP | System and method for attaching a sensor to a patient's skin |
US20090171166A1 (en) * | 2007-12-31 | 2009-07-02 | Nellcor Puritan Bennett Llc | Oximeter with location awareness |
US8070508B2 (en) * | 2007-12-31 | 2011-12-06 | Nellcor Puritan Bennett Llc | Method and apparatus for aligning and securing a cable strain relief |
US8199007B2 (en) * | 2007-12-31 | 2012-06-12 | Nellcor Puritan Bennett Llc | Flex circuit snap track for a biometric sensor |
US8897850B2 (en) * | 2007-12-31 | 2014-11-25 | Covidien Lp | Sensor with integrated living hinge and spring |
US20090171226A1 (en) * | 2007-12-31 | 2009-07-02 | Nellcor Puritan Bennett Llc | System and method for evaluating variation in the timing of physiological events |
US20090171173A1 (en) * | 2007-12-31 | 2009-07-02 | Nellcor Puritan Bennett Llc | System and method for reducing motion artifacts in a sensor |
US8092993B2 (en) | 2007-12-31 | 2012-01-10 | Nellcor Puritan Bennett Llc | Hydrogel thin film for use as a biosensor |
US20110098583A1 (en) * | 2009-09-15 | 2011-04-28 | Texas Instruments Incorporated | Heart monitors and processes with accelerometer motion artifact cancellation, and other electronic systems |
US9560994B2 (en) | 2008-03-26 | 2017-02-07 | Covidien Lp | Pulse oximeter with adaptive power conservation |
US20090247854A1 (en) * | 2008-03-27 | 2009-10-01 | Nellcor Puritan Bennett Llc | Retractable Sensor Cable For A Pulse Oximeter |
US8437822B2 (en) * | 2008-03-28 | 2013-05-07 | Covidien Lp | System and method for estimating blood analyte concentration |
US8112375B2 (en) * | 2008-03-31 | 2012-02-07 | Nellcor Puritan Bennett Llc | Wavelength selection and outlier detection in reduced rank linear models |
US8364224B2 (en) * | 2008-03-31 | 2013-01-29 | Covidien Lp | System and method for facilitating sensor and monitor communication |
US10271778B2 (en) * | 2008-06-03 | 2019-04-30 | Nonin Medical, Inc. | LED control utilizing ambient light or signal quality |
US8071935B2 (en) | 2008-06-30 | 2011-12-06 | Nellcor Puritan Bennett Llc | Optical detector with an overmolded faraday shield |
US8862194B2 (en) | 2008-06-30 | 2014-10-14 | Covidien Lp | Method for improved oxygen saturation estimation in the presence of noise |
US7887345B2 (en) | 2008-06-30 | 2011-02-15 | Nellcor Puritan Bennett Llc | Single use connector for pulse oximetry sensors |
US7880884B2 (en) * | 2008-06-30 | 2011-02-01 | Nellcor Puritan Bennett Llc | System and method for coating and shielding electronic sensor components |
US8532932B2 (en) * | 2008-06-30 | 2013-09-10 | Nellcor Puritan Bennett Ireland | Consistent signal selection by signal segment selection techniques |
US20100076319A1 (en) * | 2008-09-25 | 2010-03-25 | Nellcor Puritan Bennett Llc | Pathlength-Corrected Medical Spectroscopy |
US8364220B2 (en) | 2008-09-25 | 2013-01-29 | Covidien Lp | Medical sensor and technique for using the same |
US8417309B2 (en) * | 2008-09-30 | 2013-04-09 | Covidien Lp | Medical sensor |
US8423112B2 (en) | 2008-09-30 | 2013-04-16 | Covidien Lp | Medical sensor and technique for using the same |
US20100081912A1 (en) * | 2008-09-30 | 2010-04-01 | Nellcor Puritan Bennett Llc | Ultrasound-Optical Doppler Hemometer and Technique for Using the Same |
US8914088B2 (en) * | 2008-09-30 | 2014-12-16 | Covidien Lp | Medical sensor and technique for using the same |
DE102008056252A1 (en) * | 2008-10-07 | 2010-04-15 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Apparatus and method for detecting a respiration of a living being |
DE102008056251A1 (en) * | 2008-10-07 | 2010-04-15 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Device and method for detecting a vital parameter |
WO2010086978A1 (en) * | 2009-01-29 | 2010-08-05 | 富士通株式会社 | Photoelectric sphygmograph measurement device |
US8700111B2 (en) | 2009-02-25 | 2014-04-15 | Valencell, Inc. | Light-guiding devices and monitoring devices incorporating same |
US8788002B2 (en) | 2009-02-25 | 2014-07-22 | Valencell, Inc. | Light-guiding devices and monitoring devices incorporating same |
US8452366B2 (en) * | 2009-03-16 | 2013-05-28 | Covidien Lp | Medical monitoring device with flexible circuitry |
US20100249550A1 (en) * | 2009-03-25 | 2010-09-30 | Neilcor Puritan Bennett LLC | Method And Apparatus For Optical Filtering Of A Broadband Emitter In A Medical Sensor |
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 |
US8211030B2 (en) * | 2009-03-26 | 2012-07-03 | The General Electric Company | NIBP target inflation pressure automation using derived SPO2 signals |
US8478538B2 (en) * | 2009-05-07 | 2013-07-02 | Nellcor Puritan Bennett Ireland | Selection of signal regions for parameter extraction |
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 |
KR101604077B1 (en) * | 2009-05-26 | 2016-03-16 | 삼성전자주식회사 | Method and apparatus for transmitting biological information of user |
US20100331631A1 (en) * | 2009-06-30 | 2010-12-30 | Nellcor Puritan Bennett Llc | Oxygen saturation ear sensor design that optimizes both attachment method and signal quality |
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 |
US8378832B2 (en) | 2009-07-09 | 2013-02-19 | Harry J. Cassidy | Breathing disorder treatment system and method |
US8391941B2 (en) * | 2009-07-17 | 2013-03-05 | Covidien Lp | System and method for memory switching for multiple configuration medical sensor |
US8471713B2 (en) * | 2009-07-24 | 2013-06-25 | Cercacor Laboratories, Inc. | Interference detector for patient monitor |
US20110060224A1 (en) * | 2009-08-09 | 2011-03-10 | Tz Medical, Inc. | Non-invasive continuous doppler monitoring device for arterial blood flow to distal body parts |
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 |
US9554739B2 (en) | 2009-09-29 | 2017-01-31 | Covidien Lp | Smart cable for coupling a medical sensor to an electronic patient monitor |
US9839381B1 (en) | 2009-11-24 | 2017-12-12 | Cercacor Laboratories, Inc. | Physiological measurement system with automatic wavelength adjustment |
WO2012073069A1 (en) * | 2010-11-30 | 2012-06-07 | Spo Medical Equipment Ltd. | A method and system for pulse measurement |
US8801613B2 (en) | 2009-12-04 | 2014-08-12 | Masimo Corporation | Calibration for multi-stage physiological monitors |
US8244339B2 (en) | 2010-08-09 | 2012-08-14 | Medtronic, Inc. | Wireless cardiac pulsatility sensing |
US8571622B2 (en) | 2010-08-31 | 2013-10-29 | General Electric Company | Method for reducing power consumption in pulse oximeter systems, pulse oximeter system and pulse oximeter sensor |
US9775545B2 (en) | 2010-09-28 | 2017-10-03 | Masimo Corporation | Magnetic electrical connector for patient monitors |
US8821397B2 (en) | 2010-09-28 | 2014-09-02 | Masimo Corporation | Depth of consciousness monitor including oximeter |
US8761853B2 (en) * | 2011-01-20 | 2014-06-24 | Nitto Denko Corporation | Devices and methods for non-invasive optical physiological measurements |
US8855735B2 (en) | 2011-02-24 | 2014-10-07 | Covidien Lp | Medical sensor using photonic crystal LED |
JP5837785B2 (en) * | 2011-09-13 | 2015-12-24 | 日本光電工業株式会社 | Biological signal measuring device |
US9241672B2 (en) * | 2012-02-09 | 2016-01-26 | Sharp Laboratories Of America, Inc. | Determining usability of an acoustic signal for physiological monitoring using frequency analysis |
US9241676B2 (en) | 2012-05-31 | 2016-01-26 | Covidien Lp | Methods and systems for power optimization in a medical device |
US9241643B2 (en) | 2012-05-31 | 2016-01-26 | Covidien Lp | Methods and systems for power optimization in a medical device |
EP2687154B8 (en) * | 2012-07-20 | 2019-09-11 | CSEM Centre Suisse d'Electronique et de Microtechnique SA - Recherche et Développement | Portable device and method for determining a sleep-related parameter of a user |
US10881310B2 (en) | 2012-08-25 | 2021-01-05 | The Board Of Trustees Of The Leland Stanford Junior University | Motion artifact mitigation methods and devices for pulse photoplethysmography |
US9149196B2 (en) | 2012-09-11 | 2015-10-06 | Covidien Lp | Methods and systems for determining an algorithm setting based on a difference signal |
US9155478B2 (en) | 2012-09-11 | 2015-10-13 | Covidien Lp | Methods and systems for determining an algorithm setting based on a difference signal |
US9339235B2 (en) | 2012-09-11 | 2016-05-17 | Covidien Lp | Methods and systems for determining signal-to-noise information from a physiological signal |
US9161723B2 (en) | 2012-09-11 | 2015-10-20 | Covidien Lp | Methods and systems for qualifying calculated values based on multiple difference signals |
US9259186B2 (en) | 2012-09-11 | 2016-02-16 | Covidien Lp | Methods and systems for determining noise information from a physiological signal |
US9220423B2 (en) | 2012-09-11 | 2015-12-29 | Covidien Lp | Methods and systems for qualifying a calculated value based on differently sized sorted difference signals |
US10610159B2 (en) | 2012-10-07 | 2020-04-07 | Rhythm Diagnostic Systems, Inc. | Health monitoring systems and methods |
USD850626S1 (en) | 2013-03-15 | 2019-06-04 | Rhythm Diagnostic Systems, Inc. | Health monitoring apparatuses |
US10244949B2 (en) | 2012-10-07 | 2019-04-02 | Rhythm Diagnostic Systems, Inc. | Health monitoring systems and methods |
US10413251B2 (en) | 2012-10-07 | 2019-09-17 | Rhythm Diagnostic Systems, Inc. | Wearable cardiac monitor |
KR102023991B1 (en) | 2012-11-12 | 2019-09-23 | 삼성전자주식회사 | Device of transmitting a bio signal, device of receiving the bio signal, and method thereof |
US9768881B2 (en) * | 2012-11-29 | 2017-09-19 | Massachusetts Institute Of Technology | Devices and techniques for integrated optical data communication |
US9351688B2 (en) | 2013-01-29 | 2016-05-31 | Covidien Lp | Low power monitoring systems and method |
CN104107038A (en) * | 2013-04-16 | 2014-10-22 | 达尔生技股份有限公司 | Pulse wave signal de-noising processing method and device and pulse oximeter |
JP2014210018A (en) * | 2013-04-18 | 2014-11-13 | パイオニア株式会社 | Living body device |
FI126338B (en) * | 2013-05-15 | 2016-10-14 | Pulseon Oy | Portable heart rate monitor |
CN103549945B (en) * | 2013-10-31 | 2015-07-15 | 广州视源电子科技股份有限公司 | Method for recognizing pulse rate and blood oxygen saturation degree through cardiac contraction process characteristic |
US10188330B1 (en) | 2014-02-05 | 2019-01-29 | Covidien Lp | Methods and systems for determining a light drive parameter limit in a physiological monitor |
US10238305B2 (en) * | 2014-05-30 | 2019-03-26 | Microsoft Technology Licensing, Llc | Dynamic operation of optical heart rate sensors |
US9912144B2 (en) * | 2014-09-04 | 2018-03-06 | Analog Devices Global | Embedded overload protection in delta-sigma analog-to-digital converters |
WO2016057553A1 (en) | 2014-10-07 | 2016-04-14 | Masimo Corporation | Modular physiological sensors |
EP3206586B1 (en) | 2014-10-16 | 2021-03-24 | Viewcare Technologies 1 ApS | A method of detecting dicrotic notch |
US9743868B2 (en) | 2014-11-20 | 2017-08-29 | Qualcomm Incorporated | Circuitry to allow low current operation of a device capable of determining a blood property |
US10568525B1 (en) * | 2015-12-14 | 2020-02-25 | Fitbit, Inc. | Multi-wavelength pulse oximetry |
CN105615862B (en) * | 2015-12-21 | 2017-10-03 | 珠海格力电器股份有限公司 | Detect the method and device of heart rate |
US10799129B2 (en) * | 2016-01-07 | 2020-10-13 | Panasonic Intellectual Property Management Co., Ltd. | Biological information measuring device including light source, light detector, and control circuit |
US10582887B2 (en) * | 2016-03-17 | 2020-03-10 | Analog Devices Global | Blood oxygenation sensor with LED current modulation |
US10045721B2 (en) * | 2016-03-30 | 2018-08-14 | Intel Corporation | Apparatus, system, and method for automatic power reduction in photoplethysmography and pulse oximetry systems |
JP2018042884A (en) * | 2016-09-16 | 2018-03-22 | 株式会社東芝 | Biological signal detection device |
JP2018165737A (en) * | 2017-03-28 | 2018-10-25 | 富士通株式会社 | Drive circuit and image projection device |
US20180353111A1 (en) * | 2017-06-09 | 2018-12-13 | Covidien Lp | Systems and methods for driving optical sensors |
US20190038224A1 (en) * | 2017-08-03 | 2019-02-07 | Intel Corporation | Wearable devices having pressure activated biometric monitoring systems and related methods |
WO2020041800A1 (en) * | 2018-08-24 | 2020-02-27 | Marcelo Malini Lamego | Monitoring device and system |
TWI828770B (en) * | 2018-09-28 | 2024-01-11 | 愛爾蘭商Q生活全球有限公司 | Method and system for handling ppg signal to noise ratio |
US10874352B2 (en) * | 2018-11-05 | 2020-12-29 | General Electric Company | Systems and methods for low power pulse oximetry |
US10912505B2 (en) | 2018-11-05 | 2021-02-09 | General Electric Company | Systems and methods for low power pulse oximetery |
AU2019387364A1 (en) | 2018-11-28 | 2021-06-10 | Liberating Technologies, Inc. | Management of wireless transmission rate of control signals for power assistive devices |
US11020014B2 (en) * | 2018-11-30 | 2021-06-01 | Microsoft Technology Licensing, Llc | Photoplethysmogram device with skin temperature regulator |
US10993644B2 (en) | 2018-12-21 | 2021-05-04 | General Electric Company | SpO2 system and method |
WO2020150973A1 (en) * | 2019-01-24 | 2020-07-30 | 深圳市汇顶科技股份有限公司 | Signal adjustment method, device, chip, apparatus and storage medium |
US11903700B2 (en) | 2019-08-28 | 2024-02-20 | Rds | Vital signs monitoring systems and methods |
CN111529829B (en) * | 2020-07-07 | 2020-11-27 | 深圳市汇顶科技股份有限公司 | PPG (photoplethysmography) equipment and signal adjusting method thereof |
Family Cites Families (190)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3403555A (en) | 1966-07-18 | 1968-10-01 | Versaci | Flowmeter |
BE661207A (en) | 1968-05-13 | 1965-07-16 | ||
US3721813A (en) | 1971-02-01 | 1973-03-20 | Perkin Elmer Corp | Analytical instrument system |
US4098772A (en) | 1976-03-11 | 1978-07-04 | The Upjohn Company | Thermoplastic polyurethanes prepared with small amounts of monohydric alcohols |
USD250275S (en) | 1976-07-19 | 1978-11-14 | Hewlett-Packard Company | Self-attaching probe for use in photoelectric monitoring of body extremities |
USD251387S (en) | 1977-02-07 | 1979-03-20 | Component Manufacturing Service, Inc. | Electrical connector for electrocardiogram monitoring |
US4281645A (en) | 1977-06-28 | 1981-08-04 | Duke University, Inc. | Method and apparatus for monitoring metabolism in body organs |
USD262488S (en) | 1979-10-24 | 1981-12-29 | Novatec, Inc. | Pulse rate monitor |
US4353372A (en) | 1980-02-11 | 1982-10-12 | Bunker Ramo Corporation | Medical cable set and electrode therefor |
US4334544A (en) | 1980-04-28 | 1982-06-15 | Amf Incorporated | Ear lobe clip with heart beat sensor |
US4350165A (en) | 1980-05-23 | 1982-09-21 | Trw Inc. | Medical electrode assembly |
NL8005145A (en) | 1980-09-12 | 1982-04-01 | Tno | DEVICE FOR INDIRECT, NON-INVASIVE, CONTINUOUS MEASUREMENT OF BLOOD PRESSURE. |
GB8416219D0 (en) | 1984-06-26 | 1984-08-01 | Antec Systems | Patient monitoring apparatus |
JPS58143243A (en) | 1982-02-19 | 1983-08-25 | Minolta Camera Co Ltd | Measuring apparatus for coloring matter in blood without taking out blood |
US4621643A (en) | 1982-09-02 | 1986-11-11 | Nellcor Incorporated | Calibrated optical oximeter probe |
US4770179A (en) | 1982-09-02 | 1988-09-13 | Nellcor Incorporated | Calibrated optical oximeter probe |
US4700708A (en) | 1982-09-02 | 1987-10-20 | Nellcor Incorporated | Calibrated optical oximeter probe |
US4653498A (en) | 1982-09-13 | 1987-03-31 | Nellcor Incorporated | Pulse oximeter monitor |
US4830014A (en) | 1983-05-11 | 1989-05-16 | Nellcor Incorporated | Sensor having cutaneous conformance |
US4938218A (en) | 1983-08-30 | 1990-07-03 | Nellcor Incorporated | Perinatal pulse oximetry sensor |
US4603700A (en) | 1983-12-09 | 1986-08-05 | The Boc Group, Inc. | Probe monitoring system for oximeter |
US4714341A (en) | 1984-02-23 | 1987-12-22 | Minolta Camera Kabushiki Kaisha | Multi-wavelength oximeter having a means for disregarding a poor signal |
US4510551A (en) | 1984-05-21 | 1985-04-09 | Endeco Canada Limited | Portable memory module |
US4677528A (en) | 1984-05-31 | 1987-06-30 | Motorola, Inc. | Flexible printed circuit board having integrated circuit die or the like affixed thereto |
IT1206462B (en) * | 1984-08-07 | 1989-04-27 | Anic Spa | MULTI-WAVE LENGTH PULSED LIGHT PHOTOMETER FOR NON-INVASIVE MONITORING. |
US4928692A (en) | 1985-04-01 | 1990-05-29 | Goodman David E | Method and apparatus for detecting optical pulses |
US4911167A (en) | 1985-06-07 | 1990-03-27 | Nellcor Incorporated | Method and apparatus for detecting optical pulses |
US4934372A (en) | 1985-04-01 | 1990-06-19 | Nellcor Incorporated | Method and apparatus for detecting optical pulses |
US4802486A (en) | 1985-04-01 | 1989-02-07 | Nellcor Incorporated | Method and apparatus for detecting optical pulses |
US4685464A (en) | 1985-07-05 | 1987-08-11 | Nellcor Incorporated | Durable sensor for detecting optical pulses |
US4890619A (en) * | 1986-04-15 | 1990-01-02 | Hatschek Rudolf A | System for the measurement of the content of a gas in blood, in particular the oxygen saturation of blood |
JPS6323645A (en) | 1986-05-27 | 1988-01-30 | 住友電気工業株式会社 | Reflection heating type oxymeter |
US4759369A (en) | 1986-07-07 | 1988-07-26 | Novametrix Medical Systems, Inc. | Pulse oximeter |
US4800495A (en) * | 1986-08-18 | 1989-01-24 | Physio-Control Corporation | Method and apparatus for processing signals used in oximetry |
US4892101A (en) * | 1986-08-18 | 1990-01-09 | Physio-Control Corporation | Method and apparatus for offsetting baseline portion of oximeter signal |
US4859056A (en) | 1986-08-18 | 1989-08-22 | Physio-Control Corporation | Multiple-pulse method and apparatus for use in oximetry |
US4869253A (en) | 1986-08-18 | 1989-09-26 | Physio-Control Corporation | Method and apparatus for indicating perfusion and oxygen saturation trends in oximetry |
US4819646A (en) | 1986-08-18 | 1989-04-11 | Physio-Control Corporation | Feedback-controlled method and apparatus for processing signals used in oximetry |
US4913150A (en) | 1986-08-18 | 1990-04-03 | Physio-Control Corporation | Method and apparatus for the automatic calibration of signals employed in oximetry |
JPS6365845A (en) | 1986-09-05 | 1988-03-24 | ミノルタ株式会社 | Oximeter apparatus |
US4726382A (en) * | 1986-09-17 | 1988-02-23 | The Boc Group, Inc. | Inflatable finger cuff |
US4824242A (en) | 1986-09-26 | 1989-04-25 | Sensormedics Corporation | Non-invasive oximeter and method |
US4714080A (en) | 1986-10-06 | 1987-12-22 | Nippon Colin Co., Ltd. | Method and apparatus for noninvasive monitoring of arterial blood oxygen saturation |
US4865038A (en) | 1986-10-09 | 1989-09-12 | Novametrix Medical Systems, Inc. | Sensor appliance for non-invasive monitoring |
JPS63111837A (en) | 1986-10-29 | 1988-05-17 | 日本光電工業株式会社 | Apparatus for measuring concentration of light absorbing substance in blood |
US4802488A (en) * | 1986-11-06 | 1989-02-07 | Sri International | Blood pressure monitoring method and apparatus |
DE3639402A1 (en) | 1986-11-18 | 1988-05-19 | Siemens Ag | METHOD FOR THE PRODUCTION OF A MULTI-LAYERED CIRCUIT BOARD AND THE CIRCUIT BOARD PRODUCED THEREOF |
US4776339A (en) | 1987-03-05 | 1988-10-11 | N.A.D., Inc. | Interlock for oxygen saturation monitor anesthesia apparatus |
US4880304A (en) | 1987-04-01 | 1989-11-14 | Nippon Colin Co., Ltd. | Optical sensor for pulse oximeter |
JPS63252239A (en) | 1987-04-09 | 1988-10-19 | Sumitomo Electric Ind Ltd | Reflection type oxymeter |
US4773422A (en) | 1987-04-30 | 1988-09-27 | Nonin Medical, Inc. | Single channel pulse oximeter |
USRE33643E (en) | 1987-04-30 | 1991-07-23 | Nonin Medical, Inc. | Pulse oximeter with circuit leakage and ambient light compensation |
JPS63275323A (en) * | 1987-05-08 | 1988-11-14 | Hamamatsu Photonics Kk | Diagnostic apparatus |
JPS63277039A (en) | 1987-05-08 | 1988-11-15 | Hamamatsu Photonics Kk | Diagnostic apparatus |
US4722120A (en) * | 1987-06-23 | 1988-02-02 | James Lu | Spring clip |
GB8719333D0 (en) | 1987-08-14 | 1987-09-23 | Swansea University College Of | Motion artefact rejection system |
US4805623A (en) * | 1987-09-04 | 1989-02-21 | Vander Corporation | Spectrophotometric method for quantitatively determining the concentration of a dilute component in a light- or other radiation-scattering environment |
US4796636A (en) * | 1987-09-10 | 1989-01-10 | Nippon Colin Co., Ltd. | Noninvasive reflectance oximeter |
US4819752A (en) | 1987-10-02 | 1989-04-11 | Datascope Corp. | Blood constituent measuring device and method |
US4848901A (en) | 1987-10-08 | 1989-07-18 | Critikon, Inc. | Pulse oximeter sensor control system |
US4825879A (en) | 1987-10-08 | 1989-05-02 | Critkon, Inc. | Pulse oximeter sensor |
US4807631A (en) * | 1987-10-09 | 1989-02-28 | Critikon, Inc. | Pulse oximetry system |
US4807630A (en) * | 1987-10-09 | 1989-02-28 | Advanced Medical Systems, Inc. | Apparatus and method for use in pulse oximeters |
US4859057A (en) | 1987-10-13 | 1989-08-22 | Lawrence Medical Systems, Inc. | Oximeter apparatus |
US4863265A (en) | 1987-10-16 | 1989-09-05 | Mine Safety Appliances Company | Apparatus and method for measuring blood constituents |
DE3877894T2 (en) | 1987-11-02 | 1993-06-24 | Sumitomo Electric Industries | ORGANIC LIGHT MEASURING PROBE. |
US4854699A (en) | 1987-11-02 | 1989-08-08 | Nippon Colin Co., Ltd. | Backscatter oximeter |
US4781195A (en) | 1987-12-02 | 1988-11-01 | The Boc Group, Inc. | Blood monitoring apparatus and methods with amplifier input dark current correction |
US4846183A (en) | 1987-12-02 | 1989-07-11 | The Boc Group, Inc. | Blood parameter monitoring apparatus and methods |
US4800885A (en) * | 1987-12-02 | 1989-01-31 | The Boc Group, Inc. | Blood constituent monitoring apparatus and methods with frequency division multiplexing |
US4927264A (en) | 1987-12-02 | 1990-05-22 | Omron Tateisi Electronics Co. | Non-invasive measuring method and apparatus of blood constituents |
US4960126A (en) | 1988-01-15 | 1990-10-02 | Criticare Systems, Inc. | ECG synchronized pulse oximeter |
US4883353A (en) | 1988-02-11 | 1989-11-28 | Puritan-Bennett Corporation | Pulse oximeter |
US4883055A (en) | 1988-03-11 | 1989-11-28 | Puritan-Bennett Corporation | Artificially induced blood pulse for use with a pulse oximeter |
DE3809084C2 (en) | 1988-03-18 | 1999-01-28 | Nicolay Gmbh | Sensor for the non-invasive measurement of the pulse frequency and / or the oxygen saturation of the blood and method for its production |
DE3810411A1 (en) | 1988-03-26 | 1989-10-12 | Nicolay Gmbh | DEVICE FOR FIXING A SENSOR, IN PARTICULAR A SENSOR FOR OXIMETRIC MEASUREMENTS |
US4869254A (en) | 1988-03-30 | 1989-09-26 | Nellcor Incorporated | Method and apparatus for calculating arterial oxygen saturation |
US5078136A (en) * | 1988-03-30 | 1992-01-07 | Nellcor Incorporated | Method and apparatus for calculating arterial oxygen saturation based plethysmographs including transients |
US4964408A (en) | 1988-04-29 | 1990-10-23 | Thor Technology Corporation | Oximeter sensor assembly with integral cable |
US5041187A (en) | 1988-04-29 | 1991-08-20 | Thor Technology Corporation | Oximeter sensor assembly with integral cable and method of forming the same |
US5069213A (en) | 1988-04-29 | 1991-12-03 | Thor Technology Corporation | Oximeter sensor assembly with integral cable and encoder |
US4948248A (en) | 1988-07-22 | 1990-08-14 | Invivo Research Inc. | Blood constituent measuring device and method |
US4825872A (en) | 1988-08-05 | 1989-05-02 | Critikon, Inc. | Finger sensor for pulse oximetry system |
JPH0288041A (en) | 1988-09-24 | 1990-03-28 | Misawahoomu Sogo Kenkyusho:Kk | Finger tip pulse wave sensor |
US5099842A (en) | 1988-10-28 | 1992-03-31 | Nellcor Incorporated | Perinatal pulse oximetry probe |
US5119815A (en) * | 1988-12-21 | 1992-06-09 | Nim, Incorporated | Apparatus for determining the concentration of a tissue pigment of known absorbance, in vivo, using the decay characteristics of scintered electromagnetic radiation |
US5086229A (en) * | 1989-01-19 | 1992-02-04 | Futrex, Inc. | Non-invasive measurement of blood glucose |
US5028787A (en) | 1989-01-19 | 1991-07-02 | Futrex, Inc. | Non-invasive measurement of blood glucose |
FI82366C (en) | 1989-02-06 | 1991-03-11 | Instrumentarium Oy | MAETNING AV BLODETS SAMMANSAETTNING. |
US5596986A (en) * | 1989-03-17 | 1997-01-28 | Scico, Inc. | Blood oximeter |
DE3912993C2 (en) | 1989-04-20 | 1998-01-29 | Nicolay Gmbh | Optoelectronic sensor for generating electrical signals based on physiological values |
US5040539A (en) | 1989-05-12 | 1991-08-20 | The United States Of America | Pulse oximeter for diagnosis of dental pulp pathology |
JPH0315502U (en) | 1989-06-28 | 1991-02-15 | ||
US5090410A (en) * | 1989-06-28 | 1992-02-25 | Datascope Investment Corp. | Fastener for attaching sensor to the body |
US5058588A (en) | 1989-09-19 | 1991-10-22 | Hewlett-Packard Company | Oximeter and medical sensor therefor |
US5007423A (en) | 1989-10-04 | 1991-04-16 | Nippon Colin Company Ltd. | Oximeter sensor temperature control |
US5094239A (en) | 1989-10-05 | 1992-03-10 | Colin Electronics Co., Ltd. | Composite signal implementation for acquiring oximetry signals |
DE3938759A1 (en) * | 1989-11-23 | 1991-05-29 | Philips Patentverwaltung | NON-INVASIVE OXIMETER ARRANGEMENT |
EP0442011A1 (en) * | 1990-02-15 | 1991-08-21 | Hewlett-Packard GmbH | Sensor, apparatus and method for non-invasive measurement of oxygen saturation |
US5066859A (en) | 1990-05-18 | 1991-11-19 | Karkar Maurice N | Hematocrit and oxygen saturation blood analyzer |
US5055671A (en) | 1990-10-03 | 1991-10-08 | Spacelabs, Inc. | Apparatus for detecting transducer movement using a first and second light detector |
US6681128B2 (en) * | 1990-10-06 | 2004-01-20 | Hema Metrics, Inc. | System for noninvasive hematocrit monitoring |
US6181958B1 (en) * | 1998-02-05 | 2001-01-30 | In-Line Diagnostics Corporation | Method and apparatus for non-invasive blood constituent monitoring |
JPH0614922B2 (en) * | 1991-02-15 | 1994-03-02 | 日本光電工業株式会社 | Calibration test equipment for pulse oximeter |
EP0574509B1 (en) * | 1991-03-07 | 1999-09-15 | Masimo Corporation | Signal processing apparatus and method |
US5490505A (en) * | 1991-03-07 | 1996-02-13 | Masimo Corporation | Signal processing apparatus |
US5995855A (en) * | 1998-02-11 | 1999-11-30 | Masimo Corporation | Pulse oximetry sensor adapter |
DE4138702A1 (en) * | 1991-03-22 | 1992-09-24 | Madaus Medizin Elektronik | METHOD AND DEVICE FOR THE DIAGNOSIS AND QUANTITATIVE ANALYSIS OF APNOE AND FOR THE SIMULTANEOUS DETERMINATION OF OTHER DISEASES |
US5267563A (en) * | 1991-06-28 | 1993-12-07 | Nellcor Incorporated | Oximeter sensor with perfusion enhancing |
EP0522674B1 (en) * | 1991-07-12 | 1998-11-11 | Mark R. Robinson | Oximeter for reliable clinical determination of blood oxygen saturation in a fetus |
US5351685A (en) | 1991-08-05 | 1994-10-04 | Nellcor Incorporated | Condensed oximeter system with noise reduction software |
US5249576A (en) * | 1991-10-24 | 1993-10-05 | Boc Health Care, Inc. | Universal pulse oximeter probe |
US5385143A (en) * | 1992-02-06 | 1995-01-31 | Nihon Kohden Corporation | Apparatus for measuring predetermined data of living tissue |
US5263244A (en) * | 1992-04-17 | 1993-11-23 | Gould Inc. | Method of making a flexible printed circuit sensor assembly for detecting optical pulses |
US5273334A (en) * | 1992-05-05 | 1993-12-28 | Schopfer E Kevin | Garment carrier |
JP3165983B2 (en) * | 1992-06-15 | 2001-05-14 | 日本光電工業株式会社 | Light emitting element driving device for pulse oximeter |
US5377675A (en) * | 1992-06-24 | 1995-01-03 | Nellcor, Inc. | Method and apparatus for improved fetus contact with fetal probe |
US6342039B1 (en) * | 1992-08-19 | 2002-01-29 | Lawrence A. Lynn | Microprocessor system for the simplified diagnosis of sleep apnea |
US5366026A (en) * | 1992-08-28 | 1994-11-22 | Nissan Motor Company, Ltd. | Impact type clamping apparatus |
US5368224A (en) | 1992-10-23 | 1994-11-29 | Nellcor Incorporated | Method for reducing ambient noise effects in electronic monitoring instruments |
US5287853A (en) * | 1992-12-11 | 1994-02-22 | Hewlett-Packard Company | Adapter cable for connecting a pulsoximetry sensor unit to a medical measuring device |
US5368026A (en) | 1993-03-26 | 1994-11-29 | Nellcor Incorporated | Oximeter with motion detection for alarm modification |
US5494043A (en) * | 1993-05-04 | 1996-02-27 | Vital Insite, Inc. | Arterial sensor |
JPH09501073A (en) * | 1993-05-28 | 1997-02-04 | ソマネテイツクス コーポレイシヨン | Instrument and method for measuring cerebral oxygen concentration by spectrophotometer |
JP3387171B2 (en) * | 1993-09-28 | 2003-03-17 | セイコーエプソン株式会社 | Pulse wave detection device and exercise intensity measurement device |
US5485847A (en) * | 1993-10-08 | 1996-01-23 | Nellcor Puritan Bennett Incorporated | Pulse oximeter using a virtual trigger for heart rate synchronization |
JP3125079B2 (en) * | 1993-12-07 | 2001-01-15 | 日本光電工業株式会社 | Pulse oximeter |
JP3238813B2 (en) * | 1993-12-20 | 2001-12-17 | テルモ株式会社 | Pulse oximeter |
US5507286A (en) * | 1993-12-23 | 1996-04-16 | Medical Taping Systems, Inc. | Method and apparatus for improving the durability of a sensor |
US5575284A (en) * | 1994-04-01 | 1996-11-19 | University Of South Florida | Portable pulse oximeter |
US5491299A (en) * | 1994-06-03 | 1996-02-13 | Siemens Medical Systems, Inc. | Flexible multi-parameter cable |
US5490523A (en) * | 1994-06-29 | 1996-02-13 | Nonin Medical Inc. | Finger clip pulse oximeter |
US5758644A (en) * | 1995-06-07 | 1998-06-02 | Masimo Corporation | Manual and automatic probe calibration |
US5638816A (en) * | 1995-06-07 | 1997-06-17 | Masimo Corporation | Active pulse blood constituent monitoring |
CA2221968C (en) * | 1995-06-09 | 2007-08-21 | Cybro Medical Ltd. | Sensor, method and device for optical blood oximetry |
WO1997003603A1 (en) * | 1995-07-21 | 1997-02-06 | Respironics, Inc. | Method and apparatus for diode laser pulse oximetry using multifiber optical cables and disposable fiber optic probes |
US5853364A (en) * | 1995-08-07 | 1998-12-29 | Nellcor Puritan Bennett, Inc. | Method and apparatus for estimating physiological parameters using model-based adaptive filtering |
US5818985A (en) * | 1995-12-20 | 1998-10-06 | Nellcor Puritan Bennett Incorporated | Optical oximeter probe adapter |
AUPN740796A0 (en) * | 1996-01-04 | 1996-01-25 | Circuitry Systems Limited | Biomedical data collection apparatus |
US5746697A (en) | 1996-02-09 | 1998-05-05 | Nellcor Puritan Bennett Incorporated | Medical diagnostic apparatus with sleep mode |
US5797841A (en) * | 1996-03-05 | 1998-08-25 | Nellcor Puritan Bennett Incorporated | Shunt barrier in pulse oximeter sensor |
WO1997036538A1 (en) * | 1996-04-01 | 1997-10-09 | Kontron Instruments Ag | Detection of parasitic signals during pulsoxymetric measurement |
US6163715A (en) | 1996-07-17 | 2000-12-19 | Criticare Systems, Inc. | Direct to digital oximeter and method for calculating oxygenation levels |
EP0875199B1 (en) | 1996-09-10 | 2004-03-10 | Seiko Epson Corporation | Organism state measuring device and relaxation state indicator device |
US6018673A (en) * | 1996-10-10 | 2000-01-25 | Nellcor Puritan Bennett Incorporated | Motion compatible sensor for non-invasive optical blood analysis |
US5921921A (en) | 1996-12-18 | 1999-07-13 | Nellcor Puritan-Bennett | Pulse oximeter with sigma-delta converter |
US6343223B1 (en) * | 1997-07-30 | 2002-01-29 | Mallinckrodt Inc. | Oximeter sensor with offset emitters and detector and heating device |
US6018674A (en) * | 1997-08-11 | 2000-01-25 | Datex-Ohmeda, Inc. | Fast-turnoff photodiodes with switched-gain preamplifiers in photoplethysmographic measurement instruments |
GB2329015B (en) * | 1997-09-05 | 2002-02-13 | Samsung Electronics Co Ltd | Method and device for noninvasive measurement of concentrations of blood components |
US5865736A (en) * | 1997-09-30 | 1999-02-02 | Nellcor Puritan Bennett, Inc. | Method and apparatus for nuisance alarm reductions |
US6184521B1 (en) * | 1998-01-06 | 2001-02-06 | Masimo Corporation | Photodiode detector with integrated noise shielding |
US6179159B1 (en) * | 1998-01-26 | 2001-01-30 | Mariruth D. Gurley | Communicable disease barrier digit cover and dispensing package therefor |
US6014576A (en) * | 1998-02-27 | 2000-01-11 | Datex-Ohmeda, Inc. | Segmented photoplethysmographic sensor with universal probe-end |
WO1999058973A1 (en) * | 1998-05-13 | 1999-11-18 | Cygnus, Inc. | Method and device for predicting physiological values |
JP3404289B2 (en) * | 1998-05-22 | 2003-05-06 | 富士通株式会社 | Disk control device and control method thereof |
DE69800355T2 (en) * | 1998-06-05 | 2001-03-01 | Hewlett Packard Co | Pulse rate and heart rate matching detection for pulse oximetry |
EP1598003A3 (en) * | 1998-08-13 | 2006-03-01 | Whitland Research Limited | Optical device |
US6356774B1 (en) | 1998-09-29 | 2002-03-12 | Mallinckrodt, Inc. | Oximeter sensor with encoded temperature characteristic |
US6393311B1 (en) | 1998-10-15 | 2002-05-21 | Ntc Technology Inc. | Method, apparatus and system for removing motion artifacts from measurements of bodily parameters |
US6343224B1 (en) * | 1998-10-15 | 2002-01-29 | Sensidyne, Inc. | Reusable pulse oximeter probe and disposable bandage apparatus |
US6684091B2 (en) * | 1998-10-15 | 2004-01-27 | Sensidyne, Inc. | Reusable pulse oximeter probe and disposable bandage method |
US6261236B1 (en) | 1998-10-26 | 2001-07-17 | Valentin Grimblatov | Bioresonance feedback method and apparatus |
US6684090B2 (en) * | 1999-01-07 | 2004-01-27 | Masimo Corporation | Pulse oximetry data confidence indicator |
US6675031B1 (en) * | 1999-04-14 | 2004-01-06 | Mallinckrodt Inc. | Method and circuit for indicating quality and accuracy of physiological measurements |
US6226539B1 (en) | 1999-05-26 | 2001-05-01 | Mallinckrodt, Inc. | Pulse oximeter having a low power led drive |
US20030018243A1 (en) * | 1999-07-07 | 2003-01-23 | Gerhardt Thomas J. | Selectively plated sensor |
US6512937B2 (en) * | 1999-07-22 | 2003-01-28 | Sensys Medical, Inc. | Multi-tier method of developing localized calibration models for non-invasive blood analyte prediction |
US6339715B1 (en) * | 1999-09-30 | 2002-01-15 | Ob Scientific | Method and apparatus for processing a physiological signal |
US6385821B1 (en) * | 2000-02-17 | 2002-05-14 | Udt Sensors, Inc. | Apparatus for securing an oximeter probe to a patient |
IL135077A0 (en) * | 2000-03-15 | 2001-05-20 | Orsense Ltd | A probe for use in non-invasive measurements of blood related parameters |
US6538721B2 (en) * | 2000-03-24 | 2003-03-25 | Nikon Corporation | Scanning exposure apparatus |
US6510331B1 (en) * | 2000-06-05 | 2003-01-21 | Glenn Williams | Switching device for multi-sensor array |
GB0014854D0 (en) * | 2000-06-16 | 2000-08-09 | Isis Innovation | System and method for acquiring data |
US6606510B2 (en) * | 2000-08-31 | 2003-08-12 | Mallinckrodt Inc. | Oximeter sensor with digital memory encoding patient data |
US6505060B1 (en) * | 2000-09-29 | 2003-01-07 | Datex-Ohmeda, Inc. | Method and apparatus for determining pulse oximetry differential values |
US6434408B1 (en) * | 2000-09-29 | 2002-08-13 | Datex-Ohmeda, Inc. | Pulse oximetry method and system with improved motion correction |
US6505133B1 (en) * | 2000-11-15 | 2003-01-07 | Datex-Ohmeda, Inc. | Simultaneous signal attenuation measurements utilizing code division multiplexing |
US6985763B2 (en) * | 2001-01-19 | 2006-01-10 | Tufts University | Method for measuring venous oxygen saturation |
US6505061B2 (en) * | 2001-04-20 | 2003-01-07 | Datex-Ohmeda, Inc. | Pulse oximetry sensor with improved appendage cushion |
US6985764B2 (en) * | 2001-05-03 | 2006-01-10 | Masimo Corporation | Flex circuit shielded optical sensor |
DE10136355A1 (en) * | 2001-07-26 | 2003-02-13 | Niels Rahe-Meyer | Device for monitoring vital parameters of an animal or human body consists of a portable bag with sensors, analysis electronics and visual and audible output means as well as interfaces for connection to other devices |
GB0123395D0 (en) * | 2001-09-28 | 2001-11-21 | Isis Innovation | Locating features ina photoplethysmograph signal |
US6840904B2 (en) * | 2001-10-11 | 2005-01-11 | Jason Goldberg | Medical monitoring device and system |
US6839579B1 (en) * | 2001-11-02 | 2005-01-04 | Nellcor Puritan Bennett Incorporated | Temperature indicating oximetry sensor |
US6839580B2 (en) * | 2001-12-06 | 2005-01-04 | Ric Investments, Inc. | Adaptive calibration for pulse oximetry |
US6863652B2 (en) * | 2002-03-13 | 2005-03-08 | Draeger Medical Systems, Inc. | Power conserving adaptive control system for generating signal in portable medical devices |
KR100455289B1 (en) * | 2002-03-16 | 2004-11-08 | 삼성전자주식회사 | Method of diagnosing using a ray and apparatus thereof |
US8996090B2 (en) * | 2002-06-03 | 2015-03-31 | Exostat Medical, Inc. | Noninvasive detection of a physiologic parameter within a body tissue of a patient |
US6993372B2 (en) * | 2003-06-03 | 2006-01-31 | Orsense Ltd. | Method and system for use in non-invasive optical measurements of blood parameters |
US6992772B2 (en) * | 2003-06-19 | 2006-01-31 | Optix Lp | Method and apparatus for optical sampling to reduce interfering variances |
-
2004
- 2004-02-25 US US10/787,851 patent/US7162288B2/en active Active
-
2005
- 2005-02-25 WO PCT/US2005/006208 patent/WO2005082240A1/en active Application Filing
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- 2005-02-25 CN CNA2005800058548A patent/CN1929777A/en active Pending
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EP1722674A1 (en) | 2006-11-22 |
DE602005005964D1 (en) | 2008-05-21 |
WO2005082240A1 (en) | 2005-09-09 |
JP4756027B2 (en) | 2011-08-24 |
US7162288B2 (en) | 2007-01-09 |
US20050187446A1 (en) | 2005-08-25 |
ES2306122T3 (en) | 2008-11-01 |
US7499740B2 (en) | 2009-03-03 |
CA2556724A1 (en) | 2005-09-09 |
JP2007523732A (en) | 2007-08-23 |
MXPA06009754A (en) | 2007-03-15 |
AU2005216976A1 (en) | 2005-09-09 |
US20070208240A1 (en) | 2007-09-06 |
CN1929777A (en) | 2007-03-14 |
DE602005005964T2 (en) | 2009-05-20 |
EP1722674B1 (en) | 2008-04-09 |
ATE391454T1 (en) | 2008-04-15 |
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