Patent application number | Description | Published |
20090326349 | Consistent Signal Selection By Signal Segment Selection Techniques - According to embodiments, techniques for selecting a consistent part of a signal, including a photoplethysmograph (PPG) signal, are disclosed. A pulse oximetry system including a sensor or probe may be used to obtain a PPG signal from a subject. Signal peaks may be identified in the PPG signal. Characteristics of the signal peaks, including the amplitude levels of the signal peaks and/or the time-distance between the signal peaks may be used to determine if the PPG signal is consistent. In an embodiment, signal peaks are processed based on a consistency metric, and the processed signal peaks are compared to the consistency metric to determine if the PPG signal is consistent. If the PPG signal is determined to be consistent, the PPG signal may be further analyzed to determine an underlying signal parameter, including, for example, a patient respiration rate. If the PPG signal is determined to be inconsistent, the inconsistent portion of the signal may be removed from the overall signal or otherwise transformed. | 12-31-2009 |
20100249543 | SYSTEMS AND METHODS FOR MONITORING PAIN MANAGEMENT - The present disclosure relates to systems and methods for monitoring pain management using measurements of physiological parameters based on a PPG signal. A reference physiological parameter may be compared against a later measurement to identify a change in condition that may indicate a pain management problem. | 09-30-2010 |
20100249544 | SYSTEMS AND METHODS FOR MONITORING PAIN MANAGEMENT - The present disclosure relates to systems and methods for monitoring pain management using measurements of physiological parameters based on a PPG signal. A reference physiological parameter may be compared against a later measurement to identify a change in condition that may indicate a pain management problem. | 09-30-2010 |
20100249555 | SYSTEMS AND METHODS FOR MONITORING PAIN MANAGEMENT - The present disclosure relates to systems and methods for monitoring pain management using measurements of physiological parameters based on a PPG signal. A reference physiological parameter may be compared against a later measurement to identify a change in condition that may indicate a pain management problem. | 09-30-2010 |
20100249556 | SYSTEMS AND METHODS FOR MONITORING PAIN MANAGEMENT - The present disclosure relates to systems and methods for monitoring pain management using measurements of physiological parameters based on a PPG signal. A reference physiological parameter may be compared against a later measurement to identify a change in condition that may indicate a pain management problem. | 09-30-2010 |
20100286495 | Selection Of Signal Regions For Parameter Extraction - According to embodiments, techniques for extracting a signal parameter from a selected region of a generally repetitive signal are disclosed. A pulse oximetry system including a sensor or probe may be used to obtain an original photoplethysmograph (PPG) signal from a subject. A filter transformation may be applied to the original PPG signal to produce a baseline PPG signal. The baseline PPG signal may contain artifacts and/or noise, and a region of the baseline PPG signal suitable for extracting the signal parameter may be selected. A suitable region of the baseline PPG signal may be selected by applying one or more thresholds to the baseline PPG signal, where the values of the thresholds may be set based on derivative values, amplitude-based percentiles, and/or local minima and maxima of the baseline PPG signal. A portion of the original PPG signal corresponding to the selected region may be processed, and the signal parameter may be extracted from the processed region. In an embodiment, the signal parameter may correspond to the respiration rate of a patient. | 11-11-2010 |
20100331715 | SYSTEMS AND METHODS FOR DETECTING EFFORT EVENTS - A method and system for detecting effort events is disclosed. Effort may be determined through feature analysis of the signal as transformed by a continuous wavelet transform, which may be compared against a reference effort measure to trigger an effort event flag that signals the onset and/or severity of an effort event. For example, a respiratory effort measure may be determined based at least in part on a wavelet transform of a photoplethysmograph (PP G) signal and features of the transformed signal. A respiratory reference effort measure may be based at least in part on past values of the respiratory effort measure, and a threshold test may be used to trigger an effort event flag, which may indicate a marked change in respiratory effort exerted by a patient. | 12-30-2010 |
20100331716 | METHODS AND APPARATUS FOR MEASURING RESPIRATORY FUNCTION USING AN EFFORT SIGNAL - Breathing effort of a patient, as determined (for example) from a photoplethysmograph (“PPG”) signal from the patient, can be used in conjunction with signals from a spirometer being used by the patient to provide additional information about various characteristics of the patient's breathing. For example, such additional information may include the relationship between the patient's breathing effort and breath volume. As another example, the additional information may include the relationship between the patient's breathing effort and rate of breath flow. Still other such additional information may be derived from various combinations of spirometer and PPG output signals. | 12-30-2010 |
20100331724 | DETERMINING A CHARACTERISTIC BLOOD PRESSURE - The present disclosure relates to monitoring a characteristic physiological parameter of a patient during a suitable time period that either precedes or follows a triggering event, such as a clinician/patient interaction, that may negatively impact the physiological parameter. In some embodiments, physiological parameter values falling between one or more pre-set thresholds may be used to derive the characteristic physiological parameter. In some embodiments, tracking the physiological parameter may provide additional information about the patient's status. In some embodiments, confidence measures may be associated with, or may be used to analyze features of the patient signal to derive information about, the characteristic physiological parameter. The patient signal used to derive a patient's physiological parameter may be of an oscillatory nature or may include oscillatory features that may be analyzed to derive a characteristic respiration rate. | 12-30-2010 |
20110004081 | METHODS AND APPARATUS FOR DETERMINING BREATHING EFFORT CHARACTERISTIC MEASURES - One or more respiratory characteristics of a patient are measured by coupling patient monitor apparatus (e.g., a photoplethysmograph (“PPG”)) to the patient in order to produce a patient monitor signal that includes signal indicia indicative of effort the patient is exerting to breathe. A breathing or respiratory effort signal for the patient is extracted from the patient monitor signal. A respiratory characteristic signal is extracted (at least in part) from the effort signal. This may be done, for example, on the basis of an amplitude feature of the effort signal and a relative time of occurrence of that amplitude feature. Alternatively, the respiratory characteristic signal may be based on a relationship between two amplitude features of the effort signal, with or without regard for specifics of the times of occurrence of those amplitude features. A breath air flow meter may also be coupled to the patient, if desired, in order to produce a flow signal. One or more of the respiratory characteristic measures may also be partly based on the flow signal. | 01-06-2011 |
20110021892 | SYSTEMS AND METHODS FOR RESPIRATION MONITORING - According to embodiments, techniques for determining respiratory parameters are disclosed. More suitable probe locations for determining respiratory parameters, such as respiration rate and respiratory effort, may be identified. The most suitable probe location may be selected for probe placement. A scalogram may be generated from the detected signal at the more suitable location, resulting in an enhanced breathing band for determining respiratory parameters. Flexible probes that allow for a patient's natural movement due to respiration may also be used to enhance the breathing components of the detected signal. From the enhanced signal, more accurate and reliable respiratory parameters may be determined. | 01-27-2011 |
20110021941 | SYSTEMS AND METHODS FOR RESPIRATION MONITORING - According to embodiments, techniques for determining respiratory parameters are disclosed. More suitable probe locations for determining respiratory parameters, such as respiration rate and respiratory effort, may be identified. The most suitable probe location may be selected for probe placement. A scalogram may be generated from the detected signal at the more suitable location, resulting in an enhanced breathing band for determining respiratory parameters. Flexible probes that allow for a patient's natural movement due to respiration may also be used to enhance the breathing components of the detected signal. From the enhanced signal, more accurate and reliable respiratory parameters may be determined. | 01-27-2011 |
20110077486 | SYSTEMS AND METHODS FOR NORMALIZING A PLETHYSMOGRAPH SIGNAL FOR IMPROVED FEATURE ANALYSIS - The present disclosure relates to systems and methods for analyzing and normalizing signals, such as PPG signals, for use in patent monitoring. The PPG signal may be detected using a continuous non-invasive blood pressure monitoring system and the normalized signals may be used to determine whether a recalibration of the system should be performed. | 03-31-2011 |
20110077531 | SYSTEMS AND METHODS FOR HIGH-PASS FILTERING A PHOTOPLETHYSMOGRAPH SIGNAL - According to embodiments, systems and methods for high-pass filtering a plethysmograph or photoplethysmograph (PPG) signal are disclosed. A sensor or probe may be used to obtain a plethysmograph or PPG signal from a subject. The sensor may be placed at any suitable location on the body, e.g., the forehead, finger, or toe. The PPG signal generated by the sensor may be high-pass filtered to disambiguate certain features of the PPG signal, including one or more characteristic points. The cut-off frequency for the high-pass filter may be greater than 0.75 Hz and less than 15 Hz. The cut-off frequency for the high-pass filter may be selected to be greater than the subject's computed pulse rate. These characteristic points on the filtered PPG signal may be used to compute non-invasive blood pressure measurements continuously or on a periodic basis. For example, the time difference between two or more characteristic points in a high-pass filtered version of the generated PPG signal may be computed. The time difference may be used to compute non-invasive blood pressure measurements continuously or on a periodic basis. | 03-31-2011 |
20110245690 | SYSTEMS AND METHODS FOR MEASURING ELECTROMECHANICAL DELAY OF THE HEART - Systems and methods are disclosed herein for measuring the electromechanical delay of the heart of a patient. An electrocardiogram (EKG) signal may be used to detect heart electrical activity. Photoplethysmograph (PPG) signals may be used to detect heart mechanical activity. The electromechanical delay may be calculated based at least in part on the timing of an EKG signal and at least two PPG signals. | 10-06-2011 |
20110270048 | SYSTEMS AND METHODS FOR PPG SENSORS INCORPORATING EKG SENSORS - Techniques and structures are disclosed for using photoplethysmograph (PPG) and electrocardiographic (EKG)-based readings of a subject to determine one or more physiological characteristics of the subject. In an arrangement, a combined PPG-EKG sensor unit may be used to detect both PPG and EKG signals of the subject. The sensor unit may include a PPG sensor, an EKG sensor, and a support structure for connecting or fastening the sensor unit to the subject. The detected readings may be provided to an electronic monitor. In an arrangement, a PPG-EKG monitoring system, including the electronic monitor, may be used to determine the physiological parameters of the subject. The monitoring system may first determine an auxiliary parameter based at least in part on the EKG signal, and then compute the one or more physiological characteristics of the subject based at least in part on both the PPG signal and the auxiliary parameter. | 11-03-2011 |
20110270114 | METHODS AND APPARATUS FOR CALIBRATING RESPIRATORY EFFORT FROM PHOTOPLETHYSMOGRAPH SIGNALS - Breathing effort of a patient, as determined (for example) from a photoplethysmograph (“PPG”) signal from the patient, can be calibrated in relation to air pressure in the patient's respiratory system. This calibration can be done by subjecting the patient to varying amounts of breathing resistance; and for each such amount, concurrently measuring (1) air pressure in the respiratory system (e.g., in the oral/nasal cavity) and (2) breathing effort (from the PPG signal). Use can be made of this calibration, e.g., during a sleep study of the patient. During such a study, breathing effort, again determined from the PPG signal and occurring, for example, during an apneic event of the patient, can be used to infer air pressure in the respiratory system by using the above calibration. | 11-03-2011 |
20110270579 | SYSTEMS AND METHODS FOR SIGNAL MONITORING USING LISSAJOUS FIGURES - Methods and systems are provided for generating Lissajous figures based on monitored signals and identifying features of Lissajous figures. Features may include similarity metrics, shape change metrics and noise metrics, and may be used to determine information about the monitored signal. Features may also be used in monitoring operations, such as measurement quality assessment and recalibration. | 11-03-2011 |
20110306858 | Systems And Methods For Wavelet Transform Using Mean-Adjusted Wavelets - Methods and systems are disclosed for transforming a signal using a continuous wavelet transform based at least in part on a truncated, mean-adjusted wavelet. A wavelet may be truncated to a finite support to generate a truncated wavelet. The real part of the truncated wavelet may be forced to have a zero mean to generate a truncated, mean-adjusted wavelet. The signal may be transformed using a continuous wavelet transform based at least in part on the truncated mean-adjusted wavelet. Information may be derived about the signal from the transformed signal. | 12-15-2011 |
20120029320 | SYSTEMS AND METHODS FOR PROCESSING MULTIPLE PHYSIOLOGICAL SIGNALS - Systems and methods are provided for patient monitors which apply different sets of signal processing operations to signals to identify multiple fiducials in physiological signals. PPG signals measured at two sensor sites may be processed with a first set of processing operations and analyzed to identify fiducials that allow the calculation of a diastolic DPTT. These PPG signals may then be processed with a different set of processing operations and the results analyzed to identify fiducials that allow the calculation of a systolic DPTT. | 02-02-2012 |
20120029361 | SYSTEMS AND METHODS FOR DETERMINING RESPIRATORY EFFORT - Systems and methods for calculating a measure of respiratory effort of a subject are provided. The measure of respiratory effort may be calculated based on a differential pulse transit time (DPTT) calculated for received photoplethysmograph signals. The systems and methods may allow for the calculation of respiratory effort in absolute units, and without the need for calibrations from a device that measures blood pressure (e.g., a non-invasive blood pressure cuff). | 02-02-2012 |
20120116235 | SYSTEMS AND METHODS FOR PRODUCING AUDIBLE INDICATORS THAT ARE REPRESENTATIVE OF MEASURED BLOOD PRESSURE - Systems and methods are disclosed for producing audible indicators that are based on a subject's measured blood pressure. Audible properties of the indicators are processed to represent blood pressure. For example, the duration or volume of the audible indicators may be varied based on the values of the subject's blood pressure. The audible indicators may further be varied based on the subject's blood pressure's deviation from a normal blood pressure and/or previously calculated blood pressure. For example, the audible indicators may be indicative of changes in the subject's blood pressure over time. The audible indicators representing blood pressure may be synchronized with other audible indicators that represent other physiological parameters of the subject, such as, the subject's heart rate. | 05-10-2012 |
20120136261 | Systems and methods for calibrating physiological signals with multiple techniques - Systems and methods are disclosed herein for calibrating the calculation of physiological parameters. Two or more calibration techniques may be used to determine a relationship between physiological measurements and a desired physiological parameter, such as a relationship between differential pulse transit time (DPTT) and blood pressure. Different calibration techniques may be used in a serial fashion, one after the other, or in a parallel fashion, with different weights accorded to each calibration technique. When physiological or other changes occur, the calibration data may be stored for later use and new calibration data may be generated. | 05-31-2012 |
20120136605 | METHODS AND SYSTEMS FOR RECALIBRATING A BLOOD PRESSURE MONITOR WITH MEMORY - Systems and methods are provided for storing and recalling metrics associated with physiological signals. It may be determined that the value of a monitored physiological metric corresponds to a stored value. In such cases, a patient monitor may determine that a calibration is not desired. In some cases, a patient monitor may recall calibration parameters associated with the stored value if it determined that the stored value corresponds to the monitored metric value. | 05-31-2012 |
20120143012 | SYSTEMS AND METHODS FOR PHYSIOLOGICAL EVENT MARKING - Systems and methods are provided for storing event markers. The value of a monitored physiological metric may be monitored and compared to a reference value. A patient monitoring system may compute a difference between a monitored metric and a reference value, and compare the difference to a threshold value to determine whether a physiological event has occurred. Based on the determination, a patient monitoring system may store an event marker, trigger a response, update a metric value, or perform any other suitable function. | 06-07-2012 |
20120143067 | SYSTEMS AND METHODS FOR DETERMINING WHEN TO MEASURE A PHYSIOLOGICAL PARAMETER - Systems and methods are provided for determining when to update a blood pressure measurement. The value of a physiological metric may be monitored and compared to a reference value. A patient monitoring system may compute a difference between a monitored metric and a reference value, and compare the difference to a threshold value to determine whether to update a blood pressure measurement. The threshold value may be constant or variable, and may depend on the monitored metric. | 06-07-2012 |
20120203087 | SYSTEMS AND METHODS FOR MONITORING DEPTH OF CONSCIOUSNESS - During patient monitoring, a depth of consciousness (DOC) measure, such as a bispectral index, may be used in conjunction with additional information obtained from an awareness metric derived from one or more physiological signals, such as a photoplethysmograph signal. In an embodiment, a DOC measure may be combined with information from an awareness metric to produce a combined DOC measure. In an embodiment, information from an awareness metric derived from one or more physiological signals may be used to provide an indication of confidence in a DOC measure. In an embodiment, a DOC measure may be used to provide an indication of confidence in a depth of consciousness assessment based on an awareness metric. In an embodiment, one or the other of a DOC measure and an awareness metric may be used to provide an indication of a patient's depth of consciousness (e.g., by one “overriding” the other). | 08-09-2012 |
20120253140 | Systems And Methods For Autonomic Nervous System Monitoring - Methods and systems are disclosed for determining physiological information about a patient's autonomic nervous system based on at least one physiological signal measured from the patient and at least one known characteristic of a patient's respiration. Respiration protocol may be provided to guide characteristics of the patient's respiration. The physiological signal measured from the patient may be transformed using a wavelet transform to create a transformed signal, and a scalogram may be generated based at least in part on the transformed signal. A metric that may indicate information about the patient's autonomic nervous system may be determined from the scalogram and the known characteristic of the patient's respiration. | 10-04-2012 |
20120253141 | METHODS AND SYSTEMS FOR PASSIVE PHOTOPLETHYSMOGRAPH SENSING - Systems and methods are provided for passive photoplethysmograph sensing. A patient monitoring system may provide active sensing, passive sensing, or both. In some cases, a patient monitor may determine whether to provide passive or active sensing. Passive photoplethysmograph sensing may be used to determine physiological information such as pulse rate, respiration rate, or other information. Passive photoplethysmograph sensing may allow for reduced power consumption relative to active sensing. | 10-04-2012 |
20130079647 | SYSTEMS AND METHODS FOR DETERMINING RESPIRATION INFORMATION FROM A PHOTOPLETHYSMOGRAPH - A patient monitoring system may determine one or more reference points of a physiological signal. The system may select one or more fiducial points on the physiological signal relative to the reference points. The one or more fiducial points may be selected by selecting a point spaced by a time interval relative to one of the reference points. The time interval may be a predetermined constant, or the time interval may depend on physiological information. The system may generate a fiducial signal based on the selected fiducial points, calculate physiological information such as a respiration rate based on the selected fiducial points, or both. | 03-28-2013 |
20140012109 | CONSISTENT SIGNAL SELECTION BY SIGNAL SEGMENT SELECTION TECHNIQUES - According to embodiments, techniques for selecting a consistent part of a signal, including a photoplethysmograph (PPG) signal, are disclosed. A pulse oximetry system including a sensor or probe may be used to obtain a PPG signal from a subject. Signal peaks may be identified in the PPG signal. Characteristics of the signal peaks, including the amplitude levels of the signal peaks and/or the time-distance between the signal peaks may be used to determine if the PPG signal is consistent. In an embodiment, signal peaks are processed based on a consistency metric, and the processed signal peaks are compared to the consistency metric to determine if the PPG signal is consistent. If the PPG signal is determined to be consistent, the PPG signal may be further analyzed to determine an underlying signal parameter, including, for example, a patient respiration rate. If the PPG signal is determined to be inconsistent, the inconsistent portion of the signal may be removed from the overall signal or otherwise transformed. | 01-09-2014 |
20140073888 | NON-INVASIVE METHOD FOR MONITORING AUTOREGULATION - A system includes a controller that receives a blood pressure signal and an oxygen saturation signal. The blood pressure signal represents a non-invasive measure of blood pressure. The oxygen saturation signal represents a non-invasive measure of oxygen saturation. The controller generates an autoregulation status signal representing a status of cerebral autoregulation. The autoregulation status signal is based, at least in part, on a relationship between the measured blood pressure and the measured oxygen saturation. An exemplary method may include receiving the blood pressure signal and the oxygen saturation signal, defining a relationship between the measured blood pressure and the measured oxygen saturation, determining an autoregulation status based at least in part on the defined relationship, and generating an autoregulation status signal representing the determined autoregulation status. | 03-13-2014 |
20140073930 | MEASURE OF BRAIN VASCULATURE COMPLIANCE AS A MEASURE OF AUTOREGULATION - A system includes a controller that receives a physiological signal representing a non-invasive measure of a physiological parameter. The controller applies a compliance metric to the physiological signal and generates an autoregulation status signal that indicates a status of cerebral autoregulation in the patient. The autoregulation status signal is based at least in part on the compliance metric applied to the physiological signal. | 03-13-2014 |
20140266695 | SYSTEM AND METHOD FOR DISINFECTING AND CHARGING A SENSOR - Methods and systems are provided for disinfecting and recharging a sensor. The sensor may be a wireless sensor, or the sensor may be configured to operate in a wireless mode and in a wired mode. The system may include a charging device configured to provide power to the sensor and/or to recharge a power source of the sensor. The sensor may include a proximity detector configured to provide information relating to a proximity of the sensor to the charging device. Additionally, the sensor may include additional sensors configured to provide information relating to a disinfection process utilized to disinfect the sensor. | 09-18-2014 |
20140266696 | SYSTEMS AND METHODS FOR IDENTIFYING A MEDICALLY MONITORED PATIENT - Systems and methods provided relate to patient sensors and/or patient monitors that recognize and/or identify a patient with physiological signals obtained from the sensor. A scalogram may be produced by applying a wavelet transform for the physiological signals obtained from the sensor. The scalogram may be a three dimensional model (having time, scale, and magnitude) from which certain physiological information may be obtained. For example, unique human physiological characteristics, also known as biometrics, may be determined from the scalograms. More specifically, monitoring the changes in the morphology of the photoplethysmographic (PPG) waveform transforms (e.g., scalogram) may determine patient-specific information that may be used to recognize and/or identify the patient, and that may be used to determine a proper or improper association between the patient and the wireless sensor and/or patient monitor. | 09-18-2014 |
20140275887 | Systems And Methods For Monitoring Respiratory Depression - Methods and systems are disclosed for analyzing a physiological respiratory signal in order to monitor respiratory depression events. In certain embodiments, respiratory depression is monitored by extracting a respiratory signal from a photoplethysmograph (“PPG”) signal, identifying a morphological characteristic of the respiratory signal, and generating a respiratory condition signal. In certain embodiments, an alarm and therapeutic intervention strategy are triggered upon determination of respiratory depression event. In certain embodiments, a plurality of physiological signals are used to determine a respiratory depression event | 09-18-2014 |
20140364746 | METHODS AND SYSTEMS FOR RECALIBRATING A BLOOD PRESSURE MONITOR WITH MEMORY - Systems and methods are provided for storing and recalling metrics associated with physiological signals. It may be determined that the value of a monitored physiological metric corresponds to a stored value. In such cases, a patient monitor may determine that a calibration is not desired. In some cases, a patient monitor may recall calibration parameters associated with the stored value if it determined that the stored value corresponds to the monitored metric value. | 12-11-2014 |
20150065829 | SYSTEMS AND METHODS FOR RESPIRATION MONITORING - According to embodiments, techniques for determining respiratory parameters are disclosed. More suitable probe locations for determining respiratory parameters, such as respiration rate and respiratory effort, may be identified. The most suitable probe location may be selected for probe placement. A scalogram may be generated from the detected signal at the more suitable location, resulting in an enhanced breathing band for determining respiratory parameters. Flexible probes that allow for a patient's natural movement due to respiration may also be used to enhance the breathing components of the detected signal. From the enhanced signal, more accurate and reliable respiratory parameters may be determined. | 03-05-2015 |