Patent application number | Description | Published |
20090323049 | Systems And Methods For A Wavelet Transform Viewer - Techniques for the display of a signal with a wavelet transform of that signal in a wavelet transform viewer are disclosed, according to embodiments. According to embodiments, the wavelet transform viewer can display a plot of physiological signals such as a photoplethysmograph (PPG) signal. A portion of the plot of the signal can be selected. A wavelet transform the selected portion of the signal can be calculated and a wavelet plot of the tranformed signal can be displayed simultaneously with that signal. A plot of the selected portion of the signal can also be simultaneously displayed with both the plot of the signal and the wavelet plot. | 12-31-2009 |
20090324034 | SYSTEMS AND METHODS FOR RIDGE SELECTION IN SCALOGRAMS OF SIGNALS - According to embodiments, systems, devices, and methods for ridge selection in scalograms are disclosed. Ridges or ridge components are features within a scalogram which may be computed from a signal such as a physiological (e.g., photoplethysmographic) signal. Ridges may be identified from one or more scalograms of the signal. Parameters characterizing these ridges may be determined. Based at least in part on these parameters, a ridge density distribution function is determined. A ridge is selected from analyzing this ridge density distribution function. In some embodiments, the selected ridge is used to determine a physiological parameter such as respiration rate. | 12-31-2009 |
20090326351 | Signal Processing Mirroring Technique - Embodiments may include systems and methods capable of processing an original signal by selecting and mirroring portions of the signal to create a new signal for further analysis. In an embodiment, the signal may be a photoplethysmograph (PPG) signal and the new signal may be further analyzed using continuous wavelet transforms. Any suitable number of reconstructed new signals may be created from the original signal and scalograms may be derived at least in part from the new signals. Ridges may be extracted from the scalograms of the new signals and secondary scalograms may be further derived from the ridges. A sum along amplitudes technique may be applied to a selected scalogram and may be plotted as a function of the scale of the scalogram. Desired information, such as respiration information within the original signal, may be identified from the plot. | 12-31-2009 |
20090326353 | PROCESSING AND DETECTING BASELINE CHANGES IN SIGNALS - According to embodiments, systems and methods for detecting the occurrence of events from a signal are provided. A signal processing system may analyze baseline changes and changes in signal characteristics to detect events from a signal. The system may also detect events by analyzing energy parameters and artifacts in a scalogram of the signal. Further, the system may detect events by analyzing both the signal and its corresponding scalogram. | 12-31-2009 |
20090326386 | Systems and Methods for Non-Invasive Blood Pressure Monitoring - According to embodiments, systems and methods for non-invasive blood pressure monitoring are disclosed. A sensor or probe may be used to obtain a plethysmograph or photoplethysmograph (PPG) signal from a subject. From the signal, the time difference between two or more characteristic points in the signal may be computed. The time difference may correspond, for example, to the time for a pulse wave to travel a predetermined distance from the senor or probe to a reflection point and back to the sensor or probe. From this time difference, blood pressure measurements may be computed continuously or on a periodic basis. | 12-31-2009 |
20090326388 | Systems And Methods For Processing Signals With Repetitive Features - The present disclosure relates to systems and methods for detecting features of a signal. According to embodiments, by transposing segments of a signal, such as segments representing pulses in a PPG signal, such that they are stacked next to each other, various characteristics about the signal may be discerned such as information about repetitive features of the signal. According to an embodiment, from a PPG signal respiration information may be determined about individual breaths, blood pressure changes may be determined, and information about other physiological parameters affecting the PPG signal may be determined. | 12-31-2009 |
20090326393 | Systems and Methods for Non-Invasive Continuous Blood Pressure Determination - According to some embodiments, systems and methods are provided for non-invasive continuous blood pressure determination. In some embodiments, a PPG signal is received and locations of pulses within the PPG signal are identified. An area within a particular pulse is measured. The area may be of just the upstroke, downstroke or the entire pulse. The area may be measured relative to a time-domain axis or a baseline of the pulse. The pulse may be split into multiple sections and the area of each section may be measured. The area of one portion of the pulse may correspond to systolic blood pressure while the area of another portion may correspond to diastolic blood pressure. Empirical data may be used to determine blood pressure from the measured area by applying calibration data measured by a suitable device. | 12-31-2009 |
20090326395 | SYSTEMS AND METHODS FOR DETECTING PULSES - According to embodiments, systems and methods are provided for detecting pulses in a PPG signal. Local minima and maxima points may be identified in the PPG signal. Each minimum may be paired with an adjacent maximum forming an upstroke segment. Noise may be removed by comparing adjacent segments and ignoring segments that are too long or too large. Notches in the pulse may be identified and ignored by analyzing adjacent segments. Adjacent upstroke segments may be combined as a single upstroke if the lengths of adjacent upstroke segments are about the same, have similar slopes, and the end point of one segment is close to the start point of an adjacent segment. Segments having small temporal or amplitude difference relative to adjacent segments may be disregarded. The remaining segments may represent the pulse upticks. A sliding time window may be used instead to detect pulses in the PPG signal. | 12-31-2009 |
20090326402 | SYSTEMS AND METHODS FOR DETERMINING EFFORT - According to embodiments, methods and systems for determining effort is disclosed. Effort may relate to a measure of strength of at least one repetitive feature in a signal. Effort may also relate to physical effort or work of a process (e.g., respiratory effort) that may affect the signal (e.g., a PPG signal). Effort may be determined through feature analysis of a transformed signal that has been transformed via a continuous wavelet transform. For example, respiratory effort may be determined using a scalogram generated based at least in part on a wavelet transform of a physiological signal and analyzing features of the scalogram. | 12-31-2009 |
20090326831 | Concatenated Scalograms - Embodiments may include systems and methods capable of processing an original signal by selecting and mirroring portions of the signal to create new signals. Any suitable number of new signals may be created from the original signal and scalograms may be derived at least in part from the new signals. Regions of the scalograms may be selected based on a characteristic of the original signal. The selected regions may be concatenated, and a sum along amplitudes across time may be applied to the concatenated regions. Desired information, such as respiration information within the original signal, may be determined from the sum along amplitudes across time. | 12-31-2009 |
20090326867 | SIGNAL PROCESSING SYSTEMS AND METHODS FOR DETERMINING SLOPES OF ELECTRONIC SIGNALS - The present disclosure relates to signal processing and, more particularly, relates to determining the slope of a signal. In embodiments, first slopes between a first point in the signal and other points in the signal may be determined. Second slopes between a second point in the signal and other points in the signal may also be determined. The first and second slopes may be used to generate a histogram, and a desired slope may be selected from the preferred value of the histogram. In an embodiment, a two-dimensional Lissajous figure may be selected from a three-dimensional Lissajous figure and a histogram of the slopes within the selected Lissajous figure may be created to determine the desired slope. The desired slope may have clinical relevance (e.g., it may be used to determine a patient's blood oxygen saturation level). The three-dimensional Lissajous figure may be derived at least in part from surface signals related to two transform-surfaces. Each transform-surface may be the result of performing a continuous wavelet transform on a signal. A confidence measure may be generated with respect to determining the desired slope. | 12-31-2009 |
20090326871 | SYSTEMS AND METHODS FOR ARTIFACT DETECTION IN SIGNALS - According to embodiments, a method and system for artifact detection in signals is disclosed. The artifacts may take the form of movement artifacts in physiological (e.g., pulse oximetry) signals. Artifacts in the wavelet space of the physiological signal may be removed, replaced, ignored, filtered, or otherwise modified by determining the energy within a predefined moving area of the wavelet scalogram, comparing the determined energy within the predefined moving area of the wavelet scalogram to a threshold value, and masking at least one area of artifact in the wavelet scalogram based, at least in part, on the comparison. From the enhanced signal, physiological parameters, for example, respiration, respiratory effort, pulse, and oxygen saturation, may be more reliably and accurately derived or computed. | 12-31-2009 |
20100014761 | Methods And Systems For Discriminating Bands In Scalograms - The present disclosure is directed towards embodiments of systems and methods for discriminating (e.g., masking out) scale bands that are determined to be not of interest from a scalogram derived from a continuous wavelet transform of a signal. Techniques for determining whether a scale band is not of interest include, for example, determining whether a scale band's amplitude is being modulated by one or more other bands in the scalogram. Another technique involves determining whether a scale band is located between two other bands and has energy less than that of its neighboring bands. Another technique involves determining whether a scale band is located at about half the scale of another, more dominant (i.e., higher energy) band. | 01-21-2010 |
20100016690 | Systems And Methods For Determining Oxygen Saturation - According to embodiments, techniques for using continuous wavelet transforms and spectral transforms to determine oxygen saturation from photoplethysmographic (PPG) signals are disclosed. According to embodiments, a first oxygen saturation may be determined from wavelet transformed PPG signals and a second oxygen saturation may be determined from spectral transformed PPG signals. An optimal oxygen saturation may be determined by selecting one of the first and the second oxygen saturation or by combining the first and the second oxygen saturation. According to embodiments, a spectral transform of PPG signals may be performed to identify a frequency region associated with a pulse rate of the PPG signal. A continuous wavelet transform of the PPG signals at a scale corresponding to the identified frequency region may be performed to determine oxygen saturation from the wavelet transformed signal. | 01-21-2010 |
20100081943 | Detecting Sleep Events Using Localized Blood Pressure Changes - Techniques for detecting sleep events are disclosed. In some embodiments, a continuous non-invasive blood pressure (“CNIBP”) monitoring system may be used to obtain blood pressure values from a subject during a sleep study. Changes in the blood pressure over time may be determined and analyzed in order to identify a sleep event. The localized blood pressure changes may be interpreted in isolation or in combination with other signals collected from the subject. | 04-01-2010 |
20100087714 | REDUCING CROSS-TALK IN A MEASUREMENT SYSTEM - According to embodiments, techniques for determining one or more physiological characteristics in a measurement system which may include cross-talk are disclosed. A sensor or probe may be used to generate two or more a plethysmograph or photoplethysmograph (PPG) signals from a patient. The obtained signals may include an infrared signal and a red signal, and may be subject to an additional measurement noise. The obtained signal may be combined to form a detected signal. The detected signal may be filtered to partially or fully remove noise. The filtered detected signal may be demodulated to separate the red signal and the infrared signal. The recovered red and infrared signals may be processed by additional filters to partially or fully remove cross-talk. The processed red and infrared signals may then be used to determine physiological characteristics of a patient such as a pulse rate, a respiration rate, and a blood oxygen saturation level using the wavelet transform and/or scalogram of at least one of the processed red and infrared signals. The partial or full removal of cross-talk from the red signal and infrared signal may result in a more reliable determination of physiological characteristics than would be possible in a system in which cross-talk was not removed. | 04-08-2010 |
20100228102 | SYSTEMS AND METHODS FOR MONITORING HEART RATE AND BLOOD PRESSURE CORRELATION - Systems and methods are provided for monitoring a correlation between heart rate and blood pressure in a patient. When a characteristic of the correlation exceeds a threshold, a patient status indicator signal is sent to a monitoring device In some embodiments, the patient status indicator signal indicates a particular medical condition or alerts a care provider to a change in status. In some embodiments, the heart rate signal is used to improve a blood pressure estimate generated by a different signal. In some embodiments, the heart rate, blood pressure and correlation signals are used in a predictive mathematical model to estimate patient status or outcome. | 09-09-2010 |
20100286494 | USING COLORED PROBES IN PATIENT MONITORING - The present disclosure provides a sensor with color-coded indications that various patient physiological parameters are being monitored, such as blood oxygen saturation, blood pressure, respiration rate, and respiration effort. The sensor may sense a physical characteristic used to monitor the physiological parameter, and a visible light emitter emits visible light of a first color that is color-coded to the physiological parameter, but is not used to sense the physical characteristic. The visible light emitter may emit visibly flashing light in response to the sensor sensing a threshold value of the physical characteristic. The sensor may include a second light emitter that may sense the physical characteristic, and may emit light of a second color that is color-coded to a first or second physiological parameter. In some embodiments, the first and second colors may visibly mix. The first and second visible light emitters may emit light independently, including visibly flashing light. | 11-11-2010 |
20100312075 | Signal Processing Techniques For Aiding The Interpretation Of Respiration Signals - According to embodiments, a respiration signal may be processed to normalize respiratory feature values in order to improve and/or simplify the interpretation and subsequent analysis of the signal. Data indicative of a signal may be received at a sensor and may be used to generate a respiration signal. Signal peaks in the respiration signal may be identified and signal peak thresholds may be determined. The identified signal peaks may be adjusted based on the signal peak threshold values to normalize the respiration signal. | 12-09-2010 |
20110021929 | SYSTEMS AND METHODS FOR CONTINUOUS NON-INVASIVE BLOOD PRESSURE MONITORING - Systems and methods are disclosed herein for continuous non-invasive blood pressure (CNIBP) monitoring. Multiple reference blood pressure values may be obtained using a calibration device. These multiple reference blood pressure values may be used as calibration points for determining a relationship between the blood pressure of a patient and photoplethysmograph (PPG) signals. | 01-27-2011 |
20110028802 | METHODS AND APPARATUS FOR PRODUCING AND USING LIGHTLY FILTERED PHOTOPLETHYSMOGRAPH SIGNALS - One or more physiological conditions of a patient can be observed by obtaining a photoplethysmograph (“PPG”) signal from the patient and by only lightly filtering that signal. The light filtering of the PPG may be such as to only remove (for example) high frequency noise from that signal, while leaving in the signal most or all frequency components that are due to physiological events in the patient. In this way, such physiological events can be observed via a visual display of the lightly filtered PPG signal and/or via other signal processing of the lightly filtered PPG signal to automatically extract certain physiological parameters or characteristics from that signal. | 02-03-2011 |
20110028854 | SYSTEMS AND METHODS FOR NON-INVASIVE DETERMINATION OF BLOOD PRESSURE - Methods and systems for determining blood pressure from a pressure signal are disclosed. A patient's blood pressure may be determined by analyzing features of a wavelet transformation of a pressure signal obtained during an occlusion procedure. Ridges in a scalogram of the transformed signal may be identified and used to determine an envelope of a pressure oscillation signal, to which oscillometric blood pressure determination techniques may be applied. | 02-03-2011 |
20110074409 | Systems And Methods For Gating An Imaging Device - A method and system for automatically gating an imaging device is disclosed. Physiological process information of a patient may be derived from a plethysmographic signal, for example, by analyzing the plethysmographic signal transformed by a continuous wavelet transform. Other techniques for deriving physiological process information of a patient include, for example, analyzing a scalogram derived from the continuous wavelet transform. The physiological process information may be used to automatically gate imaging data acquired from an imaging device in order to synchronize the imaging data with the physiological process information. | 03-31-2011 |
20110276275 | Systems And Methods For Wavelet Transform Scale-Dependent Multiple-Archetyping - Methods and systems are disclosed for producing a plurality of archetype signals in wavelet space at a plurality of wavelet scales. A signal is transformed using a continuous wavelet transform based at least in part on a wavelet function. A scale dependent archetype transformed signal is computed based at least in part on the transformed signal and based at least in part on a natural periodicity of the wavelet function used to transform the signal. Information may be derived about the signal from the archetype transform signal, and stored in memory. | 11-10-2011 |
20120123689 | METHODS AND SYSTEMS FOR DISCRIMINATING BANDS IN SCALOGRAMS - The present disclosure is directed towards embodiments of systems and methods for discriminating (e.g., masking out) scale bands that are determined to be not of interest from a scalogram derived from a continuous wavelet transform of a signal. Techniques for determining whether a scale band is not of interest include, for example, determining whether a scale band's amplitude is being modulated by one or more other bands in the scalogram. Another technique involves determining whether a scale band is located between two other bands and has energy less than that of its neighboring bands. Another technique involves determining whether a scale band is located at about half the scale of another, more dominant (i.e., higher energy) band. | 05-17-2012 |
20120220247 | Systems And Methods For Tunable Wavelet Transform Analysis Of A Signal - Methods and systems are disclosed for tuning first and second wavelet functions to resolve at least one component of a signal. A first characteristic frequency corresponding to a first scale band of interest is determined, and a first wavelet function is tuned to the first characteristic frequency in at least a region of a first scale band of interest. A second characteristic frequency corresponding to a second scale band of interest is determined, and a second wavelet function is tuned to the second characteristic frequency in at least a region of the second scale band of interest. A signal is transformed for the first and second wavelet functions using a continuous wavelet transform to create a transform signal, and a scalogram is generated based at least in part on the transformed signal. | 08-30-2012 |
20120259235 | Systems and Methods for Monitoring Heart Rate and Blood Pressure Correlation - Systems and methods are provided for monitoring a correlation between heart rate and blood pressure in a patient. When a characteristic of the correlation exceeds a threshold, a patient status indicator signal is sent to a monitoring device. In some embodiments, the patient status indicator signal indicates a particular medical condition or alerts a care provider to a change in status. In some embodiments, the heart rate signal is used to improve a blood pressure estimate generated by a different signal. In some embodiments, the heart rate, blood pressure and correlation signals are used in a predictive mathematical model to estimate patient status or outcome. | 10-11-2012 |
20120310051 | Systems And Methods For Signal Rephasing Using The Wavelet Transform - Methods and systems are disclosed for defining a physiological parameter. A first physiological signal is transformed into in a complex transform space, the transformed signal having a magnitude and a phase. The transformed signal is rotated by altering its phase. The rotated signal is inverted, and the inverted signal is aligned in phase with a second physiological signal. The aligned inverted signal and the second physiological signal are combined to form a combined signal indicative of the physiological parameter. | 12-06-2012 |
20120310100 | Systems And Methods For Detecting And Monitoring Arrhythmias Using the PPG - Systems and methods for detecting and monitoring arrhythmias from a signal are provided. A signal processing system may transform a signal using a wavelet transformation and analyze changes in features of the transformed signal to detect pulse rhythm abnormalities. For example, the system may detect pulse rhythm abnormalities by analyzing energy parameters, morphology changes, and pattern changes in the scalogram of a PPG signal. Further, the system may detect pulse rhythm abnormalities by analyzing both the PPG signal and its corresponding scalogram. Physiological information, such as cardiac arrhythmia, may be derived based on the detected pulse rhythm abnormality. | 12-06-2012 |
20130007083 | SYSTEMS AND METHODS FOR COMPUTING CONTINUOUS WAVELET TRANSFORM ON A DEDICATED INTEGRATED CIRCUIT - Methods and systems are disclosed for computing one or more continuous wavelet transforms on a dedicated integrated circuit. The systems comprise an integrated circuit having a receiver, memory, and processing circuitry. The receiver receives input data corresponding to an input signal. The memory stores information corresponding to one or more wavelet functions scaled over a set of scales. The processing circuitry is configured to compute, in-parallel, various portions of a single continuous wavelet transform of the input signal based on the received input data and the stored information corresponding to a single wavelet function computed over a set of scales. | 01-03-2013 |
20130011032 | Systems and Methods for Ridge Selection in Scalograms of Signals - According to embodiments, systems, devices, and methods for ridge selection in scalograms are disclosed. Ridges or ridge components are features within a scalogram which may be computed from a signal such as a physiological (e.g., photoplethysmographic) signal. Ridges may be identified from one or more scalograms of the signal. Parameters characterizing these ridges may be determined Based at least in part on these parameters, a ridge density distribution function is determined A ridge is selected from analyzing this ridge density distribution function. In some embodiments, the selected ridge is used to determine a physiological parameter such as respiration rate. | 01-10-2013 |
20130024123 | METHODS AND SYSTEMS FOR DETERMINING PHYSIOLOGICAL PARAMETERS USING TEMPLATE MATCHING - A patient monitoring system may be configured to use template matching in determining physiological parameters. A physiological signal may be monitored, and a wavelet transform may be performed. The wavelet transform, or parameters derived thereof such as energy distribution or relative phase difference, may be compared with one or more templates using template matching. Templates may be based on, for example, physiological data, mathematical models, or look-up tables, and may be pre-computed and stored. Physiological parameters may be determined based on the template matching results. Scale variability, confidence metrics, or both, may be used to aid in determining the physiological parameter. | 01-24-2013 |
20130066173 | VENOUS OXYGEN SATURATION SYSTEMS AND METHODS - Methods and systems are discussed for determining venous oxygen saturation by calculating a ratio of ratios from respiration-induced baseline modulations. A calculated venous ratio of ratios may be compared with a look-up table value to estimate venous oxygen saturation. A calculated venous ratio of ratios is compared with an arterial ratio of ratios to determine whether baseline modulations are the result of a subject's respiration or movement. Such a determination is also made by deriving a venous ratio of ratios using a transform technique, such as a continuous wavelet transform. Derived venous and arterial saturation values are used to non-invasively determine a cardiac output of the subject. | 03-14-2013 |
20130066174 | VENOUS OXYGEN SATURATION SYSTEMS AND METHODS - Methods and systems are discussed for determining venous oxygen saturation by calculating a ratio of ratios from respiration-induced baseline modulations. A calculated venous ratio of ratios may be compared with a look-up table value to estimate venous oxygen saturation. A calculated venous ratio of ratios is compared with an arterial ratio of ratios to determine whether baseline modulations are the result of a subject's respiration or movement. Such a determination is also made by deriving a venous ratio of ratios using a transform technique, such as a continuous wavelet transform. Derived venous and arterial saturation values are used to non-invasively determine a cardiac output of the subject. | 03-14-2013 |
20130066175 | VENOUS OXYGEN SATURATION SYSTEMS AND METHODS - Methods and systems are discussed for determining venous oxygen saturation by calculating a ratio of ratios from respiration-induced baseline modulations. A calculated venous ratio of ratios may be compared with a look-up table value to estimate venous oxygen saturation. A calculated venous ratio of ratios is compared with an arterial ratio of ratios to determine whether baseline modulations are the result of a subject's respiration or movement. Such a determination is also made by deriving a venous ratio of ratios using a transform technique, such as a continuous wavelet transform. Derived venous and arterial saturation values are used to non-invasively determine a cardiac output of the subject. | 03-14-2013 |
20130066176 | VENOUS OXYGEN SATURATION SYSTEMS AND METHODS - Methods and systems are discussed for determining venous oxygen saturation by calculating a ratio of ratios from respiration-induced baseline modulations. A calculated venous ratio of ratios may be compared with a look-up table value to estimate venous oxygen saturation. A calculated venous ratio of ratios is compared with an arterial ratio of ratios to determine whether baseline modulations are the result of a subject's respiration or movement. Such a determination is also made by deriving a venous ratio of ratios using a transform technique, such as a continuous wavelet transform. Derived venous and arterial saturation values are used to non-invasively determine a cardiac output of the subject. | 03-14-2013 |
20130079601 | SYSTEMS AND METHODS FOR ANALYZING A PHYSIOLOGICAL SENSOR SIGNAL - The present disclosure relates generally to patient monitoring systems and, more particularly, to signal analysis for patient monitoring systems. In one embodiment, a method of analyzing a detector signal of a physiological patient sensor includes obtaining the detector signal from the physiological patient sensor, wherein the detector signal crosses a horizontal boundary more than once. The method also includes determining the relative time and the slope of the detector signal at each boundary crossing. The method further includes estimating the amplitude of the detector signal based, at least in part, on the determined relative time and slope of the detector signal at each boundary crossing. The method also includes determining a physiological parameter of a patient based, at least in part, on the estimate of the amplitude of the detector signal. | 03-28-2013 |
20130079606 | SYSTEMS AND METHODS FOR DETERMINING RESPIRATION INFORMATION FROM A PHOTOPLETHYSMOGRAPH - A patient monitoring system may receive a photoplethysmograph (PPG) signal including samples of a pulse waveform. The PPG signal may demonstrate morphology changes based on respiration. The system may calculate morphology metrics from the PPG signal, the first derivative of the PPG signal, the second derivative of the PPG signal, or any combination thereof. The morphology metrics may demonstrate amplitude modulation, baseline modulation, and frequency modulation of the PPG signal that is related to respiration. Morphology metric signals generated from the morphology metrics may be used to determine respiration information such as respiration rate. | 03-28-2013 |
20130079656 | SYSTEMS AND METHODS FOR DETERMINING RESPIRATION INFORMATION FROM A PHOTOPLETHYSMOGRAPH - A signal representing physiological information may include information related to respiration. A patient monitoring system may generate a plurality of autocorrelation sequences from the signal and combine the autocorrelation sequences to generate a combined autocorrelation sequence. The combined autocorrelation sequence may be analyzed to identify one or more peaks that may correspond to respiration information. Respiration information such as respiration rate may be determined based on the one or more peaks. | 03-28-2013 |
20130079657 | SYSTEMS AND METHODS FOR DETERMINING RESPIRATION INFORMATION FROM A PHOTOPLETHYSMOGRAPH - A signal representing physiological information may include information related to respiration. A patient monitoring system may utilize a wavelet transform to generate a scalogram from the signal. A threshold for the scalogram may be calculated, and scalogram values may be compared to the threshold. One of the scales meeting the threshold may be selected as representing respiration information such as respiration rate. The respiration information may be determined based on the selected scale. | 03-28-2013 |
20130080489 | SYSTEMS AND METHODS FOR DETERMINING RESPIRATION INFORMATION FROM A PHOTOPLETHYSMOGRAPH - A patient monitoring system may receive a photoplethysmograph (PPG) signal including samples of a pulse waveform. A plurality of morphology metric signals may be generated from the PPG signal. The system may generate an autocorrelation sequence for each of the morphology metric signals. An autocorrelation metric may be generated from each of the autocorrelation sequences and may represent the regularity or periodicity of the morphology metric signal. The autocorrelation sequences may be combined to generate a combined autocorrelation sequence, with the weighting of the autocorrelation sequences based on the autocorrelation metric. The combined autocorrelation sequence may be used to determine physiological information. | 03-28-2013 |
20130137945 | Pulse Rate Determination Using Gaussian Kernel Smoothing of Multiple Inter-Fiducial Pulse Periods - Systems and methods are provided for determining the pulse rate of a patient from multiple fiducial points using Gaussian kernel smoothing. Based on acquired pleth signals, each recorded fiducial pulse period is converted to a Gaussian kernel function. The Gaussian kernel functions for all recorded fiducial points are summed to generate a Gaussian kernel smoothed curve. The pulse rate of a patient may be determined from the Gaussian kernel smoothed curve. All acquired fiducial pulse periods contribute to generate the Gaussian kernel smoothing curve. The number of fiducial points utilized may change to improve pulse rate determination or provide additional functionality to the system. | 05-30-2013 |
20130172686 | SYSTEMS AND METHODS FOR DETERMINING PHYSIOLOGICAL INFORMATION USING AUTOCORRELATION WITH GAPS - A patient monitoring system may receive a physiological signal having gap portions in the received data. The gap portions may be identified and a plurality of morphology metric signals may be modified based on the identified gap portions. The morphology metric signals may be modified based on the identified gaps, and a combined autocorrelation sequence may be generated based on the modified morphology metric signals. The combined autocorrelation sequence may be used to determine physiological information. | 07-04-2013 |
20130211235 | SYSTEMS AND METHODS FOR GATING AN IMAGING DEVICE - A method and system for automatically gating an imaging device is disclosed. Physiological process information of a patient may be derived from a plethysmographic signal, for example, by analyzing the plethysmographic signal transformed by a continuous wavelet transform. Other techniques for deriving physiological process information of a patient include, for example, analyzing a scalogram derived from the continuous wavelet transform. The physiological process information may be used to automatically gate imaging data acquired from an imaging device in order to synchronize the imaging data with the physiological process information. | 08-15-2013 |
20130253341 | SYSTEMS AND METHODS FOR NON-INVASIVE CONTINUOUS BLOOD PRESSURE DETERMINATION - According to some embodiments, systems and methods are provided for non-invasive continuous blood pressure determination. In some embodiments, a PPG signal is received and locations of pulses within the PPG signal are identified. An area within a particular pulse is measured. The area may be of just the upstroke, downstroke or the entire pulse. The area may be measured relative to a time-domain axis or a baseline of the pulse. The pulse may be split into multiple sections and the area of each section may be measured. The area of one portion of the pulse may correspond to systolic blood pressure while the area of another portion may correspond to diastolic blood pressure. Empirical data may be used to determine blood pressure from the measured area by applying calibration data measured by a suitable device. | 09-26-2013 |
20130289413 | SYSTEMS AND METHODS FOR IDENTIFYING PORTIONS OF A PHYSIOLOGICAL SIGNAL USABLE FOR DETERMINING PHYSIOLOGICAL INFORMATION - A patient monitoring system may determine portions of a PPG signal that correspond to artifacts, to a baseline shift that exceeds a threshold, or to a pulse-to-pulse variability that exceeds a threshold. The patient monitoring system may identify a contiguous portion of the PPG signal that does not include the determined portions. The contiguous portion of the PPG signal may be used to determine physiological information. | 10-31-2013 |
20130296659 | ANGLE DISTRIBUTION TECHNIQUE FOR ANALYZING A PHYSIOLOGICAL SENSOR SIGNAL - The present disclosure relates generally to patient monitoring systems and, more particularly, to signal analysis for patient monitoring systems. In one embodiment, a method of analyzing a detector signal of a physiological patient sensor includes obtaining the detector signal from the physiological patient sensor, and determining a ratio of the signal between two or more channels. A distribution of the angles between the points of the ratio over time may be used to determine a true ratio or a ratio of ratios for use in the determination of a physiological parameter. | 11-07-2013 |
20140016840 | SYSTEMS AND METHODS FOR RIDGE SELECTION IN SCALOGRAMS OF SIGNALS - According to embodiments, systems, devices, and methods for ridge selection in scalograms are disclosed. Ridges or ridge components are features within a scalogram which may be computed from a signal such as a physiological (e.g., photoplethysmographic) signal. Ridges may be identified from one or more scalograms of the signal. Parameters characterizing these ridges may be determined. Based at least in part on these parameters, a ridge density distribution function is determined. A ridge is selected from analyzing this ridge density distribution function. In some embodiments, the selected ridge is used to determine a physiological parameter such as respiration rate. | 01-16-2014 |
20140058231 | SYSTEMS AND METHODS FOR DETECTING PULSES - According to embodiments, systems and methods are provided for detecting pulses in a PPG signal. Local minima and maxima points may be identified in the PPG signal. Each minimum may be paired with an adjacent maximum forming an upstroke segment. Noise may be removed by comparing adjacent segments and ignoring segments that are too long or too large. Notches in the pulse may be identified and ignored by analyzing adjacent segments. Adjacent upstroke segments may be combined as a single upstroke if the lengths of adjacent upstroke segments are about the same, have similar slopes, and the end point of one segment is close to the start point of an adjacent segment. Segments having small temporal or amplitude difference relative to adjacent segments may be disregarded. The remaining segments may represent the pulse upticks. A sliding time window may be used instead to detect pulses in the PPG signal. | 02-27-2014 |
20140275877 | SYSTEMS AND METHODS FOR DETERMINING RESPIRATION INFORMATION BASED ON PRINCIPAL COMPONENT ANALYSIS - A patient monitoring system may receive a physiological signal such as a photoplethysmograph (PPG) signal. A plurality of respiration morphology signals may be determined from the PPG signal. Principal component analysis may be performed on the respiration morphology signals, resulting in one or more principal components. Respiration information such as respiration rate may be determined at least in part from a principal component that corresponds to a respiration source signal. | 09-18-2014 |
20140275889 | SYSTEMS AND METHODS FOR DETERMINING RESPIRATION INFORMATION FROM SEGMENTS OF A PHOTOPLETHYSMOGRAPH - A physiological monitoring system may determine respiration information from a PPG signal. The system may analyze the PPG signal with respect to itself by associating values of the PPG signal with values of a time-delayed version of the PPG signal to create pairs of associated values. A subset of associated values may be identified. Respiration metric values may be determined based on the subset of pairs. The respiration metric values may be amplitude values and/or time values corresponding to the subset of pairs. The respiration metric values may be analyzed using autocorrelation, cross-correlation, or other signal processing techniques to determine respiration information such as respiration rate. | 09-18-2014 |
20140276165 | SYSTEMS AND METHODS FOR IDENTIFYING PATIENT TALKING DURING MEASUREMENT OF A PHYSIOLOGICAL PARAMETER - A patient monitoring system may include a microphone that generates a sound signal based on sound emanated from a patient. A patient monitoring unit may process the sound signal to identify respiration information such as respiration rate and to determine whether the patient was talking. If the patient was talking, a confidence value may be calculated, which may be used to generate a respiration information value. | 09-18-2014 |
20140323824 | SYSTEMS AND METHODS FOR DETERMINING FLUID RESPONSIVENESS - Provided are systems and methods for processing a physiological signal in order to determine fluid responsiveness of a subject. In some embodiments, a respiration rate of the subject is received or determined, the signal is filtered based on the respiration rate to generate a filtered signal, and the filtered signal is processed to determine fluid responsiveness. In some embodiments, regular respiration is detected and fluid responsiveness is determined when regular respiration is detected. In some embodiments, the respiration of a subject is controlled, and fluid responsiveness is determined during controlled respiration. | 10-30-2014 |
20140323874 | SYSTEMS AND METHODS FOR DETERMINING FLUID RESPONSIVENESS - Provided are systems and methods for processing a physiological signal in order to determine fluid responsiveness of a subject. In some embodiments, a respiration rate of the subject is received or determined, the signal is filtered based on the respiration rate to generate a filtered signal, and the filtered signal is processed to determine fluid responsiveness. In some embodiments, regular respiration is detected and fluid responsiveness is determined when regular respiration is detected. In some embodiments, the respiration of a subject is controlled, and fluid responsiveness is determined during controlled respiration. | 10-30-2014 |
20150057554 | SYSTEMS AND METHODS FOR MONITORING BLOOD PRESSURE - Various methods and systems for blood pressure monitoring are provided. A device for monitoring blood pressure may include a memory storing instructions for receiving one or more signals representative of one or more patient parameters, wherein at least one of the one or more signals comprises a plethysmography signal. The memory also stores instructions for determining a change in a pulse shape metric of the plethysmography signal and determining a change in a blood pressure signal over a period of time based on the one or more signals. The memory also stores instructions for determining a confidence level of the blood pressure signal based at least in part on a correlation between the change in the blood pressure signal and the change in the pulse shape metric over the period of time. The device also includes a processor configured to execute the instructions. | 02-26-2015 |