Nellcor Puritan Bennett Ireland Patent applications |
Patent application number | Title | Published |
20140257061 | 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 and a second PPG signals may be received. A spectral transform of the first and the second PPG signals may be performed to produce a first and a second spectral transformed signals. A frequency region associated with a pulse rate of the PPG signals may be identified from the first and the second spectral transformed signals. According to embodiments, a continuous wavelet transform of the first and the second PPG signals may be performed at a scale corresponding to the identified frequency region to produce a first and a second wavelet transformed signals. The oxygen saturation may be determined based at least in part upon the wavelet transformed signals. | 09-11-2014 |
20140094672 | SYSTEMS AND METHODS FOR PROCESSING PHYSIOLOGICAL SIGNALS IN WAVELET SPACE - Methods and systems are disclosed for analyzing multiple scale bands in the scalogram of a physiological signal in order to obtain information about a physiological process. An analysis may be performed to identify multiple scale bands that are likely to contain the information sought. Each scale band may be assessed to determine a band quality, and multiple bands may be combined based on the band quality. Information about a physiological process may determined based on the combined band. In an embodiment, analyzing multiple scale bands in a scalogram arising from a wavelet transformation of a photoplethysmograph signal may yield clinically relevant information about, among other things, the blood oxygen saturation of a patient. | 04-03-2014 |
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 |
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 |
20140012147 | CONTINUOUS NON-INVASIVE BLOOD PRESSURE MEASUREMENT APPARATUS AND METHODS PROVIDING AUTOMATIC RECALIBRATION - A blood pressure measurement system is configured to perform a calibration automatically when a calibration condition is satisfied. The calibration condition is based upon one or more parameters of pulse waves of a subject. The parameters may include pulse wave area; a time difference between systolic peak and reflected wave peak or dichrotic notch in the pulse wave and a shape of at least a portion of the pulse wave. | 01-09-2014 |
20140012110 | PROCESSING AND DETECTING BASELINE CHANGES IN SIGNALS - 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. | 01-09-2014 |
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 |
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 |
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 |
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 |
20130245482 | 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. | 09-19-2013 |
20130229285 | DETECTING A SIGNAL QUALITY DECREASE IN A MEASUREMENT SYSTEM - Techniques for detecting a signal quality decrease are disclosed. A sensor or probe may be used to obtain a plethysmograph or photoplethysmograph (PPG) signal from a subject. A wavelet transform of the signal may be performed and a scalogram may be generated based at least in part on the wavelet transform. One or more characteristics of the scalogram may be determined. The determined characteristics may include, for example, energy values and energy structural characteristics in a pulse band, a mains hum band, and/or a noise band. Such characteristics may be analyzed to produce signal quality values and associated signal quality trends. One or more signal quality values and signal quality trends may be used to determine if a signal quality decrease has occurred or is likely to occur. | 09-05-2013 |
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 |
20130197329 | Systems And Methods For Estimating Values Of A Continuous Wavelet Transform - According to embodiments, techniques for estimating scalogram energy values in a wedge region of a scalogram are disclosed. A pulse oximetry system including a sensor or probe may be used to receive a photoplethysmograph (PPG) signal from a patient or subject. A scalogram, corresponding to the obtained PPG signal, may be determined. In an arrangement, energy values in the wedge region of the scalogram may be estimated by calculating a set of estimation locations in the wedge region and estimating scalogram energy values at each location. In an arrangement, scalogram energy values may be estimated based on an estimation scheme and by combining scalogram values in a vicinity region. In an arrangement, the vicinity region may include energy values in a resolved region of the scalogram and previously estimated energy values in the wedge region of the scalogram. In an arrangement, one or more signal parameters may be determined based on the resolved and estimated values of the scalogram. | 08-01-2013 |
20130172767 | SYSTEMS AND METHODS FOR DETERMINING RESPIRATION INFORMATION USING PHASE LOCKED LOOP - A patient monitoring system may receive a physiological signal such as a photoplethysmograph (PPG) signal that exhibits frequency and amplitude modulation based on respiration. A phase locked loop may generate a frequency demodulated signal and an amplitude demodulated signal from the PPG signal. An autocorrelation sequence may be generated for each of the frequency demodulated signal and the amplitude demodulated signal. The autocorrelation sequences may be combined and respiration information may be determined based on the combined autocorrelation sequence. | 07-04-2013 |
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 |
20130138357 | SYSTEMS AND METHODS FOR EVALUATING A PHYSIOLOGICAL CONDITION - A method and system are provided for evaluating in patient monitoring whether a signal is sensed optimally by receiving a signal, transforming the signal using a wavelet transform, generating a scalogram based at least in part on the transformed signal, identifying a pulse band in the scalogram, identifying a characteristic of the pulse band, determining, based on the characteristic of the pulse band, whether the signal is sensed optimally; and triggering an event. The characteristics of the pulse band and scalogram may be used to provide an indication of monitoring conditions. | 05-30-2013 |
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 |
20130137936 | SYSTEMS AND METHODS FOR DETERMINING RESPIRATION INFORMATION USING HISTORICAL DISTRIBUTION - A patient monitoring system may generate an autocorrelation sequence for a physiological signal such as a photoplethysmograph signal. A series of peak values may be identified for the autocorrelation sequence. The peak values may be modified based on a historical distribution of a physiological parameter. A physiological parameter such as respiration rate may be determined based on the modified peak values. | 05-30-2013 |
20130127621 | Methods and Systems for Determining Whether to Trigger an Alarm - According to embodiment, systems and methods for processing a physiological measurement and generating alarms based on the measurement are provided. Multiple features of a single physiological measurement may be concurrently monitored to generate alarms. One or more of the features may be based on a trend of the physiological measurement. One or more of the features may be based on a wavelet transform of the physiological measurement. Different features may be used in different combinations to lower the percentage of false alarms while still recognizing valid alarm events. | 05-23-2013 |
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 |
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 |
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 |
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 |
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 |
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 |
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 |
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 |
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 |
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 |
20130046188 | METHOD OF ANALYZING AND PROCESSING SIGNALS - A physiological measurement system is disclosed which can take a pulse oximetry signal such as a photoplethysmogram from a patient and then analyze the signal to measure physiological parameters including respiration, pulse, oxygen saturation and movement. The system comprises a pulse oximeter which includes a light emitting device and a photodetector attachable to a subject to obtain a pulse oximetry signal; analogue to digital converter means arranged to convert said pulse oximetry signal into a digital pulse oximetry signal; signal processing means suitable to receive said digital pulse oximetry signal and arranged to decompose that signal by wavelet transform means; feature extraction means arranged to derive physiological information from the decomposed signal; an analyzer component arranged to collect information from the feature extraction means; and data output means arranged in communication with the analyzer component. | 02-21-2013 |
20130046187 | METHOD OF ANALYZING AND PROCESSING SIGNALS - A physiological measurement system is disclosed which can take a pulse oximetry signal such as a photoplethysmogram from a patient and then analyse the signal to measure physiological parameters including respiration, pulse, oxygen saturation and movement. The system comprises a pulse oximeter which includes a light emitting device and a photodetector attachable to a subject to obtain a pulse oximetry signal; analogue to digital converter means arranged to convert said pulse oximetry signal into a digital pulse oximetry signal; signal processing means suitable to receive said digital pulse oximetry signal and arranged to decompose that signal by wavelet transform means; feature extraction means arranged to derive physiological information from the decomposed signal; an analyser component arranged to collect information from the feature extraction means; and data output means arranged in communication with the analyser component. | 02-21-2013 |
20130046186 | METHOD OF ANALYZING AND PROCESSING SIGNALS - A physiological measurement system is disclosed which can take a pulse oximetry signal such as a photoplethysmogram from a patient and then analyse the signal to measure physiological parameters including respiration, pulse, oxygen saturation and movement. The system comprises a pulse oximeter which includes a light emitting device and a photodetector attachable to a subject to obtain a pulse oximetry signal; analogue to digital converter means arranged to convert said pulse oximetry signal into a digital pulse oximetry signal; signal processing means suitable to receive said digital pulse oximetry signal and arranged to decompose that signal by wavelet transform means; feature extraction means arranged to derive physiological information from the decomposed signal; an analyser component arranged to collect information from the feature extraction means; and data output means arranged in communication with the analyser component. | 02-21-2013 |
20130046185 | METHOD OF ANALYZING AND PROCESSING SIGNALS - A physiological measurement system is disclosed which can take a pulse oximetry signal such as a photoplethysmogram from a patient and then analyse the signal to measure physiological parameters including respiration, pulse, oxygen saturation and movement. The system comprises a pulse oximeter which includes a light emitting device and a photodetector attachable to a subject to obtain a pulse oximetry signal; analogue to digital converter means arranged to convert said pulse oximetry signal into a digital pulse oximetry signal; signal processing means suitable to receive said digital pulse oximetry signal and arranged to decompose that signal by wavelet transform means; feature extraction means arranged to derive physiological information from the decomposed signal; an analyser component arranged to collect information from the feature extraction means; and data output means arranged in communication with the analyser component. | 02-21-2013 |
20130046184 | METHOD OF ANALYZING AND PROCESSING SIGNALS - A physiological measurement system is disclosed which can take a pulse oximetry signal such as a photoplethysmogram from a patient and then analyse the signal to measure physiological parameters including respiration, pulse, oxygen saturation and movement. The system comprises a pulse oximeter which includes a light emitting device and a photodetector attachable to a subject to obtain a pulse oximetry signal; analogue to digital converter means arranged to convert said pulse oximetry signal into a digital pulse oximetry signal; signal processing means suitable to receive said digital pulse oximetry signal and arranged to decompose that signal by wavelet transform means; feature extraction means arranged to derive physiological information from the decomposed signal; an analyser component arranged to collect information from the feature extraction means; and data output means arranged in communication with the analyser component. | 02-21-2013 |
20130046161 | METHOD OF ANALYZING AND PROCESSING SIGNALS - A physiological measurement system is disclosed which can take a pulse oximetry signal such as a photoplethysmogram from a patient and then analyse the signal to measure physiological parameters including respiration, pulse, oxygen saturation and movement. The system comprises a pulse oximeter which includes a light emitting device and a photodetector attachable to a subject to obtain a pulse oximetry signal; analogue to digital converter means arranged to convert said pulse oximetry signal into a digital pulse oximetry signal; signal processing means suitable to receive said digital pulse oximetry signal and arranged to decompose that signal by wavelet transform means; feature extraction means arranged to derive physiological information from the decomposed signal; an analyser component arranged to collect information from the feature extraction means; and data output means arranged in communication with the analyser component. | 02-21-2013 |
20130046160 | METHOD OF ANALYZING AND PROCESSING SIGNALS - A physiological measurement system is disclosed which can take a pulse oximetry signal such as a photoplethysmogram from a patient and then analyse the signal to measure physiological parameters including respiration, pulse, oxygen saturation and movement. The system comprises a pulse oximeter which includes a light emitting device and a photodetector attachable to a subject to obtain a pulse oximetry signal; analogue to digital converter means arranged to convert said pulse oximetry signal into a digital pulse oximetry signal; signal processing means suitable to receive said digital pulse oximetry signal and arranged to decompose that signal by wavelet transform means; feature extraction means arranged to derive physiological information from the decomposed signal; an analyser component arranged to collect information from the feature extraction means; and data output means arranged in communication with the analyser component. | 02-21-2013 |
20130046157 | METHOD OF ANALYZING AND PROCESSING SIGNALS - A physiological measurement system is disclosed which can take a pulse oximetry signal such as a photoplethysmogram from a patient and then analyse the signal to measure physiological parameters including respiration, pulse, oxygen saturation and movement. The system comprises a pulse oximeter which includes a light emitting device and a photodetector attachable to a subject to obtain a pulse oximetry signal; analogue to digital converter means arranged to convert said pulse oximetry signal into a digital pulse oximetry signal; signal processing means suitable to receive said digital pulse oximetry signal and arranged to decompose that signal by wavelet transform means; feature extraction means arranged to derive physiological information from the decomposed signal; an analyser component arranged to collect information from the feature extraction means; and data output means arranged in communication with the analyser component. | 02-21-2013 |
20130046156 | METHOD OF ANALYZING AND PROCESSING SIGNALS - A physiological measurement system is disclosed which can take a pulse oximetry signal such as a photoplethysmogram from a patient and then analyse the signal to measure physiological parameters including respiration, pulse, oxygen saturation and movement. The system comprises a pulse oximeter which includes a light emitting device and a photodetector attachable to a subject to obtain a pulse oximetry signal; analogue to digital converter means arranged to convert said pulse oximetry signal into a digital pulse oximetry signal; signal processing means suitable to receive said digital pulse oximetry signal and arranged to decompose that signal by wavelet transform means; feature extraction means arranged to derive physiological information from the decomposed signal; an analyser component arranged to collect information from the feature extraction means; and data output means arranged in communication with the analyser component. | 02-21-2013 |
20130041240 | 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. | 02-14-2013 |
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 |
20130012792 | SYSTEMS AND METHODS FOR IDENTIFYING PULSE RATES - According to embodiments, techniques for using continuous wavelet transforms and spectral transforms to identify pulse rates from a photoplethysmographic (PPG) signal are disclosed. According to embodiments, candidate pulse rates of the PPG signal may be identified from a wavelet transformed PPG signal and a spectral transformed PPG signal. A pulse rate may be determined from the candidate pulse rates by selecting one of the candidate pulse rates or by combining the candidate pulse rates. According to embodiments, a spectral transform of a PPG signal may be performed to identify a frequency region associated with a pulse rate of the PPG signal. A continuous wavelet transform of the PPG signal at a scale corresponding to the identified frequency region may be performed to determine a pulse rate from the wavelet transformed signal. | 01-10-2013 |
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 |
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 |
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 |
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 |
20120302895 | METHODS AND SYSTEMS FOR FILTERING A SIGNAL ACCORDING TO A SIGNAL MODEL AND CONTINUOUS WAVELET TRANSFORM TECHNIQUES - According to embodiments, systems and methods are provided for filtering a signal. A first reference signal may be generated according to a signal model and a second reference signal may be generated by analyzing a continuous wavelet transform of a signal. The first and second reference signals may then both be applied to an input signal to filter the input signal according to the components of both of the reference signals. | 11-29-2012 |
20120283536 | Signal Procesing Systems and Methods Using Basis Functions and Wavelet Transforms - According to embodiments, systems and methods are provided that use continuous wavelet transforms and basis functions to provide an optimized system for the determination of physiological information. In an embodiment, the basis functions may be used to refine an area of interest in the signal in frequency or in time, and the continuous wavelet transform may be used to identify a maxima ridge in the scalogram at scales with characteristic frequencies proximal to the frequency or frequencies of interest. In another embodiment, a wavelet transform may be used to identify regions of a signal with the morphology of interest while basis functions may be used to focus on these regions to determine or filter information of interest. In yet another embodiment, basis functions and continuous wavelet transforms may be used concurrently and their results combined to form optimized information or a confidence metric for determined physiological information. | 11-08-2012 |
20120278001 | Signal Procesing Systems and Methods Using Basis Functions and Wavelet Transforms - According to embodiments, systems and methods are provided that use continuous wavelet transforms and basis functions to provide an optimized system for the determination of physiological information. In an embodiment, the basis functions may be used to refine an area of interest in the signal in frequency or in time, and the continuous wavelet transform may be used to identify a maxima ridge in the scalogram at scales with characteristic frequencies proximal to the frequency or frequencies of interest. In another embodiment, a wavelet transform may be used to identify regions of a signal with the morphology of interest while basis functions may be used to focus on these regions to determine or filter information of interest. In yet another embodiment, basis functions and continuous wavelet transforms may be used concurrently and their results combined to form optimized information or a confidence metric for determined physiological information. | 11-01-2012 |
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 |
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 |
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 |
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 |
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 |
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 |
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 |
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 |
20110307184 | LOW PERFUSION SIGNAL PROCESSING SYSTEMS AND METHODS - In some embodiments, systems and methods for identifying a low perfusion condition are provided by transforming a signal using a wavelet transform to generate a scalogram. A pulse band and adjacent marker regions in the scalogram are identified. Characteristics of the marker regions are used to detect the existence of a lower perfusion condition. If such a condition is detected, an event may be triggered, such as an alert or notification. | 12-15-2011 |
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 |
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 |
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 |
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 |
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 |
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 |
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 |
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 |
20110077484 | Systems And Methods For Identifying Non-Corrupted Signal Segments For Use In Determining Physiological Parameters - According to embodiments, non-corrupted signal segments are detected by a data modeling processor implementing an artificial neural network. The neural network may be trained to detect artifact in the signal (e.g., a PPG signal or some wavelet representation of a PPG signal) and gate valid signal segments for use in determining physiological parameters, such as, for example, pulse rate, oxygen saturation, pulse rate, respiration rate, and respiratory effort. When an artifact is detected, previously received known-good signal segments may be buffered and replace the signal segment or segments containing artifact. A regression analysis may also be performed in order to extrapolate new data from previously received known-good signal segments. In this way, more accurate and reliable physiological parameters may be determined. | 03-31-2011 |
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 |
20110071406 | Determining A Characteristic Respiration Rate - The present disclosure relates to monitoring a characteristic respiration rate of a patient based at least in part on a suitable time period that either precedes or follows a triggering event, such as a clinician/patient interaction, where the triggering event 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, monitoring the respiration rate 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 respiration rate. The patient signal used to derive a patient's respiration rate may be of an oscillatory nature or may include oscillatory features that may be analyzed to derive a characteristic respiration rate. | 03-24-2011 |
20110028813 | Systems And Methods For Estimating Values Of A Continuous Wavelet Transform - According to embodiments, techniques for estimating scalogram energy values in a wedge region of a scalogram are disclosed. A pulse oximetry system including a sensor or probe may be used to receive a photoplethysmograph (PPG) signal from a patient or subject. A scalogram, corresponding to the obtained PPG signal, may be determined. In an arrangement, energy values in the wedge region of the scalogram may be estimated by calculating a set of estimation locations in the wedge region and estimating scalogram energy values at each location. In an arrangement, scalogram energy values may be estimated based on an estimation scheme and by combining scalogram values in a vicinity region. In an arrangement, the vicinity region may include energy values in a resolved region of the scalogram and previously estimated energy values in the wedge region of the scalogram. In an arrangement, one or more signal parameters may be determined based on the resolved and estimated values of the scalogram. | 02-03-2011 |
20110028810 | Systems And Methods For Resolving The Continuous Wavelet Transform Of A Signal - According to an embodiment, techniques for estimating scalogram energy values in a wedge region of a scalogram are disclosed. A pulse oximetry system including a sensor or probe may be used to receive a photoplethysmograph (PPG) signal from a patient or subject. A scalogram, corresponding to the obtained PPG signal, may be determined. In an approach, energy values in the wedge region of the scalogram may be estimated by performing convolution-based or convolution-like operations on the obtained PPG signal, or a transformed version thereof, and the scalogram may be updated according to the estimated values. In an approach, a deskewing technique may be used to align data prior to adding the data to the scalogram. In an approach, one or more signal parameters may be determined based on the resolved and estimated values of the scalogram. | 02-03-2011 |
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 |
20110026784 | Systems And Methods For Determining Physiological Information Using Selective Transform Data - According to embodiments, a pulse band region is identified in a wavelet scalogram of a physiological signal (e.g., a plethysmograph or photoplethysmograph signal). Components of the scalogram at scales larger than the identified pulse band region are then used to determine a baseline signal in wavelet space. The baseline signal may then be used to normalize the physiological signal. Physiological information may be determined from the normalized signal. For example, oxygen saturation may be determined using a ratio of ratios or any other suitable technique. | 02-03-2011 |
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 |
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 |
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 |
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 |
20110004069 | Systems And Methods For Processing Physiological Signals In Wavelet Space - Methods and systems are disclosed for analyzing multiple scale bands in the scalogram of a physiological signal in order to obtain information about a physiological process. An analysis may be performed to identify multiple scale bands that are likely to contain the information sought. Each scale band may be assessed to determine a band quality, and multiple bands may be combined based on the band quality. Information about a physiological process may determined based on the combined band. In an embodiment, analyzing multiple scale bands in a scalogram arising from a wavelet transformation of a photoplethysmograph signal may yield clinically relevant information about, among other things, the blood oxygen saturation of a patient. | 01-06-2011 |
20100332173 | SYSTEMS AND METHODS FOR ASSESSING MEASUREMENTS IN PHYSIOLOGICAL MONITORING DEVICES - Methods and systems are provided for deriving and analyzing shape metrics, including skewness metrics, from physiological signals and their derivatives to determine measurement quality, patient status and operating conditions of a physiological measurement device. Such determinations may be used for any number of functions, including indicating to a patient or care provider that the measurement quality is low or unacceptable, alerting a patient or care provider to a change in patient status, triggering or delaying a recalibration of a monitoring device, and adjusting the operating parameters of a monitoring system. | 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 |
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 |
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 |
20100324827 | Fluid Responsiveness Measure - A method and system for measuring fluid responsiveness of a patient is disclosed. Information related to fluid responsiveness of a patient may be derived from a PPG signal, for example, by analyzing the PPG signal transformed by a continuous wavelet transform. Other techniques for deriving information related to fluid responsiveness of a patient include, for example, analyzing the amplitude modulation, frequency modulation, and/or baseline changes of a PPG signal. | 12-23-2010 |
20100324431 | Determining Disease State Using An Induced Load - The present disclosure relates to determining a patient's disease state based at least in pail on obtaining or determining certain underlying characteristics, such as vasotone, venous compliance, or ability of the vascular system to drain venous blood, of the patient's vascular system. The characteristics may be obtained by analyzing changes to a patient signal, such as the overall signal change, the rate of change, the shape of the change, changes in signal energy, or changes in the baseline and/or the amplitude of the signal, and/or the time period(s) over which the signal changes, that are caused by inducing a load on the vascular system. In some embodiments, the signal changes may be analyzed by transforming the signal using, for example, a continuous wavelet transform. The patient's health status or disease state may be determined using the one or more vascular system characteristics that influenced the signal change. | 12-23-2010 |
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 |
20100298728 | Signal Processing Techniques For Determining Signal Quality Using A Wavelet Transform Ratio Surface - According to embodiments, a wavelet transform ratio surface measure signal may be generated from two PPG signals. Values of the wavelet transform ratio surface measure signal at a given moment of time (i.e., instantaneous values) may be indicative of localized signal discrepancies within and/or between the PPG signals such as noise and signal artifacts. Spikes in the instantaneous values of the wavelet transform ratio surface measure signal may be located and used to determine a signal quality measure for the PPG signals. Characteristics of the spikes such as number, location, grouping, distribution, amplitude, and polarity may be used in the signal quality determination. | 11-25-2010 |
20100298676 | Estimating Transform Values Using Signal Estimates - According to embodiments, estimated values for a signal transform may be generated using estimated values for the signal. Signal parameters may then be determined based on the estimated signal transform. A first portion of a signal may be obtained. A second portion of the signal may be estimated. The second portion of the signal may correspond to a portion of the that is unknown, that is not yet available and/or that is obscured by noise and/or artifacts. A transform (e.g., a continuous wavelet transform) of both of the signal portions may be performed. One or more parameters corresponding to the signal may then be determined from transformed signal. | 11-25-2010 |
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 |
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 |
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 |
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 |
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 |
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 |
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 |
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 |
20100081945 | Systems and Methods for Maintaining Blood Pressure Monitor Calibration - Systems and methods are disclosed herein for maintaining the calibration of non-invasive blood pressure monitoring devices. Phase components of pulse signals detected by the blood pressure monitoring device are compared to stored baseline phase component values. If the difference exceeds a threshold, the blood pressure monitoring device is recalibrated. | 04-01-2010 |
20100081944 | Systems and Methods for Recalibrating a Non-Invasive Blood Pressure Monitor - Techniques for non-invasive blood pressure monitoring are disclosed. Data corresponding to a patient may be received from a hospital information system. The data may include, for example, drug administration data, medical procedure data, medical equipment data, or a combination thereof. Whether a blood pressure monitoring system needs to be recalibrated may be determined, based at least in part on the received data. If it is determined that the blood pressure monitoring system needs to be recalibrated, the recalibration may be performed and at least one blood pressure measurement of the patient may be computed using the recalibrated blood pressure monitoring system. | 04-01-2010 |
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 |
20100081898 | Detecting A Probe-Off Event In A Measurement System - According to embodiments, techniques for detecting probe-off events are disclosed. A sensor or probe may be used to obtain a plethysmograph or photoplethysmograph (PPG) signal from a subject. A wavelet transform of the signal may be performed and a scalogram may be generated based at least in part on the wavelet transform. One or more characteristics of the scalogram may be determined. The determined characteristics may include, for example, an energy decrease, a broadscale high-energy cone, a regular, repeated high-scale pattern, a low-scale information pattern; and a pulse band. The absence or presence of these and other characteristics, along with information about the characteristics, may be analyzed to detect a probe-off event. A confidence indicator may be calculated in connection with probe-off event detections and alarms may be generated when probe-off events occur. | 04-01-2010 |
20100079279 | Detecting a Signal Quality Decrease in a Measurement System - Techniques for detecting a signal quality decrease are disclosed. A sensor or probe may be used to obtain a plethysmograph or photoplethysmograph (PPG) signal from a subject. A wavelet transform of the signal may be performed and a scalogram may be generated based at least in part on the wavelet transform. One or more characteristics of the scalogram may be determined. The determined characteristics may include, for example, energy values and energy structural characteristics in a pulse band, a mains hum band, and/or a noise band. Such characteristics may be analyzed to produce signal quality values and associated signal quality trends. One or more signal quality values and signal quality trends may be used to determine if a signal quality decrease has occurred or is likely to occur. | 04-01-2010 |
20100017142 | Low Perfusion Signal Processing Systems And Methods - In some embodiments, systems and methods for identifying a low perfusion condition are provided by transforming a signal using a wavelet transform to generate a scalogram. A pulse band and adjacent marker regions in the scalogram are identified. Characteristics of the marker regions are used to detect the existence of a lower perfusion condition. If such a condition is detected, an event may be triggered, such as an alert or notification. | 01-21-2010 |
20100016738 | SYSTEMS AND METHODS FOR PULSE PROCESSING - According to embodiments, techniques for using continuous wavelet transforms to process pulses from a photoplethysmographic (PPG) signal are disclosed. The continuous wavelet transform of the PPG signal may be used to identify and characterize features and their periodicities within a signal. Regions, phases and amplitudes within the scalogram associated with these features may then be analyzed to identify, locate, and characterize a true pulse within the PPG signal. Having characterized and located the pulse in the PPG (possibly also using information gained from conventional pulse processing techniques such as, for example, by identifying turning points for candidate pulse maxima and minima on the PPG, frequency peak picking for candidate scales of pulses, etc.), the PPG may be parameterized for ease of future processing. | 01-21-2010 |
20100016734 | Systems and Methods Using Induced Perturbation to Determine Physiological Parameters - According to embodiments, systems and methods for non-invasive blood pressure monitoring are disclosed. An exciter may induce perturbations in a subject, and a sensor or probe may be used to obtain a detected signal from the subject. The detected signal may then be used to measure one or more physiological parameters of the patient. For example if the perturbations are based on a known signal, any differences between the known signal and the input signal may be attributable to the patient's physiological parameters. A phase drift between the perturbation signal and the detected signal may be determined from a comparison of the scalograms of the exciter location and the sensor or probe location. From the scalogram comparison, more accurate and reliable physiological parameters may be determined. | 01-21-2010 |
20100016696 | SYSTEMS AND METHODS FOR GENERATING REFERENCE SIGNALS - According to embodiments, systems and methods for generating reference signals are provided. A signal may be transformed using a continuous wavelet transform, Regions of interest may be selected from a transform or the resulting scalogram that may be used to generate a reference signal to use in filtering the signal or other signals. Cross-correlation techniques may be used to cancel noise components or isolate non-noise components from the signal. A physiological parameter may then be determined from the filtered signal or isolated components in the signal. | 01-21-2010 |
20100016695 | Methods And Systems For Filtering A Signal According To A Signal Model And Continuous Wavelet Transform Techniques - According to embodiments, systems and methods are provided for filtering a signal. A first reference signal may be generated according to a signal model and a second reference signal may be generated by analyzing a continuous wavelet transform of a signal The first and second reference signals may then both be applied to an input signal to filter the input signal according to the components of both of the reference signals. | 01-21-2010 |
20100016693 | Systems And Methods For Identifying Pulse Rates - According to embodiments, techniques for using continuous wavelet transforms and spectral transforms to identify pulse rates from a photoplethysmographic (PPG) signal are disclosed. According to embodiments, candidate pulse rates of the PPG signal may be identified from a wavelet transformed PPG signal and a spectral transformed PPG signal. A pulse rate may be determined from the candidate pulse rates by selecting one of the candidate pulse rates or by combining the candidate pulse rates. According to embodiments, a spectral transform of a PPG signal may be performed to identify a frequency region associated with a pulse rate of the PPG signal. A continuous wavelet transform of the PPG signal at a scale corresponding to the identified frequency region may be performed to determine a pulse rate from the wavelet transformed signal. | 01-21-2010 |
20100016692 | SYSTEMS AND METHODS FOR COMPUTING A PHYSIOLOGICAL PARAMETER USING CONTINUOUS WAVELET TRANSFORMS - According to embodiments, systems and methods for computing a physiological parameter are provided. The physiological parameter may be calculated using a continuous wavelet transform technique as well as using a non-continuous wavelet transform technique. More than one value for the physiological parameter may be calculated using various techniques. The values may be evaluated to select a desired value, or an average or weighted average of the values may be computed to generate a desired value. | 01-21-2010 |
20100016691 | Methods And Systems For Determining Whether To trigger An Alarm - According to embodiment, systems and methods for processing a physiological measurement and generating alarms based on the measurement are provided. Multiple features of a single physiological measurement may be concurrently monitored to generate alarms. One or more of the features may be based on a trend of the physiological measurement. One or more of the features may be based on a wavelet transform of the physiological measurement. Different features may be used in different combinations to lower the percentage of false alarms while still recognizing valid alarm events. | 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 |
20100016680 | Signal Processing Systems and Methods for Analyzing Multiparameter Spaces to Determine Physiological States - The present disclosure relates to signal processing systems and methods, and more particularly, to systems and methods for analyzing multiparameter spaces to determine changes in a physiological state. In embodiments, a first signal and a second signal may be obtained, from which a first plurality of values of a physiological parameter may be determined. At least one of the signals also may be used to generate a scalogram derived at least in part from the signal. A second plurality of values may be determined based at least in part on a feature in the scalogram. The first and second plurality of values may then be associated, and a physiological state may be analyzed using the associated first and second values. In an embodiment, the signals may be PPG signals and the associated first and second values may include a parameter scatter plot that may permit a user to determine changes in a patient's ventilation state over time. | 01-21-2010 |
20100016676 | Systems And Methods For Adaptively Filtering Signals - According to embodiments, systems and method are provided for adaptively filtering signals. A combination of filtering techniques is described in which non-wavelet based filtering techniques are used with wavelet-based filtering techniques to filter an input signal. One or more physiological parameters may then be determined from the filtered output signal. | 01-21-2010 |
20100014725 | Systems And Methods For Filtering A Signal Using A Continuous Wavelet Transform - According to embodiments, systems and methods for reducing noise in a signal are provided. A signal may be transformed using a continuous wavelet transform and a corresponding scalogram may be generated. Regions of noise may be identified from the resulting scalogram. These regions may be masked by, for example, removing, altering, or appropriately tagging the regions. After masking the regions of noise, the scalogram may be converted to a filtered signal using an inverse wavelet transform. Alternatively or additionally, desirable regions of non-noise may instead be identified from the resulting scalogram. These desirable regions may be extracted from the scalogram and an inverse wavelet transform performed on the extracted regions in order to generate a filtered signal. | 01-21-2010 |
20100014723 | SIGNAL PROCESSING SYSTEMS AND METHODS USING MULTIPLE SIGNALS - According to embodiments, techniques for signal processing using multiple signals are disclosed. A first scalogram may be generated from a first signal and a second scalogram may be generated from a second signal. A modified or masked scalogram may then be generated based on the first and second scalograms. The modified scalogram may then be used to determine at least one physiological parameter. In some embodiments, one or both of the first signal and the second signal may be photoplethysmograph (PPG) signals obtained from a pulse oximeter. | 01-21-2010 |
20100013642 | Systems And Methods For Evaluating A Physiological Condition - A method and system are provided for evaluating in patient monitoring whether a signal is sensed optimally by receiving a signal, transforming the signal using a wavelet transform, generating a scalogram based at least in part on the transformed signal, identifying a pulse band in the scalogram, identifying a characteristic of the pulse band, determining, based on the characteristic of the pulse band, whether the signal is sensed optimally; and triggering an event. The characteristics of the pulse band and scalogram may be used to provide an indication of monitoring conditions. | 01-21-2010 |
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 |
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 |
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 |
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 |
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 |
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 |
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 |
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 |
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 |
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 |
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 |
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 |
20090324033 | Signal Processing Systems and Methods for Determining Slope Using an Origin Point - The present disclosure relates to signal processing and, more particularly, relates to determining the slope of a signal. In embodiments, slopes between an origin point of the plot and at least two points in the signal may be determined. The slopes may be used to generate a histogram, and a desired slope of the signal corresponding to a preferred value in the histogram may be selected. 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 from surface signals related to two scalograms. Each scalogram 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 |
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 |
20090076398 | Continuous Non-Invasive Blood Pressure Measurement Apparatus and Methods Providing Automatic Recalibration - A blood pressure measurement system is configured to perform a calibration automatically when a calibration condition is satisfied. The calibration condition is based upon one or more parameters of pulse waves of a subject. The parameters may include pulse wave area; a time difference between systolic peak and reflected wave peak or dichrotic notch in the pulse wave and a shape of at least a portion of the pulse wave. | 03-19-2009 |