Abstract: Certain embodiments of the present disclosure provide a system and method for determining a repetitive airflow reduction of an individual. The system may include a photoplethysmogram (PPG) detection module configured to detect a PPG signal of a patient. The PPG signal may include a pulsatile AC component superimposed on a DC baseline. The system may also include a PPG baseline analysis module configured to analyze the DC baseline of the PPG signal to detect one or more threshold crossings with respect to an acceptable threshold correlated to normal breathing. The system may also include a repetitive airflow reduction determination module configured to determine an occurrence of the repetitive airflow reduction through an analysis of the one or more threshold crossings.

Abstract: A sound signal from a patient may include information that may be used to determine multiple patient parameters. A patient monitor may determine respiration information such as respiration rate from the sound signal, for example based on modulations of the sound signal due to patient breathing. The patient monitor may also determine indications of patient distress based on a trained classifier, speech commands, or sound patterns.

Abstract: A patient monitoring system may receive a physiological signal such as a photoplethysmograph (PPG) signal. A plurality of respiration morphology signals may be determined from the PPG signal. Independent component analysis may be performed on the respiration morphology signals, resulting in a plurality of independent components. An independent component corresponding to a respiration source signal may be selected from the plurality of independent components. Respiration information such as respiration rate may be determined based at least in part on the selected independent component.

Abstract: A physiological monitoring system may use one or more characteristics of an ambient signal to determine a probe-off condition. A physiological sensor may be used to emit one or more wavelengths of light. A light signal may be received that includes an ambient light component and one or more components corresponding to the emitted light. One or more characteristics (e.g., baseline characteristics) of the ambient light component may be determined and compared to one or more thresholds. The system may determine whether the physiological sensor is properly positioned based on the comparison.

Abstract: 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.

Abstract: A physiological monitoring system may determine a probe-off condition. A physiological sensor may receive a light signal including one or more wavelengths of light. The received light signal may be processed to obtain a light signal corresponding to an ambient light signal and a light signal corresponding to an emitted light signal and the ambient light signal. The signals may be analyzed to identify an inverse effect. The system may determine whether the physiological sensor is properly positioned based on the identification of an inverse effect.

Abstract: A test unit may generate a pulse signal based on a pulsatile profile and a frequency modulation component of a respiratory profile. A respiration modulated signal may be generated from the pulse signal, an amplitude modulation component, and a baseline modulation component. A patient modulated signal may be generated based on the respiration modulated signal and a patient profile. The artificial PPG signal may be generated based on the patient modulated signal and an artifact profile. The artificial PPG signal may be output to an electronic device.

Abstract: Certain embodiments of the present disclosure provide a system and method for analyzing a physiological signal detected from an individual. The system may include a physiological signal detection module configured to detect the physiological signal of the individual, a wavelet formation module configured to form a wavelet based on the physiological signal, and a wavelet transform module configured to generate a scalogram by transforming the physiological signal with the wavelet based on the physiological signal.

Abstract: A system for determining respiratory effort of an individual may include a pressure signal determination module configured to determine a physiological pressure signal of the individual, a wavelet transform module configured to transform the physiological pressure signal into a scalogram using at least one wavelet transform, and a respiratory effort determination module configured to determine the respiratory effort of the individual through an analysis of scalogram.

Abstract: 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.

Abstract: A physiological monitoring system may use photonic signals at one or more wavelengths to determine physiological parameters. The system may monitor a photoplethysmograph (PPG) signal, which may include a periodic component, and an aperiodic component. An attractor may be generated based on a first segment of the PPG signal and a second segment of the PPG signal shifted in time relative to the first segment by a time delay. The system may analyze points of the attractor that correspond to a curve, analyze the distribution of the attractor about a curve, or both, to determine a signal quality metric indicative of cycle to cycle variation in the PPG signal.

Abstract: A physiological monitoring system may use photonic signals at one or more wavelengths to determine physiological parameters. The system may receive a photoplethysmograph signal, and generated a difference signal based on the photoplethysmograph signal. The system may specify a segment of the photoplethysmograph signal and a segment of the difference signal. The system may associate each value of the segment of the photoplethysmograph signal to a corresponding value of the segment of the difference signal to generate associated value pairs. The system may compare the associated value pairs to a reference characteristic, and determine a signal quality metric based on the comparison.

Abstract: A physiological monitoring system may determine a probe-off condition. A physiological sensor may be used to emit one or more wavelengths of light. A received light signal may be processed to obtain a light signal corresponding to the emitted light and an ambient signal. The signals may be analyzed to identify similar behavior. The system may determine whether the physiological sensor is properly positioned based on the analysis.

Abstract: A physiological monitoring system may use photonic signals at one or more wavelengths to determine physiological parameters. During monitoring, a physiological sensor may become improperly positioned, which may affect the physiological attenuation of the photonic signals, and accordingly a detected light signal. The detected light signal may include an ambient light component and a signal component corresponding to the one or more wavelengths of light. One or both components may exhibit an interference signal component caused by environmental light. The physiological monitoring system may analyze the interference signal components to determine a sensor-off condition.

Abstract: A physiological monitoring system may use photonic signals at one or more wavelengths to determine physiological parameters. During monitoring, a physiological sensor may become improperly positioned, which may affect the physiological attenuation of the photonic signals, and accordingly a detected light signal. The detected light signal may include an ambient light component and a signal component corresponding to the one or more wavelengths of light. The physiological monitoring system may determine a reference characteristic based on the ambient light component, and compare the signal component with the ambient light component to determine a sensor-off condition.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A sensor system is provided for determining a pulse transit time measurement of a patient. The sensor system includes a carotid sensor device configured to be positioned on a neck of the patient over a carotid artery of the patient. The carotid sensor device is configured to detect a plethysmograph waveform from the carotid artery. The sensor system includes a temporal sensor device that is operatively connected to the carotid sensor device. The temporal sensor device is configured to be positioned on the patient over a temporal artery of the patient. The temporal sensor device is configured to detect a plethysmograph waveform from the temporal artery.

Abstract: A PPG system for determining a stroke volume of a patient includes a PPG sensor configured to be secured to an anatomical portion of the patient. The PPG sensor is configured to sense a physiological characteristic of the patient. The PPG system may include a monitor operatively connected to the PPG sensor. The monitor receives a PPG signal from the PPG sensor. The monitor includes a pulse trending module determining a slope transit time of an upslope of a primary peak of the PPG signal. The pulse trending module determines a stroke volume of the patient as a function of the slope transit time.