Abstract: An apnea analysis system may include a photoplethysmographic (PPG) sub-system, a breath detection sub-system, and an apnea analysis module. An apnea analysis system includes a photoplethysmographic (PPG) sub-system, a breath detection sub-system, and an apnea analysis module. The PPG sub-system is configured to be operatively connected to an individual and output a PPG signal from the individual. The breath detection sub-system is configured to be operatively connected to the individual and output a breath signal from the individual. The apnea analysis module is in communication with the PPG sub-system and the breath detection sub-system. The apnea analysis module analyzes the breath signal and a respiratory component of the PPG signal and, based on the analysis, identifies a presence of apnea, differentiates between obstructive apnea and central apnea, and provides an indication of the identified apnea.

Abstract: The present invention relates to physiological signal processing, and in particular to methods and systems for processing physiological signals to predict a fluid responsiveness of a patient. A medical monitor for monitoring a patient includes an input receiving a photoplethysmograph (PPG) signal representing light absorption by a patient's tissue. The monitor also includes a perfusion status indicator indicating a perfusion status of the PPG signal, and a fluid responsiveness predictor (FRP) calculator programmed to calculate an FRP value based on a respiratory variation of the PPG signal. The FRP calculator applies a correction factor based on the perfusion status indicator.

Abstract: A patient monitor for monitoring cerebral activity of a patient may include a processor configured to determine a depth of consciousness index for the patient based on electroencephalography (EEG) data and determine regional oxygen saturation for the patient based on regional oximetry data. Additionally, the processor may be configured to determine a metric associated with cerebral activity of the patient based at least in part on the one or more values of the depth of consciousness index and the one or more regional oxygen saturation values and to provide the one or more values of a depth of consciousness index and the metric to an output device.

Abstract: 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.

Abstract: 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.

Abstract: A method for monitoring autoregulation includes, using a processor, using a processor to execute one or more routines on a memory. The one or more routines include receiving one or more physiological signals from a patient, determining a correlation-based measure indicative of the patient's autoregulation based on the one or more physiological signals, and generating an autoregulation profile of the patient based on autoregulation index values of the correlation-based measure. The autoregulation profile includes the autoregulation index values sorted into bins corresponding to different blood pressure ranges. The one or more routines also include designating a blood pressure range encompassing one or more of the bins as a blood pressure safe zone indicative of intact regulation and providing a signal to a display to display the autoregulation profile and a first indicator of the blood pressure safe zone.

Abstract: A system configured to monitor autoregulation includes a medical sensor configured to be applied to a patient and to generate a regional oxygen saturation signal. The system includes a controller having a processor configured to receive the regional oxygen saturation signal and a blood pressure signal and to determine a cerebral oximetry index (COx) based on the blood pressure signal and the regional oxygen saturation signal. The processor is also configured to apply a data clustering algorithm to cluster COx data points over a range of blood pressures, identify a first cluster of COx data points that corresponds to an intact autoregulation zone for the patient, and provide a first output indicative of the intact autoregulation zone for the patient.

Abstract: During patient monitoring, a depth of consciousness (DOC) measure, such as a bispectral index, may be used in conjunction with additional information obtained from an awareness metric derived from one or more physiological signals, such as a photoplethysmograph signal. In an embodiment, a DOC measure may be combined with information from an awareness metric to produce a combined DOC measure. In an embodiment, information from an awareness metric derived from one or more physiological signals may be used to provide an indication of confidence in a DOC measure. In an embodiment, a DOC measure may be used to provide an indication of confidence in a depth of consciousness assessment based on an awareness metric. In an embodiment, one or the other of a DOC measure and an awareness metric may be used to provide an indication of a patient's depth of consciousness (e.g., by one “overriding” the other).

Abstract: A method for monitoring autoregulation includes, using a processor, receiving a blood pressure signal an oxygen saturation signal, and a regional oxygen saturation signal from a patient. The method also includes normalizing the regional oxygen saturation signal to correct for variation in the oxygen saturation signal based on a relationship between the oxygen saturation signal and the regional oxygen saturation signal. The method further includes determining a linear correlation between the blood pressure signal and the normalized regional oxygen saturation signal. The method still further includes providing a signal indicative of the patient's autoregulation status to an output device based on the linear correlation.

Abstract: A system may include a photoplethysmograph (PPG) sensor configured to be secured to a patient and to generate a PPG signal for the patient. The system may also include a motion sensor configured to generate a motion signal indicative of motion of the patient. Further, the system may include a controller configured to receive the PPG signal from the PPG sensor and the motion signal from the motion sensor, to analyze the motion signal to detect motion of the patient, and to deactivate the at least one emitter of the PPG sensor based on the analysis of the motion signal when motion of the patient is detected.

Abstract: A method for reducing alarm fatigue, specifically, combining multiple physiological parameters, such as heart rate and respiratory rate, into one index number indicative of the patient's condition. The method includes detecting the severity of the patient's condition, generating, and displaying a scaled version of that index number relative to the severity of the patient's condition. The scaled index number is displayed on a patient monitor device. The scaled index number may have a size and color value.

Abstract: A method for determining an efficacy of cardiopulmonary resuscitation (CPR) includes receiving a plethysmography signal from an oximetry sensor and an electrocardiogram (ECG) signal from an ECG sensor at a processor associated with a patient monitor, the oximetry sensor, or the ECG sensor. The method includes determining a first indicator related to the efficacy of CPR based on the plethysmography signal, using the processor. The method also includes determining a second indicator related to the efficacy of CPR based on the ECG signal, using the processor. The method further includes combining the first indicator and the second indicator to determine a combination metric indicative of the efficacy of CPR, using the processor.

Abstract: A method for monitoring autoregulation includes receiving a blood pressure signal and an oxygen saturation signal, determining a phase difference between the blood pressure signal and the oxygen saturation signal, and determining a patient's autoregulation status based at least in part on a phase difference between the blood pressure signal and the oxygen saturation signal.

Abstract: A method for monitoring autoregulation includes using a processor for receiving blood pressure data and oxygen saturation data from a patient, fitting a dynamic model to the blood pressure data and the oxygen saturation data to determine one or more parameters of the dynamic model indicative of autoregulation, and determining the patient's autoregulation status based on the one or more parameters.

Abstract: A method for monitoring autoregulation includes, using a processor, receiving a blood pressure signal, a regional oxygen saturation signal, and a blood volume signal from a patient. The method also includes determining a first linear correlation between the blood pressure signal and the regional oxygen saturation signal and determining a second linear correlation between the blood pressure signal and the blood volume signal. The method also includes determining a confidence level associated with the first linear correlation based at least in part on the second linear correlation and providing a signal indicative of the patient's autoregulation status to an output device based on the linear correlation and the confidence level.

Abstract: Methods and systems are provided for determining fluid responsiveness in the presence of noise. The system may determine an instantaneous value indicative of fluid responsiveness. In some embodiments, the system may determine a difference between an instantaneous value indicative of fluid responsiveness and a previous value indicative of fluid responsiveness, and select an update characteristic based on whether the difference indicates that the fluid responsiveness is increasing or decreasing. In some embodiments, the system may determine a parameter indicative of fluid responsiveness based on the update characteristic and a previously reported value indicative of fluid responsiveness.

Abstract: 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.

Abstract: 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.

Abstract: Methods and systems are provided for determining fluid administration. The system may determine fluid administration based on the fluid responsiveness and regional oxygen saturation of a subject. The system may receive the fluid responsiveness and regional oxygen saturation from external sources or may determine one or both based on received physiological signals. In some embodiments, the system may determine whether to administer fluid based on the fluid responsiveness and regional oxygen saturation. In some embodiments, the system may determine the amount of fluid to administer based on the fluid responsiveness and regional oxygen saturation. In some embodiments, the system may determine the effectiveness of fluid administration. In some embodiments, the system may provide an indication of the determined fluid administration so that a care-giver can implement the appropriate fluid administration. In some embodiments, the system may control the fluid administration based on its determination.

Abstract: Systems, methods, sensors, and software for providing enhanced measurement and detection of patient pain response are provided herein. In a first example, a measurement system is provided that includes a capacitive system configured to measure a capacitance signal of tissue of the patient using a capacitive sensor proximate to the tissue of the patient. The measurement system also includes a patient monitor configured to measure an electrical signal representing brain activity of the patient. The measurement system also includes a processing system configured to determine pain metrics based at least on the capacitance signal and the electrical signal, and determine a pain response of the patient based at least on the pain metrics and pain calibration information for the patient.