Abstract: A physiological monitoring system may determine physiological information, such as physiological rate information, from a physiological signal. The system may receive a calculated value indicative of a period associated with a physiological rate. The system may generated a first sorted difference signal based on a segment of the physiological signal having a size corresponding to the period. The system may generate second and third sorted difference signals based on segments of the physiological signal having sizes corresponding to a fraction of the period and a multiple of the period. The system may analyze the first, second, and third sorted difference signals, and qualify or disqualify the calculated value based on the analysis.

Abstract: A physiological monitoring system may process a physiological signal such a photoplethysmograph signal from a subject. The system may determine physiological information, such as a physiological rate, from the physiological signal. The system may use search techniques and qualification techniques to determine one or more initialization parameters. The initialization parameters may be used to calculate and qualify a physiological rate. The system may use signal conditioning to reduce noise in the physiological signal and to improve the determination of physiological information. The system may use qualification techniques to confirm determined physiological parameters. The system may also use autocorrelation techniques, cross-correlation techniques, fast start techniques, and/or reference waveforms when processing the physiological signal.

Abstract: A physiological monitoring system may process a physiological signal such a photoplethysmograph signal from a subject. The system may determine physiological information, such as a physiological rate, from the physiological signal. The system may use search techniques and qualification techniques to determine one or more initialization parameters. The initialization parameters may be used to calculate and qualify a physiological rate. The system may use signal conditioning to reduce noise in the physiological signal and to improve the determination of physiological information. The system may use qualification techniques to confirm determined physiological parameters. The system may also use autocorrelation techniques, cross-correlation techniques, fast start techniques, and/or reference waveforms when processing the physiological signal.

Abstract: A physiological monitoring system may determine physiological information, such as physiological rate information, from a physiological signal. The system may condition the physiological signal to assist in the determination of the physiological information. The system may generate a difference signal based on the physiological signal and sort the difference signal. The system may identify values in the sorted difference signal that exceed a threshold, and modify the physiological signal based on the identified values. The modification may include reducing, or otherwise limiting, some differences between adjacent values in the physiological signal.

Abstract: A physiological monitoring system may process a physiological signal such a photoplethysmograph signal from a subject. The system may determine physiological information, such as a physiological rate, from the physiological signal. The system may use search techniques and qualification techniques to determine one or more initialization parameters. The initialization parameters may be used to calculate and qualify a physiological rate. The system may use signal conditioning to reduce noise in the physiological signal and to improve the determination of physiological information. The system may use qualification techniques to confirm determined physiological parameters. The system may also use autocorrelation techniques, cross-correlation techniques, fast start techniques, and/or reference waveforms when processing the physiological signal.

Abstract: A sensor fixture is provided for operatively attaching a photoacoustic (PA) sensor to a patient. The sensor fixture includes an acoustic coupling agent that is configured to allow the transmission of both acoustic energy and light therethrough. The sensor fixture includes a bracket configured to be affixed to skin of the patient. The bracket includes a cavity, a patient side, and a sensor side. The acoustic coupling agent is held within the cavity. The patient side includes a patient opening that is configured to expose the acoustic coupling agent along the patient side. The sensor side includes a sensor opening that is configured to expose the acoustic coupling agent along the sensor side. The sensor side includes a sensor cradle that is configured to hold the PA sensor such that the PA sensor is operatively attached to the acoustic coupling agent for receiving an acoustic response from the patient.

Abstract: A physiological monitoring system may determine physiological information, such as physiological rate information, from a physiological signal. The system may generate a window of data, and determine physiological information based on the window of data. The generated window of data may include one or more samples of physiological data, from the physiological signal, and one or more initialization values. The initialization values may include random numbers, noise values, sample values, scaled values thereof, or a combination thereof.

Abstract: A physiological monitoring system may determine physiological information, such as physiological rate information, from a physiological signal. The system may generate a window of physiological data, and determine the physiological information based on the window of data. The system may use status indicators to determine when the window of data is to be updated with new data. The status indicator may include, for example, a gain change indicator, indicating a change in gain in an amplifier. Based on the status indicator, the system may, for example, set a period of time during which current physiological data is not added to the window of data. The system may smooth the transition of the physiological data before and after the period of time.

Abstract: A physiological monitoring system may process a physiological signal such a photoplethysmograph signal from a subject. The system may determine physiological information, such as a physiological rate, from the physiological signal. The system may use search techniques and qualification techniques to determine one or more initialization parameters. The initialization parameters may be used to calculate and qualify a physiological rate. The system may use signal conditioning to reduce noise in the physiological signal and to improve the determination of physiological information. The system may use qualification techniques to confirm determined physiological parameters. The system may also use autocorrelation techniques, cross-correlation techniques, fast start techniques, and/or reference waveforms when processing the physiological signal.

Abstract: A physiological monitoring system may process a physiological signal such a photoplethysmograph signal from a subject. The system may determine physiological information, such as a physiological rate, from the physiological signal. The system may use search techniques and qualification techniques to determine one or more initialization parameters. The initialization parameters may be used to calculate and qualify a physiological rate. The system may use signal conditioning to reduce noise in the physiological signal and to improve the determination of physiological information. The system may use qualification techniques to confirm determined physiological parameters. The system may also use autocorrelation techniques, cross-correlation techniques, fast start techniques, and/or reference waveforms when processing the physiological signal.

Abstract: A physiological monitoring system may determine physiological information, such as physiological rate information, from a physiological signal. The system may condition the physiological signal to assist in the determination of the physiological information. The system may generate absolute values of the physiological signal, filter the absolute values, and modify the physiological signal based on the filtered signal. The filtered signal may be shifted in amplitude prior to modifying the physiological signal. The modification may include dividing the physiological signal by the filtered signal to normalize the physiological signal.

Abstract: A physiological monitoring system may determine physiological information, such as physiological rate information, from a physiological signal. The system may apply a digital filter to the physiological signal to assist in the determination of the physiological information. The system may determine a metric based on the physiological signal, and selectively apply the digital filter to the physiological signal based on the metric. The digital filter, which may include two or more filter coefficients, may correspond to a weighted sum of the physiological signal and a difference signal corresponding to the physiological signal. The filter coefficients may be adjustable, allowing selectivity in the characteristics of the digital filter between weighting the physiological signal and difference signal.

Abstract: A physiological monitoring system may process a physiological signal such a photoplethysmograph signal from a subject. The system may determine physiological information, such as a physiological rate, from the physiological signal. The system may use search techniques and qualification techniques to determine one or more initialization parameters. The initialization parameters may be used to calculate and qualify a physiological rate. The system may use signal conditioning to reduce noise in the physiological signal and to improve the determination of physiological information. The system may use qualification techniques to confirm determined physiological parameters. The system may also use autocorrelation techniques, cross-correlation techniques, fast start techniques, and/or reference waveforms when processing the physiological signal.

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.

Abstract: A physiological monitoring system may process a physiological signal such a photoplethysmograph signal from a subject. The system may determine physiological information, such as a physiological rate, from the physiological signal. The system may use search techniques and qualification techniques to determine one or more initialization parameters. The initialization parameters may be used to calculate and qualify a physiological rate. The system may use signal conditioning to reduce noise in the physiological signal and to improve the determination of physiological information. The system may use qualification techniques to confirm determined physiological parameters. The system may also use autocorrelation techniques, cross-correlation techniques, fast start techniques, and/or reference waveforms when processing the physiological signal.

Abstract: A physiological monitoring system may process a physiological signal such a photoplethysmograph signal from a subject. The system may determine physiological information, such as a physiological rate, from the physiological signal. The system may use search techniques and qualification techniques to determine one or more initialization parameters. The initialization parameters may be used to calculate and qualify a physiological rate. The system may use signal conditioning to reduce noise in the physiological signal and to improve the determination of physiological information. The system may use qualification techniques to confirm determined physiological parameters. The system may also use autocorrelation techniques, cross-correlation techniques, fast start techniques, and/or reference waveforms when processing the physiological signal.

Abstract: A system includes a controller that receives a blood pressure signal and an oxygen saturation signal. The blood pressure signal represents a non-invasive measure of blood pressure. The oxygen saturation signal represents a non-invasive measure of oxygen saturation. The controller generates an autoregulation status signal representing a status of cerebral autoregulation. The autoregulation status signal is based, at least in part, on a relationship between the measured blood pressure and the measured oxygen saturation. An exemplary method may include receiving the blood pressure signal and the oxygen saturation signal, defining a relationship between the measured blood pressure and the measured oxygen saturation, determining an autoregulation status based at least in part on the defined relationship, and generating an autoregulation status signal representing the determined autoregulation status.

Abstract: A physiological monitoring system may determine physiological information, such as physiological rate information, from a physiological signal. The system may generate a correlation sequence using two segments of the physiological signal. The system may determine a first correlation lag value that corresponds to a peak in the correlation sequence, and also determine a second correlation lag value equal to a fraction of the first correlation lag value. The fraction may be, for example, one half. The system may qualify or disqualify the correlation lag value based on the correlation value at the second lag value. The system may compare the correlation value at the second lag value to a threshold, to the correlation sequence at the first lag value, or both.

Abstract: A physiological monitoring system may determine physiological information, such as physiological rate information, and other information, such as noise information, from a physiological signal. The system may generate a difference signal based on the physiological signal and sort the difference signal to generate a sorted difference signal. The system may identify one or more data points of the sorted difference signal as being associated with noise. For example, one or more end data points may be identified as being associated with noise based on a threshold. The system may determine a value indicative of noise based on the identified data points.

Abstract: A physiological monitoring system may determine physiological information, such as physiological rate information, from a physiological signal. The system may determine a skew metric based on the physiological signal. The system may also determine a correlation lag value corresponding to a peak in a correlation sequence derived from the physiological signal. The system may qualify or disqualify the correlation lag value based on the skew metric. The system may, for example, compare the skew metric and the correlation lag value to a reference set of skew metric values and correlation lag values to determine whether to qualify or disqualify the correlation lag value.