Low power monitoring systems and methods

Abstract

The present disclosure relates to systems and methods for collecting patient data via a monitoring system, with reduced power consumption. In one embodiment, the monitoring system is configured to emit pulses of light, and detect the light after passing through patient tissue. The light data is emitted sporadically, and a waveform is reconstructed from the sporadically sampled light data. Physiological parameters from the patient may be calculated from the reconstructed waveform. The sporadic sampling may reduce the power consumption by the monitoring system.

1 .- 20 . (canceled) 
     
     
         21 . A system, comprising:
 light drive circuitry configured to drive an emitter of a sensor at an average frequency and an average pulse width to cause the emitter to emit light into a tissue of the patient at the average frequency and the average pulse width;   a processor configured to:
 receive a set of data samples generated by a detector of the sensor based on the light that passed through the tissue of the patient, wherein the set of data samples are indicative of a physiological signal of the patient, and the average frequency and the average pulse width cause the set of data samples to comprise an average sampling frequency less than twice the Nyquist frequency of the physiological signal; and 
 calculate a physiological parameter based on the set of data samples. 
   
     
     
         22 . The system of  claim 21 , wherein the processor is configured to construct a waveform representative of the physiological signal based on the set of data samples, and the physiological parameter is calculated based on the waveform. 
     
     
         23 . The system of  claim 22 , wherein the processor is configured to construct the waveform by matching pursuit. 
     
     
         24 . The system of  claim 21 , comprising a display, wherein the processor is configured to instruct the display to display the physiological parameter. 
     
     
         25 . The system of  claim 21 , wherein the physiological parameter comprises a pulse rate. 
     
     
         26 . The system of  claim 21 , wherein the physiological parameter comprises blood oxygenation. 
     
     
         27 . The system of  claim 21 , wherein the light drive circuitry is configured to drive the emitter at irregular intervals to cause the emitter to emit light into the tissue of the patient at irregular intervals comprising the average frequency and the average pulse width. 
     
     
         28 . The system of  claim 21 , wherein the processor is configured to calibrate the average sampling frequency. 
     
     
         29 . A system, comprising:
 a processor configured to calibrate the system by:
 receiving a first set of data samples generated by a detector of a sensor based on light that passed through a tissue of a patient over a period of time, wherein the first set of data samples is indicative of a physiological signal of the patient and comprises a first average sampling frequency; 
 generating a first waveform based on the first set of data samples; 
 sampling the first waveform at a second average sampling frequency less than the first average sampling frequency to obtain calibration data samples; 
 constructing a calibration waveform based on the calibration data samples; and 
 providing a light drive signal to drive an emitter of the sensor based on an error between the calibration waveform and the first waveform. 
   
     
     
         30 . The system of  claim 29 , wherein the processor is configured to provide the light drive signal to drive the emitter at an average frequency that enables the detector to generate a second set of data samples comprising the second average sampling frequency based on light that passed through the tissue of the patient, if the error is less than an upper predetermined threshold. 
     
     
         31 . The system of  claim 30 , wherein the processor is configured to provide the light drive signal to drive the emitter at the average frequency if the error is greater than a lower predetermined threshold. 
     
     
         32 . The system of  claim 29 , wherein the first average sampling frequency is at least twice the Nyquist frequency of the physiological signal. 
     
     
         33 . The system of  claim 29 , wherein the second average sampling frequency is less than twice the Nyquist frequency of the physiological signal. 
     
     
         34 . The system of  claim 29 , wherein the processor is configured to determine the error between the calibration waveform and the first waveform by comparing a calibration physiological parameter based on the calibration waveform and a first physiological parameter based on the first waveform to one another. 
     
     
         35 . The system of  claim 29 , wherein the processor is configured to calibrate the system by iteratively sampling the first waveform at respective second average sampling frequencies less than the first average sampling frequency to obtain respective calibration data samples, constructing respective calibration waveforms based on the respective calibration data samples, calculating respective errors between the respective calibration waveforms and the first waveform, selecting the respective second average sample frequency that causes the error to be less than a predetermined threshold, and driving the emitter at a respective average frequency that corresponds to the selected respective second average sampling frequency. 
     
     
         36 . The system of  claim 29 , wherein the processor is configured to sample the first waveform at irregular intervals, thereby causing the calibration data samples to include data samples spread at irregular intervals over the period of time. 
     
     
         37 . The system of  claim 29 , wherein the processor is configured to calibrate the system periodically during a monitoring session. 
     
     
         38 . The system of  claim 29 , wherein the processor is configured to calibrate the system in response to a signal quality indication. 
     
     
         39 . The system of  claim 29 , wherein the physiological parameter comprises a pulse rate. 
     
     
         40 . A method for calibrating a system, comprising:
 receiving, at a processor, a first set of data samples generated by a detector of a sensor based on light that passed through a tissue of a patient over a first period of time, wherein the first set of data samples is indicative of a physiological signal of the patient and comprises a first average sampling frequency;   generating, using the processor, a first waveform based on the first set of data samples;   sampling, using the processor, the first waveform at a second average sampling frequency less than the first average sampling frequency to obtain calibration data samples;   constructing, using the processor, a calibration waveform based on the calibration data samples;   providing, using the processor, a light drive signal to drive an emitter of the sensor over a second period of time at an average frequency and an average pulse width that correspond to the second average sampling frequency if an error between the calibration waveform and the first waveform is less than a predetermined threshold.