System and method of determining whether to recalibrate a blood pressure monitor

Abstract

A monitor for determining a patient's physiological parameter includes a calibration device that provides a calibration signal indicative of an accurate measurement of the patient's physiological parameter. The monitor also includes a processor, which receives a noninvasive signal from a noninvasive sensor positioned over a blood vessel. The processor uses the calibration signal to calibrate a relationship between the noninvasive signal and a property of the physiological parameter. The processor also determines when to recalibrate the relationship.

1 - 23 . (canceled)  
   
   
       24 . A system for monitoring a physiological parameter, comprising: 
 an inflatable blood pressure cuff configured to provide blood pressure calibration data for a patient;    an exciter configured to induce a transmitted exciter waveform into the patient;    a photoplethysmograph configured to sense a first hemoparameter comprising blood oxygenation;    a noninvasive sensor configured to sense data related to a second hemoparameter; and    a processor configured to compute a physiological parameter using said calibraton data and said data related to said second hemoparameter, said processor configured to activate said inflatable blood pressure cuff and obtain said blood pressure calibration data when a value of said first hemoparameter indicates that recalibration is needed to obtain a desired level of accuracy.    
   
   
       25 . The system of  claim 24 , wherein said physiological parameter comprises blood pressure.  
   
   
       26 . The system of  claim 24 , wherein said exciter induces a wave propagating along an artery of the patient.  
   
   
       27 . The system of  claim 24 , wherein method of claim  1 , said second non-invasive sensor is located at a first position on an extremity of said patient and said exciter is located at a second position on said extremity.  
   
   
       28 . The system of  claim 24 , wherein recalibration is performed when said first hemoparameter exceeds a threshold value.  
   
   
       29 . The system of  claim 24 , wherein said processor is further configured to activate said blood pressure cuff to obtain said calibration data at specified intervals.  
   
   
       30 . A system for monitoring a physiological parameter, comprising: 
 an inflatable blood pressure cuff configured to provide blood pressure calibration data for a patient;    an exciter configured to induce a transmitted exciter waveform into the patient;    one or more sensors configured to produce sensor data related to one or more hemoparameters; and    a processor configured to compute blood oxygenation from said sensor data, said processor further configured to compute a physiological parameter using said calibration data and said sensor data, said processor configured to activate said inflatable blood pressure cuff and obtain said blood pressure calibration data when a value of said blood oxygenation indicates that recalibration is needed to improve computation of said physiological parameter.    
   
   
       31 . The system of  claim 30 , wherein said physiological parameter comprises blood pressure.  
   
   
       32 . The system of  claim 30 , wherein recalibration is performed when said first hemoparameter exceeds a threshold value.  
   
   
       33 . The system of  claim 30 , wherein said processor is further configured to activate said blood pressure cuff to obtain said calibration data at specified intervals.  
   
   
       34 . The system of  claim 30 , wherein said processor is further configured to activate said blood pressure cuff to obtain said calibration data during system initialization.  
   
   
       35 . A system for monitoring a physiological parameter, comprising: 
 an inflatable blood pressure cuff configured to provide blood pressure calibration data;    an exciter configured to induce a transmitted exciter waveform into the patient;    a first noninvasive sensor configured to sense a first hemoparameter comprising blood oxygenation;    a second noninvasive sensor configured to sense data related to a second hemoparameter; and    a processor configured to compute a physiological parameter using said calibration data and said data related to a second hemoparameter, said processor configured to activate said inflatable blood pressure cuff and obtain said blood pressure calibration data when a specified change occurs in said first hemoparameter.