Parameter compensated physiological monitor

Abstract

A monitor has an optical input from which a spectral characteristic can be derived. The monitor also has a non-optical input from which a parameter can be determined. A compensation relationship is determined for the spectral characteristic based on the parameter. A physiological measurement is determined based on the spectral characteristic and the compensation relationship.

1 . A physiological monitor comprising: 
 an optical sensor providing a first sensor signal responsive to a plurality of wavelengths of optical radiation after attenuation by pulsatile blood flowing within a tissue site of a patient;    a non-optical sensor providing a second sensor signal corresponding to the patient;    a processor configured to derive a spectral characteristic of the tissue site from the first sensor signal;    calibration data relating the spectral characteristic to a blood gas parameter of the patient; and    a correction applied to the calibration data in response to the second sensor signal.    
     
     
         2 . The physiological monitor according to  claim 1:   wherein the non-optical sensor has a temperature sensing element, and    wherein the second sensor signal is responsive to a tissue site temperature.    
     
     
         3 . The physiological monitor according to  claim 2:   wherein the calibration data defines a Bezier curve having end points and corresponding control points, and    wherein the correction repositions the control points so as to generate a modified calibration curve.    
     
     
         4 . A physiological monitor comprising: 
 a primary input responsive to optical properties of a tissue site of a patient;    a characteristic of the tissue site derived from the primary input;    a calibration curve relating the characteristic to a blood gas parameter for the patient;    a blood gas value derived from the primary input and the calibration curve;    a secondary input responsive to non-optical properties corresponding to the patient; and    a compensation applied to at least one of the calibration curve and the blood gas value in response to the secondary input so as to derive a compensated blood gas value that is more accurate than the blood gas value.    
     
     
         5 . The physiological monitor according to  claim 4  wherein the secondary input provides a measure of the patient's blood pH.  
     
     
         6 . The physiological monitor according to  claim 5  wherein the secondary input is a blood pH value manually entered through a user interface.  
     
     
         7 . The physiological monitor according to  claim 5  wherein the secondary input is an output from a blood pH monitor having a sensor in contact with the patient.  
     
     
         8 . A physiological monitoring method comprising: 
 generating an optical measurement at a tissue site having pulsatile blood flow;    defining calibration data relating the optical measurement to a blood gas parameter corresponding to the pulsatile blood flow;    calculating the optical measurement and the calibration data with a processor so as to generate a blood gas value corresponding to the blood gas parameter;    providing a non-optical measurement corresponding to the tissue site; and    correcting at least one of the calibration data and the blood gas value according to the non-optical measurement.    
     
     
         9 . The physiological monitoring method according to  claim 8:   wherein generating comprises attaching an optical sensor to the tissue site; and    wherein providing comprises integrating a non-optical sensor element into the optical sensor so as to make the non-optical measurement.    
     
     
         10 . The physiological monitoring method according to  claim 9  wherein integrating comprises positioning a thermistor within the optical sensor so as to take a temperature measurement of the tissue site.  
     
     
         11 . The physiological monitoring method according to  claim 8  wherein providing comprises attaching a non-optical sensor to the tissue site.  
     
     
         12 . The physiological monitoring method according to  claim 11  wherein providing further comprises taking a temperature measurement of the tissue site.  
     
     
         13 . The physiological monitoring method according to  claim 8  wherein providing comprises manually inputting into the processor via a user interface a non-optical measurement value corresponding to the tissue site.  
     
     
         14 . The physiological monitoring method according to  claim 13  wherein manually inputting comprises entering a tissue temperature value on a keypad that is in communications with the processor.  
     
     
         15 . A physiological monitoring method comprising: 
 generating a non-invasive measurement at a tissue site of a patient;    defining calibration data relating the non-invasive measurement to a blood gas parameter;    calculating with a processor a blood gas value corresponding to the non-invasive measurement;    providing an invasive measurement of the patient;    compensating the blood gas value according to the invasive measurement.    
     
     
         16 . The physiological monitoring method according to  claim 15  wherein providing comprises measuring a blood pH value for the patient.  
     
     
         17 . The physiological monitoring method according to  claim 16  wherein measuring comprises manually entering the blood pH value via a user interface into the processor.  
     
     
         18 . The physiological monitoring method according to  claim 16  wherein measuring comprises outputting the blood pH value from a pH monitor via an instrument interface to the processor.  
     
     
         19 . A physiological monitor comprising: 
 an optical sensor means for providing a tissue site spectral characteristic for a patient;    a non-optical input means for providing a compensation parameter for the patient;    a calibration means for relating the spectral characteristic to an uncompensated blood gas parameter; and    a correction means responsive to the compensation parameter for generating a compensated blood gas parameter.    
     
     
         20 . The physiological monitor according to  claim 19  further comprising a processor for applying the correction means to the calibration means.  
     
     
         21 . The physiological monitor according to  claim 19  further comprising a processor for applying the correction means to the uncompensated blood gas parameter.  
     
     
         22 . The physiological monitor according to  claim 19  further comprising a user interface means for manually entering a value for the compensation parameter into the processor.  
     
     
         23 . The physiological monitor according to  claim 19  further comprising an instrument interface means for entering the compensation parameter from an external monitor into the processor.  
     
     
         24 . The physiological monitor according to  claim 19:   wherein the calibration means comprises a Bezier curve; and    wherein the correction means comprises a control means for altering the shape of the Bezier curve.