Variable indication estimator

Abstract

A variable indication estimator which determines an output value representative of a set of input data. For example, the estimator can reduce input data to estimates of a desired signal, select a time, and determine an output value from the estimates and the time. In one embodiment, the time is selected using one or more adjustable signal confidence parameters determine where along the estimates the output value will be computed. By varying the parameters, the characteristics of the output value are variable. For example, when input signal confidence is low, the parameters are adjusted so that the output value is a smoothed representation of the input signal. When input signal confidence is high, the parameters are adjusted so that the output value has a faster and more accurate response to the input signal.

1 - 20 . (canceled) 
     
     
         21 . An apparatus for selecting output parameter values, the apparatus comprising:
 a processor configured to:
 receive an input physiological signal from a sensor coupled with a living being; 
 calculate parameter values from the input physiological signal; 
 select between a first parameter value from a trend of the parameter values and a second parameter value representing a constant average value of the parameter values within a time window, the trend having a non-zero slope in the time window; and 
 output the selected parameter value. 
   
     
     
         22 . The apparatus of  claim 21 , wherein the processor is further configured to select the first parameter value from the trend of the parameter values at a most recent time in the time window. 
     
     
         23 . The apparatus of  claim 21 , wherein the processor is further configured to select the first parameter value from the trend of the parameter values at a time in the time window other than a most recent time. 
     
     
         24 . The apparatus of  claim 21 , wherein the processor is further configured to select the first parameter value in the time window and the second parameter value in a second time window. 
     
     
         25 . The apparatus of  claim 21 , wherein the processor is further configured to calculate a signal confidence using the input physiological signal. 
     
     
         26 . The apparatus of  claim 25 , wherein the processor is further configured to make said selection using the signal confidence. 
     
     
         27 . The apparatus of  claim 26 , wherein the processor is further configured to select the first parameter value when the signal confidence is high and the second parameter value when the signal confidence is low. 
     
     
         28 . The apparatus of  claim 21 , wherein the parameter values comprise oxygen saturation values. 
     
     
         29 . The apparatus of  claim 21 , wherein the parameter values comprises blood pressure values.