Physiological trend monitor

Abstract

A physiological trend monitor has a sensor signal responsive to multiple wavelengths of light transmitted into a tissue site. The transmitted light is detected after attenuation by pulsatile blood flow within the tissue site. A processor has an input responsive to the sensor signal and a physiological parameter output. Features are extracted from the physiological parameter output. Criteria are applied to the features. An alarm output is generated when the criteria are satisfied.

What is claimed is: 
     
       1. A system for non-invasively monitoring physiological trends, the system comprising:
 a processor comprising a sensor signal input and a display driver, wherein the processor is configured to:
 receive, at the sensor signal input, a sensor signal from an optical sensor coupled with a patient, the sensor signal responsive to light attenuated by body tissue of the patient; 
 calculate a physiological parameter and a physiological parameter trend based on the sensor signal; 
 output, by the display driver, a value of the physiological parameter for presentation on a display; and 
 output an audible alarm once the physiological parameter reaches a threshold if the physiological parameter trend is not trending upward. 
 
 
     
     
       2. The system of  claim 1 , wherein the processor is further configured to suppress the audible alarm once the smoothed physiological parameter rises above the threshold, even if the physiological parameter trend is flat or trending downward. 
     
     
       3. The system of  claim 1 , wherein the processor is further configured to suppress the audible alarm once the physiological parameter trend begins to trend upward, even if the physiological parameter is under the threshold. 
     
     
       4. The system of  claim 1 , wherein the processor is further configured to calculate the physiological parameter by smoothing physiological parameter values. 
     
     
       5. The system of  claim 1 , wherein the processor is further configured to calculate the physiological parameter by integrating physiological parameter values. 
     
     
       6. The system of  claim 1 , wherein the processor is further configured to calculate the physiological parameter trend using a curve-fitting technique. 
     
     
       7. The system of  claim 1 , wherein the processor is further configured to output the audible alarm responsive to the physiological parameter trend being negative. 
     
     
       8. The system of  claim 1 , wherein the processor is further configured to output the audible alarm responsive to the physiological parameter trend being zero. 
     
     
       9. The system of  claim 1 , wherein the physiological parameter is selected from the group consisting of oxygen saturation, blood glucose, total hemoglobin concentration, blood pressure, pulse rate, and respiration rate. 
     
     
       10. A system for non-invasively monitoring physiological trends, the system comprising:
 a processor comprising a sensor signal input and a display driver, wherein the processor is configured to:
 receive, at the sensor signal input, a sensor signal from an optical sensor coupled with a patient, the sensor signal responsive to light attenuated by body tissue of the patient; 
 calculate a physiological parameter based on the sensor signal; 
 output, by the display driver, a value of the physiological parameter for presentation on a display; and 
 output an audible alarm once the physiological parameter reaches a threshold if a physiological parameter trend of physiological parameter values is not trending upward.