Physiological parameter system

Abstract

A physiological parameter system has one or more parameter inputs responsive to one or more physiological sensors. The physiological parameter system may also have quality indicators relating to confidence in the parameter inputs. A processor is adapted to combine the parameter inputs, quality indicators and predetermined limits for the parameters inputs and quality indicators so as to generate alarm outputs or control outputs or both.

1 . A method of providing cohesive physiological parameter trend data through a change in measurement site, the method comprising:
 obtaining measurements of a physiological parameter from a first measurement site of a patient and determining trend information from the measurements of the physiological parameter from the first measurement site during a first time period;   obtaining measurements of the physiological parameter from a second measurement site of a patient and determining trend information from the measurements of the physiological parameter from the second measurement site during a second time period different from the first time period;   determining a physiological trend offset for the second trend information based on the trend information from the first measurement site.   
     
     
         2 . The method of  claim 1 , wherein the physiological parameter comprises a met-hemoglobin measurement. 
     
     
         3 . The method of  claim 1 , wherein the trend offset is a difference in magnitude between two adjacent-in-time measurements, where one of the adjacent-in-time measurements is taken at the first site and the second adjacent-in-time measurements is taken from the second site. 
     
     
         4 . The method of  claim 3 , wherein the offset is a negative value. 
     
     
         5 . The method of  claim 3 , wherein at least one of the two adjacent-in-time measurements is normalized. 
     
     
         6 . A method of measuring a physiological parameter in a physiological parameter system comprising:
 obtaining measurements of a physiological parameter from a first measurement site of a patient;   determining a change in the measurement site of the patient;   obtaining a measurement of the physiological parameter from a second measurement site of the patient;   comparing the measurement of the physiological parameter at the second measurement site with the measurement from the first measurement site; and   calibrating the physiological parameter measurements at the second site with the physiological measurements at the first site.   
     
     
         7 . The method of  claim 6 , wherein calibrating comprises adding an offset to the measurement of the physiological parameter at the second measurement site. 
     
     
         8 . The method of  claim 7 , wherein the offset is calculated by subtracting the measurement of the physiological parameter at the second measurement site with the most recent physiological parameter measurement from the first site. 
     
     
         9 . The method of  claim 7 , wherein the offset is calculated by subtracting the measurement of the physiological parameter at the second measurement site with a projection of the physiological parameter at the second measurement site extrapolated from a trend line fit to the physiological parameter measurements of the first site. 
     
     
         10 - 20 . (canceled)