Perfusion trend indicator

Abstract

A perfusion trend indicator inputs a plethysmograph waveform having pulses corresponding to pulsatile blood flow within a tissue site. Perfusion values are derived corresponding to the pulses. Time windows are defined corresponding to the perfusion values. Representative perfusion values are defined corresponding to the time windows. A perfusion trend is calculated according to differences between representative perfusion values of adjacent ones of the time windows.

1 .- 18  (canceled) 
     
     
         19 . A system for detecting perfusion trend comprising:
 an optical sensor configured to detect attenuated optical radiation responsive to pulsatile blood flow in a tissue site of a patient; and   one or more hardware processors configured to:
 receive a plethysmograph waveform responsive to the detected attenuated optical radiation; 
 determine a plurality of perfusion indices corresponding to a plurality of time periods from the received plethysmograph waveforms; 
 calculate a perfusion trend based on a differential change in the plurality of perfusion indices; and 
 transmit a control input for a medical equipment based on the calculated perfusion trend. 
   
     
     
         20 . The system of  claim 19 , further comprising a display configured to output the perfusion trend on a display. 
     
     
         21 . The system of  claim 19 , wherein the hardware processor is further configured to trigger an alert based on the calculated perfusion trend. 
     
     
         22 . The system of  claim 19 , wherein the hardware processor is further configured to detect a stable time period in the plethysmograph waveform to establish a first baseline. 
     
     
         23 . The system of  claim 19 , wherein the hardware processor is further configured to, for each time period:
 calculate a plurality of time period perfusion indices;   select a first set of time period perfusion indices from the plurality of time period perfusion indices; and   average the time period perfusion indices in the first set.   
     
     
         24 . The system of  claim 19 , wherein the time period comprises 5 minutes. 
     
     
         25 . A system for monitoring perfusion trend comprising a physiological monitor including one or more hardware processors, said one or more hardware processors configured to:
 process a sensor signal responsive to light attenuated by pulsatile blood flow in a tissue site;   determine at least one plethysmograph waveform from the sensor signal;   determine a first perfusion index corresponding to a first time window in the plethysmograph waveform;   determine a second perfusion index corresponding to a second time window that begins at a later time than the first time window;   calculate a difference between the first perfusion index and the second perfusion index; and   evaluate a perfusion trend based on the calculated difference.   
     
     
         26 . The system of  claim 25 , further comprising a display configured to display the perfusion trend. 
     
     
         27 . The system of  claim 25 , wherein the one or more hardware processors are further configured to trigger an alert based on the perfusion trend. 
     
     
         28 . The system of  claim 25 , wherein the one or more hardware processors are further configured to detect a stable time period in the plethysmograph waveform to establish a first baseline. 
     
     
         29 . The system of  claim 25 , wherein the one or more hardware processors are further configured to, for each time period:
 calculate a plurality of time period perfusion indices;   select a first set of time period perfusion indices from the plurality of time period perfusion indices; and   average the time period perfusion indices in the first set.   
     
     
         30 . The system of  claim 25 , wherein the time period comprises 5 minutes. 
     
     
         31 . The system of  claim 25 , wherein the time period comprises 30 seconds.