Method and an Apparatus for Determining Hemodynamic Status

Abstract

A device and a method thereof for determining a hemodynamic state of an individual from a magnitude of a perfusion signal or a signal which is a measure of a volume of blood in the thoracic cavity of the individual, wherein the control device is configured to receive a first signal and a heart rate signal, divide the first signal into frames, wherein a frame length is determined from an oscillation period of the heart rate signal, and determine a magnitude of the first signal from at least two frames, so as to obtain a more reliable magnitude of the first signal.

1 .- 26 . (canceled) 
     
     
         27 . A device for determining a hemodynamic state of an individual from a magnitude of a first signal, wherein the first signal is a perfusion signal or a signal which is a measure of a volume of blood in the thoracic cavity of the individual, wherein the device is configured to:
 receive the first signal and a signal representative of the heart rate from the individual;   divide the first signal into frames, wherein a frame length is determined from an oscillation period of the heart rate signal; and   determine a magnitude of the first signal from at least two frames.   
     
     
         28 . The device according to  claim 27 , wherein the device is configured to combine at least two frames of the divided first signal. 
     
     
         29 . The device according to  claim 28 , wherein the magnitude of the first signal is found as amplitude of the combined first signal. 
     
     
         30 . The device according to  claim 28 , configured to standardize the first signal prior to combining at least two frames of the first signal. 
     
     
         31 . The device according to  claim 27 , wherein the frame length is determined from an average oscillation period of the heart rate signal. 
     
     
         32 . The device according to  claim 28 , configured to output a confidence measure value which indicates the similarity of the divided first signals in different frames that have been combined. 
     
     
         33 . The device according to  claim 27 , wherein the device is configured to receive a multiple number of first signals and determine a magnitude of each first signal from at least two frames of the same first signal. 
     
     
         34 . The device according to  claim 27 , configured to associate the first signals with concurrently received heart rate signal. 
     
     
         35 . The device according to  claim 34 , configured to correct for any difference in phase between the heart rate signal and the first signal. 
     
     
         36 . The device according to  claim 27 , comprising a controller for outputting a signal to a device for hemodynamic intervention in response to the determined hemodynamic state of an individual. 
     
     
         37 . A control system for hemodynamic intervention comprising a device according to  claim 36  and the device for hemodynamic intervention, wherein the controller is configured to output a signal to activate the device for hemodynamic intervention when a magnitude of the heart rate signal is above a first threshold value and a magnitude of the first signal is below a second threshold value. 
     
     
         38 . The system according to  claim 37 , wherein the device for hemodynamic intervention is an implantable device or an externally wearable device. 
     
     
         39 . The system according to  claim 27 , wherein the first signal is a lead impedance signal. 
     
     
         40 . The system according to  claim 38 , wherein the multiple frames of the first signal are collected over a predetermined time period, wherein the predetermined time period is a charge time of the device. 
     
     
         41 . A method for determining a hemodynamic state of an individual from a magnitude of a first signal, wherein the first signal is a perfusion signal or a signal which is a measure of a volume of blood in the thoracic cavity of the individual, wherein the method comprises the steps of:
 receiving the first signal and a signal representative of the heart rate from the individual;   dividing the first signal into frames, wherein a frame length is determined from an oscillation period of the heart rate signal; and   determining a magnitude of the first signal from at least two frames.   
     
     
         42 . The method according to  claim 41 , wherein at least two frames of the divided first signal are combined. 
     
     
         43 . The method according to  claim 42 , wherein the first signal is standardized prior to combining at least two frames of the first signal. 
     
     
         44 . The method according to  claim 41 , wherein the frame length is determined from an average oscillation period of the heart rate signal. 
     
     
         45 . The method according to  claim 41 , wherein the first signal is associated with concurrently received heart rate signal. 
     
     
         46 . The computer storage medium comprising code for execution by a processor, the code, when executed by a processor causing the processor to perform the method of  claim 41 .